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Climate Risk

MA Rodger at 19:36 PM on 4 November, 2024

Paul Pukite @5,
I don't see Judy Curry having flipped.

While seeing her apparently agreeing with David Walliace-Wells is remarkable, the agreement is perhaps best seen as another instance of Judy re-defining the words of others. Over the last decade, since the WUWT failed to "change the way you think about natural internal variability" (WUWT=Wyatt's Unified Wave Theory which Judy calls the Stadium Wave), Judy has taken up ambiguity as a means of manufacturing what she calls "a wicked problem" to cloud the climate debate and give room for denialists to flaunt their nonsense.

Her book 'Climate Uncertainty and Risk : Rethinking Our Response' was published last year (a 40-odd page preview HERE) and a few months back she set out the same message at the denialist GWPF's AGM.
The book runs to fifteen chapters and 340 pages. Well hidden within it, Judy sets out her same old message, this from a book review.

The need to reduce carbon dioxide emissions is much less pressing than the IPCC and the UN contend because of the implausibility of extreme emissions scenarios such as RCP 8.5 and of high values for the climate sensitivity of carbon dioxide (the warming caused by a doubling of carbon dioxide in the atmosphere). Natural variability is likely to slow down the rate of warming over the next few decades, and further time can be bought by targeting greenhouse gases other than carbon dioxide, which account for up to 45% of human-caused warming.

(Note that the 45% number is wrong. The non-CO2 forcing is no more than 35% and over tha last decade it is down to 26%.) The hidden message from Curry is that her imagined natural climate wobbles have masked the weak nature of human-caused climate change and fooled us all. So we can sit back and enjoy ourselves while we make plans for when all the oil runs out.

A New 66 Million-Year History of Carbon Dioxide Offers Little Comfort for Today

nigelj at 05:38 AM on 13 December, 2023

The information on earth system sensitivity of 5 - 8 degrees C is very sobering. There are many accounts of what a 6 degree world is like easily googled and its very inhospitable for humans and other species. Because ESS develops on long time frames we might adapt to some extent, but that doesn't really make it any less inhospitable.

This is one authors depiction of a 6 degree world based on available research. The description is based on such a world developing over the next couple of centuries and a failure to curb emissions, but even if it takes thousands of years as a result of ESS, many of the outcomes would be similar.

"Special coverage is given to the positive feedback mechanisms that could dramatically accelerate climate change. The book explains how the release of methane hydrate and the release of methane from melting permafrost could unleash a major extinction event. Carbon cycle feedbacks, the demise of coral, the destruction of the Amazon rainforest, and extreme desertification are also described, with five or six degrees of warming potentially leading to the complete uninhabitability of the tropics and subtropics, as well as extreme water and food shortages, possibly leading to mass migration of billions of people."

LINK

The IPCC seems to have focused most attention on warming and sea level rise rates by 2100. We have projections of around 3 degrees C of warming and worst case about 5 degrees, and SLR around 1 metre with a worst case 2 metres. The details on longer term trends several centuries into the future, or millenia into the future like earth system sensitivity, are buried away in their reports or not given much attention.

The IPCC have a chart buried in their reports showing a worst case of about 10 degrees C by about 2300 if equilibrium climate sensitivity turns out to be high and we just go on burning fossil fuels. Likewise by 2300 SLR could be well over 2 metres. This may be somewhat attenuated by the impacts of renewable energy already reducing projected coal use, but it would still be a big number and theres a lot of SLR already baked in even if we stop warming right now.

I wonder if this focus on year 2100 is a deliberate psychological strategy to focus on our immediate future. If they focused on the longer term trends there might be a risk that people would say why worry that won't effect me or my children.

However warming of for example 3 degrees by 2100 and one metre or so of SLR doesnt sound very scary to some people, while numbers like 5- 8 degrees longer term and SLR of 10 - 20 metres are obviously intuitively far more scary and certainly get my attention. Clearly we do need a focus on year 2100, for obvious reasons, because its in our lifetimes and adaptation would be very costly, but I wonder if a bit more attention on longer term time frames would have really shown people the huge scale of change we are facing.

A New 66 Million-Year History of Carbon Dioxide Offers Little Comfort for Today

One Planet Only Forever at 03:40 AM on 13 December, 2023

Evan @2,

Agreed that the popularity of those ‘beliefs’ are a serious problem.

Those types of beliefs get some support from statements like the one included in this press release: “The giant caveat: Earth system sensitivity describes climate changes over hundreds of thousands of years, not the decades and centuries that are immediately relevant to humans.”

That correct statement regarding the developed highly influential, but undeniably harmful, attitude and restricted consideration of many people should always be paired with a clear statement of the unacceptability of any person in leadership, or of high status, thinking that way.

As an example, the likely global average surface temperature in 2100 may seem like a decent measurement point given the increased uncertainty of modelling into the future. But it is understandably not an appropriate measure of success. Here are a set of scenarios with equal 2100 temperature values of 1.7 C (not the desired 1.5 C, but maybe considered to be well below 2.0 C):

Human rates of impacts that would increase temperature are ended without temperature impacts exceeding 1.7 C. And sustainable measures are being increasingly implemented that will reverse previous impacts. The future temperature is not expected to increase above 1.7 C and will actually be reduced beyond 2100, including confidence that there will not be increasing surface temperature due to long term potential warming feed-backs.

Human impacts peaked above 2.0 C before 2100 and have been reversed and removed back down with efforts to further reduce impacts being curtailed. Less certainty that there will be no feedback warming after 2100. Part of that uncertainty regarding future warming is uncertainty about the long term impacts of the peak temperature value and duration of the higher temperatures.

Human impacts have been been successfully limited so that the total warming by 2100 is 1.7 C. But impacts are continuing to increase after 2100.

Those 3 scenarios are not ‘equally successful’ at sustainably improving the future for humanity. Only the first one could be considered to be ‘real success’. The others are just perceptions of ‘equal success’.

Note that adaptations to the impacts of climate change are 'not improvements of the future' They are attempts to maintain developed ways of living. And repair of climate change damage is also 'attempts to maintain developed stuff'. That leads to the understanding that developed perceptions of poverty reduction and perceptions of living better than a basic decent life are unsustainable if they rely on harmful unsustainable actions like the use of fossil fuels (even abated use of fossil fuels is unsustainable).

The challenge is being clear about what developed perceptions do not deserve to be maintained as the developed harming of the future of humanity is corrected.

A New 66 Million-Year History of Carbon Dioxide Offers Little Comfort for Today

One Planet Only Forever at 08:47 AM on 12 December, 2023

This study is an important improvement of understanding. But previous leadership actions fighting against limiting the harm being done to the future of humanity is not excused by this improved understanding only now becoming available.

As an engineer with an MBA I am focused on developing sustainable improvements by learning to limit harm done and protect others from harm. I appreciate that my developed perspective is currently not the developed norm. However, for humanity to have a lasting improving future on this amazing planet, the pursuit of learning to be less harmful and more helpful to others needs to become the dominant governing understanding.

Being a civil/structural engineer, the changes of climate conditions affecting the performance of structures and surface water run-off systems has been my immediate concern. And having an MBA has helped me understand that the pursuit of profit can develop many damaging results, including powerful resistance to correcting developed behaviour. Focusing on obtaining monetary reward, or other perceptions of status, can tempt people to compromise the pursuit of limiting harm done. And it can cause people to make up excuses for benefiting from harm done.

The following quote from the press release highlights a major issue that should concern everyone: “The giant caveat: Earth system sensitivity describes climate changes over hundreds of thousands of years, not the decades and centuries that are immediately relevant to humans.”

Saying that the distant future of humanity on this ‘potentially only amazing planet humans can survive and thrive on’ is not ‘immediately relevant to humans’ is a very dangerous thing to do even if that belief is ‘more the norm these days’. It excuses the developed callous lack of concern for ‘Others and the future’ that currently significantly compromises ‘human considerations’. It excuses the ‘discounting of future climate change impacts’ to justify being more harmful today than is ‘necessary for people to live basic decent lives’.

It is important to understand that the engineering application of science requires the pursuit of significant confidence that harmful results will not occur (a very low probability of harmful results). That is what keeps bridges and buildings standing and planes in the air. That is very different from a scientific reluctance to state the potential that harm is being done until there is significant confidence regarding the specifics of the harm.

A responsible engineer discovering that something is potentially harmful should immediately act to protect against the potential harm until there is confidence allowing them to ensure the safety of the item of concern. The continuation of the ability to live as a sustainable part of the ecosystem of this amazing planet needs to be the governing human consideration. How rich or successful some people are perceived to be is rather irrelevant.

I understandably extend my ‘engineering concerns’ to the improvement of the distant future of humanity (developing sustainable improvements), even if that is to the detriment of created ‘perceptions of advancement at this immediate moment in time’. Doing something that is considered to be ‘beneficial today’ but may be significantly harmful in the distant future is unacceptable, especially if the benefits of the harmful activity cannot continue to be enjoyed in the future.

Fossil fuel use is a doubly unacceptable activity. It produces accumulating harmful results, now and into the future. And it cannot continue to be benefited from in the future that it harms. Any ethical argument for ‘the benefits of fossil fuel use’ is understandably limited to very narrow applications like ‘temporary actions that exclusively improve the life circumstances of people who suffer less than basic decent lives’.

Skeptical Science New Research for Week #49 2023

nigelj at 04:35 AM on 10 December, 2023

MS Sweet. Good information to know.

"I note that Dr. Hansen has long held an Earth System Sensitivity of 6 C. The IPCC consensus has been 3C"

The IPCC number is "equilibrium climate sensitivity", a different thing from earth system sensativity as below. Making it hard to compare the two numbers.

"By definition, equilibrium climate sensitivity does not include feedbacks that take millennia to emerge, such as long-term changes in Earth's albedo because of changes in ice sheets and vegetation. It includes the slow response of the deep oceans' warming, which also takes millennia, and so ECS fails to reflect the actual future warming that would occur if CO2 is stabilized at double pre-industrial values.[38] Earth system sensitivity (ESS) incorporates the effects of these slower feedback loops, such as the change in Earth's albedo from the melting of large continental ice sheets, which covered much of the Northern Hemisphere during the Last Glacial Maximum and still cover Greenland and Antarctica)...."

(Climate sensitivity, wikipedia)

We will probably never know any of these numbers for sure because you can't put the planet in the laboratory. (Although I think paleo studies like the one you posted have a lot of credibility - because they are based on real world conditions). But IMHO that uncertainty is not necessarily a crucial problem. Current rates of warming are bad and are having very visible effects, and huge implicatrion in the short to medium term, and so whatever the level of climate sensitivity using whatever definition, we clearly have a huge problem.

Skeptical Science New Research for Week #49 2023

michael sweet at 01:16 AM on 10 December, 2023

This MSN article, Which is apparently a press release from the Columbia Climate school describes a paper in Science. The paper is a collaboration of many scientists summarizing knowledge of CO2 concentrations for the past 65 million years. The MSN article is easy to read. Since it is a press release it would be a good OP here at SkS. I have not yet read the paper.

Unfortunately, they conclude that Earth system sensitivity, the climate response when all slow feedbacks respond, is 5-8 C. The processes involved can take a long time to equilibrate (as much as thousands of years). Still, it is a very grim conclusion. I note that Dr. Hansen has long held an Earth System Sensitivity of 6 C. The IPCC consensus has been 3C. This is unlikely to affect anyone living but bodes very bad for 1000 years from now. The question of how long the slow processes take to equilibrate is left unanswered.

At a glance - Evidence for global warming

nigelj at 05:44 AM on 2 December, 2023

I don't think PP is a denialist. Have seen his comments at RC. We sometimes just get on edge and jump to the conclusion that anyone who says "flat trend" is a denialist because its a common denialist talking point.

We know the oceans as a whole have warmed considerably since the 1980s. But then you do have a few areas with cooling like the cold blob in the nothern atlantic.

I'm eyeballing Paul Pukete's graphs of the equatorial pacific and at best I can only see a very slight warming trend from around 1970 - 2022. I mean it does look flat or near flat, so I looked for an explanation and this is interesting. I have highlighted the main pargraphs only:. It seems to be consistent with what PP is saying.

Part of the Pacific Ocean Is Not Warming as Expected. Why? BY KEVIN KRAJICK |JUNE 24, 2019

State-of-the-art climate models predict that as a result of human-induced climate change, the surface of the Pacific Ocean should be warming — some parts more, some less, but all warming nonetheless. Indeed, most regions are acting as expected, with one key exception: what scientists call the equatorial cold tongue. This is a strip of relatively cool water stretching along the equator from Peru into the western Pacific, across quarter of the earth’s circumference. It is produced by equatorial trade winds that blow from east to west, piling up warm surface water in the west Pacific, and also pushing surface water away from the equator itself. This makes way for colder waters to well up from the depths, creating the cold tongue.

Climate models of global warming — computerized simulations of what various parts of the earth are expected to do in reaction to rising greenhouse gases — say that the equatorial cold tongue, along with other regions, should have started warming decades ago, and should still be warming now. But the cold tongue has remained stubbornly cold.
Why are the state-of-the-art climate models out of line with what we are seeing?

Well, they’ve been out of line for decades. This is not a new problem. In this paper, we think we’ve finally found out the reason why. Through multiple model generations, climate models have simulated cold tongues that are too cold and which extend too far west. There is also spuriously warm water immediately to the south of the model cold tongues, instead of cool waters that extend all the way to the cold coastal upwelling regions west of Peru and Chile. These over-developed cold tongues in the models lead to equatorial environments that have too high relative humidity and too low wind speeds. These make the sea surface temperature very sensitive to rising greenhouse gases. Hence the model cold tongues warm a lot over the past decades. In the real world, the sensitivity is lower and, in fact, some of heat added by rising greenhouse gases is offset by the upwelling of cool water from below. Thus the real-world cold tongue warms less than the waters over the tropical west Pacific or off the equator to the north and south. This pattern of sea-surface temperature change then causes the trade winds to strengthen, which lifts the cold subsurface water upward, further cooling the cold tongue.

news.climate.columbia.edu/2019/06/24/pacific-ocean-cold-tongue/

2023 SkS Weekly Climate Change & Global Warming News Roundup #44

Just Dean at 23:31 PM on 6 November, 2023

Evan, It is not just Mann that disagrees with Hansen. I believe that Hansen holds the minority position here. Both Zeke and Mann reference the IPCC special report on 1.5C that warming will cease when we get to net zero emissions. To me, the IPCC represents the consensus thinking. There is a recent paper by Dvorak and Armour that reaches bascially the same conclusion, Ref. , and adresses the aerosol effect.

If you follow Zeke at theclimatebrink.com and/or X, he has addressed directly Hansen's pipeline paper and his high estimate of climate sensitivity. Also, Zeke's latest analysis of record breaking temperatures relative to the multimodel averages can be found at theclimatebrink.com.

At a glance - The tricks employed by the flawed OISM Petition Project to cast doubt on the scientific consensus on climate change

Nick Palmer at 22:24 PM on 11 August, 2023

I've always thought that the exact wording of the Oregon Petition

"no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate"

was grammatically constructed to actually have been technically signable AT THE TIME OF FIRST LAUNCH even by such climate luminaries as James Hansen.

It comes down to the artful use of "is causing" and "will cause" - instead of 'may cause' - catastrophic heating and disruption etc. The petition does not state that its wording assumes that mainstream climate science was asserting that emissions will continue to rise sharply and that climate sensitivity to CO2e was at the top end of published expectations back then (somewhere around 6°C per doubling if I remember, although 10°C was mentioned https://skepticalscience.com/climate-sensitivity-advanced.htm ) but it is the underlying insinuation (of the text) that climate science was saying these things that enables the rhetorical deceit inherent in that exact wording. It allows any scientist who was fairly familiar with the science back then to jump to the conclusions that, because such emissions rises weren't certain to take place, and that ensemble figures for climate sensitivity were showing a 'most likely' figure of ~3°C per doubling, then it was definitely not certain that 'catastrophic heating' would occur.

There is no consensus

Rob Honeycutt at 10:29 AM on 20 April, 2023

@933... Missed this one: "The only 'evidence' for the positive feedback theory are models which are trying to model something where many variables are only guesstimates."

Incorrect.

Knutti and Hegerl (2008)

Climate sensitivity is low

MA Rodger at 09:17 AM on 31 March, 2023

retiredguy @387,

Lewis (2022) 'Objectively combining climate sensitivity evidence' was given the once-over in a comment thread at RealClimate when it first appeared last year.

CO2 effect is saturated

One Planet Only Forever at 03:51 AM on 27 March, 2023

Gootmud’s comment @680 and the responses have been informative and educational. Thank you Rob, Eclectic, MA Roger, and Bob. However, based on today’s reality, I think this Rebuttal should be updated.

The potential magnitude of global warming due to a doubling of CO2, and the related denial tactic of claiming the CO2 effect is ‘saturated’ or not a significant concern, is now only an academic matter. It was an important matter for leaders to be aware of 30 years ago when it was vigorously argued against by ‘people with interests that were contrary to this improving understanding’. But since warming beyond 1.0 C has already occurred, and warming beyond 1.5 C is already likely due to a lack of responsible leadership action to limit the harm done, it is no longer a relevant leadership considerations.

Note: Disappointing people who have developed undeserved perceptions of opportunity, prosperity, advancement or superiority based on harmful unsustainable activity and related beliefs ‘is not harmful’. Governing to limit harm done is essential to the advancement of civilization.

The Story of the Week “1.5 and 2°C: A Journey Through the Temperature Target That Haunts the World” in the “2022 SkS Weekly Climate Change & Global Warming News Roundup #50” makes it clear that decades ago the following was understandable:

warming above 1.0 C risks significant harm (that is now proven by today’s reality).

warming beyond 2.0 C is very risky (hopefully that will never be proven in a near future reality).

That understanding fits with the 1.5 C ‘long term maximum harmful impact objective’ paired with the need to limit the ‘temporary peak harmful impact level’ to significantly less than 2.0 C.

The IPCC FAQ Chapter 1 provides additional information regarding the targets. An important bit of information is that 1.0 C warming was reached in 2017. When the formal global leadership agreement was established in 2015 human impacts were almost certain to exceed 1.0 C. And the significant costs of the failure to limit the peak human impacts to 1.0 C are also now harder to deny.

The reality today is: No matter what someone wants to believe regarding the sensitivity of global average surface temperature to increasing CO2 the actual evidence makes that debate irrelevant. What is now undeniable by leadership is the need for the unprofitable safe removal of carbon from the atmosphere to bring the harmful impact level back down below 1.5C. And it is also undeniable that the people who benefited most from the harm done need to do the most to limit how much worse the problem is at the peak, pay to remove the excess carbon, and help everyone harmed by the impacts of what they benefited from.

Leaders no longer need to be guided by the science of the potential rate of warming due to a doubling of CO2 levels. That type of pursuit of understanding is also ‘hopefully’ very unlikely to be relevant to the future of humanity. Responsible leadership would prevent that magnitude of harm done from ever becoming a reality.

CO2 effect is saturated

Rob Honeycutt at 01:04 AM on 25 March, 2023

Gootmud... Reading through that Happer paper is interesting in that they're essentially confirming the consensus position on man-made climate change is correct. Their climate sensitivity figure of 1.4K is the direct effect without water vapor feedback. The 2.9K is with WV feedback per M&W1967, and the 2.2K figure is with updated calculations for WV.

So, why is that 2.2K figure so much lower than the central estimates of ~2.9K/2xCO2? Well, there are other feedbacks that are not included in Happer's calculations, like ice sheet feedbacks.

This paper is a good demonstration that Happer knows the climte science is correct but he continues to speak out against it, ostensibly in order to instill doubt in the research.

Why? If you up for a little light reading, try Oreskes/Conway's The Merchants of Doubt. (Hint: it's not really about the science.)

It's also important to note, the warming we've seen over the past 60 years is largely in line with central estimates for climate sensitivity. We've increased CO2 by about 50% and we seem committed to around 1.5°C of warming. The numbers kind of work, unfortunately.

CO2 effect is saturated

Eclectic at 16:18 PM on 24 March, 2023

Gootmud @680 ,

The explanation of "Greenhouse" by Rob Honeycutt @681 is basic and straightforward, if you stop to think it through. And yet a vast number of climate-science-deniers completely fail to understand the concept (most likely because they wish to stay in denial mode).

You are right that the eminent Dr Happer (et Wijngaarden) has re-invented the wheel, and finds that all the climate scientists are correct about the climate sensitivity of atmospheric CO2 as being (roughly) 1.2 degC for CO2 change alone, without feedbacks. Here, we definitely should trust the experts.

Strangely, most of the denizens at WattsUpWithThat blog (and similar) are giving out the impression that Happer has shown them (the denialists) to be right and all the climate scientists to be wrong. Very strange indeed. Perhaps they (the denialists) are not actually reading/understanding Happer's confirmation of previously-known climate science ~ I suspect they they are in sympathy with Happer's extremist wingnut politics (which he makes no effort to hide).

Probably they are using wishful thinking, in that they use the faulty paradigm : 'Happer is an eminent scientist and he is "one of us wingnuts" ~ and therefore the mainstream scientists must be wrong.' [~ Which does not compute.]

(B) Gootmud , I must beg you to tell more about this idea you present about a CO2 laser effect at the tropopause level. I have not heard of this before (unless it is something to do with a certain notorious Congresswoman who talks of Jewish Space Lasers ).

Climate Science Denial Explained

MA Rodger at 18:20 PM on 20 March, 2023

eclectic @18,

I don't see Lindzen's opposition to the science as being motivated by religion. I see it as a scientist of some repute who lost the conclusive scientific debate over AGW in the 1980s but refused to admit defeat. While such stubbornness is not to be condemed (skepticism being a big part of the scientific process), Lindzen 'crosses the line' and sets out unscientific messages. I still remember his rather ludicrous contribution to the 1990 film 'The Greenhouse Conspiracy' (YouTube) which actually convinced me of the opposite view that AGW was real and likely a big problem being politically kicked into the long grass. (The 'crossing of the line' into non-science is not a wholly climate denier thing but they do seem to spend much more time doing it.)

Through the years, Lindzen did (indeed still does - see Lindzen & Choi 2022) continue work attempting to show that climate sensitivity is low and AGW not a problem for humanity, most famously his 'Iris Effect' which turns out to be a real effect but one having the opposite impact and one threatening significant increased warming.

The Big Picture

Bob Loblaw at 10:31 AM on 16 March, 2023

Gordon @ 3:

No.

The only "warming estimate" for the future that is presented in this blog post is "We know that the climate sensitivity to a doubling of atmospheric CO2 from the pre-industrial level of 280 parts per million by volume (ppmv) to 560 ppmv (at the beginning of 2023 we are at 420 ppmv) will cause 2–4.5°C of warming."

There is no time frame in that estimate. It refers to an unspecified future time where CO2 has doubled. It does not say when it expects us to reach that CO2 level - or even assess a probability that we will.

Scenarios such as RCP8.5 generate an expected timing of the rise of CO2 and other greenhouse gases, and you need to apply a climate model to those atmospheric composition scenarios to get an estimate of temperature rise over the period of the scenario. This blog post does not do that.

And the estimates of 2-4.5°C of warming for doubling of CO2 are largely unaffected by the temporal pathway to reach 2xCO2.

The only other use of the term "estimate" in the blog post is to do with historical values of global temperature, based on observations. Different groups use different analysis methods to "estimate" the global temperature trends, using measurements. This is not dependent on any of the climate models that are used to "estimate" future climates.

So, unless you are thinking of some other "warming estimate" that is not actually presented here...

Skeptical Science New Research for Week #52 2022

MA Rodger at 20:45 PM on 5 January, 2023

michael sweet @4,

This document 'Global warming in the pipeline' by Hansen et al does appear to need some rewriting in my view.
It explains it is the first of a pair (the second being 'Sea Level Rise in the Pipeline') and together they are perhaps akin to Hansen et al (2016) 'Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous' which was more a discussion document than a piece of science. But given 'Global warming in the pipeline' starts off with our understanding of the greenhouse effect back in the 1800s, its audience is probably not climatologists, so not a discussion document, although it does get a bit 'detailed' in places where a good understanding of climatology is required.

At 48 pages, it covers a lot of ground and as-yet I haven't read very far through it, down to page 12 which covers the assessment of ECS. But it does read a little odd.

The Abstract tells us that "improved knowledge of glacial-to-interglacial global temperature change implies that fastfeedback equilibrium climate sensitivity is at least ~4°C for doubled CO2"

The first thing that I felt odd was reference to Hansen et al (1984) 'Climate sensitivity: analysis of feedback mechanisms' but without a sign that this was such an old paper. The tempersture rise from the LGM used to calculate the ECS in Hansen et al (1984) is said to be +3.6°C, a value said to yield ECS=2.5 to 5°C. For me, that +3.6°C temperature increase is way below that usually quoted elsewhere for the post-LGM temperature rise.

And 'Global warming in the pipeline' indeed then presents higher estimates of the temperature rise from the LGM: +6.8°C (± 0.8) in Osman et al (2021), +5.9°C (± 0.3) in Tierney et al (2020) and +5.8°C (± 0.6) for land SAT from Seltzer et al (2021).

These are in keeping with values I've seen in literature for recent decades which usually sit +5°C to 6°C, perhaps the +6.8°C (± 0.8) in Osman et al (2021) a little higher than normal while some of those lower values have also persisted.

And using such LMGR temperature increases, 'Global warming in the pipeline' then calculates ECS concluding "Thus, while the LGM-Holocene climate change implies ECS =3.3-5.1°C for 2×CO2, the PGM-Eemian implies ECS ~ 4-6°C. We conclude ECS is at least approximately 4°C and is almost surely in the range 3.5-5.5°C."

What goes unsaid is that the literature used to source LGMR the temperature rise from the LGM also developes ECS values with ECS = 2.2°C to 4.3°C in Tierney et al (2020) (Fig 4 from this paper below, the R_AE accounting for 'mineral dust forcing') with Seltzer et al (2021) concurring with the central value of this, 3.4°C. For 'Global warming in the pipeline' to ignore these ECS values is entirely unscientific as we now have two values for ECS derived from LGMR which are at odds with each other.

Tierney et al (2020) Fig 4

And the use of the PMG-Eemian temperature rise to calculate an ECS value is a novel and perhaps rather too adventurous as I don't know of such a use previously. 'Global warming in the pipeline' references Rohling et al (2017), a long paper which does not itself address ECS.

So that is not a good start for a work which presents such startling findings.

Skeptical Science New Research for Week #52 2022

michael sweet at 09:48 AM on 3 January, 2023

Hairy BUtler,

I read the Hansen et al preprint and Manns response. THe Hansen paper is long and technical. To evaluate the claims is beyond my pay grade, but I can summarize Hansen's claims.

1) Hansen et al claim that studies of Paleoclimate (the climate in ages past) are the best way to estimate climate sensitivity. The current estimate of the Charney equilibrium climate sensitivity (ECS) is 3C per doubling of carbon dioxide. The ECS is the equilibtium temperature from rapidly changing thngs like atmospheric temperature and the ocean surface. It has been 3C for a long time. Recent papers have made new estimates of the last glacial maximum (LGM) global temperature that are about 3C lower than older estimates were. This results in the ECS increasing to about 4 or 5C. Mann cites the old papers to contradict Hansen. If the ECS is really 4C instead of 3C than the expected warming is significantly greater. Scientists often argue about whether or not new estimates are correct. This can take years to resolve.

2) Hansen has felt for decades that aerosol effects on climate have been underestimated. Hansen claims that current Global Climate Models (GCM's) overestimate ocean mixing and underestimate aerosol cooling effects. He provides new data to support this claim. The net effect is to lower the calculated ECS. As more and more energy comes from renewable sources the amount of aerosols in the atmosphere will decrease. Since aerosols cool the Earth the net effect is greater warming than we have already experienced.

3) Hansen defines the Earth System Sensitivity (ESS) as the final temperature reached when slow responding functions like the melting of global ice caps reach final equilibrium. This is significantly higher than the ECS, perhaps as high as 10C per doubling of carbon dioxide. The generally accepted wisdon is that ESS will take thousands of years to reach equilibrium. Hansen argues that It will be much faster. Perhaps as much as 80% of final heating in a centuary.

4) The net effect of higher ECS and ESS combined with higher aerosol effects means that there is a lot more heating in the pipeline (heating caused by carbon dioxide already in the atmosphere) than is currently believed to be the case.

5) Since Hansen expects warming to be greater than the current consensus, much more heating is already in the pipeline and that it will happen much faster than currently expected, he argues that governments need to act much faster to contain this emergency as soon as possible.

Hansen has made the argument for many years that aerosols are underestimated, ESS is higher than the current consensus and more warming is in the pipeline. He has new data in this paper to support his claims. This paper claims that the much more rapid increase in temperature he predicts will be obvious by 2050 and strong indications of his predictions will be measured in about 10 years.

Mann basically says that he doesn't buy Hansens' argument. Hopefully Gavin Schmidt at Real Climate will write a summary that will tell us the consensus view of what Hansen thinks is new data. I expect Dr. Schmidt to agree with Dr. Mann. I cannot evaluate Hansens claims, it is too technical.

In my view, Hansen is a great scientist who has been correct several times before when he stuck his neck out. He has also missed the mark on occasion. It is worrysome to have someone so talented make such a grim argument. This argument is not that different from his previous position but it has some new data to support his case. I imagine that this paper will be discussed a fair amount online but that the IPCC consensus will not change until it is 2050 and his forecasts have proven correct. Pray to whatever Gods you have that Hansen is incorrect.

If anyone else reads Hansen et al I am interested in your thoughts and/or additions on what I have posted here.

Skeptical Science New Research for Week #52 2022

Daniel Bailey at 07:57 AM on 1 January, 2023

@HairyButler

Michael Mann has tweeted against the conclusions in this paper (see these whole threads):

https://twitter.com/MichaelEMann/status/1603437412272726017
https://twitter.com/MichaelEMann/status/1603446912073764865

Reading Hansen's piece, I was wondering why he never mentioned literally at least dozen papers (going back to before the AR5) plus the most recent assessment, the AR6 (I had a hard time believing that his entire author team also missed it, too).

This illustrates the need for peer review by non-affiliated experts prior to making things public...and to rely upon primarily the major scientific assessments and the published, peer-reviewed science.

This is the salient portion of the Lunt paper from 2010 that Mann references:

"Our combined modelling and data approach results in a smaller response (ESS/CS∼1.4) than has recently been estimated using palaeo data from the Last Glacial Maximum, 21,000 years ago (ESS/CS∼2). This is probably due to the fact that transitions from glacial to interglacial conditions in the Quaternary involve large changes in the Laurentide and Eurasian ice sheets (see, for example, ref. 36), which result in a significant large-scale albedo feedback in these regions that is irrelevant for climates warmer than present. Furthermore, the main driver of Quaternary climate change is ultimately orbital forcing, which is close to zero in the global mean, and is therefore difficult to reconcile with a traditional climate sensitivity analysis."

Note the expression of the ratio of ESS to CS (Earth System Sensitivity to Climate Sensitivity). If CS=3 C (per doubling), then therefore ESS would be about 4.2 C (and not 10).

Skeptical Science New Research for Week #50 2022

nigelj at 11:11 AM on 17 December, 2022

Peppers

"Humidity and clouds cannot be modeled, tracked or controlled, which will be vexing to all the white knights out there."

We do have an understanding of clouds. Latest research:

www.washingtonpost.com/climate-environment/2022/12/12/climate-change-clouds-equilibrium-sensitivity/

What’s going on with the Greenland ice sheet?

MA Rodger at 23:09 PM on 3 September, 2022

Wayne @4,
I was in two minds on continuing our interchange, but I decided I would continue when I came across coverage of the paper underlying this SkS OP which surprisingly appeared today on the pages of my local rag with the title "Zombie ice to raise global sea level". On-line I see the same story getting into newspapers elsewhere (eg The Washigton Post).

In terms of an SLR-CO2 correlations, I don't recall seeing Hansen provide it. I believe the closest he got was in Hansen et al (2013) 'Climate sensitivity, sea level and atmospheric carbon dioxide' (with its well-used Fig 1) which looked at temperature & SLR but only inferred CO2 levels with very cursory checks to actual CO2 reconstructions.

Hansen et al (2013) fig 1
And for me, Hansen's 5m SLR by 2100 was always a bit of theorising that I struggled with. Even after it appeared properly written up in Hansen et al (2016), which at least answered the energy equations that were my initial objection to such a large SLR projections, for me it still remains more 'discussion document' than a full-blooded argued case. In my view, worrying as it is, the future SLR from Greenland & Antarctica depends on the Precipitation minus Ice-Loss balances and that puts us in the hands of climatologists for the precipitaion and glaciologists for the ice-loss. The application of paleoclimatology and whether Greenland melted out in the Eemian isn't so relevant for our future SLR.

Just to throw in my other SLR bug bear which also becomes relevant here, I've always reckoned SLR ain't gonna stop at 2100. So why do we go on so long about the 2100 SLR when by 2150, 2200, 2300 etc it's going to be seriously bigger? (A total of 2.3m SLR/ºC AGW according to IPCC AR5 fig13.14.)

The SLR-ΔCO2 relationship is of course a paleoclimate thing, so may not be immediately relevant outside the Eemian or now we have a Panama Isthmus connecting N&S America. That said, the SLR-ΔCO2 relationship is usually a step beyond what most graphics provide, but fig 6 of Rea et al (2021) 'Atmospheric CO2 over the Past 66 Million Years from Marine Archives' does provide us a ΔT-SLR-ΔCO2 graphic. Note that they do not attempt to be definitive with this CO2 reconstruction, saying "While each method has uncertainties, these are largely independent, so their broad convergence on similar CO2 histories is encouraging."
Rea et al (2019) fig 6

But I stress the idea that paleoclimate stuff should concede precedence to glaciology when it comes to the melting ice caps today and glaciology is where the paper underlying the SkS OP above comes from, Box et al (2022) 'Greenland ice sheet climate disequilibrium and committed sea-level rise'. I read that paper as saying that, as of now (2000-19), Greenland is not tipped over into melt-out mode (which I think was always seen as requiring a little more AGW to do that tipping, but nonetheless is good news to hear said) and that the Greenland melt which we are committed-to will happen in the next several decades, not several centuries, and will be mainly over by 2100.

So at least for Greenland under the AGW so-far, my bug bear (that we are in denial ignoring massive SLR awaiting us post-2100) is assuaged.

Mind, the SLR thus awaiting from Greenland isn't trivial. And there is still Antarctica. And not forgetting we still have the tiny task of halting future AGW.

The Climate Shell Game

jan21405 at 01:24 AM on 25 March, 2022

@Evan #31

Many power utilities will certify that they use "green energy credits" to ensure the power used for cars comes from renewables.

People are often subject to tempting keywords. 100% certainty that your electrical outlet is currently supplying electricity from "green sources" is only if your house is off-grid + connected to your PVe/Wind/Hydro power production system. Otherwise, your distribution company supplies a mix of energy from sources that are currently providing this energy. Just to be sure.

Also, getting a lot of EV's on the road sends the right signal to the company's making them and to the company's powering them. Hard to know where to start, but I think we need to just jump in and get things going whereever we can.

Shouldn't this discussion be scientific? This is just a chaotic shooting into a dark approach. No hypothesis verification.

I think they call this the chicken or the egg problem. :-)

For common people - yes.

If you want to run a stable distribution grid you need:

- the stable source of energy production for 24/7/365 operation (any time, any weather conditions). Today they are - Nuclear, Coal, Natural gas, Hydro (dams). You can't control the sun (irradiation, clouds) or wind (atmospheric pressure).

- for unstable energy sources you need storage with sufficient capacity. More unstable weather, more capacity for the storage.

- all the sources must be able to deliver power quality conditions (Variation in voltage magnitude, frequency, transient voltages and currents, harmonic content for AC)

- solve challenging demands for the transmission losses. More warm conditions = more losses = need more energy production. Note: I have done a study in Slovakia power grid how weather conditions have a heavy impact on the transmission losses (in period 1964-2019). And I can responsibly say that this is a very modern power grid vs UK or US.

So, we have heavy challenges:

- transform existing energy production from the fossil fuels, including YoY increment of energy production

- upgrade the obsolete power grids to keep existing power demand

- in parallel create new energy production capacities for new electric charging points (EVs, trucks, busses, ...). You can't build up these points anywhere.

- create new power grids for the new energy sources, including new transition stations, ...

- and keep it all orchestrated to achieve a sustained power supply. This is really tricky now (see below)

- and in Europe, we have an additional heavy variable - to cut off from Russia natural gas - one of the important resources for Europe power production and power grid sustainability.

Finally yes - it is about chicken or the egg:

- you can't decrease emissions with EVs charged from Coal, Oil or Natural gas power plant energy sources.

- stabilize the obsolete power grid or new demand in the existing obsolete grid.

It's similar to enjoying a healthy diet that you're preparing on a coal fire stove.

Power production needs an order. No chaotic solutions.

Some useful information:

- Jan/2021 - Europe was near heavy Blackout due to power supply failure that is suspected to have originated in Romania disrupted the Continental Europe Synchronous Area. Its frequency dropped to 48.75 Hz (target frequency 50Hz), which caused the South-East area to be separated from the rest of the grid. This disruption and a lack of operating reserves in France nearly caused a Europe-wide blackout. Luckily, the automatic activation of power stations throughout Europe and the automatic initiation of contracted load shedding in Italy (1000 MW) and France (1300 MW) kept the grid stable and prevented a blackout. This incident shows the fragility of the grid and the real possibility of a Europe-wide blackout, which we need to prevent.link

- IPCC AR6 - The latest IPCC report suggests that average wind speeds over Europe will reduce by 8%-10% as a result of climate change.

- UK’s renewables share drops to 35.9% in Q3 2021 on slow winds

- The changing sensitivity of power systems to meteorological drivers: a case study of Great Britain (Bloomfield et all,2018)

- Quantifying the sensitivity of european power systems to energy scenarios and climate change projections Bloomfield et all, 2020)

- Spain's solar energy crisis: Thousands os Spaniards bankrupt after investing in solar panels

The Climate Shell Game

Evan at 20:29 PM on 22 March, 2022

anticorncob6 @4

Thank you for your thoughts. I am trying hard not to write as a pessimist, but to help people see the true scope of the problem so that we can prescribe effective solutions. Getting to net zero will be tough, and we need to prepare for that. Whether or not we achieve net zero by 2050, we need to push to achieve that as close as possible and as fast as possible.

"Also, am I interpreting you correctly that if all carbon emissions ended right now, we'd still get to 1.7C? If so, where do you get that?"

This is tricky. If we ended all carbon emissions now, we would stabilize at something like 1.1C. But if we stabilize CO2 at something like 420 ppm and it does not drop, then we eventually warm to something like 1.7C. This is due to the Equilibrium Climate Sensitivity (ECS), which the IPCC estimates as being in the range of 2.5 to 4C increase for a doubling of atmospheric CO2 concentration. A common value used for ECS is 3C/doubling CO2. In Analogy 4 I show measured temperature and CO2 data that exhibits this ECS = 3C/doubling CO2.

2022 SkS Weekly Climate Change & Global Warming News Roundup #7

MA Rodger at 22:43 PM on 27 February, 2022

Santalives @28,
You now present a third pile of nonsense here at SkS. At least you show a level of consistency. Coe et al (2021) 'The Impact of CO2, H2O and Other “Greenhouse Gases” on Equilibrium Earth Temperatures' is as ridiculous as the other two you presented.

Coe et al (2012) claims that it addresses the issue of Equilibrium Climate Sensitivity (ECS) which, as is well known, has not been well-nailed-down by science for four decades now. So it would be quite a feat if there was even a smidgeon of promise in this paper to some contribution to the asssessment of ECS.
I could set out why this is an entirely non-scientific paper that well deserves its place in the trash can but in your ignorance you would likely see this as "one side" being disrespectful to "the other side".

So instead let me address what these numpties Coe, Fabinski & Wiegleb are doing that is so badly wrong.

The crux of the ignorance presented within Coe et al (2012) begins to congeal in their Section 1.4. Here they derive entirely on their own** a value called “n” the “energy retention factor” given "a" the "atmospheric absorptivity" (or the proportion of surface radiation gets to space through a clear atmosphere. By using HITRAN to derive "a" (the calculated percentage of surface radiation that reaches space through that clear atmosphere), they derive "n" by balancing "a" against the radiation that has to reach space to balance the incoming solar warming.
(**Note the one citation presented by the numpties for this grand work, Wilson & Gea-Banacloche [2012], is a total misrepresentation.)

The process they use runs as follows.

If a black body of 288K (representing the surface temperature) was in equilibrium with today's absorbed solar energy which equates to a 255K black body, they calculate that the energy out into space would be just 61.5% of the 288K black body radiation.
Thus, they derive for today's atmosphere (with a=a₀₎ n.a₀ = 38.5% of the surface radiation will be absorbed by the atmosphere. However, they also calculate using the grown-up HITRAN database, that the transmission through today's clear atmosphere of such 288K black body radiation would be a₀ = 73.0% allowing them to derive in their Section 2.7 a value for "n"; n = 52.7%.
And this incredibly simplistic method allows all the sceintific effort over the last four decades attempting to derive accurate ECS values to be sidestepped. Even the complex impact of clouds on this finding is sweetly side-stepped because, as they tell us in their Section 5.1, clouds are already accounted for in the derivation of "n".

And all this is their own work. No supporting evidence. What clever numpties are these Coe, Fabinski & Wiegleb.

Of course, there are feedback mechanisms to be negotiated and the numpties calculate (using simplistic assumptins) feedback values for water vapour (+18%) and the wavelength change in the radiation from a warmer world (-5%) with a net result feedback of (1.18 x 0.95 =) +12%.
They then calculate the impact of differing levels of CO2 GHGs on the absorption of surface radiation through a clear atmosphere to calculate direct warming from a doubling of CO2 (400ppm to 800ppm) of +0.45ºC (when the science is irrefutably sure the value is +1.0ºC) and thus with a feedback of +12%, they can derive ECS = +0.5ºC (when the science says +1.5ºC to +4.5ºC).

Of course, the GH-effect doesn't work in anything like the manner assumed by Coe et al (2012) so all these numpties Coe, Fabinski & Wiegleb are doing is advertising their own stupidity.

2022 SkS Weekly Climate Change & Global Warming News Roundup #7

Eclectic at 11:47 AM on 27 February, 2022

Santalives @19 , it is always a fine day for me when I come across two good jokes in a day. (A) The first is that you say you've read "nearly every one of the [over 200] Climate Myth and many of the comments." And how you felt that the comments were not arranged by date. Thank you for your personal revelations in these matters. Difficult to top.

(B) The second joke: was the David Coe et al., paper which you linked to @ WattsUpWithThat blogsite. Hilarious. Even your paper by the good professor Koutsoyiannis looks half-way sane in comparison.

Santalives, sit down and put your thinking cap on. As Philippe Chantreau [above] says, the Coe paper is wildly . . . wildly . . . inconsistent with everything that's within arm-reach of conventional climate science. IIRC, only the good Lord Monckton has ever come out with a similar figure to Coe's ultra-low 0.5K figure for total climate sensitivity to CO2. And Monckton seems to produce new & wildly high/low ECS figures annually (but with a strong bias toward Zero).

Now, I've looked through the WUWT assessment of the Coe paper. Not encouraging, at all. As usual, a number of commenters there deny that CO2 absorbs radiation and/or deny that there is any GreenHouse Effect whatsoever. At my own time of writing [>80 comments] no expert scientist has appeared to make comment at WUWT . Especially no climate scientist. Yes, that is the usual lofty standard of scientific analysis at WUWT .

# However, Santalives, if you scroll down to a couple of comments by Rud Istvan [an intelligent & well-informed guy, if you make allowance for his bad case of motivated reasoning on climate] . . . you will find he shows that some semi-respectable "contrarian" scientists such as Judith Curry and Richard Lindzen give a climate sensitivity of 1.1 - 1.2 for CO2 alone [without the large additional feedback from H2O ].

'Nuff said. The Coe paper you mentioned is simply garbage. Santalives, please remember the acronym GIGO ~ where sometimes you see the Garbage going In . . . and sometimes (e.g. with Coe et al., ) you see the Garbage coming Out.

# Oh, Santalives, I did come across a joke yesterday :

"My math teacher really hated negative numbers. Hated them. He would stop at nothing to avoid them."

2022 SkS Weekly Climate Change & Global Warming News Roundup #7

Philippe Chantreau at 09:37 AM on 27 February, 2022

The "article in point" claims this: "In fact, the
climate sensitivity to a doubling of CO2 from 400ppm to
800ppm is calculated to be 0.45 Kelvin."

However, there has already been over 1 degree of temperature increase compared to pre-industrial, with the concentration going from 290 ppm to 400 ppm and we are nowhere near equilibrium for 400, which would take some time.

I did not see in the paper a competing explanation for the measured increase. I also did not see why exactly they believe that all the rest of the litterature that concludes the equilibrium sensitivity for a doubling of pre-industrial concentration is around 3 degrees is wrong.

The argument against feedbacks is not very detailed and amounts to little more than hand-waving. It flies in the face of an extensive body of research into the glacial/interglacial transitions associated with Milankovitch cycles.

At first glance, I am not very impressed. Hopefully, more qualified commenters will look into it. I am also not sure about the publication where this piece appeared.

SkS Analogy 1 - Speed Kills: How fast can we slow down?

Evan at 09:46 AM on 20 February, 2022

We're running that experiment right now. Is it your suggestion that we continue with this global experiment until the atmospheric CO2 concentration recahes 560 ppm so that we can verify what the climate sensitivity is? Of course, if the world leaders listen to your suggestion, we will then be stuck with 560 ppm CO2, because it ain't easy to remove once it's in the atmosphere.

I vote we rely on the well-developed physics and skip your suggested atmospheric experiment.

By the way, filling a container with air and CO2 is not the same as filling the atmosphere with air and CO2. There are a few differences.

It's albedo

MA Rodger at 00:09 AM on 10 February, 2022

blaisct @115,

The Wiki reference you cite giving 0.8 is presumably this paragraph which provides a statement of Equilibrium Climate Sensitivity with ΔTs = λ ΔF and λ = 0.8ºC/Wm^-2.

With ECS usually given as the ΔTs for a doubling of CO2 where ΔF = 3.7Wm^-2, ECS = 3ºC. This is the usual 'central' value given for ECS. IPCC AR6 Ch7 calls 3ºC "the best estimate."

"Based on multiple lines of evidence the best estimate of ECS is 3°C, the likely range is 2.5°C to 4°C, and the very likely range is 2°C to 5°C."

But this increase in EEI for the period 2001-20 cannot be used as a value for ΔF in ECS equations.

How weather forecasts can spark a new kind of extreme-event attribution

Bob Loblaw at 00:03 AM on 13 January, 2022

The problem I have with the "it's not climate change, it's greenhouse gases" narrative is that the chain of causality never ends. And at each step of the chain, the contrarians will come up with an excuse to ignore it.

After "it's greenhouse gases", the contrarians wll come up with one of the following bogus arguments:

It's not CO₂, it's water vapour.

Methane is a more powerful greenhouse gas.

Climate sensitivty is low.

CO₂ lags temperature

etc.

Once you successfully argue that it is CO₂, then you get

Human CO₂ emissions are minor

Volcanoes emit more CO2 than humans

CO₂ is coming from the ocean

The rise in CO₂ is natural

etc.

and then if you manage to establish that the rise in CO₂ is due to burning fossil fuels, you get all the "it's not bad", "technology will save us", "you'll hurt the poor", etc arguments.

There are many such arguments on the Skeptical Science "Arguments" page. I have only linked to a few.

It's albedo

coolmaster at 09:19 AM on 10 September, 2021

BL@78

BL: you double-down on your claim of a strong cooling effect for clouds. Let's examine some actual science.

I have already sent you the current science in this regard. The graphics for the global radiation balances all_sky, clear_sky, land & ocean were created and published by Prof. Dr. Martin Wild / ETH Zurich. He is a very nice person and lead author of the IPCC AR6 WGI Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity. (Chapters 7.2.1 and 7.4.2.4.3 are relevant for our topic.)
You will not find our topic much more actual and precise anywhere, and if you continue to have doubts about the strong cooling influence of clouds - you should contact with Prof. Dr. M. Wild directly.

BL: summary diagrams are summary diagrams - not detailed models."
You will surely see that a slr volume of 1335km³ / year has to be distributed globally and that I therefore use global, summarizing radiation balances.

Using the posted information in the explanatory file on land use and irrigation,

https://www.frontiersin.org/articles/10.3389/feart.2020.00245/full

you also have the opportunity to observe my claims about irrigation, cloud formation, precipitation, temperature, radiative forcing etc. on a more regional level.

BL: ...it condenses to form cloud, but this is not always the case. ...So will this "extra" moisture cause more clouds? Maybe. Maybe not.
You have provided no scientific justification for this claim, or references to suitable scientific publications to support it. You are completely wrong here. You claim that there is some kind of rest room for water vapor in the atmosphere. Could you please prove that.
99,999% of atmospheric water vapor will form a cloud before it return as precipitation. Dew e.g. is also considered to be a form of precipitation.

BL: As a consequence of increasing evporation, the location where the evaporation occurs will also see less thermal energy transfer to the atmosphere, so temperatures are also affected.
Yes Sir - that´s what I mean. More latent heat flux = less sensible(thermal as you say) heat flux. H²O in the air will form clouds - dry and hot air in the atmosphere will kill them. Soil and air temperatures will decrease - and that's exactly what I intend to do with my strategy. You should also know that the extra amount of 1% precipitation/irrigation/evaporation is planed to released predominantly in spring / summer allways into a relatively unsaturated, dry and hot clear_sky atmosphere, which most closely corresponds to a drought period or desert.

Intensification of the global hydrological cycle is a robust feature of global warming, BUT at the same time, many land areas in the subtropics will experience drying at the surface AND in the atmosphere. This occurs due to a ! limited water availability ! in these regions, where the cloudiness is consequently expected to decrease.

Your speculations about different clouds, with their different effects on the albedo and SW / LW radiation effects, are not conducive to the discussion and are unimportant for my assessments. In a dry, hot, sunny high pressure atmosphere, I guess at least that mostly convective fair-weather clouds or thunderclouds (cumulus or c.-nimbus) will arise.

1% more precipitation / evaporation will not have a major impact on the general cloud pattern. The natural regional variability of the amount of precipitation is often 200mm or more between dry and humid years. Since 9mm more or less per year will regionally cause no noticeable changes in the cloud regime. Maybe there will be 3-4 rainy days/year instead of increasing hours of sunshine.
BL: Coolmaster's diagrams are nice pictures that help illustrate a few aspects...
Again - these diagrams are not mine. They are calculated by professionals of IPCC experts. You have no clue about the difference between water- & air cooling, heat capacity & efficiency. That's your problem - not mine.

How Increasing Carbon Dioxide Heats The Ocean

MA Rodger at 02:47 AM on 6 August, 2021

steve37341 @69,

As Elcectic @70 suggests, the question you pose concerns a complex and dynamic situation.

But if what you ask is reduced to the question of whether a +2°C in global surface temperature is a bigger kick to the climate (and thus the ocean temperature) than a 33% increase in CO2 (from 300ppm to 400ppm), the very basic response would be the +2°C is the strongest. A simple 33% incease in CO2 would result in a forcing of +1.54Wm^-2 which for an Equilibrium Climate Sensitivity of +3.2°C per 3.7Wm^-2 (the central estimate of ECS) would result in a surface warming of +1.33°C.

Adding more realistic assumptions would quickly impact that result. Thus, for instance, one early added consideration is that a surface temperature increase would be greater over land than ocean raising the question of whether your +2°C is a global figure or a surface (atmosphere) increase measured over the ocean.

It's not bad

Eclectic at 19:07 PM on 16 July, 2021

TVC15 @390 :-

Permit me some general waffle : my comment is that you should be half'n'half ~ half optimist, half pessimist. The global situation is going to get bad but not catastrophic. Yes, we are going to blow straight past the 1.5 degree mark in global surface temperature rise since pre-industrial. The rise already (over 170 years) is about 1.1 degrees, and this makes a mockery of any contrarian who opines that the CO2-doubling Climate Sensitivity is less than roughly 2.0 degrees (and seems most likely to be in the 2.5 to 3.0 degree range at equilibrium ~ which also fits with non-historic data e.g. the paleo data).

With extraordinarily good management, we might conceivably halt the rise by 2.0 degrees . . . but our political track record so far is poor.

It is not just the politics, but technological advances which are still required. Sure : cheaper solar & wind technologies are coming, but we really should have started seriously developing these at least 10 years before we actually did. (But the past cannot be changed.)

The 2050 date for "carbon neutral" will require more than the present-day solar & wind, even at half of today's prices. Energy storage is absolutely necessary ~ and I am looking to bulk storage of electrolytic hydrogen. Hydrogen to provide electricity via fuel cells (at small scale) or steam-driven turbines at large scale (possibly combined-cycle?).

The second leg to stand on, is a hugely-increased supply of liquid hydrocarbon [octane / kerosene / diesel types] produced from non-fossil feedstocks, by means of catalytic / enzymatic / fermentational technology. In brief, we need to produce these hydrocarbons at a scale little short of present-day fossil fuel consumption. For a great amount of our energy usage, these hydrocarbons are necessary ~ and I suspect it will take many decades after 2050 , before we could replace such hydrocarbon fuels.

Extinction of a very large slice of animal/plant species . . . is arguable. Extinction of the human race ~ certainly impossible. The casualty rate may be high in the future ~ but extinction, no way. Mass migration of "climate refugees" will increase as sea level rise and heat waves occur, and there will be major social disruption. "Interesting Times" , as the old Chinese saying goes.

Why the Miocene Matters (and doesn’t) Today

Reuben Fraser at 21:06 PM on 10 July, 2021

As 'this is' my 'first post' on 'Skeptical Science', I have decided to 'respectfully' introduce myself, even though I don't expect anyone to reply. 'Thank You!' That is, to the providers s of this website, and more specifically for howardlee, whose post back on 12 Feb. 2015 has introduced me to this website: Why the Miocene Matters (and doesn’t) Today.

I am accustomed to writing comments for the New York Times, and that is what has led me via a roundabout route to this website. It began when someone's comment informed me about something which I was unaware:

"Concentrations of CO2 in the atmosphere were as high as 4,000 parts per million (ppm, on a molar basis) during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years."

In the above I am quoting Wikipedia, rather than the person who made the comment, because that is my everday routine: turning to Wikipedia for further information about something which I have read in the NY Times; or otherwise, because there is a new artist about whom I am unfamiliar in the top 10 on the Apple Music charts for the U.S., U.K., South Korea or Spain, the four that I am happy to follow, it being routine to turn to their Artist Discography to download their most commercially successful songs.

The specific Wikipedia article about Climate Change that I am quoting above is Carbon dioxide in Earth's atmosphere; and their reference for what I have quoted is the Australian National University's Professor Tony Eggleton (2013) A Short Introduction to Climate Change, Cambridge University Press, p. 52. However, his text then redirects the reader to his chapter 8 for his references. Via many further such steps, I eventually found the following key reference: Hansen J, Sato M, Russell G, Kharecha P. 2013 Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans R Soc A 371: 20120294; as this provides an excellent graph of relatively recent Climate Change, most notably the mid-miocene climatic optimum (MMCO).

Thermal Maximum and Climatic Optimum in the Mid-Eocene and Mid-Miocene

The New Climate War by Michael E. Mann - our reviews

Nick Palmer at 06:31 AM on 16 June, 2021

I think you lot are trying to hard to prop up a very long standing meme, originated by Greenpeace and subsequently promoted by, IMHO, political forces not related to pure climate science. I've never said that Big Oil should have done what they did, just that their motivation to do it may not have been that which was attributed to them by that meme. FWIW, I think the true culpability of Big Fossil Fuel is not for resembling the activist meme of them being shadowy psychopaths intent on destroying the world for profit but rather for being like the punk in Dirty Harry who, when neither of them knew for certain whether there were any bullets left in the Magnum, recklessly took a chance and paid the price.

If you've ever seen that analogy used in the climate wars, I originated it. My argument to denialists back then was that, by analogy, 'denier punks' had a right to risk their own lives by believing that there were no climate change bullets left, or that possible low climate sensitivity meant that any bullet would be nearly a blank, but that they had a much greater responsibility to not take any view which would put everyobdy else in the world at risk if they were wrong. I had long discussions about this general concept with Greg 'What's the worst that could happen' Craven whose approach of risk analysis I still think is far superior at getting through to the majority of the public rather than the 'This is what the science says', 'Oh no it isn't', 'Yes it is', shouting match that the public arena is.

I came to my ideas from a lot of experience over several decades debunking 'ordinary' denialism, but I also found it quite often necessary to debunk alarmists too, who went much further than the peer reviewed science actually said. Alarmism gives deniers a lot of amunition to smear the actual science, in the minds of the public, by proxy. A lot of current denialism consists of holding up the silliest statements of extremists to ridicule, rather than attacking the science directly, but unfortunately that rebounds badly on the actual science in the public's view who have little way of knowing which of the very confident sounding sides are accurate or legit.

Long before John Cook started off the whole Denial 101 F.L.I.C.C initiative, I had been made well aware of the multiple deceptive rhetorical 'tricks' used by ordinary denialists to deny the peer reviewed science. I also became aware that the vast majority actually completely believed their position, whether it was the 'almost mainstream' luke-warmer position or the weirder 'against the second law of thermodynamics' pseudoscience types. What I did notice was that, say, in the comments of WUWT, virtually none of the former ever criticised the latter. It was only a very, very few, such as Mosher, who took on the real loonies. I also came to see that the reverse was also the case in environmentalist literature. Apart from a few such as myself, who has always tried to root out any mistakes, delusion or deceptions wherever they may be found, activist alarmism in publicly available media seemed to get a 'free pass' from those who normally argued the science, such as skepsci types. For what it's worth, I find it much harder to deal with activists, rather than with the more moderate 'denialists' as activist ideology isn't really based on a rational bullet-proof knowledge of the science, but rather on persuasive memes and Hans Eysenck's 'hobgoblins' to scare the public. I couldn't help noticing that BOTH sides used the same techniques of misdirection, cherry picking etc although, back then, it tended to be the more extreme - the incorrigibles of the denialist side - who did the lion's share of it. In the last few years, as the political aspects of the climate arena have suddenly popped out of the closet far more than ever before, and the sides have become ever more partisan, I'd say 'what lies beneath' the surface of people on all sides debating climate policy is surfacing.

I used to sit on my former Government's Energy panel, which was set up to deal with energy policy relating to climate science and the energy transitions required and I became pretty well connected with some significant movers and shakers in the climate science arena, both scientists, civil servants and media folk. For what it's worth, the panel also had representatives on it from gas and oil 'fossil fuel' corporations, plus the area electricity supplier. That's another reason why I'm virtually certain that the Greenpeace/Oreskes meme, that even some smart people seem to have swallowed hook, line and sinker, is a fair distance from the truth. The meme has a lot of the smell of simplified 'hobgoblins to sway the public' about it, rather than it being a completely accurate piece of historical reportage...

Anyway, it's been interesting to see the, in my view somewhat biased, kick-back from long term Skepsci followers. I think what I might do in due course is approach John Cook to see if we can arrange a Zoom meeting. He and Stephan Lewandowsky are right at the forefront of the 'psychological' approach to deconstructing denialist attitudes and methods. Maybe they'll be more welcoming of a new hypothesis than others...

The New Climate War by Michael E. Mann - our reviews

Bob Loblaw at 05:42 AM on 13 June, 2021

Oh, Nick. You're repeating yourself, and it does not stand you in good stead.

"The short answer is that Big Oil continued to support the "B.S. factories" because they were effective at trying to protect those corporations against unwarranted attack."

I really hope that you do not consider sound science (even with uncertainties) to be "an unwarranted attack".

If you are referring to non-scientific organizations such as Greenpeace, then I hope that you are not saying that unwarranted attacks justify B.S., simply because it is "effective".

"...most seem to have been happy to accept Greenpeace et al's interpretation of events as gospel..."

A strawman position...

"I refer you again (3rd time) to my quote of Carbonbrief's article and the words of top climate scientist Andrew Dessler of Texas A&M Uni."

Repeating the quote is certainly not necessary. Using phrases such as "top climate scientist" represent an argument from authority. I was already teaching undergraduate and graduate climatology courses when Andrew Dessler was still a grad student. I had and have direct knowledge of the primary peer-reviewed scientific literature from that time.

I hope that you do not think that the 1.5C to 4.5 C sensitivity range is a complete summary of climate science.

I hope that you do not think that there was a huge amount of uncertainty regarding the lower limit back in the 1980s. There was lots of uncertainty of regional effects. Lots of uncertainty about cloud feedback effects (but unlikely to be strongly negative).

From the 1990 IPCC sumamry for policy makers:

There are many uncertainties in our predictions particularly with regard to the timing, magnitude and regional patterns of climate change, due to our incomplete understanding of:

• sources and sinks of greenhouse gases, which affect predictions of future concentrations
• clouds, which strongly influence the magnitude of climate change
• oceans, which influence the timing and patterns of climate change
• polar ice sheets which affect predictions of sea level rise

These processes are already partially understood, and we
are confident that the uncertainties can be reduced by
further research However, the complexity of the system
means that we cannot rule out surprises

THe 1990 IPCC report includes quite a bit of discussion about these uncertainties, and what needs to be done to sort them out.

One of the very few sources of a realistic argument for low sensitivity was Lindzen's "Iris effect". As Lindzhen had a good reputation as a meteorologist, this hypothesis was taken seriously. It did not pan out.

Most of the rest of the "sensitivity is low" arguments were B.S. Many were clearly B.S. in the 1980s - and are still B.S. now, even though they keep getting repeated..

Dessler may feel that the uncertainty was underestimated. Do you have any evidence of an actual number that he would put on it?

Did Exxon choose to push the known uncertainties and realistic scientifically-supportable possibitiies? No. As you admit, they chose the Baffle Them With B.S. option.

You seem to feel that was justified on their part. I do not.

"...the views of sensitivity at the time were just not solid enough to mandate massive corporation change..."

...but they were solid enough to start to invest considerable money (albeit probably peanuts for Big Oil) in the B.S. factories, in an attempt to preserve and maximize corporate profits for as long as possible.

If Big OIl's approach was so honorable, then why did they try to hide the path of the money and keep their name off it?

If you were to argue that Big Oil's corporate responsibility is to maximize shareholder value regardless of ethics, then I would concede the point.

The New Climate War by Michael E. Mann - our reviews

Nick Palmer at 02:48 AM on 13 June, 2021

I realise I've got an uphill struggle with you lot because you are unlikely to have heard anyone arguing this position before - most seem to have been happy to accept Greenpeace et al's interpretation of events as gospel without deconstructing it enough. When one has been deconstructing the deceit, delusion and/or dumbness from the various denialist factions for decades, as I have, one can't help it if one sometimes notices the very same methods being used by our 'side'. I personally think that demonising Big Oil's past activities and misrepresenting them as if they were real denialism is very counter-productive. Apart from anything else, one of the most powerful arguments I use against tricksy denialist rhetoric is that these days even Big Fossil Fuel fully accepts mainstream climate science and they acknowledge that something serious needs to be done to avoid the very unacceptable risks. I point that if there was a trace of reality in the arguments that have sucked them in, Big Oil's scientists would have noticed and their corporate execs would have then beaten a wide path to the doors of the sceptic/contrarian/denialists with wheelbarrows full of cash to learn about their magic get-out-of-jail-free cards. When I challenge denialists to explain, if they are so sure of their beliefs, why this is not happening, and never did happen, they either shut up or go off into the lala land of conspiracies I list later on. In either case, the wider audience sees they have nothing real...

Bob Loblaw@25 wrote:

"Give me a break. I was studying climatology for 10 years before Hansen's speech, and a dozen years before the 1990 IPCC report"

I refer you again (3rd time) to my quote of Carbonbrief's article and the words of top climate scientist Andrew Dessler of Texas A&M Uni.

C.B.: "In 1979, the Charney Report from the US National Academy of Sciences suggested that ECS was likely somewhere between 1.5C and 4.5C per doubling of CO2. Nearly 40 years later, the best estimate of sensitivity is largely the same.
However, Prof Andrew Dessler at Texas A&M University pushes back on this suggestion. He tells Carbon Brief:

I think that the idea that ‘uncertainty has remained the same since the late 1970s’ is wrong. If you look at the Charney report, it’s clear that there were a lot of things they didn’t know about the climate. So their estimate of uncertainty was, in my opinion, way, way too small"

"Back in 1979, climate science was much less well understood than today. There were far fewer lines of evidence to use in assessing climate sensitivity. The Charney report range was based on physical intuition and results from only two early climate models.

In contrast, modern sensitivity estimates are based on evidence from many different sources, including models, observations and palaeoclimate estimates. As Dessler suggests, one of the main advances in understanding of climate sensitivity over the past few decades is scientists’ ability to more confidently rule out very high or very low climate sensitivities."

I'm not disputing that the basic science of radiative physics and the simple climate modelling of ECS of 'how many degrees per doubling' has been around a long time. As a matter of fact, as a science geek, I knew about some of the scientific views in my later teens (early 70s) - about the time I stopped buying aerosols (apart from WD40...) to protect the ozone layer. The uncertainty of outcome referred to by Dessler is to the 'known unknowns' and 'unknown unknowns' at the time and these were very significant. The (some of) CMIP6 model problems were mentioned just to show that even today some crucial feedback mechanisms affecting ECS are still being nailed down 40 years later.

It is the solidarity or otherwise of the climate sensitivity figures AT THE TIME of the memos and documents cherry picked in 'Exxon Knew' which is at the very nub of whether, as the populist environmentalist narrative goes, Exxon were evil or, as I am convinced, just cautious because the views of sensitivity at the time were just not solid enough to mandate massive corporation change without a lot more scientific work to more reliably figure out what ECS was (not to mention the Transient and Earth system sensitivities too). If Exxon's scientists told their bosses that, as Dessler wrote, Charney's figures were waay more uncertain than Charney thought they were, that is not evidence of psychopathic evil, it's just evidence of good scientists offering a very valid criticism of another scientist's work.

Sure, at the time, Exxon's own scientists acknowledged the basic 'settled' science but of course they would also acknowledge the great uncertainties which the 'anti's turned a blind eye to. There was nothing sinister about that and it is the attribution of malignant motives to Big Oil by Greenpeace et al that I have a serious issue with. There is so much deceit, deception, propaganda, selective and misleading information from all sides out there that I think our 'side' should clean up its act and disavow all that stuff and just stick to the best peer reviewed science, the best risk analysis and not indulge in dubiously demonising (probably) innocent'ish corporate behaviour that has been, in my view, massively misrepresented or rule out many solutions, as Mann has done, which have great potential thus making 'the answers' much harder to achieve.

The New Climate War by Michael E. Mann - our reviews

Nick Palmer at 00:01 AM on 10 June, 2021

Here's a live link to the skepsci article which I neglected to do in my previous long comment

https://skepticalscience.com/climate-sensitivity.htm

The New Climate War by Michael E. Mann - our reviews

Nick Palmer at 23:49 PM on 9 June, 2021

When activists try to bad mouth Exxon et al they speak from a 'post facto' appreciation of the science, as if today's relatively strong climate science existed back when the documents highlighted in 'Exxon knew' were created. Let me explain what I think is another interpretation other than Greenpeace/Oreskes'/Supran's narratives suggesting 'Exxon knew' that climate change was going to be bad because their scientists told them so as far back as the 70s and 80s. Let me first present Stephen Schneider's famous quote from 1988 (the whole quote, not the edited one used by denialists).

"On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but – which means that we must include all doubts, the caveats, the ifs, ands and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climate change. To do that we need to get some broad based support, to capture the public’s imagination. That, of course, means getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This “double ethical bind” we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both."

I submit that part of the apparently damning content of the documents was exactly caused by Exxon's scientists, Schneider-like, simplifying their message to initially present it to their corporate employers. In exactly the same way that the denialosphere combed though the Climategate emails to find apparently damning statements and then interpreted them through a filtered 'lens' to insinuate fraud and data manipulation, usually by editing out context etc and even previous and subsequent sentences which changed the meaning completely, I submit that Greenpeace's 'Exxon knew' team did that too. They knew that the majority of people who read their report would assume that the current science that projects the bad consequences that we are (fairly) sure about today was as rock solid back way back then as it is now and would therefore jump to their desired conclusion that Big Capitalist Oil was just being evil. I'm absolutely not suggesting that Greenpeace's team were consciously being deceptive, just that they allowed their zealotry to run away with them so they saw just what they wanted to see...

Today's science, that projects bad outcomes, was by no means solid back then. I think that what Big Oil should be fairly accused of is the much less 'evil' culpability of not adequately informing the public about the full probabilities of the risks - which again is the 'Schneider' method of tailoring one's output for one's audience. Perhaps they didn't get "the right balance is between being effective and being honest" quite right. As denialists will endlessly tell us, the use of fossil fuels has been on balance a huge boon to humanity and I suspect that past one-dimensional calls by activists (including those I naively made!) to not use or explore for any more fossil fuels almost overnight, to a corporate mind, would require a public relations strategy to counter that extremist view while waiting for the science to get solid enough to start serious corporate planning for change should it be needed.

'Ban all exploration for or use of fossil fuels today' is a frequent call of today's extremists and no doubt they are sincere that they think the risks are such that such draconian action must be justified, and that things such as new technology, carbon capture, Gen3/4 nukes, agricultural changes etc must be Machiavellian Big Industry just manouevring to do nothing now to protect their financial bottom lines - delaying tactics that must be resisted. I think Professor Mann too has fallen in to the trap of feeling 'certainty' about what he thinks the solutions should be and this has lead to his dismissal, even libellous characterisations, of those who offer up a more nuanced way forward. Activists who call for an immediate ban on fossil fuels and 100% renewables by next Tuesday do not seem to realise that they are thinking in a one-dimensional way. Their 'solution' might address climate change, but such a solution would instantly cause enormous global disruption and would likely spark off the mother of all global economic recessions, which would rapidly cause long lasting extreme global hardship much greater, at least in the short to medium term, than anything global warming is scheduled to do for several decades.

So what were the 'uncertainties' back then? Some of the most important parameters plugged into climate models are those for climate sensitivity. While (widely varying) estimates existed before 2000 it only got well constrained and modelled within firm(ish) limits by papers published after then. Check out the links in this Skepsci article to see when the major papers were published.
https://skepticalscience.com/climate-sensitivity.htm

Here is Carbonbrief.org explaining the lack of certainty back then

"From Carbon Brief https://www.carbonbrief.org/explainer-how-scientists-estimate-climate-sensitivity

"In 1979, the Charney Report from the US National Academy of Sciences suggested that ECS was likely somewhere between 1.5C and 4.5C per doubling of CO2. Nearly 40 years later, the best estimate of sensitivity is largely the same.
However, Prof Andrew Dessler at Texas A&M University pushes back on this suggestion. He tells Carbon Brief:

Activists try to insinuate that the documents and memos show that Big Oil 'knew the scientific truth' back then and adopted a position of denial, or psychopathic deception for the sake of profits, in the face of noble environmental groups campaigning against them because they also 'knew the truth' too. Much though it pains me to admit it, I was part of the campaigning certainy of those groups back then. I used to coordinate a Friends of the Earth area group and all the material I saw did not mention any of the scientific doubts and the uncertainties which featured in the scientific literature. I trusted it - it was the same thing we see today when such as Extinction Rebellion go waay over the top with the certainty of their assertions and the cherry picked nature of the information they present to the public. This is why I think that all sides - denialist/alarmist/doomist/sceptic etc - use misleading rhetoric to spin their narratives. I realise that many of the environmental activist 'troops' in their crusades like to feel certain that they know the 'truth' that Evil Big Industry had psychopathically tried to hide but I think total honesty is necessary to enable the public to judge the situation properly, so that policy changes we need are not based on the shifting sand that the 'divine deception' of the rhetoric of extremist campaigners and political forces is. Noble cause corruption is not a good strategy whether it is that of the greens, the left or right.

It's not as if even today's science is completely bulletproof, as a new paper about clouds shows. Consideration of it offers up an explanation as to why the new CMIP6 models are running too hot, and that is because observations show that some parameters plugged into current cloud models about longevity, warming and precipitation are wrong which mean that clouds cool more than previously thought. It doesn't,as it happens, change what we need to do but it does demonstrate that even today a fairly major part of the mechanics of climate changee can - uh hm - be changed.

New paper on clouds
https://www.carbonbrief.org/cooling-effect-of-clouds-underestimated-by-climate-models-says-new-study

2021 SkS Weekly Climate Change & Global Warming Digest #1

Dr. S. Jeevananda Reddy at 17:47 PM on 11 January, 2021

Negelj

Global Warming: It is an estimate of the annual average part of temperature trend. The trend of 1880 to 2010 is 0.6oC per century in which global warming component is 0.3oC – 1951 to 2100 is 0.45oC – according to linear trend. But in reality it is not so as the energy component is constant over which superposed sunspot cycle. However, the reliability depends up on the data used. For example number of stations in around 1850 were < 100 and by around 1980 [started satellite data collection started around this time] they were more than 6000 and with the availability of satellite data the number of stations drastically come down to around 2500. The satellite data covered both urban-heat-island effect and rural-cold-island effect and showed practically no trend – US raw data series also showed this. However, this data was removed from internet [Reddy, 2008 – Climate Change: Myths & Realities, available on line] and replaced with new adjusted data series that matches with ground data series. Here cold-island effect is not covered. With all this, what I want say is warmings associated with solar power plants is added to global warming. How much?? This needs collection of data for all the solar power stations. Met station covers a small area only but acts like UHI effect – I saw a report “surface temperatures in downtown Sacramento at 11 a.m. June 30, 1998 – this presents high variation from area to area based on land use [met station refers to that point only]. So, solar wind power plants effect covers similar to heatwaves and coldwaves. Here general Circulation Pattern plays main role.

Nuclear Power: Nuclear power production processes contribute to “global warming process” while hydropower production processes contribute to “global cooling process”; the nuclear power production processes don’t fit into “security, safety & economy” on the one hand and on the other “environment & social” concepts; unlike other power production processes, in nuclear power production process different stages of nuclear fuel cycles are counted as separate entities while assessing the cost of power per unit and only the power production component is accounted in the estimation of cost of power per unit; carbon dioxide is released in every component of nuclear fuel cycle except the actual fusion in the reactor. Fossil fuels are involved in the mining-transport-milling conversion-processing of ore-enrichment of the fuel, in the handling of the mill tailings-in the fuel can preparation-in the construction of plant and it decommissioning-demolition, in the handling of the spent waste-in its processing and vitrification and in digging the hole in rock for its deposition, etc. and in the manufacturing of necessary required equipment in all these stages and thus their transportation. In all these stages radiological and non-radiological pollution occurs – in the case of tail pond it runs in to hundreds of years. Around 60% of the power plant cost goes towards the equipment, most of which is to be imported. The spent fuel storage is a critical issue, yet no solution was found. Also the life of reactors is very short and the dismantling of such reactors is costly & risky, etc., etc.

Michael Sweet/ Negelj

In 70&80s I worked and published several articles relating to radiation [global solar and net and evaporation/evapotranspiration] – referred in my book of 1993 [based on articles published in international and national journals]. Coal fired power plants reduces ground level temperature by reducing incoming solar radiation. In the case of Solar Panels create urban heat island condition and thus increases the surrounding temperature. In both the cases these changes depends upon several local conditions including general circulation patterns. Ground condition plays major role on radiation at the surface that define the surface temperature [hill stations, inland stations & coastal stations] – albedo factor varies. Also varies with soil conditions – black soil, red soil. Sea Breeze/land breeze – relates to temperature gradient [soil quickly warm up and quickly release the heat and water slowly warm up and slowly release heat] and general circulation pattern existing in that area plays the major role in advection.

Response to Moderator

See some of my publications for information only:

Reddy, S.J., (1993): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries, www.scribd.com/Google Books, 205p; Book Review appeared in Agricultural and Forest Meteorology, 67 (1994):325-327.
Reddy, S.J., (2002): Dry-land Agriculture in India: An Agroclimatological and Agrometeorological Perspective, BS Publications, Hyderabad, 429.
Reddy, S.J., (2008): Climate Change: Myths & Realities, www.scribd.com/Google Books, 176.
Reddy, S.J., (2016): Climate Change and its Impacts: Ground Realities. BS Publications, Hyderabad, 276.
Reddy, S.J., (2019a): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries [2nd Edition]. Brillion Publishing, New Delhi, 372p.

2.1.2 Water vapour

Earth’s temperature is primarily driven by energy cycle; and then by the hydrological cycle. Global solar radiation reaching the Earth’s surface and net radiation/radiation balance at the Earth’s surface is generally estimated as a function of hours of bright Sunshine. Total cloud cover [average of low, medium & high clouds] has a direct relation to hours of bright Sunshine (Reddy, 1974). Cube root of precipitation showed a direct relation to total solar radiation and net radiation (Reddy, 1987). In all these latitude plays major role (Reddy & Rao, 1973; Reddy, 1987). Evaporation presents a relation with net and global solar radiation (Reddy & Rao, 1973) wherein relative humidity plays an important role that reduces with increasing relative humidity. If ‘X’ is global solar radiation received under100% relative humidity then with the dryness [with relative humidity coming down] it may reach a maximum of 2X; and under net radiation also with increasing relative humidity net radiation is reduced. That means water vapour in the atmosphere is the principal component that controls the incoming and outgoing radiation and thus temperature at the Earth’s surface. Thar Desert presents high temperature with negligible water vapour in the atmosphere as maximum energy reaches the earth’s surface. However, these impacts differ under inland (dryness), hill (declining temperature with height – lapse rate) & coastal (wetness) locations and sun’s movement (latitude and declination of the Sun — seasons) (Reddy & Rao, 1973). IPCC integrated these under “climate system” and the advective condition by general circulation pattern [GCP].
Cold-island effect [I coined this, see Reddy (2008)] is part of human induced climate change associated with changes in land use and land cover. Since 1960’s to meet the food needs of ever increasing population, started intensive agriculture – conversion of dryland to wetland; & creation of water resources; etc. In this process increased levels of evaporation and evapotranspiration contributed to raise in water vapour up to around 850 mb levels in the lower atmosphere. Unusual changes in water vapour beyond 850 mb level [for example at 700 mb level] become a cause for thunderstorm activity (Reddy & Rao, 1978). Wet bulb temperature (oC) at the surface of the Earth provides the square root of total water vapour (g/cm2) in the vertical column of the atmosphere; and also wet bulb temperature (oC) is a function of dry bulb temperature (oC), relative humidity (%) and square root of station level pressure (height) relative to standard value in mb [p/1060] (Reddy, 1976). Thus, unlike CO2, water vapour presents a short life with steadily increasing with land use and land cover changes. However, met network in this zones have been sparse and thus the cold island effect is not properly accounted under global average temperature computations. Though satellite data takes this in to account, this data series were withdrawn from the internet and introduced new adjusted data series that matches with adjusted ground data series. Annual state-wise temperature data series in India wherein intensive agriculture practices are existing, namely Punjab, Haryana & UP belt, showed decreasing trend in annual average temperature – cooling. Some of these are explained below:

Reddy (1983) presented a daily soil water balance model that computes daily evapotranspiration, known as ICSWAB Model. The daily soil water balance equation is generally written as:

▲Mn = Rn – AEn – ROn - Dn

In the above equation left to right represent the soil moisture change, rainfall or irrigation, actual evapotranspiration, surface runoff and deep drainage on a given day (n). The term Actual Evapotranspiration [AEn] is to be estimated as a function of f(E), f(S) & f(C), wherein they represent functions of evaporative demand on day n, soil & crop factors, respectively. As these three factors are mutually interactive, the multiplicative type of function is used.

AEn = f(En) x f(S) x f(C)

However, the crop factor does not act independently of the soil factor. Thus it is given as:

AEn = f(En) x f(S,C) and f(S,C) = K x bn

Where f(S,C) is the effective soil factor, K = soil water holding capacity [that varies with soil type] in mm and bn is the crop growth stage [that vary with crop & cropping pattern] factor that varies between 0.02 to 0.24 — fallow to full crop cover conditions (with leaf area index crossing 2.75). Evaporative demand is expressed by the terms evaporation and/or evapotranspiration. Evaporation (E) and evapotranspiration (PE) are related as:

PE = 0.85 x E [with mesh cover] or = 0.75 x E [without mesh cover].

However, the relationship holds good only under non-advective conditions [i.e., under wind speeds less than 2.5 m/sec]. Under advective conditions E is influenced more by advection compared to PE. In the case of PE, by definition, no soil evaporation takes place and thus PE relates to transpiration only – where the crop grows on conserved soil moisture with negligible soil evaporation. With the presence of soil evaporation, the potential evapotranspiration reaches as high as 1.2 x PE or E with mesh cover. McKenney & Rosenberg (1993) studied sensitivity of some potential evapotranspiration estimation methods to climate change. The widely used methods are Thornthwaite and Penman presented 750 mm and 1500 mm wherein Thornthwaite method is basically uses temperature and Penman uses several meteorological parameters (Reddy, 1995).
In this process the temperature is controlled by solar energy but moisture under different soil types [water holding capacity] it is modified. This modified temperature cause actual evapotranspiration and thus water vapour. This is a vicious circle. For example average annual temperature in red soils Anantapur it is 27.6oC; in deep black soils Kadapa it is 29.25oC & in medium soils Kurnool it is 28.05oC. That means, local temperature is controlled by soils.
Reddy (1976a&b) presented a method of estimating precipitable water in the entire column of the atmosphere at a given location using Wet Bulb Temperature. The equations are given as follows:

Tw = T x [0.45 + 0.006 x h x (p/1060)1/2]

W = c’ x Tw2

Where T & Tw are dry and wet bulb temperatures in oC; h is the relative humidity in %; p is the annual normal station level pressure in mb [1060 normal pressure in mb, a constant] ; W is the precipitable water vapour in gm/cm2 and c’ is the regression coefficient.
WMO (1966) presented methods to separate trend from natural rhythmic variations in rainfall and assessing the cycles if any. (Late) Dr. B. Parthasarathy from IITM/Pune used these techniques in Indian rainfall analysis. Reddy (2008) presented such analysis with global average annual temperature anomaly data series of 1880 to 2010 and found the natural cycle of 60-years varying between -0.3 to +0.3oC & trend of 0.6oC per century [Reddy, 2008]. This is based on adjusted data series but in USA raw data [Reddy, 2016] there is no trend. The hottest daily temperature data series of Sydney in Australia shows no trend [Reddy, 2019a]. Thus, the trend needs correction if the starting and ending point parts are in the same phase of the cycle – below and below or above and above the average parts. During 1880 to 2010 period two full 60-year cycles are covered and thus, no need to correct the trend as the trend passes through the mean points of the two cycles.

3.2.4 What is global warming part of the trend?

According to IPCC AR5, this trend of 0.6oC per century is not global warming but it consists of several factors:
a. More than half is [human induced] greenhouse effect part:
i. It consists of global warming component & aerosols component, etc. If we assume global warming component alone is 50% of the total trend, then it will be 0.3oC per Century under linear trend;
ii. Global warming starting year is 1951 & thus the global warming from 1951 to 2100 [150 years] is 0.45oC under linear trend;
iii. But in nature this can’t be linear as the energy is constant and thus CSF can’t be a constant but it should be decreasing non-linearly;
iv. Under non-linear condition by 2100 the global warming will be far less than 0.45oC and thus the trend will be far less than half;
b. Less than half the trend is ecological changes [land use and land cover change] part – mostly local & regional factors:
i. This consists of urban-heat-island effect and rural-cold-island effect;
1. Urban-heat-island effect – with the concentrated met network overestimates warming;
2. Rural-cold-island effect – with the sparse met network underestimates cooling;

2.2.1 Uncertainty on “Climate Sensitivity Factor”

The word “climate Crisis” is primarily linked to global warming. To know whether there is really global warming, if so how much, climate sensitivity factor plays the main role. Climate sensitivity is a measure [oC/(W/m2)] – how much warming we expect (both near-term and long-term) for a given increase in CO2? According to Mark, D. Zilinka (2020), “Equilibrium climate sensitivity, the global surface temperature response to the CO2 doubling, has been persistently uncertain”.
Recent modelling data suggests the climate is considerably more sensitive to carbon emissions than previously believed, and experts said the projections had the potential to be “incredibly alarming”, though they stressed further research would be needed to validate the new numbers. Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, said. “Climate sensitivity is the holy grail of climate science. It is the prime indicator of climate risk.
The role of clouds is one of the most uncertain areas in climate science because they are hard to measure and, depending on altitude, droplet temperature and other factors can play either a warming or a cooling role. For decades, this has been the focus of fierce academic disputes. Catherine Senior, head of understanding climate change at the Met Office Hadley Centre, said more studies and more data are needed to fully understand the role of clouds and aerosols. With this vital disputes how anyone can say there is global warming without solving this issue; so I said “global warming hysteria factor is climate crisis”.

2021 SkS Weekly Climate Change & Global Warming Digest #1

Dr. S. Jeevananda Reddy at 21:46 PM on 10 January, 2021

nigelj

on the solar and wind — see the reference I quoted earlier.

About nuclear power — I am against this and fighting on this. In India Hydropower is the major component after coal and in USA it is nuclear power — equivalent to hydropower % in India with coal % similar.

Coal power — the dust compensate the heat at the power station. Also water is used to cool some of it.

CO2 levels in SH are nearly one-third of NH. Also prior to 1960 a smooth increasing CO2 curve is an hypothetical curve.

IPCC claim that CO2 can cause catastrophic global warming. Because CO2 is not capable of causing significant global warming by itself, their contention is that increased CO2 raises temperature slightly and that produces an increase in water vapour, which does have the capability of raising atmospheric temperature. However, it is not the case, and on the contrary water vapour/relative humidity controls the energy coming from the Sun that controls the temperature at the ground. Since 1960 with the steadily rising irrigated agriculture and development of water resources caused steady rise in water vapour in the atmosphere but it has short life – not cumulative like carbon dioxide. That means under cold-island effect the temperature must decrease. This was recorded in satellite data. But later this data series were withdrawn from the internet and introduced new data series that matches with adjusted ground data series. Also annual state-wise temperature data series where intensive agriculture practice exists, namely Punjab, Haryana & UP belt showed decreasing trend in annual average temperature. Also climate sensitivity factor that converts CO2 in to heat/temperature is heuristic so far. Also the trend in global average annual temperature is not global warming but it is a part of trend is global warming that to based on adjusted data series.

A recent report states that CO2 level of 1970 was the height in the last 800,000 years — which is false observation. In fact CO2 measurements started around 1960 — According to WMO Fact Sheet 4 of August 1989— 45 stations of which 3 from SH and no station in tropics.

According to Freja Vamborg, a senior scientist at C3S, it is unquestionably an alarming sign that May 2020 has been the warmest month on record globally. However, even more concerning is the facts that average temperatures of the last 12 months have become one of the hottest 12-month-periods ever recorded in our dataset. Of course, this does not as such represent a long-term climate trend, as monthly temperature deviations vary, and some regions showed below average conditions. May 2020 tied with May 2016 for average global land and ocean temperatures, while April 2020 was on par with April 2016 for the hottest temperatures since records began in 1880. The global average temperature for May 2020 was 15.7oC (60.3oF), according to two independent measurements by the European Copernicus Climate Change Service (C3S) and the US National Oceanic and Atmospheric Administration’s (NOAA) included in the State of the Climate: Global Climate Report for May 2020. -— Both studies found abnormalities over Siberia and the Arctic Ocean with temperatures about 10.0oC (18oF) above average for this time of the year. That means these part of irregular variation part of natural variability. This is nothing to do with the CO2 linked global warming.

CO2 effect is saturated

Eclectic at 07:50 AM on 28 October, 2020

Aoeu @587 , permit me to add my 2 cents as well.

The WUWT article is a "nothingburger" - and worse.

The WUWT editor has given a completely fallacious headline. (Typical for WUWT) The article is based on a paper - unpublished - by two scientists, one of whom is the eminent Dr Happer. It is claimed that Happer's paper has been knocked back by three major journals . . . and reading the paper soon shows why a scientific journal would not bother to publish this paper.

You will see from the above comments by MA Rodger and Tom Dayton, that the Happer paper comes out with a CO2-doubling Climate Sensitivity of 2.2 degreesC . . . a finding which is wildly misrepresented by the WUWT editor. This 2.2C sensitivity is slightly below the 3.0 figure which is a fairer "average" of sensitivity assessments (based on paleo and modern empirical evidence). So really nothing new there.

The paper has two weaknesses. It makes no allowance for cloud effects (the paper is a "clear sky" model). And as a minor point, it uses constant relative humidity in its modeling. Apart from that, I have no particular criticism to make . . . other than the humorous one where a typographical error shows "temperature region" where "temperate region" was meant ;-)

Clearly the Happer paper is not worth publishing.

Sadly, the blog WUWT is trumpeting this paper to the skies (excuse pun). WattsUpWithThat and its denialist clientele are always desperate to make much of anything at all which comes even within a million miles of casting some doubt on mainstream climate science.

Aoeu, have a look at the WUWT comments column below the article. There are all sorts of frothing-at-the-mouth comments . . . that this new paper overthrows all previous climate science / disproves the Greenhouse effect / exposes the incompetence & corrupt criminality of all the thousands of climate scientists worldwide. Etcetera. All the usual WattsUpWithThat nonsense and crackpot lunacy. But among all the madness, you will find a few pearls of wisdom by the genuine scientist Nick Stokes (who is thoroughly hated by the usual WUWT clientele).

We can expect the Happer paper will be a Nine Day Wonder in many parts of the bloggy Deniosphere . . . until they abandon it for the Next New Thing (by Lord Christopher Monckton or whoever). It is all very entertaining . . . but it ain't science.

Climate's changed before

Eclectic at 12:10 PM on 22 October, 2020

MA Rodger @835,

Thanks. Yes, I had heard that the "frozen Thames" events had occurred even during the Medieval Warm Period (though those are never mentioned by Denialists).

I was interested in the "meme" of Thames freezings being held up as an example of the world-chilling severity of the Little Ice Age. And as I was saying to Hal Kantrud (who seems just starting out on learning about climate science) . . . the main point to remember is that the LIA and the MWP were pretty small beer compared with earlier climate changes.

As you yourself know very well, the LIA is greatly misrepresented by the climate-science Deniers :-

(a) Firstly, they exaggerate its severity ;

(b) Secondly, they falsely claim that our modern rapid warming is (somehow) "just a rebound from the LIA" .

(c) Thirdly - with amusingly unintended irony - they claim that the huge temperature excursions of MWP & LIA make the modern warming look insignificant . . . and yet at the same time they claim that the planet's Climate Sensitivity is so very low that we need not be concerned about the "slight" warming effect of anthropogenic CO2 emissions. Superb!

MA Rodger, you might not have seen it . . . but on one of the Denialist blogs recently, a particular Denier asserted that (by his calculation) Earth's Equilibrium Climate Sensitivity was around 0.4 degreesC. Improving on that, he then (based on the negligibly-small rise in CO2 which he attributed to humans) calculated that, of the modern warming, only 0.02 degreesC was human-caused. To repeat: 0.02 degreesC. Not a misprint. (Ah, who needs to pursue comedy, when so much is freely available on the Denier blogs! )

Spreading rock dust on fields could remove vast amounts of CO2 from air

Eclectic at 18:25 PM on 14 August, 2020

Daveburton @17 , the Moderators at SkS are typically rather sparing in "striking out or striking through" plain nonsense (such as your CO2 comment in #10 ).

Alas, the Moderators at WUWT are even more sparing : have a look at the comments columns at WUWT ~ where 80 or 90% of comments would get the chop, if moderation were applied by the criterion of common sense.

Dave, you have misunderstood the Moderator's response at #10 . He was not asking for a Gish Gallop. Implicit was the request (in accordance with the Modus Operandi here at SkS ) that you select the individual topics where you think the mainstream science is faulty or tied to poorly-pragmatic conclusions. (And contrary to your "models" comment, the pragmatic conclusions are based on ordinary physics & common sense ~ reinforced by the paleo evidence. None of this "61 floors and okay so far" business. The "models" projections/estimations may or may not give further insights into the climate processes & possibilities . . . but the models are definitely not the foundation of climate science. )

So, please select one individual topic which you believe is "wronged" ~ and discuss that one in the most appropriate thread here at SkS. And when that topic has been suitably discussed/resolved . . . then select your No. 2 choice, and find the right thread for that. And so on.

Good luck. (But it seems you are unaware of the sensitivity of maize yield, to heat waves.) And you may be in danger of becoming a skeptic (and thus with little chance of "life" on the WUWT blogsite.)

2020 SkS Weekly Climate Change & Global Warming Digest #30

John Hartz at 23:49 PM on 27 July, 2020

The most definitive article about the reserch findings is most likely the one writen by the paper's authors and posted on Carbon Brief. Here's the introduction to the article...

After four years of labour and detailed discussions by an international team of scientists, we are able to quantify better than ever before how the world’s surface temperature responds to increasing CO2 levels.

Our findings, published in Reviews of Geophysics, narrow the likely range in “equilibrium climate sensitivity” (ECS) – a measure of how much the world can be expected to warm for a doubling of CO2 above pre-industrial levels.

Constraining ECS has remained a holy grail in climate science ever since US meteorologist Jules Charney suggested a possible range of 1.5C to 4.5C in his 1979 report. His estimate was largely based on the world’s first two global climate models, which gave different estimates of 2C and 4C when they performed a simple experiment where atmospheric CO2 levels were doubled.

Since then, despite more than 40 years of research, much improved understanding of atmospheric processes, as well as many more detailed observations, this range has stubbornly persisted.

Now, bringing together evidence from observed warming, Earth’s distant past and climate models, as well as advances in our scientific understanding of the climate, our findings suggest that the range of ECS is likely to be between 2.6C and 4.1C.

This narrowed range indicates that human society will not be able to rely on a low sensitivity to give us more time to tackle climate change. But the silver lining to this cloud is that our findings also suggest that very high ECS estimates are unlikely.

Guest post: Why low-end ‘climate sensitivity’ can now be ruled out by Piers Forster, Zeke Hausfather, Gabi Hegerl, Steven Sherwood & Kyle Armour, Carbon Brief, June 22, 2020

Note: This article will be reposted in its entirety on this website later this week.

2020 SkS Weekly Climate Change & Global Warming Digest #30

nigelj at 17:30 PM on 27 July, 2020

Some free details and opinions on the new climate sensitivity study here.

2020 SkS Weekly Climate Change & Global Warming Digest #30

sailrick at 14:20 PM on 27 July, 2020

I admit I haven't read the article on climate sensitivity, but I'm confused. I read two other articles about the new study and they said 2.6-4.1 C was the new range.

Climate sensitivity is low

Cedders at 01:29 AM on 24 July, 2020

The big news announced yesterday is the narrowing of equilibrium climate sensitivity (ECS) from a combination of paleoclimate and historical measurements and feedback modelling, a study which will feed into IPCC AR6. As I understand it, ECS is now very likely (90% likely) to be within 2.0‐5.7 °C, and likely (66% probability) to be 2.6‐3.9 °C, with a longer tail above 4.5 °C than below 2 °C. Anyone 'gambling' on low sensitivity would lose. Sherwood et al, "An assessment of Earth's climate sensitivity using multiple lines of evidence", Reviews of Geophysics, 2020. http://dx.doi.org/10.1029/2019RG000678

The following long review tells me more than I need to know about feedbacks of all kinds: Heinze et al, "Climate feedbacks in the Earth system and prospects for their evaluation", Earth System Dynamics, 2019. https://doi.org/10.3929/ethz-b-000354206
Although there may be 'black swan' events and earth-system feedbacks, the idea that climate scientists aren't including albedo or cloud changes in models is incorrect.

More recent info on feedbacks in the latest CMIP6 models is in Meehl et al, "Context for interpreting equilibrium climate sensitivity and transient climate response from the CMIP6 Earth system models", Science Advances, 2020. https://doi.org/10.1126/sciadv.aba1981 and Zelinka et al, "Causes of Higher Climate Sensitivity in CMIP6 Models", Geophysical Research Letters, 2020. https://doi.org/10.1029/2019GL085782, the latter including a nice figure S7 showing the contribution of different feedbacks in different models.

Climate sensitivity is low

scaddenp at 12:39 PM on 8 July, 2020

leehoe - do you understand the difference between Equilibrium Climate Sensitivity (often just climate sensitivity) and Transient Climate sensitivity? The box on pg 1110 of the IPCC WG1 has some explanation.

Discussions around estimates of climate sensitivity from the instrument record here especially the Marvel et al paper. And also here for earlier work by Otto, Curry, Lewis

Models are unreliable

Deplore_This at 08:53 AM on 5 July, 2020

@Tom Dayton 1234

Climate sensitivity is absolutely critical to accurately scientifically predict ACC as are the natural causes of CC. Regulatory policy decisions are based on those predictions. But that is a discussion for another article in SkS.

Models are unreliable

Deplore_This at 08:41 AM on 5 July, 2020

@Tom Dayton 1232

BTW I've already been through the climate sensitivity part of SkS.

Models are unreliable

Tom Dayton at 08:36 AM on 5 July, 2020

Deplore_This: Also, you seem to be overweighting the practical importance of the exact value of sensitivity. If you're in a car 200 feet from a rock wall, heading directly toward that wall, it doesn't really matter much if your speed is 50 or 60 miles per hour; the consequences are bad enough in either case that you should be applying the brakes right now. For climate change there is the additional urgency that the problem gets worse as time goes on, so even if sensitivity is on the low end, that merely delays the same bad consequences by an inconsequentially few years. Yet another time urgency comes from the fact that the primary causes (in particular greenhouse gas emissions) and feedbacks (e.g., lower albedo from loss of ice) are impossible to reverse on time scales that will be useful. Ice loss, for example, effectively is permanent on human timescales. Another problem with delaying action is that warming accelerates due to feedbacks, sort of like interest accruing on a loan. The longer you wait to pay, the more money you need to pay.

Models are unreliable

Tom Dayton at 08:04 AM on 5 July, 2020

Deplore_This: It is impossible for you, or anyone else, to evaluate that statement "without relying on someone else's opinion." Because science is a collaborative enterprise. Even, and 100% of, the scientists who create GCMs rely on other people's opinions--critically so. Certainly you can reduce your reliance on someone else's opinion, by learning about climate science. Computer simulated GCMs are only a tiny portion of that climate science. And trying to learn climate science by directly trying to learn computer simulated GCMs is an utterly doomed approach. Several people have given you multiple resources for learning enough climate science for you to start to be able to rely less on other people's opinions. You could stop rejecting those suggestions out of hand.

With regard to the particular claim you mentioned, you could start with the "How sensitive is our climate?" post here on SkS. Read the Basic tabbed pane first, then the Intermediate, then the Advanced. To dig in a bit more, go to RealClimate and type "sensitivity" into the Search box at the top right, then peruse the resulting posts. If you want to jump to cutting edge research on that topic, see the recent RealClimate post about the CMIP6 models.

Models are unreliable

Deplore_This at 07:47 AM on 5 July, 2020

@Tom Dayton 1230

Alright, I’ll simplify this. How to I evaluate the following claim without relying on someone else’s opinion? (I’ve already read the IPCC reports).

“There is growing evidence that climate models are running too hot and that climate sensitivity to carbon dioxide is at the lower end of the range provided by the IPCC. Nevertheless, these lower values of climate sensitivity are not accounted for in IPCC climate model projections of temperature at the end of the 21st century or in estimates of the impact on temperatures of reducing carbon dioxide emissions.”
-— Judith Curry, the former Chair of the School of Earth and Atmospheric Sciences at my alma mater
https://www.thegwpf.org/content/uploads/2017/02/Curry-2017.pdf

Models are unreliable

MA Rodger at 21:24 PM on 4 July, 2020

It is an interesting thought that somebody who uncritically references both a GWPF publication (ie Briefing Paper No 24) that attempts to trivialise the usefulness of climate models (as @1193) and the 2019 Dutch denialist petition to the UN that attempts to reverse the global consensus on AGW (as @1194) would somehow obtain a deep enough understanding of the limitations of GCMs to form a useful judgement on ECS from a rather basic course on the subject, especially given that such a judgement could be gained more simply by other means.

The CLINTEL petiton (CLINTEL is basically an attempt to create a Dutch version of GWPF, the latter having been quite successful in masquerading as an educational charity and finding fertile ground within influential parts of right-wing UK politics) and the GWPF publication both contain the same bold assertion which is fundamental to their denialist argument that GCMs cannot be relied upon.

"The world has warmed at less than half the originally-predicted rate, and at less than half the rate to be expected on the basis of net anthropogenic forcing and radiative imbalance. It tells us that we are far from understanding climate change." CLINTEL petition.

"There is growing evidence that climate models are running too hot and that climatesensitivity to carbon dioxide is at the lower end of the range provided by the IPCC." GWPF Briefing Paper No24.

I would suggest the commenter first considers whether it is correct and proper to present such argument rather than attempting to "get under the hood and see how the models work for myself and to evaluate the predictive sensitivity of these models."

Operations Research (Operational Research my side of the pond) is only narrowly about the mathematics so I am intrigued that somebody with an "extensive background in operations research" (as per described @1162) would consider 'getting under the hood' as the first response to having "read criticism of the validity of the climate temperature models referenced by the IPCC."

Models are unreliable

Eclectic at 17:04 PM on 4 July, 2020

Philippe C , I may have to back-pedal on my skepticism about your Questionable Lady hypothesis. There does indeed seem to be a Curry worship of almost Sub-Continental dimension. Perhaps the good Doctor has a Mrs Hyde facet to her personality?

Deplore_This , your truculence & tone-policing are a red flag. So much so, that your "search for a GCM course" seems merely a pretext for your postings.

Yet if you do have a genuine concern about the value of climate models, then please express those concerns in your own words. Without doing a "cut and paste" from the typically vague and non-substantive rhetoric which is the standard output of Dr Curry.

You seem not to be aware that the GCM's are not the basis of climate science nor are they the basis of expectations of continued global warming & the consequential major problems. The basic physics / paleo climate evidence / and the past 150 years of empirical evidence of climate response to rising atmospheric CO2 . . . all combine to give adequate grounds for policymakers to take urgent action to reduce CO2 emissions.

Climate models can sometimes be used as a test bed for certain sub-components of climate or energy fluxes. And they can (famously) produce a large range of interesting projections. But their pragmatic usefulness for projections, is low for the present & near future.

And that should be very obvious to you, when you take note of the wide range of Equilibrium Climate Sensitivity which is generated by the typical models. In other words, Deplore_This , you will largely be wasting your time if you pursue "a course in GCM's" . You really really do need to study the basic science of climate.

Models are unreliable

Deplore_This at 15:00 PM on 4 July, 2020

@ Eclectic, @Bob Lowlaw, @Philippe Chantreau, The moderator

Your sophomoric comments memorialize your lack of credibility and reflect poorly on all of the proponents of this website and to some extent to the entire climate science profession. Your adolescent giddiness that you can slander me and the moderator will strike my response that challenges your opinion demonstrates that in your little sandbox here you are not practicing science. If Judith Curry was your Professor I’m sure she’d be embarrassed at your unprofessional and juvenile behavior.

From my perspective your behavior here demonstrates that she is right “We've lost a generation of climate dynamicists. These are the people who develop theories and dig into data on the system and really try to find out how the system works. We've ceded all that to climate models, and the climate models are nowhere near good enough. The climate models were designed to test sensitivity to CO2. They don't even do a very good job at that…we've lost a generation of climate dynamists, and that's what worries me greatly.”
web.archive.org/web/20170105183617/www.eenews.net/stories/1060047798

And in the end, you’ve all failed to answer my question so what is your reason for being here.

Good day.

Models are unreliable

Deplore_This at 01:23 AM on 4 July, 2020

@scaddenp 1187

Thank you for your response. To answer your question here this is an example of scientists who disagree with the IPCC’s conclusion on GCMs:

“GCMs are important tools for understanding the climate system. However, there are broad concerns about their reliability:

GCM predictions of the impact of increasing carbon dioxide on climate cannot be rigorously evaluated on timescales of the order of a century.

There has been insufficient exploration of GCM uncertainties.

There are an extremely large number of unconstrained choices in terms of selecting model parameters and parameterisations.

There has been a lack of formal model verification and validation, which is the norm for engineering and regulatory science.

GCMs are evaluated against the same observations used for model tuning.

There are concerns about a fundamental lack of predictability in a complex nonlinear system.

There is growing evidence that climate models are running too hot and that climate sensitivity to carbon dioxide is at the lower end of the range provided by the IPCC. Nevertheless, these lower values of climate sensitivity are not accounted for in IPCC climate model projections of temperature at the end of the 21st century or in estimates of the impact on temperatures of reducing carbon dioxide emissions. The IPCC climate model projections focus on the response of the climate to different scenarios
of emissions. The 21st century climate model projections do not include:

a range of scenarios for volcanic eruptions (the models assume that the volcanic activity will be comparable to the 20th century, which had much lower volcanic activity than the 19th century

a possible scenario of solar cooling, analogous to the solar minimum being predicted by Russian scientists

the possibility that climate sensitivity is a factor of two lower than that simulated by most climate models

realistic simulations of the phasing and amplitude of decadal- to century-scale natural internal variability

The climate modelling community has been focused on the response of the climate to increased human caused emissions, and the policy community accepts (either explicitly or implicitly) the results of the 21st century GCM simulations as actual predictions. Hence we don’t have a good understanding of the relative climate impacts of the above or their potential impacts on the evolution of the 21st century climate.”
-— Judith Curry, the former Chair of the School of Earth and Atmospheric Sciences at my alma mater
https://www.thegwpf.org/content/uploads/2017/02/Curry-2017.pdf

Models are unreliable

Deplore_This at 08:33 AM on 3 July, 2020

@scaddenp 1177

Thank you for your response. I don’t know what an AOGCM computer model looks like under the hood which is why I am looking for a university course on them. I have a minor in math, I took differential equations, I’ve taken Physics in Engineering school, I’ve not only written computer code but in my career I’ve project managed the creation of multi-million dollar IT systems. I wasn’t planning on writing a half million lines of code but I haven’t seen anything yet that would make me believe I would be in over my head working with an AOGCM model. But I haven’t been successful finding a way to actually work with one.

I am somewhat confused by your comment. I would think there would be a plethora of courses on climate modeling otherwise how would all of the climate scientists learn how to construct and evaluate them? We have legions of climate researchers at the EPA, who taught them?

I understand the paleoclimate approach but I am specifically interested in understanding the more sophisticated AOGCMs, specifically their fidelity on climate sensitivity. I’ve gone through the WG1 report and read the results and conclusions. But there are scientists who disagree with their conclusions. To understand the competing arguments I’m trying to educate myself on the models they are using and how they are used. I thought that taking a university course on the subject would be a good approach but not finding one I am stuck. How do the climate researchers at the EPA get the knowledge of which expert and model to believe? What course would they take?

Thank you again for your help.

Models are unreliable

scaddenp at 07:44 AM on 3 July, 2020

Climate models are around 0.5 million line of code created by discipline experts for each of the climate processes. Starting from scratch to write your own is somewhat ambitious. Note that they are not statistically based so I am skeptical that a background in stats or operations research would help you much. The background requirement is numerical solution to systems of partial differential equations. No shortage of courses of these.

I cannot comment on US university or course, but going into serious atmospheric sciences here would be based on undergraduate degree in physics and maths. The numerical solution of systems of partial differential equation is specialist area of mathematics - numerial analysis. Our institute (geology/geophysics) typically has mathematicians, programmers and subject specialists working together on problems of this kind of class.

I still think predicting the base level of future isnt that hard. If surface irradiation increases, then surface gets warmer. The complicated bit is by how much will feedbacks magnify that effect. (Equilibrium Climate Sensitivity) And yes, predictions of future are based are done by AOGCMs. However, there are also paleoclimate constraints on climate sensitivity. Too crude compared to models but good enough to cause serious concern. Again, the WG1 report is good place to find the papers on emperical constraints on climate sensitivitiy.

Models are unreliable

Deplore_This at 05:57 AM on 2 July, 2020

I am an anthropogenic climate change skeptic because I’ve read criticism of the validity of the climate temperature models referenced by the IPCC. I am not a climate researcher by training or profession and to satisfy my scientific curiosity I’ve been trying to find a university course in climate temperature modeling including CO2 sensitivity analysis. From my undergraduate degree I have an extensive background in operations research, mathematics, computer science and basic physics and chemistry courses for Engineers. So I can’t imagine there is any computer modelling that will be beyond my ability.

I’ve looked at the undergraduate and graduate curriculum for the top US environmental science universities and have found only one course on climate modeling. Penn State offered METEO 523 in Spring 2020 and only 6 of 30 seats were filled and the course has been since dropped.

Can anyone suggest a climate modeling course I can pursue? Sorry to ask here but I’ve spent a lot of time searching and have come up short.

Thank you.

Skeptical Science New Research for Week #23, 2020

michael sweet at 05:39 AM on 14 June, 2020

The Guardian newspaper has had a lot of articles about climate change lately.

This article talks about the new model runs for the IPCC AR6 due next year. About 25% of the models have climate sensitivity of 5C compared to teh range of 2-4.5C (3C is commonly used) that has been found for about 40 years. 5C would be much worse change than 3C.

There were not a lot of references to original articles but I found the article to be a reasonable summary for laymen on this topic. (I do not read a lot about climate sensitivity but I have heard about these new models with higher sensitivity.) Apparently changes in cloud modeling (long known to be a weak area) have lead to this increase.

This RealClimate article from November 2019 discusses this issue with more technical detail.

Climate sensitivity is low

RedBaron at 06:52 AM on 14 May, 2020

@381 Deplore This. Everyone has seen this argument. It was a well known published "merchant of doubt" argument full of logic fallicies and false premises designed to mislead people like you... which unfortunately it seems to have worked so far. However, if you are honestly seeking a University level course, I suggest you change your google search terms to "statistical modeling" and /or "statistical modeling of climate change" and you will find a whole lot of universities in the world can help you.

And yes sensitivity is a factor in all of them. In some as a constant and in a few papers there are calls for sensitivity as a variable to fine tune accuracy.

However, the statement, "The theory is based upon modeling climate sensitivity to CO2" is false. Called a false premise logic fallacy.

Actually global warming is based on empirical evidence.

Climate sensitivity is low

Deplore This at 03:36 AM on 14 May, 2020

I am an anthropogenic climate change denier because I have never found any scientific evidence that supports it. The theory is based upon modeling climate sensitivity to CO2 and as you state: “In truth, nobody knows for sure quite how much the temperature will rise”.

We hear regularly from the media that 90+% of scientists believe in anthropogenic climate change but my question is how many scientists are actually trained and practice climate modeling?

Given the lack of curriculum on climate modeling it is apparent that all climate science curriculum is based upon the assumption of anthropogenic climate change without providing any scientific evidence or expertise. This isn’t science, it’s group think. So the opinion of those 90+% so called scientists is based upon blind faith rather than science. This isn’t science it’s a hoax.

I remain interested in finding a quality course in climate modeling.

YouTube's Climate Denial Problem

Eclectic at 23:08 PM on 8 April, 2020

MA Rodger , the marvellous WUWT that you call rogue planetoid, is not a planet nor a planetoid. It is more of a moon or lunar body, orbiting the real universe yet not truly part of it. Yet it draws sustenance from the real universe, just as a tick draws sustenance from its unwilling host. (You can see that I am laboring to get lunar & tick into the same sentence, to describe WUWT . . . but sadly the intended pun is an uphill labor, and I had better retract it, and move on.)

For my sins (and for the pleasure of Schadenfreude ) and for my education in the field of psychopathology I am often reading parts of the comments columns at WUWT. (Of the lead articles there, I would say that 80% of them are not worth reading or maybe just worth a very high-speed skim.) But the comments columns are a goldmine of mental pathology.

Not every commenter there is intellectually and/or morally insane. There are a few notable exceptions ~ pre-eminent is Nick Stokes, who is always worth reading. Nick is a very well-informed scientific thinker who is regularly (and blandly) correcting the the usual errors & inanities of the run-of-the-mill commenters at WUWT. He is balanced and scientifically accurate . . . in short, he is the complete opposite of the typical on-line Denialist. And they hate him for it, and bay for his blood. Most non-denialists are quickly booted out by the website proprietor (Mr Anthony Watts) and his Moderators. Yet Nick Stokes endures, year after year (and AFAICT he is unfailing correct in his observations). I am sure Anthony Watts keeps tolerating Nick Stokes ~ partly as a demonstration of the [cough] civilized & open-minded nature of the WUWT website . . . as a token "contrarian" [i.e. mainstream scientist] . . . and possibly also as a piece of raw meat to keep inflaming the rabid dogs who frequent the WUWT columns (and who keep the website hit-rate high, for the benefit of the routine on-line advertisers).

And yes, just recently WUWT has been serving up quite a bit of Covid-19 headlines ~ that's out of the ordinary for the site, but surely no worse than all other media outlets at present. The usual WUWT articles are sourly scoffing or sneering [e.g. anti-Thunberg] or generally anti-renewables . . . spiced up with the occasional mathematical clangers from Christopher Monckton as he comes up with his bi-annual mathturbational "proofs" that the Equilibrium Climate Sensitivity is only 1.1 degrees or 0.5 degrees or whatever (or that the scientific Consensus was not 97% but actually 33% or 4% or whatever). And sometimes other scientific Mc Experts demonstrate (in completely different & incompatible ways) how the mainstream scientists are all wrong about climate.

WUWT puts up several new headlines each day. It's important to keep the flock supplied with fresh clickbait. And I must admit they occasionally have a brief but interesting article of general interest, including astronomy news. After all, this is a serious science-based website !

It's CFCs

MA Rodger at 02:52 AM on 7 March, 2020

Do note that the paper discussed above Polvani et al (2020) 'Substantial twentieth-century Arctic warming caused by ozone-depleting substances' has been the subject of some corrections. And for the record, I would answer the question of EGS @17 "Would that not be evidence that climate sensitivity to CO2 must be much lower than previously modeled?" with a flat "No!"Given the comment thread since, I'm not sure that any explanation would be helpful.

It's CFCs

EGS at 02:40 AM on 7 March, 2020

This is clearly outdated. Polvani et al. showed that ozone depleting chemicals alone account for 1/3 of all anthropogenic global warming between 1955-2005. The papers I cited above all show that anthropogenic, CH4, N20 O3, and black carbon contribute more than previously thought. I don't understand why these far more potent anthropogenic greenhouse gasses/particles get relegated to relative insignificance, not least since CFC, HFC, SF6, tropospheric O3, N02, and black carbon have unambiguous anthropogenic sources. Increased ppm of C02 is also anthropogenic, but you can't impute the kind of radiative forcing and amplification feedbacks to it and not apply those to these even more potent greenhouse gasses, otherwise there would have been far more warming than we have been able to measure. Something has to give up some radiative forcing in oder to get anything like the warming we have been able to measure. The underappreciation of CFCs and other GHGs is likely why climate models have been running hot. Michael Mann is himself aware that there are problems with the climate forcing theories. He coauthored a paper in Nature Geophysics in 2017 (https://www.nature.com/articles/ngeo2973) that argued that the failure of climate models to align with the measured level of tropospheric warming since 2000 is unlikely to have been caused by natural variability and model error in climate sensitivity but rather in “systematic deficiencies in some of the post-2000 external forcings used in the model simulations.“

It's CFCs

EGS at 01:42 AM on 7 March, 2020

Could ozone depleting chemicals and the other GHGs (with a large revision downward of CO2 radiative forcing and amplification feedbacks?) explain a modestly warming upper troposphere, higher tropopause, and a cooling stratosphere that are among the markers of anthropogenic climate change? Wouldn’t that also align with the strong empirical evidence of very little global warming since the preindustrial era until 1950 that then really accelerated after the 1950s and 1960s as CFCs, HFCs, halons, and SF6 emissions skyrocketed from their industrial use as refrigerants, solvents, propellants, and electrical insulating gasses? The spike in anthropogenic warming from N20 and CH4 could likewise be timed with the massive intensification of agriculture enabled by large-scale application of nitrate fertilizer and changes in land use patterns (deforestation) accompanying the green revolution since the 1970s. This was a time that was also accompanied by dramatically increased diesel tractor and diesel vehicle use, skyrocketing bunker fuel emissions from the expansion of container shipping, and rising heating oil emissions from a switch from coal to oil, which could account for much of the rest of the increase in N20, much of the tropospheric O3, and a large part of the fine particulate emissions increases. The timing of the acceleration of warming would also strongly imply a weaker climate sensitivity to C02 forcing and a greater cumulative forcing of these other greenhouse gasses. It was, after all, in the 1980s and 1990s that global warming really accelerated, not earlier. Would that not also align well with the much stronger warming over the poles (mostly accounted for by CFCs, HFCs, N20, tropospheric O3), strong stratospheric cooling from the depletion of/hole in the polar stratospheric 03 layer, and the much weaker than expected tropical upper tropospheric temperature anomoly and the weaker than expected deep ocean warming?

Skeptical Science New Research for Week #9, 2020

MA Rodger at 20:31 PM on 6 March, 2020

swampfoxh @1,

Your question doesn't 'ring any bells' with me and the authors you mention don't seem to lead anywhere that I can see.

The 1,500 year timescale is occasionally mentioned as the time it takes the ocean waters to re-appear at the surface and so reach CO2-quilibrium with the atmosphere. That is part of what Goreau (1990) 'Balancing Atmospheric Carbon Dioxide' addresses but it is not the same as timescales for temperature equilibrium under otherwise-fixed CO2 levels.

Rohling is the lead author of Rohling et al (2009) 'Antarctic temperature and global sea level closelycoupled over the past five glacial cycles' and this does consider multi-millennial equilibrium timescales but this concerns sea level. There is a connection in that the melt-out of, say, Greenland would both impact sea level and temperature as the albedo change constitutes a slow climate feedback (see this SkS post). But over such multi-millennial timescales with Milankovitch cycles in operation, it would require more than "modest" climate forcings to be significant.

More directly addressing your question, the ice cores do show a small increase in CO2 levels over the last 8,000 years. This would provide roughly a 0.3Wm^-2 climate forcing which (slow and fast feedbacks so perhaps a sensitivity of 6ºC) could have given a total temperature rise of +0.5ºC. Yet spread over eight milennia, any residual effect today would be now miniscule.

CO2 graph 10000 years

It's CFCs

EGS at 12:25 PM on 6 March, 2020

Would that not be evidence that climate sensitivity to CO2 must be much lower than previously modeled? These other GHGs would presumably have the same water vapor amplification feedbacks as CO2 (as non-condensing atmospheric gasses) and produce the expected lower adiabatic lapse rates of warmer water vapor, would they not? Or does water vapor resonate more readily with the discrete wavelengths of infrared radiation emitted by vibrating CO2 molecules? Are those wavebands already saturated so that any additional CO2 emissions can’t add much more radiative heat? In other words, if CO2 is as radiatively powerful as modeled, there should have been dramatically more global warming since the onset of industrialization, especially since the 1950s when these other GHGs really began to be emitted on a very large scale.

It's CFCs

EGS at 06:46 AM on 6 March, 2020

Very recent work led by Lorenzo Polvani and an international team of scientists just published in January 2020 by Nature Climate Change (https://www.nature.com/articles/s41558-019-0677-4)
argues that large amounts of global and arctic warming are actually due to ozone depleting chemicals (CFCs, HFCs, other halons, and nitrous oxide [N20]), no less than 1/2 of all warming in the arctic and no less than 1/3 of all global warming between 1955 and 2005. These ozone depleting chemicals are trace gasses measured in parts per billion but have global warming potentials 100s to many 1000s of times greater than CO2. CFC-11 and CFC-12 are 19,000 and 23,000 times more radiatively efficient than CO2 per molecule. The global warming impact of methane has apparently also been underestimated, with one new study by Hmiel et al. in Nature arguing that anthropogenic CH4 releases have been 25-40% greater then previously thought (https://www.nature.com/articles/s41586-020-1991-8). Another study by Thompson et al. in Nature Climate Change from November 2019 showed that N20 emissions have been rising far more than the IPCC had assumed since 2009 (by an estimated factor of 2.3!) (https://www.nature.com/articles/s41558-019-0613-7). According to the US EPA, the global warming potential of N20 is 265-298 times greater than CO2 over a 100 year timescale (https://www.epa.gov/ghgemissions/understanding-global-warming-potentials). Tropospheric ozone (O3) is both a potent direct greenhouse gas and plays a role in the lifetime and effectiveness of other greenhouse gasses. According to research by Jim Hansen and others published in the Journal of Geophysical Research (2006), tropospheric O3 is estimated to have caused no less than 1/3 to 1/2 of the observed recent trends in arctic warming in the winter and spring, when O3 is easily transported to polar regions from lower latitude urban centers https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2005JD006348. Tropospheric O3’s direct cumulative radiative forcing when combined with fine particulates like black carbon is believed to possibly outweigh that of all the CO2 released since the beginning of the industrial era https://www.pnas.org/content/pnas/early/2010/02/02/0906548107.full.pdf. Sulphur hexaflouride (SF6) is perhaps the most potent anthropogenic greenhouse gas, and its emissions have been rising rapidly from use as an electrical insulator. Its 100 year global warming potential per molecule is estimated at 23,000 times that of C02. Its atmospheric abundance is low at 8.60 parts per trillion volume, but it is rising at a linear rate by 0.33 pptv per year and can persist in the environment for more than 1000 years. https://www.atmos-chem-phys.net/17/883/2017/acp-17-883-2017.pdf

Climate's changed before

scaddenp at 06:41 AM on 26 February, 2020

"Does not show any evidence of direct ...for a direct GHG temperature relationship"

Physics and chemistry predict that temperature will correlate with GHG for milankovich forcings. The data supports that prediction.

Here they are from Epica directly overlain.

And here is a correlation plot, though the GHG forcing instead of CO2 concentration since there is non-linear relationship between CO2 concentration and forcing.

Source:

Shows a pretty good relationship if you ask me - or statistically calculate it. I dont think you are articulating your problem with the graphic well enough.

"The lack of correlation between temperature and GHG in the presence may be due to a lag of the temperature change since the last couple of years."

I suspect English is not your first language, but I cannot parse your meaning here. "a couple of years" is not something discernable on UoC graphic. If you mean present time, (since say 1970), then climate (not weather) is strongly correlated with GHG levels. Even more strongly correlated with total radiative forcing (taking into a account all influences on climate). Note of course that decadal-level variations in temperatures are not driven by GHG. Claiming that science predicts constant, temperature/GHG relationship is a straw-man fallacy.

How deniers maintain the consensus gap

One Planet Only Forever at 02:39 AM on 24 February, 2020

MA Rogers @4, In addition to your comment regarding Crichton, in a speech to a US Congress Committee more than a decade ago he also 'questioned the validity of climate science' by declaring that any science that had a 400% range of results could/should be dismissed as unreliable science.

He was likely referring to the 'warming due to a doubling of CO2 being a range from 1.5C to 6.0C'. But he did not include that awareness and understanding. He just mentioned that there was something in climate science with a 400% range of results. That would only seem to indicate unreliability and would be accepted without question by someone who has little interest in learning about what is actually being discussed, especially someone who has developed beliefs of superiority relative to others that would be compromised, be corrected, by actually improving their understanding of the issue.

That acceptance without question also applies to people who liked claims made regarding the illegally obtained emails of climate scientists. They accepted the claims without question. And they still try to tease out some version of questionable comments made by climate scientists - without ever questioning anything said by the likes of Crichton that they instinctively liked, partly because one of the popular New Age Myths is that your Gut Instinct, First Impression is most likely correct about anything and everything. Investigating and thinking about things, expanding awareness and improving understanding only messes stuff up.

And the range of 1.5C to 6.0C actually indicates a consensus of understanding that increased CO2 will result in global warming. A lack of consensus that increased CO2 would result in global warming would look like a range of -5.0C to +6.0C for a doubling of CO2. Also, the range from 1.5C to 6.0C at the time showed that the science was skeptical about declaring a consensus about that aspect of the science. And the recent refinements of the range of climate sensitivity have provided more evidence of robust science and the direction of development towards a stronger consensus regarding that aspect of the science.

Australia's wildfires: Is this the 'new normal'?

Mark Thomas at 09:26 AM on 20 February, 2020

Nigelj@19, I was thinking along very similar lines. Comparing temperatrure trend over time against deforrestation rates and global warming trend, humidity and rainfall.

Forest Hydrogeology and impacts of deforestation evidence points to big contributions to climatic change, at much more than a localised climate. Articles I have refered so far in this thread have many references within (I can if people want a list). I mean now that I think about this it comes across as common sense. When you visualise Australia, and compare pre-european invasion land cover to the current land cover ... I can see it would drive up temperature, increase arid conditions and reduce moisture. I will further support this idea with references below.

The comparison of an area deforested to forested and moisture and temperature impacts is presented in my first comment (Mark Thomas @3) which shows a regional area in Western Australia before and after measurements. Shows dramatic impact.

Regarding Australia wide...

Available for free online (woohoo!! how all science should be) at AGU100 this paper presents modelling comparions on climate in Australia pre-european and modern day conditions.

'Modeling the impact of historical land cover change on Australia's regional climate' 2007 by C. A. McAlpine J. Syktus R. C. Deo P. J. Lawrence H. A. McGowan I. G. Watterson S. R. Phinn

LINK

The report discusses in detail the modelled variability in temperature and moisture. (I am going to try to link in some figures ... this is my first time writing on a science discussion site, )

The report investigation aim (Introduction) "...The question then is ‐ is Australia's regional climate sensitive to land cover change?....."

..."However, the effect of LCC [Land Cover Change] on the Australian climate has been a secondary consideration for climate change projections, despite the clearing of over 1.2 million km2 or ∼13% of the continent since European settlement.

The regions of greatest LCC are southeast Australia (New South Wales, Victoria and South Australia, cleared 1800‐mid 1900s), southwest Western Australia (1920–1980s), and more recently inland Queensland [Australian Surveying and Land Information Group (AUSLIG), 1990; Barson et al., 2000]. Nair et al. [2007], using satellite observational data, showed that replacement of half the native vegetation by croplands in southwest Western Australia resulted in a decrease of 7 Wm−2 in radiative forcing. They argue that general circulation models tend to underestimate the radiative forcing of LCC by a factor of two."

in section 3.2 discusses pre european and current forest modelling temperature trends 2002/2003 drought.

LINKED Image

"[18] The simulated warmer and drier conditions in eastern Australia are cumulatively impacting on surface and sub‐soil moisture, and likely to be affecting vertical moisture transport processes, changing the partitioning of available water between runoff and evaporation. This has important, largely unrecognized consequences for agricultural production and already stressed land and water resources. Further, the simulated increase in temperatures in the sensitivity experiments, especially in southern Queensland and New South Wales, for the 2002/2003 drought, is consistent with the observed trend of recent droughts being warmer than previous droughts (1982, 1994) with a similar low rainfall [Nicholls, 2006]."

The report concludes

..."[19] The findings of our sensitivity experiment indicate that replacing the native woody vegetation with crops and grazing in southwest Western Australia and eastern Australia has resulted in significant changes in regional climate, with a shift to warmer and drier conditions, especially in southeast Australia, the nation's major agricultural region. The simulated changes in Australia's regional climate suggest that LCC [Land Cover Change] is likely a contributing factor to the observed trends in surface temperature and rainfall at the regional scale. While formal attribution studies are required, the outcomes raise important questions about the impact of LCC on Australia's regional climate, and highlight a strong feedback effect between LCC and the severity of recent droughts impacting on Australia's already stressed natural resources and agriculture."

Now at a global research level for Land Cover Change .....

Research paper in Science Direct, presented in the Global Environmental Change Journal, Volume 43, March 2017, Pages 51-61

LINK

Trees, forests and water: Cool insights for a hot world

".....As illustrated in Fig. 2, solar energy that might otherwise drive transpiration and evaporation remains in the local landscape as heat, raising local temperatures. This can result in dramatic changes across different land-use environments. Heatwave conditions can amplify these effects. Warmer temperatures appear to result in greater temperature differentials between forested and open-field environments, though broad-leaved species may have stronger impacts on cooling than conifers (Renaud and Rebetez, 2009, Zaitchik et al., 2006). Maintaining tree cover can reduce high temperatures and buffer some of the extremes otherwise likely to arise with climate change."

LINKED Image

Fig. 2. Surface temperature distribution in a mixed landscape with forest.

For me, I am seeing that ecology needs to play an equal part of the conversation regarding climate change mitigation as much as CO2. The more I read about land cover changes and their impacts the more I see it needs to be a bigger part. They are not seperable. I note the following conclusion from the above reference 'Trees, forests and water: Cool insights for a hot world'.

... in section 9 "Though the 2015 UNFCCC Paris Agreement has again turned attention to the carbon-related role of forests, the agreement likewise emphasizes that mitigation and adaptation agendas are to be handled in synergy. Much can still be done to improve implementation.

The effects of forests on water and climate at local, regional and continental scales provide a powerful adaptation tool that, if wielded successfully, also has globally-relevant climate change mitigation potential....."

Thankyou Nigelj for encouragement to do comparison trends of climate and land based conditions and potential impacts, I see how important this is to turning the tide of climate change and anthropogenic damage, I have a new project it seems :)

There is no consensus

Eclectic at 15:38 PM on 7 January, 2020

Hmmph. If Dr Curry were an actor, then you would see her in B-grade movies, at best.

Dr Lindzen would be the equivalent of Marlon Brando in his last few years ~ someone who once received some respect from those in the industry . . . but was now "washed up" and coasting along on the remnants of his past reputation. Sic transit.

Dr Happer . . . also the Emeritus Syndrome, plus something a bit uglier.

Let's move on from the Ad Hom sketches, and look at the actual arguments that Curry puts forward as a "contrarian".

Her arguments ~ well, she doesn't have any really. She has asserted that for late 20th Century warming, "up to about 60%" of it might (possibly) be caused by a concurrence of several long-cycle periodic ocean current phases (multi-decadal Atlantic overturning current plus other much longer century/multi-century cycles . . . cycles which most scientists consider to be no more than a twinkle in the eye of their "discoverers"). In other words, a load of balderdash. But a straw which the desperate denialists like to grasp at.

All the while, Curry wears heavily-shaded glasses which are pachyderm-polarised to show very little of the Elephant in the Room i.e. CO2 .

Yes, Curry does admit that CO2 has a mild effect on global warming, but maintains that after you subtract the surface warming effect of those concurrent ocean cycles, the remaining minor warming shows that CO2 is a minimal problem because it must be that the planet's ECS (climate sensitivity) is quite low.

That's about the size of it. The rest of her rhetoric is simply empty rhetoric ~ confusing & vague distractions from the underlying reality. Just what certain American senators/Congressmen wish to hear. So they call her up to speak to "committees" and thus provide themselves with a veneer of excuse to take no action on AGW.

Essentially Curry is a misinformer, through the use of vagueness and innuendo. Like an expensive barrister arguing for a guilty-as-sin client, she usually does not step over the line of absolute mendacity. Not quite.

There is no consensus

scaddenp at 06:46 AM on 16 December, 2019

Just a minor point - anyone saying "they cant get their papers published" - in any field, let alone climate science, - ask them to publish their reviewers comments. I will bet that most wont, largely because I think the "papers" are mythical and simply a rhetorical point, but others would be embarrassing. If they are prepared to do so, then sure, you can read the comments and see whether you think the reviewers have a point.

As to sensitivity, someone who thinks ECS is 1 degree is frankly a denier not a skeptic. This requires the existance of unobserved negative feedbacks and really only "exists" in the statistical evaluation of error not in the physics. Against this is the overwhelming evidence of net positive feedback.
You need speculative processes to drive the ice-age cycles with a sensitivity of 2.0 or less. On the other hand, an ECS of 2.5 or higher fits well with known physics, observations and models. That is where the evidence is pointing. Lukewarmers are generally trying frantically to magnify unquantified uncertainties to support a ideologically or identity based positions. Wishful thinking not evidence-based thinking.

There is no consensus

MA Rodger at 03:14 AM on 16 December, 2019

PatrickSS @856,

You say that there is "an argument between the people who think that doubling CO2 will raise the world temp by about 1C ... and those who think that doubling CO2 will raise the world temp by about 3C ..." Do you consider the folk saying that Equilibrium Climate Sensitivity (from 2 x CO2) is about +1.0ºC to be more than just a few contrarians and that their supporting evidence is well-founded? And if you do consider them to be thus, providing a serious scientific position, perhaps you should name their leading members so their position within the 'consensus' can be properly adjudged along with showing how numerous they are and how well-founded their arguments.

Here Are 3 Climategate Myths That Have Not Aged Well

nigelj at 07:24 AM on 1 December, 2019

nyood @23, I hear you about Wigley but you are not seeing the bigger picture. He has ultimately been proven incorrect by the longer passage of time, so the obvious increasing temperatures since 2014, and the increasing levels of concern coming from the IPCC and most of the climate science community.

You are also again taking a few comments by a couple of scientists utterly out of context, and also assuming this somehow represents thousands of scientists and you just cannot do that. There is no rigour in your 'scepticism'.

Again the emails you list are no big deal as far as I'm concerned. Scientists argue and bicker like anyone, and will obviously not like some junk science being published. Of course they are political in terms of talking about processes and organisational issues, anyone is, and this is a far cry from letting personal party politics intrude.

You have no smoking guns, no fraud or serious errors, no party politics, nothing, so your comments look more and more like paranoia to me.

You say "This is wrong to me, ten years ago we were estimating with a warming of 3°C, now we have come to the lowest threshold of 1,5°C. To me the explanoray power of the IPCC declines towards none."

I assume you are talking about climate sensitivity. You are wrong. The IPCC has not said climate senstivity is at the lower threshold of 1.5 degrees, and you provide no internet link to where they have said that.

All the IPCC have said is climate sensitivity is somewhere between 1.5 degrees and 4.5 degrees. Most published research is around 3 degrees, and the latest modelling also finds this. Papers finding climate sensitivity of 1.5 degrees have not been widely accepted and have flaws. Some relevant material:

skepticalscience.com/climate-sensitivity.htm

www.sciencemag.org/news/2019/04/new-climate-models-predict-warming-surge

"The Soon and Baliunas paper couldn’t have cleared a “legitimate” peer review process anywhere....I do not want such peolpe (Mann) to advise our gouverments, can you understand that?"

You say you don't want people like Mann advising governments, despite the fact he has exposed some real problems with the Soon and Balinaus paper and the peer review process at that point. You make no sense at all. You should be thanking Mann, not criticising him. It's his job to identify problems, as well as do research.

Here Are 3 Climategate Myths That Have Not Aged Well

michael sweet at 00:47 AM on 1 December, 2019

Nyood at 23:"

Most of your post is simply repeating the arguments used when the climate gate emails first came out. These were all shown to be false many years ago. Your posts are just sloganeering old denier points.

You claim additionally

"This is wrong to me, ten years ago we were estimating with a warming of 3°C, now we have come to the lowest threshold of 1,5°C. To me the explanoray power of the IPCC declines towards none."

This claim is simply false and uninformed. The 1.5C threshold in the SR5 report was based solely on analysis of the "pause" data. The past 5 years of data have demonstrated conclusively that that analysis was incorrect. Getting all worked up and angry about false claims does not help to solve any problems. You are reading too many denier web sites who deliberately lie to you.

Currently the world temperature is 1.2C above pre-industrial. We are only at 410 ppm CO2 and doubling is 540 ppm. There is at least 0.5C warming in the pipeline. We are already far over 1.0C heating you suggest for doubling and are nowhere near doubling carbon.

The claim of low sensitivity was never very strong and it has been proven incorrect by the increase in temperature. Very unfortunately, recent modeling studies have found that the best fit is from models with sensitivities over 4.5C. Pray that those studies are incorrect since if they pan out we are already far past any reasonable threshold for disaster.

CO2 lags temperature

Hank11198 at 23:40 PM on 30 November, 2019

Looking at figure 2 the global temperature shows an increase of 3.5C and a CO2 increase of about 1.5. This would indicate a higher climate sensitivity that the 3.0C per the IPCC. Is this just one of the calculations that shows a higher climate sensitivity?

Also the global temperature change is 3.5C while the Antarctic temperature change is 2.0C. Doesn’t temperature change increase as the area included decreases (global vs more local)?

It's the sun

scaddenp at 12:55 PM on 7 November, 2019

socialfox - estimates of climate sensitivity seek to answer what would the change of temperature for a given effective increase in radiation at TOA. Changes in GHG concentration, albedo are back-calculated to an effective change in TOA radiation. ie. As if the incoming solar radiation was changing. The direct contribution to radiative flux from a change in GHG is a known quantity (~4W/m2 for a doubling, which falls out the Radiative Transfer Equations and has been empirically verified in various ways). It is not something deduced from the temperature response, but resultant feedbacks (water vapour, albedo, cloud cover) that contribute to actual change in temperature are not well known and hence the wide range of estimates for climate sensitivity. Climate sensitivity is estimated from a variety of methods including paleoclimate and models.

Note that models do not assume a climate sensitivity - it is an emergent property from the model so I dont see the circularity.

CO2 was higher in the past

nyood at 04:18 AM on 7 November, 2019

@MA Rodger

(1a) "To present a value for CO2 forcing without providing evidential support is not axiomatic,
either in the sense of it being self-evident or (probably in the sense you intend) unquestioningly-evident.
The evidence can be presented should you so wish and, uncontroversially beyond-question, it is correct.

You yourself present @92 an unsupported evaluation of CO2 forcing, providing a maximum value which appears novel and controversial in the extreme.
You fail to present any evidential support which in the circumstance is turning this discussion into a pantomime.
Perhaps you could correct the untenable postion you create for yourself by providing that missing evidence."

(1a) The evidence that i imagine you would provide, will all result in the question: What is missing? This is manifested in the fact that you will get no exact value for CO2 sensitivity, despite known elemental spectral laws regarding infrared absorption. In other words: We are still estimating with 1,5°C - 4,5°C per doubling (?).

The theory that CO2 reaches a "saturation" already, is just the most likely aproach to me. However the forcings of HHE/LPC could be even that strong
that they shrink down all other factors making them neglectable, not "needing" any other explanation to temperature.

The major evidence i can deliver here is the fact that the so called saturation for each GHG is one of the known unkwons and that there are countless debates
on this issue, underlining how unsolved this whole matter is.

"(1b) Your confused statements regarding HHE/LPC appear to contrdict the geographical situation as commonly understood,
in that the "Land mass" Gondwawa sits static over the "Polar Circle" throughtout this period.
You need to consider how it is your LPC appears then disappears within this period when the contition you say causes LPC remains unchanging?"

(1b) I see no contradiction, in my former post i gave you the 2 links with the continental distribution, matching my theory.(Ordovizium, Silur)

I see what you are getting at though wih Schwanck slide 11: The pictures with the "paleo glacial reconstruction". They use a static continental distribution here. It is more likely that the continents were merging towards the hirnation. In a larger perspective the continents definetly move towards the pole, documented by the ordovician with the silurian as a whole. The ice needs to build up and the Boda event interrupted the glaciation process by reducing ice albedo.

"(2) Your cut-&-paste from the Schwark & Bauersachs slides appears particularly inept as support for your assertion "in fact it doubts CO2 as a driver."
If you, for instance, examine Slide 11 you will see your assertion is fundamentally contradicted."

What is contradicted here? Slide 11 shows the Boda event and its CO2 emissions, the CO2 does not matter to me, regarding temperature, the factors that matter are albedo reducing ashes and dust.

If you are refering to this sentence on page 11: "atmospheric emission of large amounts of CO2 and subsequent climate warming, and.."

Then i can only tell you that Schwarck et.al are using the neglectable CO2 sensitivity axiomata here. The reason why the Katian doubts ´CO2 as a driver´ is because it marks, with all other epoches preceeding the LPC event, the time where CO2 fails to work as assumed. Where should it show its significant forcing if not here?

"(3) Here you really do dip into uncomprehensibility. Do note that the Schwark & Bauersachs slides do not ever say CO2
dropped to present atmospheric levels 400-odd million years ago.
The statement you misread from Slide 23 says purely that CO2 varied "between 8-16 x PAL and near PAL."
The value 1500ppm can be taken from their Slide 11."

(3) Well, it does not matter to me, if you want it can be 1500ppm, i would not consider that close to PAL though. PAL would just makes sense to me since the ordovician

is compareable to all other LPC events.

Near Pal makes sense to me because it would reach common glacial CO2 levels. I have not enough knowledge of solubility.

Near Pal is enough for me to support the theory when it comes to: All equilibrium events and the transitions inbetween happen in the same fashion, despite varying CO levels.

"(4) If it is not land at the polar circle that creates your LPC condition; if it is ice-covered land,
you do then reqire to explain the forcing that allows the growth/shrinkage of that ice.
And in doing so, your theory now lacking the tectonic element, do consider that you are now describing a climate feedback not a climate forcing."

The factor that you are missing here is indeed a fundamental one. It is the fact that snow will not accumulate ice sheets on the sea.
The double proof for this is the arctic sea, with Greenland within the polar circle.

In fact with your misunderstanding here it makes me wonder if continental drift as a time dependet factor is included in the prognostications and not only be representd by the, in itself correctly implemented, ice albedo.

In other words:Fundamently excluding a long term factor of warming.

CO2 was higher in the past

nyood at 05:33 AM on 2 November, 2019

According to this recent study we have a way more accurate view on this issue now:

Schwark2019

In the Hirnation Event Summary:

"Massive perturbations of the atmospheric and hydrosphericcarbon cycle occurred with CO2concentration varying between 8-16 x PAL and near PAL over short periods of time." PAL means Present Atmospheric Level.

This is quite remarkable, it tells us that a glaciation is capable to absorb even CO2 ammounts of 6000ppm. It does not matter how high CO2 Levels are, a glaciation will happen when the following event occurs:

Sufficent Landmasses within the Polar Circles (LPC).

Going through all time periods, we can show how decisive landmasses at the polar circles are. Note that the polar circles represent a very narrow area at the north and south borders on these pictures. Greenland todayis a good example as it forms the only northern ice shield, mainly being within the arctic circle, while edging Canada and Russia are not inland iced.

Cambrian warm period, Landmasses in the Polar Circles (LPC): 0%-10%

Cambrian

Ordovician hirnantion glacial event antarctic LPC 100%:

HirnantionEvent

Silurian cold LPC antarctica 90%:

Silur

Devonian warming LPC 10% - 40% :

Devon

Carboniferus glaciation, Continents drop back to the south pole antarctic LPC: 90%-100%

Karbon

Permian Cold with late permian transition towards mesozoic Pangea arctic LPC 80% - 100%:

Perm

Triassic warming, antarctic PLC 10%-20%, arctic PLC 70% to 90%. only Southern PLC decisive? Arctic inland ice forming reversed with the jurassic? Triassic north pole contradicton.

Trias

Jurassic, Landmasses moved away from the arctic cycle. arctic LPC 10%-20%. antarctic LPC 5%-10%.

Jura

Cretateous, sea level rise noticeable, deglaciation at its maximum, transition to upcoming glacial period, Antarctica moving south. Antarctic LPC 80%-100%:

Kreide

Today, Cenozoic glacial period Antarctica resting at the pole once again. Greenland LPC 10% -20%, Antarctica 90%-100% LPC.

With an Ockham attempt i want to make 3 main arguments on why CO2 is not needed and not likely to play any thermal role at all:

1.Faint Sun Paradox,Snowball Earth and the Hot House Equilibrium.

The faint sun paradox is not a paradox. It is another evidence of how strong the terrestial force Ice Albedo is and therefore again the continental distribution.

Even with a 25% lesser sun, Oceans occur,hence the term "paradox".While precambrian snowball effects due to a supercontinent at the south pole, demonstrate the lesser sun effect.

The so called paradox underlines the trumendos forcings of Albedo and it describes the fundamental drive towards a hot house equilibrium whenever the poles are uncovered by land.

This Basic heating Trend that is strong enough to even compensate the faint sun paradox puts CO2 further away from having any thermal influence. This basic heat trend is documented by all the terminations of glacial epoches and even more so in the precambrian, with a barrier where no more heating seems possible.

So we keep in mind that we have a Glacial period during the ordovician to the early silurian, with Co2 levels around up to 6000ppm.

2. Carboniferous CO2 Levels

The carboniferous marks the point where the flora takes an increased influence on CO2 levels.

T°Co2overview

The late devonian till the middle carboniferus show how CO2 is absorbed while temperatur takes ~90 mio years to "follow".The reason temperature goes down is as usual, the continental drift towards the south pole.

What we eventualy see is a double decline in CO2.

The jurassic-cretaceous meeting of CO2 and temperature speaks for itself.

3. Today,GISS and an estimated CO2 sensitivity of 1,5°C

The uncertenty itself on the CO2 sensitivity after 30 years of research tells us per se that the science is not settled. IPCC on a global warming of <ahref=https://www.ipcc.ch/sr15/chapter/chapter-1/>1,5°C

"Past emissions alone are unlikely to raise global-mean temperature to 1.5°C above pre-industrial levels (medium confidence)"

"1.5°C emission pathways are defined as those that, given current knowledge of the climate response, provide a one- in-two to two-in-three chance of warming either remaining below 1.5°C

or returning to 1.5°C by around 2100 following an overshoot."

GISS actualy does show us a trend towards 1°-1,5°C ~2100 a.d. It is the natural interglacial trend. There is no evidence that our warming period is unique in its rate of warming compared to past medieval epoches

or to the past 11 Interglacials in our ice cores

The lowest model called the "russian model"

What is with Planck and Bolltzmann? my guess is Lüdeckepage19
and others are right, the saturation is already reached at PAL with 1°C

Since the Ordovian showed how much CO2 can be absorb in the oceans, acifidication of the ocean due to human emissions might be the bigger threat. Even though most of the CO2 was embeded in limestone, hence the CO2 "starvation".

Welcome to Skeptical Science

Eclectic at 13:18 PM on 7 October, 2019

Carol @67 ,

it would be helpful if you gave some indications of your initial thoughts based on your own general knowledge of modelling. And on what practical benefits might be expected from an examination of Eyring's ideas. [ Like you, I have only read the paper's Abstract and some minimal commentary. ]

Pragmatically, climate models seek to assess climate sensitivity (transient and equilibrium). As you will find elsewhere in SkepticalScience articles, the paleo climate evidence points to an ECS of around 3 degrees for CO2 doubling. And the modern historical evidence (planetary surface temperatures during the past 150 years) shows a rise of nearly 1K for a CO2 rise of "halfway to doubling" ~ which indicates a Transient CS of nearly 2K . . . and presumably an ECS close to 3K , as well.

As Greta Thunberg might say :- We should be putting on our running shoes in dealing with the global warming, regardless of whether the latest cimate models come up with an ECS of 2.5 or 5 degrees. ( The latter figure does seem surprisingly high, and may as critics suggest, derive from inaccurate cloud factors. )

2.5 degrees is quite bad enough !

It's not us

MA Rodger at 22:48 PM on 1 October, 2019

richieb1234 @98,

The basic problem you face trying to simply show a tight correlation between forcing & temperature is the impact of large short-term changes in climate forcing caused by volcanoes superimposed on the slower changes in climate forcing, as shown here in IPCC AR5 Fig 8-18. (The numbers are available in AR5 AII table 1.2.)

IPCC AR5 Fig 8.18

Because of these more dynamic changes, I have found the task involves far more than forcing and sensitivity. Even using a simple Climate Response Function (the timed progression of a warming resulting from a forcing based on the sensitivity - see for instance Hansen et al (2011) who discuss these at some length.) doesn't overcome the problem. You would end up having to set up what is undeniably a model to convert forcing into the resulting global temperature change. (I would add here that in 1910 the climate system was far from in-balance and so 1910 is not a good date to begin such modelling.) And for such a model not to be actually emprirically-based, you would probably end up with a full GCM model whose credibility has, as you say, been criticised by climate denialists.

This is what is being shown in the link @99. But I would ask if you need the modelling to present the message that the climate forcing of recent times forcing is overwhelmingly anthropogenic with the only significant effect from natural forcing being those short-term volcanic forcings. If the forcings are overwhelmingly anthropogenic, it is surely difficult to argue that it is not the same for the warming.

There are genuine climate alarmists, but they're not in the same league as deniers

Postkey at 17:43 PM on 8 September, 2019

” . . . Actually, we show that aerosol-induced cooling is currently only ~0.4°C (see 3rd figure in the CarbonBrief article). Higher aerosol sensitivity would be incompatible with the observed mid-century hiatus. Plus, current warming would be overestimated if transient sensitivity was higher than we report. The neat thing is that the temporal evolution of (warming) anthropogenic greenhouse gases and (cooling) aerosols is not a mirror image. Hence they can both be constrained fairly robustly now.”www.realclimate.org/index.php/archives/2019/06/unforced-variations-vs-forced-responses/#comments

Models are unreliable

NoctambulantJoycean at 07:24 AM on 31 August, 2019

@rupisnark 1151

Christy's offers his usual distortions that he's been giving for decades. His core argument is that climate models exaggerate bulk tropospheric warming, especially in the topics, and this results from climate models over-estimating climate sensitivity (over-estimating CO2-induced warming). His conclusion is wrong, and the discrepancies he points out are primarily not due to model error, but instead primarily due to errors in inputted forcings for the models, along with internal variability and observational uncertainty (ex: Christy showing tropospheric warming estimates contaminated by stratospheric cooling). So the models aren't greatly over-estimating climate sensitivity.

If you want an introduction to this subject, then I recommend reading "A response to the “Data or Dogma?” hearing", "Fact sheet for “Causes of differences between model and satellite tropospheric warming rates”", along with the papers with the following DOI numbers: 10.1175/JCLI-D-16-0333.1 ; 10.1038/NGEO2973 ; 10.1002/2017GL073798

Here is a list of some of the problems:

1) If bulk tropospheric warming was muted relative to surface warming, especially in the tropics, then that would be a sign of a muted negative lapse rate feedback. That would increase climate sensitivity, not decrease it, contrary to what Christy claims. And there's plenty of evidence of a multi-decadal, positive water vapor feedback.
2) If Christy's position was right, then we'd expect to see a strong model vs. observational analyses discrepancy pre-1999. But we don't. We instead see it post-1999, as one would predict if the issues were with errors in inputted forcings over that period, not over-estimated climate sensitivity.
3) The models don't greatly exaggerate temperature responses to volcanic eruptions in the way one would expect if Christy were right about over-estimated climate sensitivity.
4) A number of papers showed that errors in inputted forcings largely explained residual post-1999 differences between surface analyses vs. models; that would also imply a contribution to post-1999 bulk tropospheric discrepancies as well.
5) Christy has a decades-long history of too hastily jumping to model error as an explanation, when the actual explanation was something else. This includes the notorious case in which he claimed models over-estimated satellite-based bulk tropospheric warming, when actually Christy screwed up the sign of the diurnal drift correction for his UAH satellite-based analysis.

There are other problems with Christy's position, but I think that list should be enough to get you started.

IPCC's land report showed we're entering an era of damage control

Evan at 01:07 AM on 30 August, 2019

Thanks for the article John.

We live in an age of large-scale distrust of government and organizations. The IPCC is saying that we can stay below 1.5C if we all sacrifice and do herculean things to modify the way we farm, eat, produce energy, ...

Meanwhile we've hit 415 ppm CO2 (more or less) and CO2 is accelerating upwards (just take a look at your favorite form of the Keeling curve). Using a climate sensitivity of 3C/doubling CO2, 415 ppm CO2 means we have already locked in 1.5C warming, unless we can drop atmospheric CO2 to below 400 ppm. That requires either that the optimistic science reports are all correct (unlikely), or that everyone on Earth pulls together to do the right things and that a lot of the scientific reports are correct (still unlikely).

CO2 is not just increasing, it is accelerating upwards. Do we have a realistic chance of doing any more than stopping the upward acceleration of CO2 by 2030?

Assuming that the responsible people of the Earth respond during the 2020's by sacrificing and doing as much as they can, how will they feel when we blow by 1.5C? Will trust in the IPCC begin to erode along with trust in all other government organizations?

We need to do all of the things these reports say, we need to remake the energy and food system. I get that and agree.

But perhaps we need to motivate people by simply saying that we need to stabilize climate ASAP. That there is no time to waste, because severe effects are upon us and will continue to worsen until we stabilize CO2, without citing specific levels. There is no realistic hope of staying below 1.5C, so telling people we can do that can only lead to distrust and anger when we blow by it.

Medieval Warm Period was warmer

scaddenp at 08:10 AM on 27 August, 2019

yes. Where no temperature measurements exist, then proxies are all you have.

Dont let a denier take you down the path of believing that climate theory depending on paleoclimate studies. Paleoclimate studies are useful testing grounds - if our current understanding of climate cannot reproduce measurements of temperature given the uncertaintites in the temperature measurement and our understanding of the forcings operating at the time, then the theory would be in trouble. Not the case. Paleoclimate is also useful in constraining climate sensitivity. However, uncertainties in estimating solar output, aerosols, albedo and temperature all create significant limits compared to analysing the physics of the climate system today.

Millions of times later, 97 percent climate consensus still faces denial

MA Rodger at 00:40 AM on 20 August, 2019

Doug_C @19,

I rather disagree with your comment or at least feel it sould be better explained.

There are certainly differing qualities of work that comprise denialism. There is a large protion of that denialist work that is incompatable with very basic science. (I'm not sure that your mention of Quantum Mechanics is entirely correct or helpful to your assessment.) There is also a large protion of that denialist work that is incompatable with scientific data and thus contrdicts the resulting inferences that can be established by that data. None of this is a great distance from your comment.

What I don't see is any remaining denialist work that is properly supported by evidence. The entirety of the 3% sitting beyond the 'consensus' is surely incompatable with the scientific data and it is actually not a proper constituent part of the science.

What I particularly feel is a step too far is suggesting that:-

"The few percents of research that show doubt are simply there as part of the uncertainty that is inherent in science, it may as well be stated in terms of a 100% consensus when it comes to evidence driving policy on global warming."

This statement is saying that there exists "uncertainty ... inherent in (the) science" which is exactly the denialist message. The likes of, say, Richard Lindzen or Judith Curry who constitute the 3% outside the 'consensus' will argue that there is enough uncertainty to infer that Climate Sensitivity is low and thus AGW will not be a problem.

Now, we can see that Lindzen with his cloud iris theorising or Curry with her large natural climate wobbles are part of the scientific process. But the doubt they may have sown scientifically is long dispelled. What we are left with is the likes of Lindzen & Curry continuing to spread their now-unscientific message to policymakers as though it was legitimate science. It is unscientific to represent these messages as scientific and their messages ar become part of the "finely tuned stream of disinformation" (although the "tuning" may not be a conscious process on their part).

And masquerading as legitimate science, their message can then be presented as though it had the same scientific standing as the IPCC Assessment Reports rather than a loony fringe opinion, indeed one balanced by those who grossly exaggerate AGW.

I note you use the word "existential" without making plain to what it applies - ie what it is that has its existence threatened by AGW. I would suggest that it is but that loony fringe (that is balanced by the denialist looney fringe) that describes AGW as an existential threat to the human race when AGW is surely only an existential threat to the world economy whose collapse would not be a pretty sight and likely reduce human populations to a fraction of today's total.

Millions of times later, 97 percent climate consensus still faces denial

MA Rodger at 20:27 PM on 18 August, 2019

Postkey @14,

While Monckton continually lays on the bunkum, his grand work Monckton, Soon, Legates, Briggs, Limburg, Jeschke, Whitfield, Henney & Morrison (2018-unpublished) 'On an error in applying feedback theory to climate' surely demonstrates the apex of his incompetence. (I should mention that some of the many co-authors may be unaware of their co-authorship.) According to the write-up on the planet Wattsupia, Monckton's grand work was supposed to set out how:-

1. It can be proven that an elementary error of physics is the sole cause of alarm about global warming – elementary because otherwise non-climatologists might not grasp it.
2. It can be proven that, owing to that elementary error, current official mid-range estimates of equilibrium sensitivity to anthropogenic activity are at least twice what they should be.

Monckton's bunkum certainly goes beyond incompetence, but Monckton's grand work takes it to a new mind-numbingly high level.

Models are unreliable

MA Rodger at 00:39 AM on 14 August, 2019

I had a second, more focused look at Sarkomaa & Ruottu (2019) and find it a worthless piece of work.

Clouded by ♥ a confusing use of English & ♥ not-scientific presentation, these elderly Finnish professors provide an account riven with ♥ unsupported but controversial assertions, ♥ silly mathematical constructs and ♥ mathematical models that entirely fail to capture the workings of climate (let alone AGW).

Such a conclusion does need some further demonstrating.

......

♥I don't think their poor use of English needs demonstrating.

♥The lack of scientific presentation is shown many times. As an instance, they insist (p6) that:-

"If all linear radiation coefficients of clouds are set zero, the SRclimate model of Appendix 4 [and of their design] calculates about 100 W/m2 increase of solar energy flux to the ground and about 13 °C increase of the mean temperature of the ground. This agrees with the generally known fact that when cloud comes in front of the sun temperature decreases. Thus, IPCC’s climate change claim should be based on calculations with negative, instead of the positive cloud feedbacks."

Their "generally known fact" is of course simplistic nonsense and the absence of "general agreement" is all too evident in Zelinka et al (2017), a reference cited by Sarkomaa & Ruottu. Yet this diparity is not addressed by Sarkomaa & Ruottu who instead treat us to mention of a peurile interchange with Finish climatologists (p6).

♥The lack of science extends to a large number of obviously unsupported controversial assertions. An example:-

"Figure 1[*] Figure shows that the mean temperature of the ground has been always varied and it is sure, that the variation is going to continue. During the latest 50 thousand years the mean temperature of the ground has increased about 6 ºC and that the increase is going on. On long term decreasing trend can be noticed which is due to inevitable decrease of nuclear reactions in the sun. The hundreds year trends are due to variation of surface temperature of the sun. These variations have nothing to do with CO2 concentration in the atmosphere."

[* on Page 20. Figure plotting global temperatures of last 2Myr based on Snyder (2016), Zachos et al (2008), Lisiecki & Raymo (2005) and 800kyr of Vostok ice core data scaled at 1:2. These first two references contradict the "nothing to do with CO2" assertion.]

♥The nonsense is aided by the use of silly mathematical calculations presented seemingly for no reason. Their equation 4.16a p52 presents an easily understandable example, it being a formula for an average global temperature for time t=0 to t=a obtained by integration over the surface of a sphere. Quite how anyone would obtain formula to use in such an integration of average temperature of a planet (Sarkomaa & Ruottu describe it as being "entirely impossible") or for what purpose they present the formula is not explained.

♥Perhaps their main conclusion is expressed within their blog commentary of their analysis which translated @1145:-

"It follows from Planck's Law and the equation for spectral radiance that the effect of increasing atmospheric carbon dioxide on global temperatures is asymptotic, not progressive."

Here Planck's Law is what within AGW is usually expressed in climatology as the Stefan-Boltzmann relationship although here its exact application is not entirely clear.
"Spectral radiance" is described as "The basic physical concept of radiative heat transfer" (p66) and the "asymptotic" level (which is found to be 288K, the average global temperature which the modelling is set to) appears to be the equilibrium temperature which, of course, will be arrived-at in a manner "asymptotic, not progressive" (as in their eq 5.1) as the equilibrium temperature is approached. The modelling is then used to demonstrate that there will be no significant increase in surface temperature if there is more CO2 in surface air. The result should actually be zero because the air has not been allowed to increase in temperature (the AGW effect is not driven by surface phenomenon) and so cannot have any extra radiative effect to warm the surface. All that happens is the IR path-length decreases within the CO2 absorption bands at the same rate at which the amount of CO2 emiting this IR increases - thus zero effect.
Sarkomaa & Ruottu actually report that in the absence of other GHGs, the "increase of carbon dioxide concentration has strong influence on the mean temperature of the ground." Their Fig 5 p73 is missing the 0.0005 'multiplier' plot but the other plots would suggest a 'climate sensitivity' of 1.0ºC at 0.0005 but this value for 'sensitivity' looks to be increasing exponentially as the 'multiplier' decreases. So if the 'multiplier' were reduced to zero, climate sensitivity (for a CO2 doubling) would be infinite.
But with the 'multiplier' at 1 and GHGs properly represented in their model, the "increase of carbon dioxide concentration has practically no influence on the mean temperature of the ground." Yet, as stated above, given what they are apparently modelling (which is not climate sensitivity), the answer should be zero.

Models are unreliable

MA Rodger at 06:38 AM on 12 August, 2019

The article linked @1143 runs to ninety-three pages and is the work of a couple of rather old Mechanical Engineering Professors, Pertti Sarkomaa & Seppo Ruotu (whose surname translates as 'Swedish'). Their work in thermodynamics explains their easy use of maths.

At first glance, their modelling does not appear to address the mechanisms of AGW so if they conclude that increased CO2 is not an agent of warming, that would be no surprise. The article is not well presented with presumably some of the problem resulting from language difficulties.

An account of their work more easily understood is presented in a blog on the site that holds the up-load of the article linked @1143. (Its comment thread may be worth examining.) Of course, the blog-page is in Finnish but that is no great barrier in this day & age. The blog runs to 700 words, not an impossible length for an SkS thread. A translation of it runs:-

Professors: The IPCC Climate Hysteria is a religion without logic

Professors Pertti Sarkomaa (Professor of Heat and Flow Technology and Combustion Engineering) and Seppo Ruottu (Professor Emeritus of Technical Thermodynamics) approached the Rural Media and sent their thoughts on the IPCC report, the IPCC Climate Hysteria. In their view, the IPCC's climate change projections are based on completely erroneous calculations.

IPCC calculations are based on climate models

The calculations in the IPCC monitoring reports are based on climate models that use heuristic parameters such as radiation constraint, cloud feedback, and climate sensitivity that have no physical equivalent or objectively correct value and are not known, required, or permitted by the exact laws of flow and thermal dynamics. The use of said heuristic quantities in climate models is in itself a fatal mistake and indicates that their users do not understand flow and thermal dynamics.

The meteorological scientific community recognizes that, despite decades of research, there is no certainty about the hallmark of cloud feedback. Every common sense person understands that even if the sign of a key parameter of a mathematical model is unknown, the results produced by the model are incorrect. Because cloud feedback is a heuristic that has no physical equivalent, there is no objectively correct value that can be determined. The decades-long study of Cloud Feedback is the most incomprehensible blunder in modern science.

Positive cloud feedback values have been used in the calculations accepted by the IPCC so that a staggering increase in carbon dioxide concentration from 300 ppm to 600 ppm, which would not actually occur, would increase the global mean global equilibrium temperature generated by the calculations by 2-5 ℃. Meteorologists call this change in temperature sensitive to climate sensitivity.

With positive cloud returns from calculations approved by the IPCC, the sensitivity of the climate is two to five times the warming of the lower atmosphere caused by the actual increase in atmospheric carbon dioxide from 280 ppm to the present 410 ppm. So climate sensitivity depends entirely on the cloud response you choose.

It follows from Planck's Law and the equation for spectral radiance that the effect of increasing atmospheric carbon dioxide on global temperatures is asymptotic, not progressive. If the atmospheric carbon dioxide concentration were to increase by the next 130 ppm, the effect of the increase on global average temperatures would be smaller than the increase that had already occurred. The climate sensitivity of the IPCC calculations is completely unrealistic.

Clouds are known to reduce the average solar energy flux on the Earth's surface by about 100 W / m2, so negative calculations should have been used instead of positives in calculations approved by the IPCC. Thus, the IPCC's climate change projections are based on completely erroneous calculations. When the effect of carbon dioxide on global average temperatures is calculated in accordance with the laws of flow and thermal dynamics, the effect is found to be insignificant.

We have provided our calculations to leading Finnish meteorological experts and asked them to prove their potential errors. No errors have been addressed. Nonetheless, the meteorologists who have committed themselves to the IPCC claim are categorically dogmatic, ”say Finnish professors Pertti Sarkomaa and Seppo Ruottu.

Carbon dioxide has no effect on global warming

The climate has changed during the Earth's existence and in the future. It is affected by a plurality of randomly variable quantities with their mutual random interconnections.

According to our research, the effect of atmospheric carbon dioxide on surface and ground-level temperature is insignificant, even if the atmospheric carbon dioxide content doubles compared to the present one. The change would be only a few hundredths of a degree Celsius.

According to our understanding, e.g. The IPCC climate models that underlie the Paris Climate Convention and the climate projections and key measures to "save the world" derived from them are both erroneous and illogical.

The efforts of the IPCC to minimize carbon in the natural cycle and the atmosphere and to switch from fossil fuels to electricity and mechanical energy generation to biofuels will lead to a reduction in energy and food production and biodiversity. Long-term adherence to the IPCC's aspirations and recommendations will lead to mankind's disaster as fossil fuels run out over the next 100 years.

Therefore, the remaining fossil fuels should be used in such a way that, when depleted, the Earth's carbon cycle, which sustains life in the world, produces the greatest amount of biodiversity-compatible biomass.

In Lappeenranta 03.08.2019, Best regards. Pertti Sarkomaa Seppo Ruottu - Professori, TKT.

Models are unreliable

Postkey at 18:25 PM on 7 August, 2019

The 'models' have been 'improved'?

“… Incredibly, at least eight of the latest models produced by leading research centres in the United States, the United Kingdom, Canada and France are showing climate sensitivity of 5°C or warmer.
When these results were first released at a climate modelling workshop in March this year, a flurry of panicked emails from my IPCC colleagues flooded my inbox."

www.themonthly.com.au/issue/2019/august/1566136800/jo-lle-gergis/terrible-truth-climate-change

Models are unreliable

scaddenp at 07:19 AM on 31 July, 2019

Strange comment. Models predict that climate is changing fast so I dont see how rapid change makes them wrong. However, no climate modellers is claiming that models are 100% accurate. Not even close. They have no skill at decadal level prediction but do at climate (30 year average) level. Climate sensitivity estimates are still too wide for comfort (2-4.5), however, they remain the best tools we have for predicting further climate.

How could global warming accelerate if CO2 is 'logarithmic'?

scaddenp at 08:31 AM on 30 July, 2019

richieb1234 - while the Stephan-Boltzmann law gives you relation between radiative power to 4 power of temperate (so the doubling CO2 would raise temp by 1.1C), it is less useful than you might think for estimating actual surface temperature. You cannot raise (or lower) temperature without other feedbacks coming in. These operate on very wide timescales from very fast (water vapour increase), through decadal scale of albedo change from less ice, to century/millenia feedbacks in carbon cycle. Add in the complexity of cloud feedbacks (both +ve and -ve), and you get the wide range of estimates on climate sensitivity.

The human fingerprint in the daily cycle

scaddenp at 07:13 AM on 19 July, 2019

Schmidt is merely building on a long line of other papers and the paper is effectively a "quick a dirty" for the purposes of informing public discussion. From abstract:

"Much of the interest in these values is however due to an implicit
assumption that these contributions are directly relevant for the question of climate sensitivity."

ie. it doesnt have a lot of relevance to the practise of climate science. Actual model codes are integrate over all gases and all absorbtion bands simultaneously. They reproduce observations of the radiation spectra with exquisite accuracy. Climate depends on how the system plays as a whole and the individual contributions of the gases in any particular atmospheric composition is of little practical interest.

Climate sensitivity is low

Eclectic at 10:41 AM on 14 July, 2019

Penguin, the response to the JK&PM paper is huge laughter.

A paper based on limited observations ( over just 25 years ) and giving a "calculated" climate CO2 sensitivity of 0.24 degreesC (transient sensitivity) . . . is laughable.

Also amusing, is the paper title. JK&PM themselves did no experiment !

Climate sensitivity is low

michael sweet at 09:32 AM on 14 July, 2019

Penguin,

In hte paper you cite they claim that climate sensitivity is derived completely from cliamte models. That is false. there are several ways to derive climate sensitivity from data includig paleoclimate data. I note they provide no citations to support their claims. They will only be read by skeptics.

They assume that the change in cloud cover forces the change in temperature. That is completely backwards. Cloud cover is a response to the change i temperature and not the casue of the change. In order to chage the temperature you have to add energy. Changes in clouds do not add energy.

Where to find big ideas for addressing climate change

RedBaron at 11:13 AM on 9 July, 2019

@1 bjchip,

Yes, Savory has a big idea with even more potential than the other "Big Ideas" mentioned in this article. It is also included in a more limited way as part of project drawdown as well. So there is that as well.

In my opinion there is no solution to AGW that doesn't include this at least in part, because it is the only current technology both scale-able enough and also fiscally sound that humans have available in their tool kit at the moment.

Otherwise the evidence suggests even 100% elimination of fossil fuels won't be enough and the legacy carbon will continue to heat the surface for decades at minimum and maybe even 100's of years. We have about .5c thermal inertia of the oceans: climate inertia; and we also have 1.5c loss of albedo from melting ice as a feed back:
Hansen and Sato Estimate Climate Sensitivity from Earth's History, and likely another 1c from various other reinforcing feedbacks like methane releases from melting permafrost and vegetative die off of areas due to climate zones moving faster than biomes can adjust.

So somewhere around 1.5-3.0 c additional warming if emissions went to zero today.

The only technology capable of reversing this is in fact what Savory proposed, and is indeed beginning to do on 10's of millions of acreas already through his worldwide network he set up.

THE GLOBAL SAVORY NETWORK

Is there a case against human caused global warming in the peer-reviewed literature? Part 1

michael sweet at 07:13 AM on 9 July, 2019

Ritchieb1234,

Answering your query from here, I do not read a lot about very old temperatures. Searching online I found most of the skeptic blogs had coments on your paper but no real science blogs talked about it. I thought I had read a review of it but it must have been a comment somewhere.

The abstract states that Davis performed a correlation study of CO2 and temperature over the past 450 million years. He does not mention any other forcings that he considered.

Only skeptics think that CO2 is the only factor that affects climate. 450 million years ago the sun was much weaker than it is today. You must consider that in your analysis which Davis apparently neglected to do. In addition, volcanic activity was higher 450 million years ago, since there was more radioactivity in the Earth, and that must also be consdered. Other forcings like dust and albeido affect temperature and must be considered in a real analysis.

Since Davis neglected to consider all the known forcings in addition to the CO2 forcings his results have little meaning. I note that he confirms that high CO2 time periods coincide with mass extinctions. How could that happen? If you search you can find a paper by real scientists who consider all the forcings and show that past temperatures are predicted by current science.

If you waste time readig skeptic bogs you will never be able to understand AGW.

Re recent skeptic publications: Every year more skeptics give up. The quality of skeptic papers like Davis's are very low and real scientists do not read them. A few fossil fuel companies pay people like Davis to publish their stuff. Nic Lewis pushes very low climate sensitivity. Recent record temperatures show that Lewis is wrong but he persists.

Realclimate occasionally posts on skeptic papers if you read their old stuff. Tamino also comments on stuff posted on skeptic blogs.

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