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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recent Comments

Comments 13151 to 13200:

nigelj at 08:57 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

Evan @8, good points. There are indeed several benefits to changing to renewable electricity and direct air capture really has just one in that it removes CO2. However I would just suggest theres still a perception issue with both.

I think its more of a timing issue. By the time people wake up fully to the more immediate threats from extreme weather and that climate change is here with a vengeance, at that point (but not before) they may start to see the need for projects like direct air capture in addition to reducing emissions at source. I mean by then we may be in a siutation of just having to do everything possible pretty quickly.

And playing devils advocate, people might actually be more receptive to negative emissions projects because it means they dont have to make as many painful adjustments to their own lives.

However this is not how I want things to happen. Its just the odd way that people probably react. The way I see it is ideally the focus should be on renewable energy, and negative emissions technologies should ideally be a last resort just to mop up remaining emissions that we simply struggle to reduce. I think the case for this has been made plenty of times.

Evan at 08:18 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

nigelj@7 There are immediate benefits to switching from fossil fuels to renewable energy, such as low running costs, business planning that is possible when you don't have to be concerned about volatile energy prices, and for countries like China, reduced demands on an already overtaxed water supply (i.e., wind and solar don't need cooling water like fossil-fueled power plants do). There are many immediate and tangible reasons to switch to renewable energy, and corporations that are used to planning 30 years into the future readily choose renewables for these reasons.

But even though renewables can be cheaper in the long run for individuals, people are slow to adopt solar, geothermal, and superior insulation because of the high upfront cost. It is hard work to convince someone to pay more upfront even though it will benefit them 10 years down the road. What benefit is there for removing CO2 from the atmosphere? The benefits are decades in the future, and they are not as tangible as the savings from a geothermal system will be. I am skeptical that we will ever convince a majority of people that to support CO2 removal, because it is not in their best interest: it is only in the best interest of their children and grand-children, provided they trust the scientists who telling them that.

What we're finding with the recent hurricanes, wildfires, drought, etc. is that we will have an increasingly difficult time paying the bills for the warming to which we've already committed ourselves (in the US it seems we just borrow more money to pay for the damages). I'm not sure how we're going to convince people to pay to remove CO2.

nigelj at 07:55 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

Evan @6, just to clarify I think our primary emphasis should be on reducing use of fossil fuels and converting to renewable electricity generation because we know how to do this and I think it looks affordable. I see direct air capture as something that might be useful in the future, and it appears more feasible and affordable than I previously realised, but its no magic answer because its still quite high cost (if you read the link I posted) and commonsense suggests we would need millions of these instillations and it wont be easy.

I mean I think the most likely pathway forwrds is going to require a combination of reductions of burning fossil fuels and negative emissions technologies like BECCS and direct air capture. This is afterall the conclusion the IPCC has reached.

Now to your points. You say of direct air capture: "That is, we will be asked to pay year after year to remove CO2 from the environment with little or no perceived benefit." Well yes, but I think you could make the exact same criticism of simply reducing use of fossil fuels couldn't you? I think the challenge is really to convince the public that both have benefits even if results are not as obvious as we would like.

The challenge we face is certainly partly technical. Nobody would say reducing emissions and / or sucking them out of the atmosphere is easy. I would simply argue its not as difficult or economically disruptive as the pessimists claim, at least in theory.

The problem is indeed that the public might not percieve much benefit. The problem is about convincing people and motivating people and the sort of global cooperation required. The issue has become politically tribal, there is psychological denial of the problem (which is understandable) and so on.

I do suspect that once change gains some momentum, and becomes accepted, it will also be taken for granted even if results are not immediately obvious. Its a tipping point sort of thing.

Evan at 06:01 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

nigelj@5 The problem with any CO2-removal technology is that you first need to demonstrate the horrible future you are avoiding to motivate people to pay for something that has no immediate payback. That is, we will be asked to pay year after year to remove CO2 from the environment with little or no perceived benefit. The only benefit is the knowledge that we avoid a future worse than we will have. But that relies on trusting the scientists and their models. All of this is an academic exercise. If the air is foul, people are getting sick and they can't see 100' down the street, then we can motivate paying to clean up the air with pollution-control equipment. But how do you demonstrate to the average voter that they should pay year after year to avoid a future that is only predicted in computer models and that they are not now experiencing?

We have to first experience the future we are trying to avoid.

I am sure you and others will shoot holes in this analysis, but that is how I learn.

wilddouglascounty at 05:52 AM on 20 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

I think you are right: the scientific community is pretty good about saying that increasing extreme weather event frequency and severity is attributable to changes in the earth's atmospheric and oceanic chemistry. But most of the public does not read scientific journals. Instead they read things like the following:

"How climate change causes extreme weather" http://theweek.com/articles/797032/how-climate-change-causes-extreme-weather

"Climate change causes severe storms that damage our homes, crops, and cost more than hundreds of millions in insurance claims." in https://www.ontario.ca/page/why-we-need-address-climate-change

"Climate Change Causes Extreme Weather Like Smoking Causes Cancer, Scientist Says" in https://www.globalcitizen.org/en/content/climate-change-linked-to-heatwaves-fires/

"Where’s the proof climate change causes the polar vortex?" in https://thehill.com/opinion/energy-environment/368355-wheres-the-proof-climate-change-causes-the-polar-vortex

...and on and on and on.

In the public forums that we are all part of, it benefits moving the discussion ahead if we keep bringing up the true causes of the changing climate, reminding folks that it's not some abstraction called "climate change," rather it is human emissions that are overwhelming our planet's ability to maintain a homeostatic balance. That's all I'm advocating for, because we need to quickly shift gears to looking at ways to change those emissions.

nigelj at 05:46 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

Evan @4, I agree totally, and I should have mentioned renewable energy costs. The only reason I focussed on direct air capture is Climate Adam mentioned it, and I seldom have time to cover all issues.

Wind power is now the lowest cost option in many countries and solar is close, (Lazard does a really good analysis) so its just insanely ridiculous to claim that changing to these sources would be a major economic disaster. I also dont buy that it is even economically disruptive. Nobody is suggesting it would be done in just one year but the longer things are delayed, then yes the more challenging it will become.

jenikhollan at 05:18 AM on 20 October 2018

There’s one key takeaway from last week’s IPCC report

A link to the assembled whole Report, in its Oct 8 version:

http://amper.ped.muni.cz/gw/ipcc_cz/SR1.5_K_2018-10-08.pdf

hope it helps, Jenik

nigelj at 05:15 AM on 20 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty,

Your concern appears to be that the media say "climate change is causing more extreme weather". I have heard them say this, and superficially this is illogical because some people might see climate change as changing weather patterns, so obviously changing weather patterns are not causing changing weather patterns. But climate change is actually technically a change in the heat balance of the atmosphere longer term. I think most people more or less understand this, or at least interpret the issue as "global warming" is causing more extreme weather patterns, so I dont think theres likely to be huge confusion out there that you think there might be.

But I think you are right that more specific explanations are needed on just what it is that is causing the more extreme weather.

Evan at 05:12 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

nigelj@1 The problem with the "it's not too expensive" argument is that renewable energy is not only "not too expensive", but in many cases (maybe most cases) it is cheaper than alternative, fossil-fuel energy. Yet we continue to meet tough resistance to adoption of technologies that are not only good for the environment, but good for the average person. Sucking CO2 out of the air, whatever the cost, will not happen easily.

MA Rodger at 03:41 AM on 20 October 2018

CO2 increase is natural, not human-caused

chromedome49 @24,

The 45% isn't written in stone. Using the MLO data for atmospheric CO2 and the emissions estimates from Global Carbon Project, the 45% value has remained pretty much the multi-decadal value since 1990. Over the period 1960-90, the Airborne Fraction had been slowly increasing from an early value of 35%.

There are a lot of waggles along the way. Over the period since 1959, annual Airborne Fractions have varied from 20% all the way up to 80%. The El Nino is one big factor in these waggles, as are big tropical volcanoes. Taking multi-year averages, the percentage is still a bit waggly. After the rise to 1990, there was a short sharp dip caused by the eruption of Pinatubo in the early 1990s, a rise into the 2000s due to the high incidence of El Ninos then a dip into the 2010s due to all the La Ninas.

Where the Airborne Fraction goes in coming years? If we begin to reduce the acceleration of our emissions, it should start to drop, and drop quicker if our emissions begin to fall. Mind, all the waggles will prevent a clear sight of any such a drop for some time.

chromedome49 at 02:17 AM on 20 October 2018

CO2 increase is natural, not human-caused

MY question is this: Since the total annual amount of CO2 has increased on an annual basis, the amount of CO2 from Earth keeps going up as well. I've seen reports that say "our" Co2 is absorbed to the rate of about 55%. That is consistently evey year. If, as some assume, all of earth's CO2 is absorbed, in ever larger amounts, how come our 45% is always left over?

One Planet Only Forever at 00:27 AM on 20 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty,

I have seen statements like "... climate change resulting in ..."

Of course saying climate change results in something is not the same as saying climate change causes something.

ELIofVA at 00:24 AM on 20 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

The emphasis on 1.5C or 2.0C above preindustrial levels of CO2 is very abstract to most people. Even among scientist, there is much debate about what level of emissions achieves these goals and what the damage will be. I encourage the Climate Change movement look at the net zero carbon emissions economy referenced in the Paris Climate Accord. This is simpler to understand. Since we are already above the CO2 concentration level that causes amplifying affects (melting ice cap, reduce reflection of light converting to heat in dark ocean ,increased methane from melting tundra, increased humidity in the air, et). a simpler concept to understand is that if concentrations are going up, that is bad. Net zero provides a measurable milestone when CO2 stops going up. We know exactly how much above net zero emissions in the average of air samples over a year compared with the same for previous years. Reducing our emissions to the amount that can be sequestered achieves net zero. Because the CO2 concentration will be much higher when and if we achieve net zero, the video noted we need to withdraw carbon from the air. The only way to draw down CO2 in the air is to reduce emissions to less that what can be sequestered. It is not emissions that are the problem. It is emissions in excess of what can be sequestered. Sources of sequestration can include yet to be invented technical withdrawl. However, it does not have to. Most of our human caused emissions are in the carbon cycle. I develop the concept of a Net Sequestration Economy in this blog, netsequestrationeconomy.wordpress.com and YouTube Video . If the world averaged the emission of Costa Rica, a country with health care and social safety net that rates high on happiness indexes, we would be removing 5 gigatons CO2 (over 2ppm)/year. This is without break through geo engineering scheme. When our culture at large understands the demand by nature to limit emisisons to less than what can be sequestered, we will have a chance. Until we do, the steps to achieve it will not be supported. Please nurture this understanding so we can solve the problem.

One Planet Only Forever at 00:21 AM on 20 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty,

I am not sure I have ever encountered science reports, or even reliable media source reports, that say "climate changes causes (anything)" (I do not follow "Other News Media" which, by its less professional nature, may poorly present many things).

I will pay more attention for that type of statement.

Can you point to locations in the recent IPCC report where that type of statement is made?

One Planet Only Forever at 00:14 AM on 20 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty,

Got it now. Thanks for the clarification.

It is ioncorrecrt to say "climate change "causes" increasingly severe and frequent extreme weather events". Anyone who has presneted a point like that should be advised to say "human induced climate change due to global warming caused by burning fossil fuels is seen in many ways including increasingly severe and frequent extreme weather events"

Postkey at 21:05 PM on 19 October 2018

There’s one key takeaway from last week’s IPCC report

Is this 'a key takeaway' from last week’s IPCC report?

“B4.1. There is high confidence that the probability of a sea-ice-free Arctic Ocean during summer is substantially lower at global warming of 1.5°C when compared to 2°C. With 1.5°C of global warming, one sea ice-free Arctic summer is projected per century. This likelihood is increased to at least one per decade with 2°C global warming. . . . ”

http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdf

Buzzy at 13:55 PM on 19 October 2018

Ivar Giaever - Nobel Winning Physicist and Climate Pseudoscientist

Ivar Giaever also said that climate scientists come up with a hypothesis to suit their biases then set about proving it.

However, he knows full well that all science starts with a hypothesis but scientists then must try to disprove their own hypothesis. That's how science works!

wilddouglascounty at 12:46 PM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

One Planet 12

I am merely pointing out that saying that climate change "causes" increasingly severe and frequent extreme weather events is a confusing statement because it is the increasingly number of more severe extreme events that changes the climate. It is the elevated carbon fraction in oceanic and atmospheric composition that "causes" increasingly severe and frequent extreme weather events, not the change in the statistical averages of those weather events, otherwise known as the climate. You don't need to use the steroids in sports example if you don't like it; there are plenty of other apt attributions of carbon as the reason for the changing weather patterns instead of confusing people by saying that "climate change" caused it. Come up with your own.

One Planet Only Forever at 07:07 AM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty,

I believe it is less helpful to try to get someone to relate to climate science in the same way that they relate to sports, rather thna simply telling them the basics of climate science.

I also doubt that the change of term would actually change many minds. The reasons people are choosing to disbelieve and dismiss climate science has little to do with 'difficulty relating to the language'.

As I presented, climate science is pretty simple to understand. It is just hard for some people to 'accept the required corrections of the ways they are living'. And changing the words would not make it 'easier to accept that required correction'.

MA Rodger at 05:42 AM on 19 October 2018

Venus doesn't have a runaway greenhouse effect

Eclectic @262,

I'm not sure whether you want (1) an appraisal of the various Nikolov & Zeller papers or (2) an appraisal of Nikolov & Zeller. (Note we move further off-topic.)

On the first point, the V&R/N&Z (2014) Moon temperature doesn't seem controversial. Their Mars temperature has been involved in criticism from David Grinspoon but I would ask that if the Mars temperature results of Nikolov & Zeller (2015)(withdrawn) are in error, I would be interested to see the results that demonstrate that error.

Of coure, their grand theory of a pressure-driven global temperature is so much cods-wallop. Yet published cods-wallop is not unknown and can at times be a useful exercise. Note Grinspoon's comment here:-

Rather than aiming to be a universal paradigm-buster, Grinspoon said the study is better served as a handy mathematical approximation. “It’s a kind of clever, back-of-the-envelope way to calculate planet temperatures,” Grinspoon said. Should scientists find themselves with limited exoplanet data, something like the Volokin and ReLlez model could be a simple way to approximate distant temperatures.

On the second point, the record shows that up to 2006 the pair have a history of publication but not in climatology. They turned climate skeptics in about 2010 and their first attempts at overturning AGW were dreadful enough to give them a reputation of swivel-eyed lunatics, apparently preventing publication of later work. The the pseudonyms were an attempt to overcome this rejection. It worked. Their 2014 paper has not been withdrawn. Their 2015 was published bu then withdrawn. Today they have a publisher who will publish any old crap of a denialist persuasion (described with others here), thus facilitating the publication of the dubious Nikolov & Zeller (2017).

nigelj at 05:38 AM on 19 October 2018

1.5 Degree Climate Limit: Small Number; Huge Consequences

Thank's Mr Adam. Imho the report on 1.5 degrees is good science with a welcome sense of urgency. Finally The IPCC are spelling out harsh realities in strong language. Took a while to get there.

The danger is that people will start to think we face an impossible task, and countries may be tempted to say its "every man for himself" and retreat into Nationalism just when the appropriate respose is Internationalism and promotion of more altruistic values. I mean the timing of Trumps "presidency" and Brexit could not be more unfortunate. But what is the point of existance if we dont look beyond ourselves to other people and countries in a helpful spirit of altruism? Ultimately everyone benefits from this, if only people could see this.

In fact negative emissions technology including direct air capture may not be as expensive as people think, according to this article. However I'm not suggesting this in any way means we can go on burning fossil fuels, it just shows that climate mitigation is not as cost prohibitive as some people like to claim.

One other thing. IPCC projections state that if we continue to burn fossil fuels its possible that warming could exceed 10 degrees celsius above early industrial baselines by the year 2300. This gets forgotten in the focus on the year 2100, and I appreciate the science community doesn't focus so much on the longer term because of the risk it will create a feeling that we have plenty of time to solve the problem. We don't! But warming of over 10 degrees would be catastrophic, and simply cannot be allowed to happen. Fossil fuel burning simply has to stop, and the sooner it is phased down the easier it will be.

nigelj at 05:02 AM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

It wouldn't matter what Trump says on climate change, and how contradictory or absurd it is, his followers will follow. People love authoritarian blowhards, bullies, and anti intellectuals and as long as the economy seems ok everything must be fine in la la land.

Trump's approval rating is back up to 44% which shows what Americans really value.

nigelj at 04:48 AM on 19 October 2018

There’s one key takeaway from last week’s IPCC report

Art Vandelay @24, yes the polar cell would help keep aerosols near the arctic, although I recall reading somewhere that the boundaries of the cell have started to shift south due to the warming effect basically weakening the cell, sort of similar to the meandeing jet stream. So its complicated.

But anyway yes cost might be the main limiting factor. I suppose automated aircraft are a possibility. The other problem is politics. Countries like Russia see mining opportunities in an ice free Arctic, so would probably not be supportive of the idea. Not that one country should be allowed to dominate proceedings.

wilddouglascounty at 02:34 AM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

One Planet @ 9,

The reason for the clarification is so that the average "Joe" understands the role that steroids play in sports, and knows that the enhanced "performance" from even a little increase is illegal for good reason. Furthermore, it is confusing to attribute a baseball player's enhanced performance to "batting average change," which is exactly what we are doing when we attribute increased freqency and severity of extreme weather events to "climate change." We need to start referring to the sources of those changes, just like we do with steroids, so the public understands the connection, and once they do, we can move ahead. If new langage helps, it should be used. If you can do it with existing langauge, that's fine, too.

One Planet Only Forever at 01:33 AM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

wilddouglascounty@7,

The debate is very powerfully fueled by desires to personally benefit from the understandably unsustainable and harmful burning of fossil fuels.

The CO2 impacts are the most significant recently understood harmful consequence of the burning (an understanding that was pretty solid in the late 1970s). Many other harmful conequences have been identified, with some of them sort of mitigated by government regulation.

The developed socioeconomic-political systems have developed unsustainable perceptions of superiority of some people relative to others. And those undeserving Winners have proven that they will not willingly have their developed perceptions corrected. And the developed socioecoinomic-political systems have actually allowed them to powerfully resist being corrected.

Changing terms is unlikely to change 'willingness to understand'. The term climate change is not difficult to understand in the context of a simple understanding of the science. This site has many levels of presentation of the fundamentals. It is simple enough that I can make my own presentation as follows:

CO2 is a very important trace element in the atmosphere. Without it, the surface of the planet would be significantly cooler.
CO2 is increasing dramatically due to fossil fuel burning and other human activities. There is no other plausible explanation for the increased CO2.
Increased CO2 leads to more solar energy staying in the planet's system. The global average surface tempreature has been rising in response. The planet's climate system is complex and the global average surface temperature has its ups and downs, but the trend is clear.
Increased energy in any system will change the system. So climate change is what is happening because of increased energy in the planet's climate system due to human impacts affecting the system.

That concluding statement is the same as 'juicing the climate'. And anyone fully familiar with the above string of connected points would get a reference to carbon-juicing.

But using that term is unlikely to change the mind of anyone who has developed a personal preference for ways of personally benefiting and enjoying their life that they have to understand are unacceptable, and need to be given up, if they choose to better understand the climate science.

Also, if the scientific community started using that term there would be claims that they are just making up new names. People have already claimed that climate science 'changed' the term it used even though the science has always been about improved understanding regarding 'the connection between increased CO2, global warming and climate change'.

John S at 00:52 AM on 19 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

In a recent BBC news panel discussion wih denier Myron Ebell (Competitive Enterprise Institute) the host effectively silenced Ebelll a couple of times by saying something like "now lets stop there; again, you're saying you know more than the scientists ... but you don't .. because they're the scientists, so lets move on from that .."

wilddouglascounty at 23:20 PM on 18 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

I believe that the whole debate has been obscured by terminology, specifically looking at the changing weather patterns and referring to it as climate change--hear me out a bit. Scientists have a good understanding of the causes that drive the changing weather patterns and increasing severity/frequency of extreme weather events, but when they summarize that dynamic as being “caused” by “climate change,” it confuses many, many people. We need to look at it more like baseball. That's because “climate” is an abstraction, i.e. the averages of actual weather events over time. “Climate” is very analogous to the “batting average” of a baseball player, which is an abstraction created by averaging the numbers of hits and misses the player performs over the baseball season, right? But if the player’s batting average jumps 50 points, from say .250 one season to .300 the next season, we start looking for the reasons. If blood tests show that the player has started using steroids this season, we say that the player’s batting average jump was “caused” by his using steroids because of what we know about the physiological effects of steroids on the human body. It’s not that he doesn’t possess a wide range of skills that got him to the major league in the first place; it just means that those skills were enhanced through the presence of steroids. When he steps up to bat and hits another home run, we say that the home run was “juiced” or likely assisted by his use of steroids. What we DON’T say is that the home run was “caused” by the increase in his batting average.

But that’s exactly what the media and the scientific community has latched onto saying about the increasing frequency and severity of weather events. In baseball, enhanced performance is clearly understood to be an outcome of steroid use, and not referred to as “batting average change,” which sounds nonsensical and confusing. The scientific community clearly understands the physical role of carbon in the atmosphere and oceans and with great confidence can say that the resulting changed atmospheric and oceanic chemistry is what is driving the more extreme weather events, oceanic acidification and sea level rise. Excess carbon in these system and the resultant changes is “juicing” the atmosphere in the same way that steroids can juice the baseball player’s performance, and if we start saying that Hurricane Michael and Hurricane Florence were carbon-juiced weather events or some such terminology, the public will “get it” and will be more likely to move past the climate change debate and get down to what we’re going to do to get the carbon back into the earth so our weather patterns, sea levels and acidification will gradually return to levels we can live with.

Eclectic at 23:12 PM on 18 October 2018

Venus doesn't have a runaway greenhouse effect

Correction to last paragraph :-

N&Z/V&R

Eclectic at 23:09 PM on 18 October 2018

Venus doesn't have a runaway greenhouse effect

MAR@261 , my concern with Zeller / Rellez and his partner Nikolov / Volokin was more to do with the accuracy of the data they provide.

Since the retraction of their 2015 paper (a jocular scandal, at minimum) and pointed criticisms from Gavin Schmidt, as well as by David Grinspoon [re some fudging of Mars temperature and pressure data], it casts even more of a shadow on their 2014 paper ~ which in one sense was a re-run of the unphysical ideas of Gerlich & Tscheuschner.

I am not sure how much of the N&Z/V&Z business was an elaborate leg-pull. Or perhaps they have simply "gone emeritus" and become denialist.

MA Rodger at 20:49 PM on 18 October 2018

Venus doesn't have a runaway greenhouse effect

Eclectric @260,

My personal position is that I do not recall reading Nikolov & Zeller before. There are certainly within it some worrying constructions within their model, that is worrying for a science faced by deluded AGW contrarians. (It may be diferent if you are researching exoplanetry climate.) Particularly worrying is the idea of the density of an atmosphere being a (or indeed 'the') contributing factor to the greenhouse effect. There is also the acceptance of the 37% result from Volokin & ReLiez which I consider to be badly wrong. (That is the idea that all airless rocky planets, if without an atmosphere like our Moon would have an average surface temperture 37% less-than a temperature calculated globally using the S-B equation j=σT^4.)

But Nikolov & Zeller do present good accounts of the literature of lunar and Martian temperatues and also calculate a Martian temperature in a reasonable manner, something I've not seen elsewhere.

Volokin & ReLiez I do remember as I did some simplistic calculations to unpack their 37%. I can repeat these with more confidence since Williams et al (2017). What I don't recall is their use of the Diviner Lunar Radiometer Experiment data (as used by Williams et al) to check their Moon calculations. That is a useful calculation.

-----

Setting out the simplistic calcs that show the 37% value is misused for the Earth (& Mars as well):-

The 37% does occur on the Moon. Thus using S-B to calculate the lunar average temperature yields 270K, an over-estimation of some 70K. Only a small portion of this 70K is due to the zonal temperature range (hot tropics, cold poles), perhaps 5K of the 70K. The rest is due to the diurnal range. The Moon with a 708 hour 'day' has a very large diurnal range. Averaged across all zones, the range is 90K to 360K. It is this diurnal range that drops the remaining 65K below the S-B estimate. An Earth stripped of its atmosphere with a 24 hour day will have a smaller diurnal range (perhaps 40% of the lunar range). This is the point where Volokin & ReLiez "briefly explore" the issue. They examining the heat storeage of the planet surface thro the night, feeding conclusions back into their simplified modelling and find hardily any difference (0.3K) due to the 24 hour day. Somewhere they have forgotten Hölder’s Inequality (errors due to averaging a non-linear function) from which that 65K derives. The Moon's temperature between any single 29½ hour period (those used by Williams et al) varies up to a maximum of 114K while the Moon over the full 708 hours varies 267K, thus the 114/267=40%. If the Earth's 24 hour 'day' waggles temperature by only 40% of the Moon's 708 hour 'day', the Hölder’s Inequality shrinks massively, back-of-fag-packet perhaps from 65K to 10K.

Now, magically, add on the zonal 5K and subtract the 15.7K non-greenhouse zonal-heat-transfer effect (this value from Volokin & ReLiez) and the Earth non-GHG temperature returns to the S-B estimated value. This then magically returns us to a 255K non-GHG Earth and thus the 33K GH-effect we all know & love.

Art Vandelay at 13:56 PM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

nigelj@23,

From what I've read there would need to be annual injections during the northern spring, but injecting into the lower stratosphere or tropopause would still be an effective solution, because over the poles the stratosphere falls to roughly half the average height of the tropical stratosphere, and aerosols would be mostly washed out by polar cells during northern fall & winter. Similarly, much of the soot and pollution coming out of tropical developing nations ends up on the ice caps.

My guess is that getting the aerosols up there at a reasonable cost would be the hard part.

nigelj at 13:17 PM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

Nigelj, Art Vandelay @18 just to clarify, my understanding is sulphate aerosols from coal fired power stations tend to be regional in their effects, because they affect the lower atmosphere, but they are short lived because they get washed out pretty quickly. According to the link I posted, to provide a powerful effect that lasts years sulphates would have to be injected right up in the stratosphere and this means they tend to disperse globally with all sorts of global effects and problems. So to confine an effect to the arctic would require injection of aerosols into the troposphere, but they would have to be replenished constantly, and possibly permanently.

nigelj at 11:52 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

Art Vandelay @18, yeah I do recall reading that sulphate aerosols tend to be regional in their effects. The following research is interesting and highlights some of the problems with the whole strategy. I mean I do see a certain inevitability that technical fixes like may be used, and could buy time, but I prefer not to tak about it too much, because it takes the focus off doing the number one priority which is to reduce emissions.

Yes population is on track to head towards about 10 billion before stabilising. If the world adopted more procative policies it could be lower.

But my point was that meat eating is a very inefficient use of land, and if we all changed to a vegetarian diet, or even just a low meat diet then there would probably be enough land to sustain a larger population without needing massive levels of deforestation. In an ideal world of course. However the case for adopting a vegetarian or low meat diet is becoming quite strong in terms of more efficient use of land, the methane problem, and also general health and longevity. So the population / food problem could I think be largely solved by more efficient use of land with a more vegetarian diet, so your argument that "CO2 is plantfood" is not a justifiable solution to this particular problem.

I agree however that 10 billion looks like it is pushing the worlds carrying capacity to the limits such that any problem will spread and become critical. I think thats a really interesting observation. There will be no slack in the system. You see it already in the way the global financial crash became "global".

Its also painfully obvious that we are already using resources at a prodigious rate, and this will leave a depleted stockpile for future generations that cannot be fully resolved by recycling. Population growth will make this so much worse, and reduced population growth is a relatively pain free solution.

The climate implications of population growth are interesting. Most of the population growth is in the third world like Africa, and they have the lowest per capita use of fossil fuels, something likely to continue, so population growth is not quite as large a climate problem as it first seems.

nigelj at 11:30 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

Jef @17

"Having said that it is obvious that we can not eleminate or even reduce FFs in the economy and not expect extreme economic repercussions."

I would question this. I suppose it depends on how you define extreme economic repercussions. This wording has rather a negative connotation. There will be a dislocation but I would challenge the contention that such repercussions have to be extremely negative.

For example various reports have found most countries can completely transition from fossil fuel to renewable electricity generation at a cost of 1% of a countries yearly gdp output, spread over approximately 25 years. The maths is actually pretty simple. For comparison purposes most western countries spend considerably more on just the old age pension each year, so I cannot see that such an energy transition could really be cause extreme economic repercussions and certainly not significantly negative ones. Yes theres more to it than electricity generation, but this puts it into perspective.

Another example. Transitioning to a low meat diet would achieve a lot, and yes it would be a dislocation for farmers and consumers, but I don't think you could accurately call it some extreme economic problem, and its not as if crop farmers don't make plenty of money. In fact converting farms from one product to another often happens rather quickly as food preferences and market opportunities change. Its more of a motivational problem.

Moderator Response:

[PS] Jef is so far just make vague and unjustified assertions. Unless he can show the basis for his belief and quantify expected economic loss for transition, this is little more than FF propoganda regurgitated. Further sloganeering from him without evidence will be deleted.

nigelj at 11:17 AM on 18 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

John Hartz @4, thanks and interesting, but if "the free market" was going to solve the climate problem, it would have done so by now, or at least have had a discernable effect, but pretty much all the evidence I have seen is that any climate progress of any significance has come from government subsidies, cap and trade schemes, regulations, taxes, and the like.

I think the problem is the profit motive and vested interests in fossil fuels are just too strong, leading to pollution, and the whole trajedy of the commons problem. No doubt some corporations do act responsibly on their own initiative, without having to be pushed by the state, but they are clearly in a minority.

I think the "eco rights" dogma about a true level playing field goes along the lines of "if all government influence was removed from the economy, we would have some economic paradise" like the Ayn Rand school of thought. I don't believe it for a second, and never have, and historical examples of laissez faire capitalism or something close to it do not support the contention that laissez faire is an optimal system. Having said that, I think government interventions should be sparing, and evidence based and time limited.

Art Vandelay at 11:17 AM on 18 October 2018

Republican lawmakers react to the IPCC report – ‘we have scientists’ too!

Interestingly, just published today was a report on falling CO2 emissions.

www.usnews.com/news/national-news/articles/2018-10-17/greenhouse-gas-emissions-fall-almost-3-percent-in-2017

Noting that the recent emissions reductions are to a great extent linked to the price of gas relative to coal, but moving forward as renewables become increasingly price competitive it will be natural market forces that drives emissions reductions in the energy sector, so the administration's views on climate change will become increasingly less important.

Art Vandelay at 10:31 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

Micheal Sweet@ 19,

No, not just a feeling. I defer to higher authorities and published studies such as: rsta.royalsocietypublishing.org/content/366/1882/4007

Injecting aerosols at high latitudes gives best bang for buck and limits side effects eslewhere, because they're flushed more radiply naturally from the atmosphere. Bear in mind that sulphate or similar aerosol injections could be restricted to northern summer months.

Ftr, I'm not advcocating geoengineering but it's my personal belief that it will eventually become a component of climate change mitigation strategy.

michael sweet at 10:06 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

Art Vandelay,

Adding sufate aerosols to the atmosphere is well known to cause severe drought. Reducing sunlight reduces evaporation from the ocean. This is observed after vocalnic eruptions. Do we really want to cause world wide drought?

I doubt that any significant effect can be kept over the poles. Can you provide a citation to support your claim this is possible or is it just a feeling that you have?

Art Vandelay at 09:27 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

nijelj@14, I think it might be possible to geoengineer with atmospheric aerosols at high latitudes , reducing polar amplification, without significant climate impacts at lower latitudes. Sure there are risks but at some point the risk of not doing something will become even greater, so I think it's inevitable.

Global population is expected to rise by 30% before levelling off, and that itself will necessitate further extensive land clearing which will release lots more carbon stores from the biosphere above and beyond per capita fossil fuel emissions, so it's unlikely that emisisons growth will be constrained until population growth is very close to zero.

Changing to a vegan diet may help to reduce methane emissions though more likely is the development of livestock feeds that achieve similar, because global consumption of beef is still accelerating, due mostly to increasing demand in the developing world.

Life will indeed be interesting post 2050 with a global population of >10 billion. That's pretty much the earth's carrying capacity, so every significant natural disaster, which includes droughts, floods, fires, storms, earthquakes etc will have an immediate global impact.

I think we're in for some radical societal changes too, and that probably includes the end of the laissez faire economic model.

jef12506 at 09:25 AM on 18 October 2018

There’s one key takeaway from last week’s IPCC report

I know that this comment is way late to get any viewing but I respectfully submit it in response to moderators of my comments.

If you read my comment you understand that FFs are the global economy. There is no aspect of the global economy that is not completely dependent on FFs at some level and the largest % of the global economy is FF related. Having said that it is obvious that we can not eleminate or even reduce FFs in the economy and not expect extreme economic repercussions.

The number 1 problem with AGW/climate change understanding and effective response is the willful ignorance of this simple fact.

Its like focusing on the cancer cells of lung cancer and completely misunderstanding the part that cigaretts plays in that dynamics. A weak analogy I admit but please try and understand.

This can be extrapolated out to just about every aspect of earths biospheres degredation. The global economy, the thing that supposably we need to increase in order to keep people from suffering and dying is 100% reliant on FFs, mining, deforestation, industrial ag, global distribution, etc. Please stop perpetuating the lie that we can keep doing all these things but in a "green" way.

Moderator Response:

[JH] You are now skating on the thin ice of excessive repetition which is prohibited by the SkS Comments Policy. Please read the Comments Policy and adhere to it.

[PS] Again, I pointed you to peer-reviewed research pointing to exactly how renewables can replace FF. In contrast you have simply repeated your assertion without any supporting evidence. This is a science-based site - if you want to make an argument you need to back it with evidence.

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