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Postkey at 17:47 PM on 8 September 2019There are genuine climate alarmists, but they're not in the same league as deniers
An alternative scenario?
'However, new research published in Science by Hebrew University of Jerusalem Professor Daniel Rosenfeld shows that the degree to which aerosols cool the earth has been grossly underestimated, necessitating a recalculation of climate change models to more accurately predict the pace of global warming.
And, they discovered that aerosols' cooling effect is nearly twice higher than previously thought.
However, if this is true then how come the earth is getting warmer, not cooler? For all of the global attention on climate warming, aerosol pollution rates from vehicles, agriculture and power plants is still very high. For Rosenfeld, this discrepancy might point to an ever deeper and more troubling reality. "If the aerosols indeed cause a greater cooling effect than previously estimated, then the warming effect of the greenhouse gases has also been larger than we thought, enabling greenhouse gas emissions to overcome the cooling effect of aerosols and points to a greater amount of global warming than we previously thought," he shared.' -
Postkey at 17:43 PM on 8 September 2019There are genuine climate alarmists, but they're not in the same league as deniers
” . . . 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
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sailrick at 16:46 PM on 8 September 2019There are genuine climate alarmists, but they're not in the same league as deniers
Here is the rest of what McPherson said in his comment
"This Catch-22 of abrupt climate change, termed the McPherson Paradox by Bill R. Eddy, takes us down the wrong path regardless of the direction of industrial activity, assuming we are interested in maintaining habitat for vertebrates and mammals on Earth. A decline in the aerosol masking effect means loss of habitat for human animals, with human extinction soon to follow. Yet the liars at Deep Green Resistance, Extinction Rebellion, and other organizations are still promoting the dismantling of industrial civilization while claiming to be committed to the continuation of life on Earth." -
sailrick at 16:42 PM on 8 September 2019There are genuine climate alarmists, but they're not in the same league as deniers
I was recently reading comments at a Facebook post, where McPherson's was cited. His claim is that by reducing fossill fuels emissions, the resulting decrease of sulfur aerosols will cause worse warming.
McPherson himself posted a comment. Here is an excerpt
"Civilization is a heat engine, but slowing or stopping civilization heats Earth even faster than the ongoing warming resulting from this set of living arrangements. The impact of the aerosol masking effect has been greatly underestimated, as pointed out in an 8 February 2019 article in Science. As indicated by the lead author of this paper on 25 January 2019: “Global efforts to improve air quality by developing cleaner fuels and burning less coal could end up harming our planet by reducing the number of aerosols in the atmosphere, and by doing so, diminishing aerosols’ cooling ability to offset global warming.” The cooling effect is “nearly twice what scientists previously thought.” That this February 2019 paper cites the conclusion by Levy et al. (2013) indicating as little as 35% reduction in industrial activity drives a 1 C global-average rise in temperature suggests that as little as a 20% reduction in industrial activity is sufficient to warm the planet 1 C within a few days or weeks."
Could someone comment on his claim about aerosols? -
swampfoxh at 15:53 PM on 8 September 2019SkS Analogy 20 - The Tides of Earth
Evan...agreed. It was a sloppy estimate not really intended to say much except to point to the possibility that the Sixth is going to take "awhile" to become a global catastrophe regarding species extinction. And to William...yes, Bill Ruddiman is a "neighbor" of mine here in Virginia. I know his work well and consider it of great value in the literature. I thought that some dialog on predicting the GGE trends might be interesting in the Big Picture of the Big Five.
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One Planet Only Forever at 13:50 PM on 8 September 20192019 SkS Weekly Climate Change & Global Warming News Roundup #36
It is obviously too easy to promote popular support for harmful and incorrect beliefs and actions in supposedly more advanced nations.
Improving awareness and understanding applied in pursuit of the Ethical Objectives of 'Do No Harm' and 'Help Others, particularly those who are less fortunate, less aware or lacking in understanding' is a major thing that humanity potentially has 'going for it'.
However, improving awareness and understanding can be a threat when a group, such as these 400, improve their awareness and understanding of how they can abuse the flaws in the developed socioeconomic-political systems to interfere with, and potentially set-back, the development of a sustainable improvable future for humanity.
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wili at 09:07 AM on 8 September 2019Skeptical Science New Research for Week #35, 2019
From top quoted article: "...rational cost–benefit analyses..."
wtf??
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Human 2932847 at 21:13 PM on 7 September 2019The North Atlantic ocean current, which warms northern Europe, may be slowing
No I agree, there's some controversy there. I would call it disagreement, which has different social connotations, but you could use controversy too.
So, would it be fair to say that we've moved on from the simplistic idea of the Gulf Stream alone keeping Europe warm - which I believed until reading Seager's debunk - and air currents have a larger role to play, whether as much as Seager says or not ?Because the picture I'm getting here is that a Gulf Stream slow down or stop would not be as catastrophic as once thought, but still problematic.
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william5331 at 18:07 PM on 7 September 2019SkS Analogy 20 - The Tides of Earth
There is a very believable theory that the highly unusual stability of our present interglacial, up to recently, was due to our output of Greenhouse gasses from the use of the plow, forest clearing and Rice cultivation. Previous interglacials have begun to slide back into a glacial period almost as soon as the interglacial begins. See the book Plows Plagues and Petroleum by Ruddiman.
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Eclectic at 14:09 PM on 7 September 2019CO2 is plant food
Wowzee , you are being an alarmist about "dangerously low CO2 levels".
Without the recent human intervention, it would still have taken millions of years for CO2 to have fallen to a level dangerous to the "C3 metabolism" types of plants (which are so important for our food production).
And taken even longer to be dangerous to the "C4 metabolism" plants [maizes , grasses , etcetera] . . . assuming that they did not make further evolutionary adaptation to low CO2.
As for the very distant future (as atmospheric CO2 gets gradually absorbed into rock-carbonate form) . . . then sure, the humans of that time will know the lessons of the distant past [= 20th Century AD] and will know that all they need do is dig up and burn a few gigatons of coal/oil every 100,000 years or so.
Makes sense for us to stop burning coal/oil . . . and leave it in the ground in case our ultra-distant descendants should ever need it as an easy way to raise CO2 and warm the climate ! That's the sensible and responsible thing for us to do at present.
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wowzeewuwu at 13:33 PM on 7 September 2019CO2 is plant food
During the Carboniferous period the level of CO2 in the atmosphere was three times that of 1750, and double that of 2019. The Carboniferous period had lush forests, and a great deal of the coal, methane, and crude oil that was trapped in the Earth came from that period. Plants seem to thrive in high CO2 concentrations.
It can be projected that had humans not come along and extracted and burned fossil fuels, CO2 levels would in the future go so low for this critical plant nutrient that plants would be unable to grow. In the long-term, I believe humans' greatest contribution to life on Earth is our re-introduction of CO2 into the atmosphere.
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Eclectic at 13:26 PM on 7 September 2019Water vapor is the most powerful greenhouse gas
Wowzee , if you are talking about the "GreenHouse" Effect keeping the Earth's surface warmer than freezing point . . . then certainly the effective strength of H2O's GHEffect is larger than CO2's GHEffect. This has been known for a very long time. Yes, a very long time.
It may be best if you stop thinking in terms of H2O being the "dominant" GHE gas. It is not. Or rather, in using dominant , you make a misleading & poor choice of words — if you are trying to mean that it is H2O which dominates or controls the situation.
A horse is far stronger / heavier / more powerful than its human rider. But it is the lightweight rider that dominates/controls what the horse does.
So too, the CO2 controls the climate (along with control by changes in solar output & levels of reflective aerosols, of course).
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wowzeewuwu at 12:33 PM on 7 September 2019Water vapor is the most powerful greenhouse gas
Water vapor absorbs more solar energy than CO2 per molecule. There are many more molecules of H2O in the atmosphere than CO2. If the amount of absorbed solar energy exceeds the amount of thermal infrared energy that escapes into space, temperatures will rise.
Burning one molecule of methane produces one molecule of CO2 and two molecules of H2O. Similar chemical product ratios for burning gasoline, coal, and deisel.
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wowzeewuwu at 12:24 PM on 7 September 2019Water vapor is the most powerful greenhouse gas
https://earthobservatory.nasa.gov/features/EnergyBalance/page7.php
Please see the graph from the NASA graph, both H2O and CO2 absorb in the infrared (12 - 14 micrometer) range. The water vapor window is only slightly affected. Also keep in mind that the concentration of CO2 in the atmosphere is only a fraction of H2O.
This is why water vapor is the dominant greenhouse gas.
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wowzeewuwu at 12:12 PM on 7 September 2019Water vapor is the most powerful greenhouse gas
Water vapor is the dominant greenhouse gas, not CO2. The reasons include 1.) water absorbs infrared light much better and across a broader spectrum than CO2 which prevent the Earth from cooling off and 2.) the density (i.e. percentage) of water vapor in the atmosphere is much greater than CO2. Physics says that the higher the density a chemical in a medium the higher percentage of light it will absorb.
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Evan at 04:59 AM on 7 September 2019SkS Analogy 20 - The Tides of Earth
swampfoxh @3 and 4. My only caution would be that you are using linear logic. That is, you are dividing 120,000 by 43 to estimate how long the 6th mass extinction will take. I would expect that extinction-level processes are highly non-linear. I would also expect that proceeding 43 times faster than a "well-understood" event means that it will likely happen much, much faster than 120,000/43 years. I am not an expert in this area, so I will stop here and hope that an expert will chime in.
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swampfoxh at 04:10 AM on 7 September 2019SkS Analogy 20 - The Tides of Earth
Of course, we made a number of assumptions about how long it took for Earth to proceed from general "goldilocks" conditions to the climate hell of the End Permian, selected 120,000 years, then applied the current rate of GGEs and fudged to get our Sixth Extinction to mature to a 90/97% die off by the year 4880.
How far off are we???
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swampfoxh at 03:57 AM on 7 September 2019SkS Analogy 20 - The Tides of Earth
Thanks for bringing up Milankovitch Cycles. We talk about this in my climate class: Climate Change: Impact of an Outlaw Species. I'll just throw in the calculations we did to compare the current Sixth Extinction with the end Permian along with the effects of the M-cycles. Our best guess was that the Sixth is motoring along some 43 times faster than the End Permian. Anyone out there have a better number?
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MA Rodger at 20:18 PM on 6 September 2019It's cosmic rays
unknownwallet @111,
(I should point out that you do not address the bogus cosmic ray theory which is the actual subject of this comment thread.)
You say "i'd really to ask someone to prove me wrong" so let's kick off with your statement number one (which is also illustrated top left in the collection of graphics in your third URL).
By volume, the percentage of water vapour in the atmosphere is 0.4% (and roughly half that by weight), thus much lower than the 2% value you present. In a dry atmopshere, today's CO2 levels top 400ppm(v) or 0.04% (0.06% by weight). Again this is greatly different to your value of (0.02 x 0.0362 =) 0.072%.
Today's CO2 levels are (1 - 280/400 =) 30% anthropogenic thus 0.012% of the total atmosphere by volume (0.018% by weight) where as you say 3.4% of CO2 is due to human activity and thus 0.0025% of the atmosphere.
(I should also mention the graphic below top left on your third URL which gives different values again 1% for all GHGs, of which 4% CO2, of which 4% is anthropogenic.)
The raw volumes/weights of GHGs in the atmosphere is not in a very good gauge of their impact on the climate. Water vapour, for instance, is only present at the levels we see because the long-lived GHGs (which are predominantly CO2) It is long-lived GHGs that raise global temperatures and it is only this increased temperature that to allow the atmosphere to hold such levels of water vapour. And despite there being ten-times-more water vapour (by volume) than CO2 in today's atmosphere, its contribution in boosting the GH-effect is far less than 10x (even when cloud is factored in).
The one value you provide that is entirely a mystery but also fundamental to your argument is the percent of CO2 - "only 3.4% of CO2 is due to human activity." Where does that 3.4% value come from?
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unknownwallet at 15:53 PM on 6 September 2019It's cosmic rays
i respectfully disagree.
1. Only 2% of the atmosphere is greenhouse gases, only 3.62% of that is CO2 and only 3.4% of CO2 is due to human activity
2. CO2 lags temperature changes by 800 years
3. Sea levels have already been rising for the past 8000 years
4. Climate change model's predictions have all been overestimates
5. There has been no global warming for 18 years
6. There has been no increase in the frequency of storms since 1954
7. There has been no increase in the frequency or severity of droughts in the US
8. Warming in the past (before human history) has been far more drastic in the past indicating that current warming is not human causedcheck these infographics to understand more,
#https://anonfile.com/N28bb553n0/1561633804542_gif
#https://anonfile.com/P88eb85dnb/1561631378053_png
#https://anonfile.com/Rc83b055n2/1561629956134_png
i'd really to ask someone to prove me wrong.
human made global warming isn't a huge deal, and there are bigger threats than this.
Moderator Response:[DB] Pretty much every point you make is disproven on other threads here. Use the Search function to find a more appropriate thread. After you read them and the comment threads attached, if you still have concerns, place those concerns there, not here.
Please stay on-topic.
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One Planet Only Forever at 13:11 PM on 6 September 2019Consensus on consensus hits half a million downloads
markpitsusa@1,
In addition to the points made by nigelj in the comment @2, I have replied to your related recent comment on the SkS OP "The true cost of fossil fuels (Response to the Climate Myth "Renewables are too expensive" (a comment that also referred to Nordhaus). My comment there is regarding the ethical considerations that the likes of Nordhaus seem to not consider, or not be aware of.Improving awareness and understanding of climate science is an essential part of the required ethical actions. The book "A Perfect Moral Storm: Climate Change, Intergenerational Ethics and the Problem of Moral Corruption.", by Stephen M. Gardener, provides a comprehensive explanation/evaluation of the ethical issues related to climate science, including providing reasons why improving awareness and understanding of climate science is challenged (some people have developed powerful motivations to not want to improve their awareness and understanding, and have developed powerful motivations to not want others to improve their awareness and understanding). -
One Planet Only Forever at 12:35 PM on 6 September 2019Renewable energy is too expensive
Markpittsusa@20,
Do some research into "Discount Rates" applied to evaluating how much harm it is OK for the current generation to cause because portions of the current generation do not want to give up on enjoying current-day (status quo) ways of living (that they have a perceived high status in), that are undeniably harmful to future generations.
Discounting the future with a 'Discount Rate' basically declares the harm done to future generations to become irrelevant as long as it happens far enough in the future.
Ethically (essentials of Ethics are Do No Harm to Others; Help the less fortunate), there is no acceptable amount of harm that can be done to Others, and future generations are Others (a massive pool of Others, almost infinite, unless their future numbers are discounted).
So, ethically it is questionable to include a discount rate in evaluations of how much harm it is acceptable to do to future generations compared to the benefits the current generation would have to give up to not harm the future generations. And given the lack of knowledge (uncertainty regarding anticiated harm, or missed due to ignorance of a potential harm) regarding how much harm is actually going to be done to the future, an amplification of the expected future harms would be more appropriate in an evaluation of acceptability than a discount rate.
With that understanding in mind, understand that Nordhaus and Stern both applied 'discount rates' in their evaluations. Stern uses a lower discount rate and determines that rapid reduction of fossil fuel use is the correct economic action (and that is still using a discount rate).
Of course if the ethical unacceptability of harming Others was admitted then there would be no way to justify anything other than the immediate ending of the increase of harm being done to the future generations.
The incorrectly developed economy of today puts current day humanity in an ethical bind. And the lack of responsible actions by the more fortunate through the past 30 years has made the ethical challenge worse.
Ethically, the required action is immediate ending of the pursuit of benefit from fossil fuels by current day humans. Except that ethically it is also necessary to 'help the less fortunate'. So the ethical refinement of the required action would be that the most fortunate must lead the effort to end the use of fossil fuels and assist the less fortunate adapt to the harm already being done, and help the less fortunate develop in ways that minimize their use of fossil fuels (essentially the fundamental basis for the Kyoto Accord - read the Kyoto Accord and the understandings that were established as the basis for developing the Kyoto Accord).
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scaddenp at 10:29 AM on 6 September 2019Medieval Warm Period was warmer
Just noticed this paper which looks at global coherence of warm and cold periods over last 2000 years. Not only was MWP not globally coherent but also the LIA had similarly mixed global distribution. Unlike the current warming period...
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Evan at 10:27 AM on 6 September 2019SkS Analogy 20 - The Tides of Earth
ubrew12, the complete statement that you partially quoted is
"On 100,000-year cycles the global average temperature varies by 5°C, which causes variation in sea level of 120 m (400 ft). That is a lot!"
"That is a lot" refers to a change of sea level of 120 m, not to the temperature change alone. I think many people are unaware that the Earth, through regular, normal, recent cycles, experiences sea level changes of 120 m.
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nigelj at 07:26 AM on 6 September 2019Consensus on consensus hits half a million downloads
markpittsusa @1
As to your question on "what we should do now" to mitigate the climate problem I suggest read the IPCC reports here. Broadly speaking mitigating climate change comes down to adopting renewable energy solutions, which will resolve the majority of the problem, but not all of the problem.
The remainder of the problem is solved with supporting strategies of adopting negative emissions technologies through both enhanced natural sinks and systems of carbon capture and storage, and a moderate reduction in per capita use of energy and carbon intensive products.
Of course some warming is locked in, so adaptation to climate change is necessary.
Moderator Response:[PS] This discussion is showing signs of heading offtopic rapidly. Discussions of political solutions belong elsewhere.
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nigelj at 07:14 AM on 6 September 2019Consensus on consensus hits half a million downloads
markpittsusa @1
"All these articles on concensus are a waste of time. Even most Republicans who oppose legislation believe there is global warming. "
No the consensus articles are not a waste of time. While most republicans do indeed believe climate is changing, as you say, the more important issue is whether they think humans are causing it, because this will influence what responses they think are appropriate. It's very possible that only a minority of republicans think humans are causing climate change discussed here so its still important to better communicate the consensus studies to the public.
"The real question is what should we do now, which in turn depends upon the target for warming. Should the target be 1C, i.e., the current level? 1.5C which is the political solution reached with island nations? Maybe 2C, the original UN target? Or higher as Nordhaus argues, more like 3.5C?
Limiting warming to 1 degree is impossible because we have already passed this number (refer to the NASA Giss temperature record or Hadcrut). Getting warming back down to 1 degree would be possible but would take time and would require amongst other things negative emissions technology on a vast scale at huge cost.
Can you provide a link to some evidence that 1.5% is a political solution. According to the IPCC here the reasons are "Furthermore, the report finds that "limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being" and that a 2 °C temperature increase would exacerbate extreme weather, rising sea levels and diminishing Arctic sea ice, coral bleaching, and loss of ecosystems, among other impacts."
In any event 1.5 degrees is what the IPCC are suggesting, and they are the expert panel appointed to review these things.
Nordhaus number of 3.5 degrees has come in for a lot of compelling criticism for example here. He fails to consider a whole range of climate impacts and makes some overly optimistic economic assumptions.
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ubrew12 at 05:34 AM on 6 September 2019SkS Analogy 20 - The Tides of Earth
"On 100,000-year cycles the global average temperature varies by 5°C... That is a lot!" Is it 'a lot'? 5C in 50,000 years is 0.01C per century. The temperature change over the last century is seventy times higher, i.e. 0.7C per century. I got tired of hearing the phrase 'climate changes naturally' (implying the current change is also natural) so I did some digging. Looking at the global average temperature over the last 22,000 years, I calculated the temperature change per century for each of the last 220 centuries (further back in time these were estimates). The plot of those 220 centuries is a normal distribution with an average change of 0.014C per century, and a standard deviation of 0.077C per century. By ordinary 3-sigma statistics, the claim that last centuries 0.7C change is 'natural' is easily disproven (3-sigma is 0.24C per century). Since 1993 the atmosphere has warmed at a rate of 2.24C per century, approximately ten times the rate at which it no longer could be considered 'natural', using that 220-century bell curve as a guide. Climate indeed changes naturally. Ordinary statistics proves the current change is not even remotely natural.
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markpittsusa at 03:36 AM on 6 September 2019Consensus on consensus hits half a million downloads
All these articles on concensus are a waste of time. Even most Republicans who oppose legislation believe there is global warming.
The real question is what should we do now, which in turn depends upon the target for warming. Should the target be 1C, i.e., the current level? 1.5C which is the political solution reached with island nations? Maybe 2C, the original UN target? Or higher as Nordhaus argues, more like 3.5C?
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markpittsusa at 03:10 AM on 6 September 2019Renewable energy is too expensive
This expose does not reflect careful analysis. Whether renewable energy is cheap or expensive depends upon the time table and extend to which it is to be employed.
According to Nordhaus, who as you know just won the Noble Prize for his work in this area, 3.5C is the optimal target in terms of mitigation. He includes all the costs (and more) that are mentioned in this article.
I will not try to repeat his arguments since there are readily accessible in his own words. The best place to start is, for most readers, will be his book “The Climate Casino.”
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MA Rodger at 20:20 PM on 5 September 2019The North Atlantic ocean current, which warms northern Europe, may be slowing
Human 2932847 @23-25,
The article you cite appears a bit odd. Riser & Lozier (2013) 'Rethinking the Gulf Sream' describes itself presenting "Three new climate studies [that] indicate that our long-held belief about the Gulf Stream’s role in tempering Europe’s winters may not be correct. Yet the studies themselves do not agree." Yet these three are hardily "new" dating from 2002, 2009 & 2011. (the 2002 paper being our old friend Seager et al).
And such a finding wouldn't show "much sign of controversy"?
Riser & Losier (2013) does set out the two sides of the Seager controversy before pointing to that recent detailed modelling suggests it unlikely that meltwaters will "shut down" the AMOC.
I have tried to stress that the research is more interested in the fate of the AMOC and measuring the trends so far, rather than the effects of slowdown on Europe (such effects bring the issue we discuss here). There is detailed modelling (more recent that Riser & Lozier 2013) desribed in this RealClimate OP by Rahmstorf. This work is all about identifiying a fingerprint of AMOC strength in SST data. It does demonstrate the AMOC fingerprint caused by slowing. And regarding the cooling of Europe, note the cooling ocean temperatures up-wind of Europe.
And "where these questions are more settled"? This is an area of active research. To keep up with it, the "questions" of interest need some defining.
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Capistan at 12:29 PM on 5 September 2019More Carbon Dioxide is not necessarily good for plants.
If we can successfully reduce CO2 we should be back to get back to the ice age. It can be done with regressive taxes on fuel food and the basics, might get the population down as a boonus.
Moderator Response:[PS] Sloganeering, offtopic, and strawman arguments. You might like to learn difference between pigovian and regressive taxes.
Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
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David Kirtley at 09:31 AM on 5 September 2019Understanding adjustments to temperature data
frankprice @63: I located Zeke's 2nd installment: Understanding Time of Observation Bias, but I'm not sure what/where the 3rd installment is. That post was supposed to be about "automated pairwise homogenization".
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frankprice at 07:09 AM on 5 September 2019Understanding adjustments to temperature data
I don't see a Lessons from Predictions in the upper right–hand corner. Where are parts 2 & 3??
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Kselia at 01:59 AM on 5 September 2019UAH atmospheric temperatures prove climate models and/or surface temperature data sets are wrong
Hi. Sorry for the heavy necromancing, but I find the "Major corrections to the UAH temperature trend over the years" tables shown at the bottom of both levels of explaination to be not very helpful, unless one already knows what they see. In the article linked right above them, it is properly explained what the highlighting is supposed to mean (red: suggested by outsiders, but not applied by UAH; blue: applied by UAH and makes up half the trend) and how the numbers are to be understood in context. I believe it could be helpful to either add a small explaining paragraph or remove the figure here altogether, but emphasize that more information on the messed up corrections can be found follwing the link.
Thank you for this amazing resource on Climate Change!
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Human 2932847 at 18:02 PM on 4 September 2019The North Atlantic ocean current, which warms northern Europe, may be slowing
Neglected to link the Sci Am article - here http://fds.duke.edu/db/attachment/2372
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Human 2932847 at 18:01 PM on 4 September 2019The North Atlantic ocean current, which warms northern Europe, may be slowing
This Scientific American summary goes into the debate over Seager's stuff. It's from 2013 and so has it been superceded ? It says -
"recent modeling studies with higher resolution of ocean currents suggest that fresh Arctic meltwater may pour mostly into currents that are more restricted to the coastlines and there-fore have less influence on the open ocean, where downwelling primarily occurs. Even if freshwater significantly affected the amount of waters downwelled in the North Atlantic, it turns out to be highly unlikely that this change would effectively shut down the Gulf Stream. A shutdown is unlikely because the path and the strength of the Gulf Stream depend largely on the speed and direction of the large-scale midlatitude winds."
Which doesn't sound like much of a threat.
What would be a good source for the latest theories about the Gulf Stream, AMOC etc where these questions are more settled ?
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Human 2932847 at 17:37 PM on 4 September 2019The North Atlantic ocean current, which warms northern Europe, may be slowing
I don't see much sign of controversy , though, apart from here.
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DrivingBy at 13:00 PM on 4 September 20192019 SkS Weekly Climate Change & Global Warming News Roundup #35
@William
1. "I seem to remember that Florida is where the well off; those that made their money ignoring climate change, have retired to."
2. ""Sea level rise and monster storms couldn't happen to a more deserving people.""
It appears you have never been to, much less lived in Florida.
People who saved and are able to afford a pleasant retirement did not do so by "ignoring climate change", they did so by a dozen different means. Some made retirement nest eggs from saving 7% every year from age 23, some had public sector retirement at age 55, then continue working in some other capacity while collecting a generous pension. Some were the person who opened the town's best roti-roll joint and then 3 satellites, some developed an app that took off. Some were in government or other forms of organized crime.
What they have in common is that they wasted no time being gloating over bad things happening to people more successful than themselves.
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Bob Loblaw at 10:56 AM on 4 September 2019CO2 effect is saturated
GwsB:
You have received a rather negative reaction, because you have made some pretty strong claims based on some faulty reasoning. Regulars here can be pretty impatient with such proclamations from newcomers.
Let me try to explain where your error lies. To begin, thanks for making it clear just what you think "CO2 effect is saturated" means - often people that make that argument are less than clear. You have based your argument on the (correct) observation that very little IR radiation can travel directly from the surface to space.
The part where your argument breaks down is actually hinted at in your post. You state that IR radiation absorbed in the atmosphere can be re-radiated - sometimes up, sometimes down. Eventually, that energy will be emitted to space, but it is delayed. Let us look at the implications of that.
Radiation absorption is a logarithmic function, expressed by Beer's Law. If a certain thickness of the atmosphere can absorb 10% of the IR radiation,and transmit 90%, then the amount passing directly through is 0.9 of the original value. The next layer (same properties) then transmits 90% of 90%, or 09.*0.9=0.81. The third layer will allow 0.93 = 0.729, and so on.
The figure below shows that decline. It also shows the same result for a case where each layer transmits 95%, instead of 90%. The layer-by-layer sequence for 0.95 is 0.95, 0.952, 0.953 etc. Note the following:
- After 200 layers, both curves show essentially zero transmission, fitting your "saturated" argument.
- In the middle, however, the two curves are clearly not the same.For a coefficient of 0.9, it takes almost 23 layers to reduce transmission to 0.1. For a coefficient of 0.95, it takes almost 46 layers. (Yes, the doubling of the distance is an exact mathematical result of Beer's Law, and the per-layer doubling of absorption from 0.05 to 0.1.)
The "saturation" argument fails to include that intermediate difference, and that is where it goes very, very wrong. This difference in how much IR radiation is transmitted how far is essential to understanding the greenhouse effect. Adding CO2 has a neglible effect on how much IR radiation can pass directly from the surface to space in a single step, Adding CO2 does affect how far IR radiation gets in a single step, and this affects how many steps it will take before it can finally reach high enough in the atmosphere to escape to space.
You can see this in the figure I provide, if you read it from right to left - i.e., think of the right as the surface, and the left as space. IR radiation emitted upward (to the left) at layer 10 has a 39% chance of escaping to space for a coefficient of 0.9, but a 63% chance for a coefficient of 0.95.
(Note: the values and layers in the diagram are purely illustrative. Radiation transfer in the atmosphere needs to be calculated at many different wavelengths, not a single number as shown above. The general principle is correct, though.)
As CO2 or other greenhouse gases increase, the IR lost to space originates at a higher altitude, where the atmosphere is colder. This means less IR lost to space, until the atmosphere can warm to compensate.
An analogy for your "saturation" argument would be a foggy night, where you can't see the building two blocks away, but you can see a building one block away. From the perspective of the distant building, visibility is "saturated" - no light from the distant building is reaching your eye. Does this mean that adding more fog has no effect? No, because additional fog will eventually make it impossible to see the building that is only one block away.
Proper examiniation of the effects of adding CO2 to the atmosphere requires that the effects throughout the atmosphere be included, not just the direct transmission from the surface to space in a single step. And the calculation that include all those effects show clearly that adding CO2 leads to surface and tropospheric warming.
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william5331 at 06:00 AM on 4 September 20192019 SkS Weekly Climate Change & Global Warming News Roundup #35
I seem to remember that Florida is where the well off; those that made their money ignoring climate change, have retired to. Sea level rise and monster storms couldn't happen to a more deserving people. A nice twist is that the poorer people live on an inland ridge while the rich, retired are right down on the beach.
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Eclectic at 01:33 AM on 4 September 2019CO2 effect is saturated
GwsB @525 ,
you have completely failed to understand the CO2 (and H2O) mechanism of "greenhouse".
Before you embarrass yourself by making further comments about CO2 saturation, please read & think about Dana's OP, and check out RealClimate & other information above.
Moderator Response:[PS] Please watch tone.
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MA Rodger at 01:25 AM on 4 September 2019CO2 effect is saturated
GwsB @525,
You ask if that Wiki graph you show @525 is misleading. It certainly is!!
That Wiki graph simply shows the chance of a photon travelling vertically through today's atmosphere without a particular species of GHG absorbing it en route. It shows nothing of how many such photons would be travelling at each wavelength or even in what direction. The CO2 absorption band at 2.7μm is stopping solar radiation coming in from the sun not IR going out. The CO2 absorption band at 4.3μm sits in the gap between incoming solar radiation and outgoing IR - there are effectively no photons to be absorbed so it has no relevance to climate. And the inability of a photon to travel un-absorbed by GHGs out through the atmosphere does not prevent the mechanisms of the greenhouse effect from gaining strength through additonal levels of GHG. And I should add that the Wiki page you took the graph from provides a woeful attempt to describe the mechanisms of the GH effect.
You say "The basic physics is simple: A photon of light at a wavelength of 14 μm [15μm] is passed from one CO2 molecule to the next performing a kind of random walk until it exits the atmosphere. There are two exits, outer space and the earth. Saturation means that a photon starting from the earth has very little chance of exiting to outer space." The effect of this 'saturation' is solely that there will be a random walk as all photons will be absopbed. This does not of itself make the chances of IR resulting from that absorption exiting into space small.
Interestingly, you cite Zhong & Haig (2013) 'The greenhouse effect and carbon dioxide' yet you fail to acknowledge the finding of that paper which is "We conclude that as the concentration of CO2 in the Earth’s atmosphere continues to rise there will be no saturation in its absorption of radiation and thus there can be no complacency with regards to its potential to further warm the climate."
Instead you set out contradictory conclusions of your own - "The total negative impact is almost cancelled by the positive impact around 15 μm."
The GH-effect works because the emission & re-emission of IR from the atmosphere containing GHGs will only occur at those same wavebands which subject to are absorption. But the rate of re-emission is set by air temperature. As the temperature drops through the troposphere, the point where emissions will get out into space through the thinner upper atmosphere; that point in the troposphere will be colder. Thus the GHG at that higher altitude will re-emit less IR because it is colder. The more the GHG in the atmosphere, the higher the altitude and the bit of troposphere which emits into space and thus the less IR is emited.
Of course, as the graphics in Zhong & Haig show, that mechanism will go into reverse as the altitude becomes high enough to reach the stratosphere. In the stratosphere, temperature rises with altitude and so the more GHG the greater the IR emissions into space. This is the mechanism which you mention being apparent in their Fig5b which you say results in the increasing GH-effect being "almost cancelled." However, the extra GHG effect of CO2, although reduced with increasing CO2 concentrations in the well-konwn logathithmic relationship, does not peak even if the 15μm band is taken in isolation. It keeps on increasing. And at CO2 levels above 2500ppm(v), the 15μm band is boosted by a compound absorption band at 10μm.
The climate forcing of CO2 does not hit an upper limit. In the words of Zong & Haig (2013), "as the concentration of CO2 in the Earth’s atmosphere continues to rise, there will be no saturation in its absorption of radiation."
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Philippe Chantreau at 23:26 PM on 3 September 2019CO2 effect is saturated
GwsB "the wings have little effect"
That is false.
The links at the bottom of this page to RC's saturated gassy arguments threads explains it, as well as other sources.
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GwsB at 19:49 PM on 3 September 2019CO2 effect is saturated
In the discussion about the effect of CO2 on the climate there are certain images which may be said to incorporate the essential part of the arguments. Such iconic graphs are the driving force in changing one's view of the world. A good example is the sun with the planets rotating around it. This stopped all phantasies about what happens at the edge of the (flat) earth. This iconic image made it possible to sail Westward in 1492 in order to reach India.
For CO2 the iconic image is the rippled increasing graph of the CO2 concentration as measured at Mauna Loa from 1960 onwards, sometimes extended over the past thousand years by observations from tree rings and ice cores to obtain the "hockey stick". For the influence of CO2 on climate the iconic graph is given in Wikipedia https://en.wikipedia.org/wiki/Greenhouse_effect (last updated 23 August 2019)
Caption: "Atmospheric gases only absorb some wavelengths of energy but are transparent to others. The absorption patterns of water vapor (blue peaks) and carbon dioxide (pink peaks) overlap in some wavelengths. Carbon dioxide is not as strong a greenhouse gas as water vapor, but it absorbs energy in longer wavelengths (12–15 micrometers) that water vapor does not, partially closing the "window" through which heat radiated by the surface would normally escape to space."
The graph shows that the effect of water vapour, H2O, is much greater than the effect of CO2. It also shows the saturation of the absorption due to CO2. The first argument (about water vapour) is valid. We can't do anything about the concentration of H2O though, except perhaps by increasing the temperature. So we will just have to accept this effect. The second argument (about saturation) is also valid. The absorption at wavelength 4 - 4.4 μm is 100% over most of the region, and so too at 12-15 μm. In comparison with H2O the peaks of CO2 are very steep and the wings have little effect. It is only the thin peaks at 2 μm and at 4.9 μm which will grow significantly if the concentration of CO2 is increased.
The basic physics is simple: A photon of light at a wavelength of 14 μm is passed from one CO2 molecule to the next performing a kind of random walk until it exits the atmosphere. There are two exits, outer space and the earth. Saturation means that a photon starting from the earth has very little chance of exiting to outer space. It is almost certain to exit the atmosphere to the earth, where like shortwave radiation it will be re-emitted at a different wavelength. Even if the new wavelength with probability a half lies in an absorption band of CO2 or H2O, this only means a stay of execution. In the end the photon will escape to outer space through one of the long wave gaps in our atmosphere.
The graph in Figure 2 in Zhong & Haigh (2013) is perhaps more precise, but the vertical scale runs over twelve orders of magnitude, (twelve orders of magnitude is from one mm to a million km, or from one gram to a Megaton). The result of this scale is that I am not able to comprehend the significance of the graph. Figure 5b, bottom, gives the difference between the radiative flux for the present level of CO2 (389 ppmv) and a level increased by a factor 32 (12500 ppmv). The total negative impact is almost cancelled by the positive impact around 15 μm. This impression is reinforced by Figure 6a where the graph is practically horizontal beyond 400 ppmv. In Figure 6b we see an increase in the slope beyond ten thousand ppmv. In that graph the horizontal axis is logarithmic and runs up to a million ppmv, which is a pure CO2 atmosphere. These results are based on models and therefore should be taken with a pinch of salt.
The conclusion is: The direct impact on the temperature of the earth of the increase in CO2 from the present level of around 400 ppmv is relatively small. This is due to saturation at the bands where CO2 absorbs long wave radiation.
Is the graph above misleading? It is described as "(Illustration adapted from Robert Rohde.)". Clicking on Robert Rohde results in the message: www.globalwarmingart.com refused to connect.
If anyone knows a better graph I would be very happy to obtain a link.There is a nice course on climate denial presented by the University of Queensland https://courses.edx.org/courses/course-v1:UQx+Denial101x+1T2019/course/ The course is free of charge and contains a huge amount of good information on climate change. Unfortunately the course does not address the topic of the absorption of CO2 at specific wavelengths. Neither does the basic rebuttal by dana 1981.
The near saturation of CO2 at present levels makes it difficult to convince people to vote for a cut in CO2 emissions or for a tax on such emissions.
Moderator Response:[RH] Your image was breaking the page formatting. I can add it back in but it needs to be smaller than 450 px wide, which for that image was going to render it unreadable.
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nigelj at 17:38 PM on 3 September 20192019 SkS Weekly Climate Change & Global Warming News Roundup #35
Hurricane Dorian is another slow moving Hurricane thus potentially being more damaging. Slow moving hurricanes are associated with climate change and dump more rain.
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nigelj at 07:20 AM on 3 September 2019IPCC's land report showed we're entering an era of damage control
OPOF @20
"The 'high meat and fat diets' are often promoted as weight loss diets. The science indicates that people on such diets should be carefully monitored by medical professionals to ensure "
Yes and I have generally promoted the same. The low carbs high meat and fat diets might make sense as a temporary thing to loose weight, but not as a permanent diet. People should eventually transition back to a sensible sort of balanced diet like the Mediterranean diet.
The trouble is the low carbs high meat and high fat diets are being promoted as a permanent thing, certainly by at least some experts and many of the people who have tried them. I see this all over the internet. I had to loose weight last year hence my interest.
This creates an awful mixed message for society where one group are saying reduce meat consumption and eat more plants (carbs) for the sake of the planet, and other groups are saying eat high meat low carb diets. The health authorities need to give a much more resolved, consistent and clear message.
Of course the problems of eating too many calories especially if they are mostly white carbs are well known. I would not advocate that. The answer looks like its about balance and keeping total calorie intake moderate within healthy guidlelines, and keeping the white carbs component of this sensible as well. Asians and Italians eat like this and do not have big diabetes or heart disease issues.
And it has to be said that its not even that clear that such high meat diets loose more weight than other diets in the long run, however if someone is diabetic then a high meat low carbs diet does become pretty imperative.
"The key is understanding that the high meat consumption diets liked by people who grew up being impressed by people who could afford to eat large amounts..."
Yes absolutely. Adults only need 60 grams of protein a day which is not very much, and it can come from meat or plants. High meat consumption is indeed more about habit and displays of status. However some meat in the diet seems fine to me in moderation, and another reason is because much of our land only really suits cattle grazing and can't be easily converted to crops.
Finally humans evolved as omnivores, ie we eat quite a varied diet with a bit of everything, and it's also important to enjoy our food. I'm reluctant to change this towards extreme sorts of diets, unless theres very solid science based evidence.
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One Planet Only Forever at 01:38 AM on 3 September 2019IPCC's land report showed we're entering an era of damage control
nigelj@19,
The 'high meat and fat diets' are often promoted as weight loss diets.
The science indicates that people on such diets should be carefully monitored by medical professionals to ensure that their health is not compromised by the strict temporary diet. In some cases, just a minor 'cheat' on the diet can cause major harm to internal organs because the body systems are not in an adaptive state that is able to respond to the 'cheat'. And the person on such a diet still has to learn how to eat a healthy diverse diet that will not return them to the condition they tried to correct.
The key is understanding that the high meat consumption diets liked by people who grew up being impressed by people who could afford to eat large amounts of meat are not healthy (and the protein from 4 oz of meat is all that a body will process from a meal). And that 'perception of superiority of eating lots of meat' is an unsustainable impression (just as the impressions of over-sized, over-powered personal transportation or housing is unsustainable).
There is a massive variety of healthier reduced meat diets that can be enjoyed that maximize the use of locally sustainably grown products (including appropriately limited amounts of locally produced meats). And those diets, combined with adding activity like walking and biking rather than 'powered transport' will result in sustainable healthier weight loss, it will just take longer than the 'crash diets'.
Improving awareness and understanding is hard to do in societies that are flooded with misleading advertising that harmfully develops easily impressed people who want what they develop a liking for 'quicker, easier, and cheaper', people who declare that they cannot and will not give up something they have developed a liking for.
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nigelj at 07:05 AM on 2 September 2019IPCC's land report showed we're entering an era of damage control
Driving By @14 was perhaps a bit snarky, but does raise a very interesting and pertinent issue on diet. Dietary advice is indeed very contradictory, with seemingly well qualified people promoting diets that are low in meat and fat consumption, like the Mediterranean diet, and vegean diets (no meat) and others promoting high meat and fat diets like Atkins, Ketosis, and the Paleo Diet (technically a high fat diet but people will achieve this with higher meat consumption).
People must be utterly confused, and plenty express this on websites.
The high meat diets are in total contradiction to advice to reduce meat consumption for the good of the planet.
Personally I think moderately low meat mediterranean diet makes the most sense all things considered. Italians and Greeks apparently have good health and longevity. Humans are omnivores.
While meat is an inefficient use of resources, many grasslands grazed by cattle dont really suit crop production, so this suggests to me the only practical answer is moderately low meat diet.
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nigelj at 06:41 AM on 2 September 2019IPCC's land report showed we're entering an era of damage control
I want to clarify my point @10. I was responding briefly to wjohnallen @7 who it seemed to me made an odd sort of statement namely " it turns out that a cow consumes more CO2 than it belches out as CH4 (on a CO2eq basis at a GWP of 25).Who knew that ruminants on grass pastures are carbon negative? " That seems an impossibility as I explained. Tell me why I would be wrong.
However I accept there is good evidence that cows can managed to encourage higher rates of grass growth and thus more sequestration of atmospheric carbon by that grass and its products of decomposition in the soil. I've said this before. This seems like a different issue to wjohnallen's point. This would make cows carbon negative, although its not all that clear to me just how carbon negative they would be.
I think science of the methane cycle was being confused with mitigation by enhanced soil sinks.
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One Planet Only Forever at 04:31 AM on 2 September 2019IPCC's land report showed we're entering an era of damage control
For the benefit of those who choose not to read the 1972 Stockholm Conference report, it includes the following in its opening statements:
"3. Man has constantly to sum up experience and go on discovering, inventing, creating and advancing. In our time, man’s capability to transform his surroundings, if used wisely, can bring to all peoples the benefits of development and the opportunity to enhance the quality of life. Wrongly or heedlessly applied, the same power can do incalculable harm to human beings and the human environment. We see around us growing evidence of man-made harm in many regions of the earth: dangerous levels of pollution in water, air, earth and living beings; major and undesirable disturbances to the ecological balance of the biosphere; destruction and depletion of irreplaceable resources; and gross deficiences (sic), harmful to the physical, mental and social health of man, in the man-made environment, particularly in the living and working environment."
That was understood by Global Leadership 47 years ago. How about today? What has been learned by many of the Winners of competition for personal benefit, popularity and profit? They appear to have learned how to fight against improving awareness and understanding, including influence on the stories that get told and believed, and abusing their power to 'bake correction resistance into the systems (including laws and their enforcement) that they can influence' (william's steady point that the people Paying the Piper powerfully influence the actions of Leadership).
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