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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 76601 to 76650:

Composer99 at 04:39 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
And of course, going in circles on Texas droughts in this thread is going off-topic. I think this thread is the most topical for 2011 droughts in Texas. Bringing my own contribution back on topic, I find it unfortunate (some understatement involved) that (a) the majority of Republicans who are running to represent their party in the 2012 Presidential election are so deep in denial about climate change and (b) the one who isn't is probably not, at least the way things appear at present, likely to secure his party's nomination.

Alexandre at 04:37 AM on 26 August 2011

Lessons from Past Climate Predictions: IPCC FAR
Base period for figures 2 to 5 is the year 1765? Thanks for the informative post, Dana. I've been curious about this comparision, which is in my view even more telling than Rahmstorf 2007.

Composer99 at 04:19 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
I think that trying to de-couple ENSO from global climate behaviour (global warming) is not a productive way to distribute causality for such things as the Texas drought. That said, suggesting La Niña without acknowledging the importance of warmer baseline temperatures from AGW and the tendency for extreme weather to become more extreme as a result of the warming, strikes me as disingenuous.

Eric the Red at 04:04 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
Stephen, With regards to the drought in Texas, La Nina is the persistent cause. I was making no reference to temperatures, either daytime or nighttime, but to the rainfall, or rather lack thereof. This past La Nina was the most severe, and neither is the current drought. Texas has experienced worst droughts at lower temperatures than have occurred this year. We have a strong historical connection between La Ninas and drought in Texas, but not so with global warming. No dichotomy, no double standard.

muoncounter at 04:00 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
Maybe the point is that the exceptional, record-shattering heatwave/drought is generally blamed by the deniers of AGW on la Nina. The rest of us aren't so sure of that easy assessment any more. Look at John N-G's fingerprint analysis to see just how exceptional this drought is -- and how ignorant Guvna Perry must be to deny it. The old proverb 'may you live in interesting times' should be updated to 'may you live in exceptional times.'

JoeRG at 03:42 AM on 26 August 2011

Lessons from Past Climate Predictions: Wallace Broecker
Can anybody explain what remains as a natural forcing if Sun and Volcanoes are excluded, and how this remnant is able to form a cycle (as used in the model)? It must be an important one to drive temperatures in a range of nearly 0.8K within 100 years, but I've never heard of it and I found no explanations of it in any of the IPCC publications. But it is of course necessary to know about to call the model discussed here a proper one.

dana1981 at 02:51 AM on 26 August 2011

Lessons from Past Climate Predictions: IPCC FAR
Charlie - which data? The caption says that the observational data is from GISTEMP. If you mean the model adjustment, the source is the IPCC FAR projected GHG forcing (Figure 1) vs. the actual forcing (from the IPCC AR4, stated below Figure 1). It's a GHG forcing model, so I took observed GHG changes into account. As I said, the model doesn't account for aerosols. That's one reason why the "best" 2.5°C sensitivity is probably a bit on the low side, even though the model matches observations quite well (also noted in the post).

JosHagelaars at 02:38 AM on 26 August 2011

OA not OK part 20: SUMMARY 2/2
Thank you all very much for the very informative posts on this interesting subject. It also helped to refresh my rather rusty chemical knowledge. Nice to have it combined as a booklet. Regards, Jos

Charlie A at 02:35 AM on 26 August 2011

Lessons from Past Climate Predictions: IPCC FAR
What is the source of data for Figures 4 and 5 ? Did you adjust both aerosols and GHG forcings, or just GHG ?

Stephen Baines at 02:18 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
Apirate I think EtR is drawing a false dichotomy and invoking a double standard. We should (and do) acknowldge the influence of ENSO and other factors in the SW weather patterns. But wouldn't we be remiss if we didn't also acknowledge the likely role of warming - given that we know it is occuring? Why is mere mention of AGW with respect to record breaking temps to be avoided? That seems more like a political position than a scientific stance. Think of it this way. The La Nina just past was substantial, but not the most severe on record. The la Nina can explain a persistent pattern of drought in the SW...but it cannot explain the degree to which this summer has spawned an enourmous number of temp records, nor can it explain the disproportionate number of nighttime temp records. La Nina (and other factors) that influence weather patterns at regional scales are important. However, the the diel signature of warming and its extreme nature are perfectly consistent with a role of global warming, distinct from La Nina.

Composer99 at 02:05 AM on 26 August 2011

A new SkS resource: climate skeptics and their myths
I do not think it as at all inappropriate to refer to those who oppose mainstream climatology on AGW as 'deniers' or even 'denialists' as long as it can be shown that they are: - in the first case, engaged in denying a phenomenon which has ample evidentiary support without bringing sufficient evidentiary support to their positions. - in the second case, extending this denial into a systematic misrepresentation of the evidence. The attempt to take offence at this terminology by drawing attention to Holocaust denial is a red herring.

otter17 at 01:43 AM on 26 August 2011

GHG emission mitigation solutions - a challenge for the Right?
Great article idea. I think this may have been mentioned before, but I bet getting rid of fossil fuel subsidies would be palatable to all political stripes, in the USA at least. Other than that small effort, the conservative/libertarian minds at the highest levels of government have had decades to think about the answer to this policy question. If they haven't come up with anything but attacks on the science yet, it is unlikely they will ever come up with a solution. Business as usual along with repealing environmental and utility regulations seems to be their solution. Apparently, the market can solve the global warming issue if we just wait and see it perform its magic. This may conflict a bit with the point of the article, but I feel like the radicals among the conservative/libertarians ought to be ignored in the policy debate. They had their chance already. Outreach to the uninformed middle ground folks and moderate conservatives ought to be top priority. If an information campaign were successful, many of the moderates will see the kooky nature of conservative climate science denial. With enough people firmly established in the science and its implications for our society/economy, denialism will be increasingly viewed in the public eye as fringe. I say converting hardcore deniers directly is probably not as efficient as outnumbering them. A three prong campaign to inform the reasonable middle ground, keep the disinformation in check, and move forward with solutions such as an equitable carbon tax seems to be the best overall strategy to me.

apiratelooksat50 at 01:33 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
EtR at 38 "The Texas heatwave is generally blamed on the strong La Nina. Passing it off as AGW influenced is the type of misinformation that is causing people to distrust climate scientists, as shwon in the previously posted polls." Darn good point.

CBDunkerson at 01:15 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
Paul D wrote: "Statistically if they (politicians) all studied the science and came to their own conclusions, you would get some Democrats being skeptic and some Republicans pro AGW." That would only be true if there were some science which supported a position skeptical of AGW. There isn't. Indeed, by the same reasoning we should see Democratic politicians who deny evolution... rather than that too being a purely Republican position. In 'news' and politics there often seems to be a search for false 'balance' even on issues which are entirely one sided.

Paul D at 01:08 AM on 26 August 2011

Republican Presidential Candidates vs. Climate Science
Dana@17 said: "no, there aren't any prominent Democratic politicians who are climate "skeptics"." Statistically if they (politicians) all studied the science and came to their own conclusions, you would get some Democrats being skeptic and some Republicans pro AGW. So the only conclusion, is that both sides are largely ignoring the science. The current situation defies science in many ways.

les at 00:26 AM on 26 August 2011

A new SkS resource: climate skeptics and their myths
Wow indeed. John Cook runs this site from his own pocket + donations + volunteer support. Then announces publicly he's been give a [well deserved IMHO] fellowship... and the bizarrosphere goes "Busted! SkS is a funded propaganda machine". The reality distorting force is ~~strong~~ a bit wishy-washy with these ones...

Dikran Marsupial at 23:38 PM on 25 August 2011

It's cosmic rays
Sphaerica Indeed, a good example of how not to communicate is Svensmark and Calders book "The Chilling Stars", which essentially attempts to explain every change in (paleo) climate to GCR (slight over-statement there, but only slight) before the fundamental work demosntrating that GCRs actually could affect climate (nevermind whether they did). As a scientist (of sorts) I cringed reading the book, not because the theory is bad, but the lack of perspective which is potentially maximising the height of the fall they are setting themselves up for. I am always very suspicious of any paper that comes with a press release suggesting its findings are contraversial; most often such a paper either (a) doesn't actually support the message of the press release or (b) turns out to be wrong or (c) both. It is much easier to think of examples where this is true than it is for papers that actually did merit controversy.

Bob Lacatena at 23:28 PM on 25 August 2011

It's cosmic rays
58, Dikran, Well said. The only thing that I would add would be that anyone should look at that study and its conclusions and from it recognize that such research is absolutely in its infancy. It is going to develop and progress as it should, but it needs to build its very foundations before it can progress to making many meaningful conclusions about effects on climate. It is not going to challenge current climate science anytime soon (which says nothing about whether it ever will or won't), and skeptics need to avoid trying to use such research, and every resulting paper which will merely represent another baby step in the process, as a debate tool to be used to provide one more "let's wait and see, we don't know enough about clouds and GCRs yet" excuse. Let it just be good science at work.

Dikran Marsupial at 23:08 PM on 25 August 2011

It's cosmic rays
Eric, I completely agree (I try to be a good scientist, but I try to avoid talking to myself as much as possible ;o) as do the RC chaps. The really interesting thing about the CLOUD project as far as the climate debate is concerned is that it is a good example of how science and science funding actually works. Skeptic often say that government agencies will not fund their work, but CLOUD is a big project (see the number of authors) with big funding (about 12MECU IIRC), that aims to investigate the very most basic physical underpinnings of an alternative hypothesis (for which there is only the most circumstantial evidence). It also shows that skeptical hypotheses can and do result in good basic science of general interest to the research community. It also shows that the outcome of an experiment can be very interesting and useful, even if it doesn't provide much support for the working hypothesis (and hence suggest new lines of enquiry or provide support for an existing line etc). A really good experiment is one that has a 50-50 chance of corroborating or refuting an hypothesis as these are the ones that provide the most information about science (in an information theoretic sense). This means we should expect experiments to reject the working hypothesis on a regular basis (a significant minority of experiments); it shows that the research is "sharp".

Bob Lacatena at 23:06 PM on 25 August 2011

It's cosmic rays
54, muoncounter, Really, I find your anti-denial of such science to be the antithesis of all that science represents. As Dorothy would tell you, anti-Em may not be the Wicked Witch of the West, but she's no Glinda the Good Witch, either. That, my friend, makes this entire topic a horse of a different anti-color. Or would that be an anti-horse? I suppose I should visit WUWT to be set straight on such issues.

Eric the Red at 22:48 PM on 25 August 2011

It's cosmic rays
Dikran, Their experiments produced between ten and a thousand times fewer aerosol particles than found in nature, which basically means that they have not determined the cause of the aerosol formation in our atmosphere. The results were not what they hoped for in that no climatic conclusions could be drawn from their work. But as any good scientists will tell you, this study will inspire more research in the area.

Bob Lacatena at 22:45 PM on 25 August 2011

Understanding the CO2 lag in past climate change
243, Dr. Doom,

My simple calculation of climate sensitivity is < 1.9C. In scientific studies, the lowest estimate is 0.5C. Various studies put the lower bound at 1.5C. IPCC claims < 1.5C is unlikely. But may I add not impossible.

This is a gross distortion of the facts. You say "various studies put the lower bound at..." but then make no mention of the median expected sensitivity, or the upper bound. It strikes me as just so much gamesmanship to be that blatantly manipulative with a presentation of the facts. "But I may add not impossible?" Meaning what, exactly? It's not impossible that I would find a million dollars on the street tomorrow. What's your point? If you want to be engaged, you must do so with more honesty. No one wants to get into the mud with someone who seems to enjoy it.

It didn’t say whether there is a saturation CO2 concentration in the upper troposphere.

More gamesmanship. My college chemistry text never explicitly stated that gremlins don't live in the spaces between electrons. Do I also need to worry about that? Or do scientists need to conduct multiple studies of your issues just to put your personal concerns at ease (as well as designing and building an Interspacial Gremlin Detection Apparatus to lay my own fears to rest)? But I can answer that question. Science is warning of climate change due to increasing CO₂ in the atmosphere. This, by fairly simple logic, leads one to the obvious conclusion that CO₂ in the upper troposphere is not saturated, and will not be in the near future, because if that were the case no climate change would occur. No explicit statement statement to that effect is necessary. There are also myriad paleoclimate studies (see here and here and here and here and here and here and here and here and here and just about every paper that you bother to look at here) that demonstrate that CO₂ levels have been much, much higher in the past (by a whole order of magnitude), along with global mean temperatures, further evidence that if there is a saturation point, we're currently nowhere near it.

But if there is a clear cut answer, scientists should say that CO2 saturation is physically impossible.

Why? Who cares? The point is that it's not saturated, we're increasing CO₂ levels, and it's dangerous. Your questions appear to be only so much "how many angels can dance on the head of a pin" speculation, of no value to anyone attempting to understand the relevant science. Make a valid point, or pose a worthy question. The positions you've presented appear to be distractions with no merit whatsoever.

muoncounter at 22:45 PM on 25 August 2011

Republican Presidential Candidates vs. Climate Science
EtR#38: If OPEC/big oil was the concern, then where is the support for 'cheap, reliable American coal'? What happened to all those 'clean coal' TV ads? Banished to the SciFi channel? "Gerrymandering has create many districts which push towards both extremes" You have the process exactly backwards; redistricting is done by the party in control of the state legislatures. Extremists win local elections, take control of state houses (look at Wisconsin, for example) then redraw the electoral maps to suit their candidates - and that can win a presidential election (see: Tom Delay). "generally blamed on the strong La Nina." Off-topic; but not so much any longer. You're forgetting the hallmark of this heatwave: nighttime cooling isn't getting the job done; that's not an elNi/laNa effect - but it is a greenhouse symptom.

HK at 22:40 PM on 25 August 2011

OA not OK part 19: SUMMARY 1/2
Nice summary, Doug, but I have two remarks: In figure 2 – Carbon reservoirs – shouldn’t the change in atmospheric carbon since the industrial revolution be +40 percents instead of +21 percents? And in your last sentence: "However, the amount of released fossil fuel CO2 is less than the amount of extra CO2 that is currently in the atmosphere." I guess it should be: "However, the amount of extra CO2 that is currently in the atmosphere is less than the amount of released fossil fuel CO2."

Eric the Red at 22:36 PM on 25 August 2011

GHG emission mitigation solutions - a challenge for the Right?
Scaddenp, What technological solutions do you feel are available, or could be made available in the next decade to reduce the consumption of either coal or oil? Political posturing aside, which technologies have the potential to be implemented?

Eric the Red at 22:24 PM on 25 August 2011

Republican Presidential Candidates vs. Climate Science
Muon, I still disagree that the polls are indicating confusing among the general population. Belief in global warming is but one reason to support government investment in alternate energy. Energy independence from OPEC and the big oil companies or cheap alternatives to rising oil prices are some others. I do not trust the politicians or bureaucrats on either side of the debate when it comes to scientific understanding, and I do not believe that most other people do either (although I have heard people claim it is so because they heard it from whomever). Yes, Obama is moving towards the center. The polls show similar thinking from the moderate camp of each party through the independents in the center. Those outside this area will find difficult running come election time. Both Conservative Republicans and Liberal Democrats are outside this area and unless their constituents feel likewise, have election night struggles. Gerrymandering has create many districts which push towards both extremes allowing many of the politicians to get elected. The Texas heatwave is generally blamed on the strong La Nina. Passing it off as AGW influenced is the type of misinformation that is causing people to distrust climate scientists, as shwon in the previously posted polls.

Dikran Marsupial at 21:47 PM on 25 August 2011

Understanding the CO2 lag in past climate change
Dr Doom Point #1 Full equilibrium temperature is only reached after the thermal inertia of the oceans is achieved. That takes thousands of years. The estimate given by Schwartz is for short term perturbations of the climate system, e.g. due to volcanic eruptions, not long term changes in forcings due to e.g. a rise in atmospheric CO2. Schwartz certainly is not ignorant, but your interpretation of his work is clearly incorrect (further discussion of Schwartz' work belongs on the thread I linked to above). Your calculation may be in the range considered plausible by the scientific community, however the method used to obtain the estimate was based on faulty assumptions, as explained earlier in the thread. The fact that your result is plausible doesnt correct the error in the reasoning. In science it is not enough to get the answer right, the chain of reasoning by which it was obtained and the assumptions used must also be valid. Point #2 the fact that dy/dx tends to 0 as x tends to infnity does not imply that there is a meaningful limit to CO2 radiative forcing, at least not one that has any bearing on a discussion of climate. Point #3, as I have already explained, CO2 radiative forcing does not saturate, no logarithmic function saturates because as dy/dx tends to zero as x tends to infinity, at that point y tends to infinity. So if you really insist, you could say that a logarithmic relationship saturates at infinity. You write: "If there is, what is the limit?" I have told you repeatedly that there is no limit, other than the trivial limit you will get when the atmosphere is 100% CO2 and contains all of the available carbon and oxygen on the planet.

Bob Lacatena at 21:37 PM on 25 August 2011

A new SkS resource: climate skeptics and their myths
100, les, Wow. I knew Motl was wrong on the science, but I didn't know he lived in such an angry bizarro opposite-world. He says (I still can't believe it... my fingers feel dirty just having done the copy/paste):

So I started to maintain a list with names of the most notorious alarmists and the number of years they should spend in prison (not to speak about the separate "electric chair" list). You're encouraged to do the same thing.

Anyone who can't see the difference between the post here at SkS and that sort of behavior needs a major perspective adjustment.

Robert Murphy at 20:19 PM on 25 August 2011

Understanding the CO2 lag in past climate change
# 243: "There is not enough time in the 2oth century to attain equilibrium sensitivity. 100 years are not enough?" Riddle me this: Is the atmospheric CO2 concentration in equilibrium? Has it stopped increasing? Therein lies your answer.

les at 18:15 PM on 25 August 2011

A new SkS resource: climate skeptics and their myths
55 Tom Curtis - "This is a witch hunt." Just for everyone's amusement, from the Dept. of fact-twisting... http://motls.blogspot.com/2011/08/john-cook-will-receive-lots-of-money.html

Dr. Doom at 17:43 PM on 25 August 2011

Understanding the CO2 lag in past climate change
I stopped reading the comments because the personal references continue. I’m not the subject of this blog so my knowledge or ignorance is irrelevant. What matters is the explanation why an argument is right or wrong. Point #1 There is not enough time in the 2oth century to attain equilibrium sensitivity. 100 years are not enough? If you start at the end of 20th century up to present, that’s 11 years. Still not enough? Mind you, Schwartz initially estimated the time constant at 5 years. Later he adjusted it to 8.5 years. Other estimates are 15 to 17 years. All are below 100 years. Are they all ignorant? My simple calculation of climate sensitivity is < 1.9C. In scientific studies, the lowest estimate is 0.5C. Various studies put the lower bound at 1.5C. IPCC claims < 1.5C is unlikely. But may I add not impossible. Gregory put it at 1.6C with 90% confidence level. Schwartz put it at 1.9C plus or minus 1.0C. Right smack my simple calculation. All these figures are within my estimate. Are they all ignorant? Point #2 As already demonstrated, a logarithmic function indeed as a limit of zero on dy/dx. Do you still need proof that this is true? Point #3 Is the CO2 effect saturated? Clearly my answer is no. Or else I wouldn’t be computing the CO2 sensitivity. I would have just said it’s futile because the sensitivity is zero. You misunderstood my point. My question was, is there a saturation effect as implied by the CO2 sensitivity which is logarithmic? Obviously it is not saturated now but will it ever be? If there is no such thing, dy/dx should not converge to zero. It should not be a logarithmic function. Let’s develop a non-logarithmic function. Hulburt did not falsify the CO2 saturation hypothesis. To quote this website: “the details of the absorption in the lower troposphere do not matter since heat "is spread around and transferred upward by convection". In other words, what govern the energy balance of the earth is the radiative balance in the upper troposphere and CO2 concentration there does matter.” So it’s the CO2 concentration in the upper troposphere that matters, not the lower troposphere. It didn’t say whether there is a saturation CO2 concentration in the upper troposphere. Definitely there is less CO2 molecules in upper than in lower troposphere. But if there is a clear cut answer, scientists should say that CO2 saturation is physically impossible. If so, it means CO2 can absorb more than the solar flux of 342 W/m^2. There is no limit. Not even by the finite solar energy. If there is, what is the limit? For those who wish to reply, please no more personal references of “ignorance” or whatever positive or negative personal attributes. Just address the arguments. Don’t be too defensive, I’m not trying to falsify AGW. I’m just interested in climate science.

Response:

[DB] Playing the "injured bird" routine just smacks of tone troll. DM aready went this route with you, so please just focus on the science.

Ignoring previous comments due to the perceived tone is specious.

actually thoughtful at 16:59 PM on 25 August 2011

Republican Presidential Candidates vs. Climate Science
Eric the red - can you provide an example of thinking for themselves amongst those who are denying climate change? I assume we can rule out those that parrot the mindless talking points of the radio hosts. "Thinking for themselves" implies critical thinking. I am at a loss to come up with a widely accepted denier position that includes critical thinking; indeed it would appear most denier positions require a lack of critical thinking (take a look around this site for examples). There are certainly a few issues where more research is required (ocean heat content, my old favorite, for one). But were is that nuanced, critical thought and position amongst the right in the US? To my eyes it has been in steep decline for the last 10 years or so. The election of Bush (and rejection of Al Gore) seemed to mark an inflection point where the right began to support some pretty major departures from fact based science to form their worldview.

actually thoughtful at 16:53 PM on 25 August 2011

Republican Presidential Candidates vs. Climate Science
I find it highly ironic that Texas is suffering from an AGW influenced heat wave (as in loss of life, loss of business, agriculture losses) - as in SUFFERING. Yet the leader of that state is the biggest shill for it is not happening. Does he not know what state he represents?

barry1487 at 16:10 PM on 25 August 2011

Climate Skeptic Fool's Gold
BTW, I emailed Gavin Schmidt suggesting a short feature at realclimate on this footnote in science history. I make the same request here. Ray Sorenson has replied to an email from me laying out a little detail as to how he came across the entry in Annual of Scientific Discovery, and another interesting item regarding a near-simultaneous discovery of the heat absorbing properties of CO2 by another researcher (1863). I've asked for permission to reproduce portions of the email and provided him a link to this thread. I'll update here if he has any issues with this.

Doug Mackie at 14:33 PM on 25 August 2011

OA not OK part 6: Always take the weathering

second summary post

Doug Mackie at 14:33 PM on 25 August 2011

OA not OK part 6: Always take the weathering
@rjowens: Please clarify your point. From the post above:

But, as we shall see in later posts, when atmospheric CO2 is high then more acidic rain causes more weathering and that consumes CO2 to lower the atmospheric CO2. Only problem is that this happens over a geological time scale.

Doug Mackie at 14:29 PM on 25 August 2011

OA not OK part 18: Been this way before