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  1. And let’s not forget that the media largely misreported the results of this study because the authors use a very strained definition of the term “next decade.”
    http://climateprogress.org/2008/05/02/nature-article-on-cooling-confuses-revkin-media-deniers-next-decade-may-see-rapid-warming/

    As I explain, the Nature study is consistent with the following statements:

    * The “coming decade” (2010 to 2020) is poised to be the warmest on record, globally.
    * The coming decade is poised to see faster temperature rise than any decade since the authors’ calculations began in 1960.
    * The fast warming would likely begin early in the next decade — similar to the 2007 prediction by the Hadley Center in Science (see http://climateprogress.org/2007/08/15/climate-forecast-hot-and-then-very-hot/).
    * The mean North American temperature for the decade from 2005 to 2015 is projected to be slightly warmer than the actual average temperature of the decade from 1993 to 2003

    Comment by Joseph Romm (ClimateProgress) — 13 May 2008 @ 4:30 PM

  2. I just heard the Keenlyside cooling prediction used on the radio to argue that
    there is no such thing as a climate crisis (by a guy from the office of Sen.
    James Inhofe, he of the hoax comment). Thanks for making this a betting matter,
    RC. It gives the question a higher profile. Scientific American says that ice
    sheets are sliding faster toward the sea. I’d say that’s a crisis .

    Comment by Bird Thompson — 13 May 2008 @ 4:32 PM

  3. So the Chaiten eruption isn’t going to get big enough to call off the bet?

    [Response: Doesn't look like it. Not enough SO2. - gavin]

    [Response: And as I pointed out in response to an earlier similar comment, extratropical eruptions like this rarely give rise to a significant global mean cooling. - mike]

    Comment by skids — 13 May 2008 @ 4:34 PM

  4. Re the Chaiten eruption, from what I’ve read, a volcano needs to emit at least 1 million tons of sulfur dioxide into the stratosphere to have an effect on global temperature. Chaiten has only emitted an estimated few thousand tons of sulfur dioxide:
    http://ap.google.com/article/ALeqM5h6XCGT4X37OvMVvC6CA6UaDMeriAD90GHEFO0

    Comment by John Cook — 13 May 2008 @ 5:10 PM

  5. Very interesting thanks.
    Recent evidence suggests that CO2 has now reached the level of 387 parts per million – what is the total figure for CO2 equivalents – probably more significant?
    Are we yet at a tipping point?

    Comment by Martin Pierard — 13 May 2008 @ 5:46 PM

  6. Thank you very much for these 2 articles. I used the first 4000 characters of the first one on alternet.org/environment already.

    All bachelors level degrees, including journalism and English, should require the engineering and science core curriculum. Journalists do the journalism thing to sell papers. The journalism thing is exactly the wrong thing to do when reporting science. RealClimate needs to be read by the whole world. You are often too mathematical for almost everybody. Your concepts are mathematical. Nonetheless, RealClimate should be what everybody reads directly for themselves, if they can. A wager is a good idea and I think it is working for those who come in contact with your story in some way.

    Comment by Edward Greisch — 13 May 2008 @ 6:40 PM

  7. Last week I criticised your bet as I thought it trivialised the issues involved but I understand your rationale better now.

    This post is exactly why this site is so popular for lay-people: it provides a clear explanation of climate change science and informed debate on current topics. Your best posts, like this one, allow lay-people to “see inside the heads” of how climate scientists think. For any objective, critical thinker reading your work the explanations of the assumptions you are making and the sources of error you identify both explain the issues involved and build confidence to accept your conclusions.

    As you say, your “assessment could of course be wrong” but a critical thinker reading your work is looking for the evidence and reasons you present to support your argument.

    Well done and thanks.

    Comment by Chris McGrath — 13 May 2008 @ 7:51 PM

  8. Dear group,

    It seems a pity that you have had to use this hammer to crack a nut; but it works!!!

    If only… If only they had let their paper speak for itself and had left out the big claim. The sadness is that if we bury this and I suspect you, others and simply the passage of time will. The interesting part (can and how oscillations be predicticted) will be buried alongside the headline result.

    To me it seems such a pity for them and all of us.

    Best Wishes

    Alex Harvey

    Comment by Alexander Harvey — 13 May 2008 @ 8:04 PM

  9. Why not propose your bet to Inhofe? The guy is utterly shameless.

    Comment by Ron Taylor — 13 May 2008 @ 8:06 PM

  10. RE:#6,

    I have a journalism degree technically, but I have three times as many science credits in environmental biology, physical science, and work as an endangered species biologist for the US Forest Service and others. It’s a good point though since most top reporters come from Ivy league schools where no such requirement exists. Not so at public universities. Since graduating a couple of years ago, (non-traditional) I’ve not landed so much as an interview for a reporting job. Editors are science averse like that guy in Ely, Nevada! It’s a real problem.

    Comment by Mark A. York — 13 May 2008 @ 9:13 PM

  11. Evidence shows that CO2 is going up at over 3% per year…Faster than in the highest IPCC scenario. Interesting to see if it continues at this rate…and what is causing it…drought?

    Good thing for the bet that there is a lag time.

    [Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]

    Comment by Richard Ordway — 13 May 2008 @ 10:35 PM

  12. Two excellent posts regarding Keenlyside, et al. As others have said, the paper is already being used to excuse denialists’ delusions despite the fact that the authors, themselves, say clearly that their paper does not contradict AGW and should not be used to assert it does. Rapid Climate Change is a real and present danger that short-sighted denialists/industrialists pay scant attention to. The delays in action created by the lies, distortions and muzzling done by Exxon and the Bush administration have already put the world into a percarious position given that climate changes are happening all over at far faster rates than ever considered possible just a year ago. Too many of the citizens of the US and Britain still believe there is substantive scientific uncertainty about climate change – even as George Bush lives in a “green,” off-grid home and now says climate change is real.

    One change I’m sure the Keenlyside authors couldn’t have considered is the much-more-rapid-than-expected release of methane in the Arctic that was reported in the last week or so. (Can’t find link now, but the results will do: http://www.csmonitor.com/2008/0428/p01s04-wogi.html )

    Keep up the good fight with good science.

    Cheers

    Comment by ccpo — 13 May 2008 @ 10:52 PM

  13. “Thanks for making this a betting matter, RC. It gives the question a higher profile.” I agree, but I wonder why RC does, as the higher profile gives the lie to the notion that there is universal scientific consensus on AGW. Granted Keenlyside predicts only a temporary reprieve before AGW predominates again, I doubt that nuance will make to the coverage of a Warming vs. Not Warming bet. RC fears the media is making an issue of Keenlyside temperature flattening — I see the media in comfortable lockstep with AGW proponents regardless of an occasional Keenlyside blip on the screen. AGW sells more papers, so to speak, than its absence. I admire the courage of RC’s convictions, then, because it has nothing to gain if the bet is won and everything to lose if the bet is lost.

    Comment by wmanny — 13 May 2008 @ 11:05 PM

  14. #13, wmanny that is such an disingenious, inaccurate, and lazy post.

    There is broad scientific consensus on the reality of anthropogenic climate change but there still a huge amount of ongoing research into many of the details. Keenlyside and his colleagues deal with some of the details but expressly state they not doubt the broad consensus view on the reality of anthropogenic climate change.

    Your suggestion that the bet offered by RealClimate “gives the lie to the notion that there is universal scientific consensus on AGW” is just plain wrong.

    Your comments about RealClimate’s motives and your suggestion that they are driven by “convictions” rather than good science indicate you are too lazy to engage them in a debate based on science and evidence.

    If you want to do some background reading on the scientific consensus statements (you seem in real need of it), there is a good compilation of them (with links) at http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change .

    Comment by Chris McGrath — 14 May 2008 @ 1:05 AM

  15. Re #13 “media in comfortable lockstep with AGW proponents” might have less to do with comfort and more to do with honest reporting. After all, they spent 20 years “comfortably” reporting the debate about AGW, but that debate is finally over, so the media have simply moved with the news. Can’t expect anything less, nor anything more, than that from the media.

    I guess I’m of two minds about this whole affair. Sure, let’s not let the “debate” thing derail us again just because a couple guys with a model think there might be a flat spot in the warming trend, if you hold the chart up to the light just so and squint.

    On the other hand… who gives a poop anymore? Seriously, it’s getting to the point where anyone who stands up in a crowd and says “my dog knows more about climate than Jim Hansen” is not going to like the reaction he gets. People in the streets are reading the reports carefully now, and what they are finding there gives little comfort. Setting aside the price of oil and its immediate impact on food, there is still enough going on with climate change and related water and agriculture issues to cause a prudent soul to glance around for an exit.

    Well we’re 7 billion prudent folk all glancing around nervous, and I’m not the first to point this out. And going forward, anyone says all this is just smoke and mirrors to get grants to study tree rings is advised not be standing under a sturdy limb and holding a rope when he’s saying it. If you follow my meaning.

    Comment by Cat Black — 14 May 2008 @ 1:42 AM

  16. I love that “monotonously”! Maybe monotonically? Or is this another example of the transAtlantic divide in language?

    John

    [Response: Thanks John, fixed that. Not transAtlantic, but we're not all born native speakers of the global language of science. -stefan]

    [Response: Actually, I almost changed that when were editing, but I thought monotonously was a little more apt.... - gavin]

    Comment by John Gribbin — 14 May 2008 @ 1:50 AM

  17. Latif’s group does not have much experience in modelling the MOC. But how could they (and the Nature reviewers) have overlooked so many obvious red flags? The fact that the hindcasts with their method perform worse than a standard IPCC scenario, the number of failed previous cooling predictions, the negative skill in the Gulf Stream and deep-water formation regions… should these not have cautioned them against going to the media to forecast a pause in global warming? Your bet does a good service, but I fear that it cannot undo the damage that they have already done in confusing the media public about global warming.

    Comment by Matthew Brunker — 14 May 2008 @ 2:20 AM

  18. Gavin, you responded at #11 that emissions are rising at 3% per year while concentrations only rise at 0.5% per year. That is somewhat logical because there was already some concentration before we started any emissions. However there is another phenomenon that I have been unable to understand, and I would like to know if there is any theory that explains it.

    Between the 80′s and the 90′s, man-made emissions of carbon from fosil fuels increased from about 5 billion tons per year to about 6.5 billion tons per year, which means a 30% increase in how much CO2 we put into the atmosphere yearly. However, the ratio at which CO2 concentration increases in the atmosphere slowed down between the 80′s and the 90′s, from 1.6 ppm/year to 1.5 ppm/year. Is there an explanation for that? Do you think it could be related to the rising temperatures and how it affects the Earth’s capability to sequester atmospheric CO2 by natural processes like the photosintesis of the plants? Or is there something else? And whatever the cause may be, is it predicted in the models?

    Thanks.

    Comment by Nylo — 14 May 2008 @ 2:56 AM

  19. “Even today, the fact that a few scientists predicted a global cooling in the 1970s is still used to undermine the credibility of climate science”

    Why does the HadCRU3 temperature data not show the cooling in the 1970s? Does the forecast of Keenlyside et al for this period, of a cooling, reflect the cooling in the 70s from other datasets?

    Comment by Alex Thomas — 14 May 2008 @ 3:04 AM

  20. Re: coupling shock

    Nice summary. I read the paper as saying that they are restoring to SST anomalies rather than the raw SSTs themselves – does this make a difference?

    [Response: Not to the coupling shock problem. -stefan]

    Comment by Ed — 14 May 2008 @ 3:13 AM

  21. There is no need to bet when you stick to the science (and measured data and observations as much as possible). The green line “forecast” for the period 1995-2000 in the graph above is well below actual observations for the same period. This speaks for itself.

    Also, evidence of the affects of global warming from many parts of the world speaks for itself – melting ice, droughts, increasing water supply problems in big cities like Barcelona etc.

    What causes doubt and confusion is that the effects of global warming are not uniform around the globe and there are always weather fluctuations (that may even increase in scale and predictability) as global warming progresses. Global circulation patterns are very complex and the effects of any changes are so difficult to predict on a local, regional level. This is why we need a focus on regional and local studies, observations, and assessment that do not depend so heavily on models.

    Professor Molina, Nobel Prize (chemistry) issued a stark warning recently (April, 2008) by suggesting that, “…long before we run out of oil, we will run out of atmosphere”. Professor Santilli (nominationed for the Nobel Prize in chemistry and physics) has raised the issue of atmospheric oxygen depletion – particularly in some of our largest cities around the world. The Chinese, for example, have planted a forest twice the size of New York’s Central Park on a 1,750-acre site north of the Olympic village in Beijing, to raise oxygen levels. Nearly a dozen factories are also closing or relocating outside Beijing, and factories hundreds of kilometres away will suspend operations for the duration of the olympics.

    Our emissions to the atmosphere impact on natural processes, the environment, and health in very many ways – the ozone hole was the first big warning. It is so important that we learn, inform and educate on the basis of the best known science – illiminating guesswork (and certainly no bets)!

    Comment by Gareth John Evans — 14 May 2008 @ 3:24 AM

  22. Re: RMS error and correlation skill

    The supplementary information to the paper has an interesting figure – Supp. Fig. 2c shows the difference in RMS (root mean square) error (as compared to the correlation maps shown in the main paper) between the hindcasts and non-initialised cases. There it demonstrates that the RMS error in the Atlantic is worse in the forecast cases compared to the non-initialised cases. There are a few regions where the forecast appears more skillful in this metric of skill, which could be viewed as more relevant when making forecasts.

    Comment by Ed — 14 May 2008 @ 3:38 AM

  23. You are always very polite and diplomatic. The guts of this story is really quite funny: a group of climate scientists manages to sell a weird model result, most likely an artifact due to an inadequate modeling technique, as a sensational forecast to Nature and the world media…

    I think the lesson of this story is that it is rather problematic that new climate science papers are now all over the media within hours of appearing in a journal, with political implications being discussed before the scientific community had time to properly assess and discuss the new study.

    Comment by Mark — 14 May 2008 @ 4:34 AM

  24. Brilliant article review, I hope I can capture some of the magic in the paper I am reviewing today. I understand the gist of coupling shock, but can you provide an example of how it would play out, and what can be done to identify and quantify this result.

    Comment by Mauri Pelto — 14 May 2008 @ 7:00 AM

  25. Re #22, yes the media has to learn that peer review is not the end of the scientific process but part of an ongoing process of validation and verification before it is allowed into the hallowed halls of scientific truths.

    Comment by pete best — 14 May 2008 @ 7:10 AM

  26. Whilst bets are of no use in determining the underlying physical reality, they are very useful in sorting out people’s real level of confidence in their predictions. This can be a useful indicator how strongly we lay-people should factor them into out considerations.

    I do hope Keenlyside’s team post here, their take would be interesting. From a policy and adaptation point of view such efforts to make more accurate short-term predictions could be valuable, if time bears out their predictions.

    #5 Martin Pierard,
    I wouldn’t think of a single global tipping point as such, what’s important in this respect are the different climate subsystems. In that respect you may find this page interesting:
    http://www.pik-potsdam.de/infodesk/tipping-points

    #17 Nylo,
    Those CO2 increments seem all over the place to me, when viewed on a short term basis:
    http://www.esrl.noaa.gov/gmd/ccgg/trends/ scroll down to global average.
    1998 is interesting, but without looking at what’s happening regionally I wouldn’t read too much into most of the year-to year variance. What is apparent is that on a multi-year basis the ppm/year increase is going up, try something like a 5 year moving average to filter inter-annual difference for the full record.

    With regards CO2 emissions uptake, have you read David Archer’s post on this? http://www.realclimate.org/index.php/archives/2007/11/is-the-ocean-carbon-sink-sinking/

    #19 Gareth John Evans,
    Out of interest, the Arctic Oscillation/North Atlantic Oscillation (which are intrinsically linked) seem to have a key role in both the Arctic ice loss (outflushing through the Fram Strait) – Rigor/Wallace) and the Mediterranean drying e.g. Figen Mekik’s post at RC http://www.realclimate.org/index.php/archives/2007/10/sweatin-the-mediterranean-heat/

    Professor Molina, Nobel Prize (chemistry) issued a stark warning recently (April, 2008) by suggesting that, “…long before we run out of oil, we will run out of atmosphere”.

    Mmmmm, I’m far from convinced.

    Comment by Cobblyworlds — 14 May 2008 @ 7:12 AM

  27. wmanny #13–Let’s get one thing straight. The consensus of scientists on climate change is that humans, by releasing massive amounts of the greenhouse gas, CO2, into the atmosphere, are largely responsible for the current epoch of warming. Keenlyside et al. is part of that consensus, not a challenge to it.

    You say, “I see the media in comfortable lockstep with AGW proponents… ”

    Well, I’ve always found the truth to be more comfortable than any lie. Actually, the media lag far behind the scientists in terms of the level of consensus. If they really understood the science, then the occasional outbursts by denialists would generate no more notice than a fart in polite company–a little embarassment for the offender, but no overt comment.

    Comment by Ray Ladbury — 14 May 2008 @ 7:59 AM

  28. Re #10

    ” It’s a good point though since most top reporters come from Ivy league schools where no such requirement exists.”

    That’s certainly not true of the one where I teach.

    Comment by Phil. Felton — 14 May 2008 @ 8:11 AM

  29. It is true that old fears of a new ice age did not originate with climate scientists [edit - no nonsense please] and I confess to being someone who worried about such things at that time. But was I wrong? When estimates of a possible return of an ice age still vary between this week and 50,000 years why should I be confident that the guys with tenure and titles have a handle on it?

    In that large, mysterious (to me, anyway) context, listening to climate scientists boldly predict changes or non-changes in the range of tenths of degrees over a mere 10 or 20 years strikes me as more than just a tad beyond hubris and more like a standard deviation or two into the delusional range. One volcanic burp, one solar belch, a passing cosmic cloud or some butterfly flapping its wings in New Jersey and entire models can become just really bad computer games.

    I admire the creativity and genius in climate modeling and the insights it can provide but when you guys start thinking it’s real, maybe it’s time to back away from the keyboard for a bit.

    Without the ugly constraints of the overarching politicized death struggle, there is a beauty even in the uncertainties of this pursuit. To minimize or even fail to investigate uncertainties lest it give comfort to the denialist foe is no way to live.

    Comment by CarbonSink51 — 14 May 2008 @ 8:49 AM

  30. #29 – the phenomenon of greenhouse gases retaining heat at the surface of the earth operates on decadal scales, and the orbital variations (Milankovitch cycles) which cause the waxing and waning of the ice ages operate on millennial scales, and both are fundamental physical processes, and are not elucidated by computer models. Nothing is going to change those results, short of a complete refutation of fundamental physics – unlikely.

    The computer models deal with the actual energy and matter flows within, and in and out of the system, and do not account for random geological or cosmological events, such as volcanic eruptions or asteroid impacts, solar disturbances, etc. However, these computer models are also based in fundamental physics, and the random events can be modelled as well, if not predicted in advance.

    Comment by Thomas Lee Elifritz — 14 May 2008 @ 9:23 AM

  31. This begs a question. Should you lose the bet, what ramifications does that have for AGW theory? How many years of cooling will it take before AGW theory is debunked? Let’s see a commitment from RC staff on this. How many years of continued cooling will it take for AGW theory to be rejected? You like bets, then place one on that.

    [Response: None. About 20. Like I said. Lot's of bets have been offered - few taken. - gavin]

    Comment by Richard Wakefield — 14 May 2008 @ 9:23 AM

  32. CarbonSink51, Spoken like a man who doesn’t understand the science. Look, the GCMs are complicated, and yes there are uncertainties, but the fundamental reality, the 800 pound gorilla in the room is the fact that CO2 traps outgoing infrared radiation. Since such radiation is the only way energy escapes the climate system, that has to heat things up. Since the only escape clause is some magical negative feedback that kicks in to keep climate from warming above its current level, and since there is no such mechanism known and further since climate has warmed above this level in the distant past, I’d say this is pretty darned unlikely. Those who look to such a mechanism are appealing to Disney’s first law–Wishing will make it so.

    Comment by Ray Ladbury — 14 May 2008 @ 9:40 AM

  33. Sad to say, I keep hearing people — and these are bright people — say “I don’t believe in global warming.” I don’t know how to get away from paralyzing fear that must be the driver of this sort of comment — they don’t want to believe it.

    I’m writing a novel with a denier in it, and tried to come up with a carp about the GW science that hasn’t been used. Just my luck, I decide the denier announces that global cooling has begun! reality imitating art…

    Comment by veritas36 — 14 May 2008 @ 9:46 AM

  34. > 21, Gareth

    Molina was talking about climate change.

    Santilli? Look him up. Utterly off topic.

    Comment by Hank Roberts — 14 May 2008 @ 9:52 AM

  35. You don’t have permission to access /~stefan/Publications/Journals/rahmstorf_climdyn95.pdf on this server.

    [Response: I made a local version you shouldn't have a problem with (link above). - gavin]

    Comment by Chad — 14 May 2008 @ 10:05 AM

  36. [Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]

    Hi Gavin,

    I clearly heard the exact phrase “over 3%” deliberately and clearly stated yesterday at a government-funded research institute in Boulder at a presentation by a visiting publishing scientist using the latest sources who is researching the latest CO2 trend anomalies.

    Of course, this is my own personal opinion, the researcher might have been exagerating (I doubt it..the researcher would have been crucified by other publishing experts present..not to mention their reputation) and my statement is not in any way connected to any single institution.

    Comment by Richard Ordway — 14 May 2008 @ 10:54 AM

  37. This is nice, that climate scientists have reached consensus. If you want to convice the general public to the “tipping point” that we actually as a society begin to do something about it. You must preserve your credibility, and resist the temptation to say, every time that there is a hot day or a hurricane “see-it is global warming”. Because surely then when there is a cold day or a calm season, you have taught the deniers.
    And when the arctic ice melts – faster than the models predict – who can say this is AGW?

    Alien (Only art, no science)

    [Response: If you care to look, we have been remarkably consistent on that point. - gavin]

    Comment by Alien — 14 May 2008 @ 11:26 AM

  38. Re #36: Possibly a reference to the increase in the rate?

    Comment by Steve Bloom — 14 May 2008 @ 12:07 PM

  39. And when the arctic ice melts – faster than the models predict – who can say this is AGW?

    Why do you think it’s melting? Global cooling?

    Comment by dhogaza — 14 May 2008 @ 12:35 PM

  40. You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.

    Comment by Ray Ladbury — 14 May 2008 @ 12:36 PM

  41. RE#38 I think that we are in deep doo doo a’la AGW. I am just pointing out that if the speed of arctic ice melting is outside the parameters that are predicted by the model, then the model might be wrong.
    Alien

    Comment by Alien — 14 May 2008 @ 2:07 PM

  42. As one that repeatedly asked that you rescind your bet in favor of a gentleman’s bet, I commend you for agreeing to a non-financial bet. I still believe that the wager is too high but it will be interesting if Keenlyside et. al. will respond with terms that are more fitting with science and its discussion – perhaps a year’s subscription to Nature magazine for the inner city high school of the winner’s choice.

    One question on your logic that I don’t quite understand (and perhaps I am misinterpreting the chart at the top of the article). You state in point 2 that since there are two false cooling forecasts that the model is suspect. While I grant you that the large gap in the late 90s is of huge concern, isn’t that same concern warranted with the large continuous gap from actual in the IPCC hindcast from 1965 to 1985?

    Comment by Sean O — 14 May 2008 @ 2:20 PM

  43. “You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.”

    No biggie, but Gavin I’m sure has my two IP addresses. One of them is rather blatent and has been so for the two years or so that I’ve been posting on this blog.

    Comment by Richard Ordway — 14 May 2008 @ 2:37 PM

  44. Re #42 Sean O,

    No there isn’t a concern about the IPCC model and the small deviations from the measured temperature evolution during the period around 1970-1985. The IPCC models make no claim to reproduce every variation in the temperature evolution in response to enhanced greenhouse forcing. That’s the whole point, of course. Everyone recognises that the Earth undergoes a warming response to enhanced greenhouse forcing. In general it’s recognised that prediction of the so far unpredictable phenomena (El Nino’s, La Nina’s, the fine details of ocean circulation oscillations, volcanos and any solar variation outwith the 11 year solar cycle) that provide short term modulation of any trend is likley to be unfruitful at present.

    However Keenleyside et al are claiming to be able to predict the trend incorporating these short term modulations. Therefore Keenleyside’s assertions concerning the short term should be subject to the degree of scrutiny commensurate with their particular claim. That doesn’t apply to the IPCC simulations since they make no such claim of being able to predict short term modulations of the long term trend. That’s obvious isn’t it?

    Comment by Chris — 14 May 2008 @ 3:21 PM

  45. Re #18: Nylo says “Gavin, you responded at #11 that emissions are rising at 3% per year while concentrations only rise at 0.5% per year. That is somewhat logical because there was already some concentration before we started any emissions.” Actually, you are trying to compare two numbers that have completely different meanings…It is an apples-to-oranges comparison. The 3% per year is the amount by which the emissions are increasing…and (assuming that the fraction of this that stays in the atmosphere is constant) this would then be essentially proportional to the second derivative of the concentration of CO2 in the atmosphere with respect to time. However, the 0.5% per year is the rate at which the concentration of CO2 in the atmosphere is increasing…i.e., it is essentially the first derivative of the concentration of CO2 in the atmosphere with respect to time.

    Thus, whether this 0.5% value is less than, greater than, or equal to the 3% value is irrelevant. It is sort of like trying to figure out if my weight in pounds is less than my height in centimeters and attaching some deep meaning to it.

    Comment by Joel Shore — 14 May 2008 @ 3:51 PM

  46. #1

    “As I explain, the Nature study is consistent with the following statements:

    * The “coming decade” (2010 to 2020) is poised to be the warmest on record, globally.
    * The coming decade is poised to see faster temperature rise than any decade since the authors’ calculations began in 1960.
    * The fast warming would likely begin early in the next decade — similar to the 2007 prediction by the Hadley Center in Science”

    If 2005-2015 turns out to be cooler than 1995-2005, do you think that would be cause to question the projected warming for 2010 to 2020? What about longer projections? I guess my main question is: what projections of warming can be accurately assessed for their true accuracy in the short term (next ten years or so)?

    Comment by Jared — 14 May 2008 @ 4:19 PM

  47. #44

    “Everyone recognises that the Earth undergoes a warming response to enhanced greenhouse forcing.”

    But what is debatable is the degree of that warming response, and what amount of forcing correlates into how much warming. And how much of the warming seen in the past century is conclusively due to GHG.

    Comment by Jared — 14 May 2008 @ 4:24 PM

  48. > debatable

    Wrong concept, for scientific work.
    Try for publishable. It’s harder, but it’s useful.

    Comment by Hank Roberts — 14 May 2008 @ 4:49 PM

  49. Re: 27

    “Actually, the media lag far behind the scientists in terms of the level of consensus.”

    No doubt. Generally, the public forms views by what it sees in the media and internet (not peer-reviewed journals, academia, scientific conferences, or the consensus from the major science academies) and what I see in the general media a pretty even mix, with many outlets covering contrarians exclusively (such as the WSJ op-ed columns to name one of many). The result is that the same handful of contrarian names get constantly recycled to the point where they have long reached virtual celebrity status. It’s a little disconcerting.

    RC is an outstanding site and I’m amazed at the patience the scientists express here, but for every site of this quality there seem to be several junkscience.coms.

    Comment by gmb — 14 May 2008 @ 6:47 PM

  50. Why did GISSTEMP for March fall from 0.81 deg to 0.68 deg?
    http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
    This makes the first 4 months of 2008 the coolest since 2000.
    PJ

    Comment by Peter Johns — 15 May 2008 @ 1:27 AM

  51. I’ve just finished reading an article in a popular Italian newspaper titled “The catastrophe of the catastrophists” in which the “pause in global warming” forecast in Nature is deliberately depicted as a terrible debacle for the community of climate scientists.
    Unfortunately we don’t have resources like Real Climate in our own language to question such silly arguments and a lot of people will just believe what they read in the newspaper. Quite sad..

    Comment by Paolo Morelli — 15 May 2008 @ 4:50 AM

  52. Ref 50 Peter Johns asks “Why did GISSTEMP for March fall from 0.81 deg to 0.68 deg?
    http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
    This makes the first 4 months of 2008 the coolest since 2000.” Presumably because that is what actually happened; the “measured” temperature for April 2008 was 0.68 C. If the satellite data reported daily for May is representative of GISTEMP, then the May figure will be around the same number.

    Comment by Jim Cripwell — 15 May 2008 @ 8:40 AM

  53. Why did GISSTEMP for March fall from 0.81 deg to 0.68 deg?

    Actually it rose from 0.33C the month before to 0.68C.

    Is there any particular reason why you think comparing Feb ’07 with Mar ’08 is more valid than comparing Feb ’08 with Mar ’08?

    Is there any particular reason why you think such month-to-month comparisons are meaningful in the first place?

    Oh, and the question, Alex, is “What is La Niña”.

    Comment by dhogaza — 15 May 2008 @ 9:07 AM

  54. I never believed there would be a pause in global warming, thanks for your article about it.

    I have a nephew who is a student at Princeton University and he is pursuing a degree and career regarding how to save the planet from global warming problems. I’m going to email him the link to this blog. He might already have it, but I’m going to email it to him anyway.

    I just read a magazine article about how we could be getting fuel from algae, and be able to get rid of our dependence on fossil fuel. Wouldn’t that help to slow down the global warming?

    Thanks for the good work and the good fight!

    Comment by Pebbles — 15 May 2008 @ 9:38 AM

  55. Re #45 Joel Shore: You are completely right. But that was not the point I was trying to make. As you say, the 3% should be, if anything, proportional to the second derivate of the concentration of CO2 in time. And that is what I addresed next. How could it be, that during the eighties and the nineties the emissions were growing at about a full 3% per year, and yet the second derivate of the concentration was 0 or slightly negative?

    My guess was that the rising temperatures did the miracle, and because they stopped rising in 2000, now the second derivate is positive. But in the eighties and the nineties, an improved response by the photosintesis of plant life due to increased temperatures would have been able to neutralise all of the extra emissions we were sending to the atmosphere with respect to the emissions of 1980, and becaue of that the increase in the concentration of CO2 (the first derivate) became constant (i.e. the second derivate was 0).

    Cobblyworlds in #26 suggested that the fact that we have more CO2 in the atmosphere has made the oceans be able to also keep more CO2, taking it from the atmosphere. He is right about the physics of the process. However I doubt that that is the real reason, for 2 things: first, the absolute change in concentration of CO2 was very little as to absorb that much; second, the ocean temperatures were increasing at the same time, which means they can absorb less CO2, because of another phenomenom called outgassing, which may well cancel or even override the first one. And third, we are still rising our emissions, the conentrations are still increasing, and it is like the ocean stopped absorbing CO2. Why? It makes no sense. The photosintesis hypothesis looks better correlated with the known events we are experimenting, and also has a well known physical process to support it.

    [Response: This is all very well, but wrong. You have to explain the O2 change (Keeling et al) and the d13C changes as well. They clearly point to the fact that the ocean has been the net sink for almost all the carbon (uptake by land in some areas is mainly balanced by deforestation in others). Plus we have direct inventories of ocean carbon that confirm the rise (see IPCC AR4 2.3.1). - gavin]

    Comment by Nylo — 15 May 2008 @ 10:02 AM

  56. re 32
    We could deal with one 800 pound Silverback in the room. The problem is that there are two big gorillas in the room – the other one is the ice sheets. Together, They are likely to cause quite a ruckus.

    Comment by Aaron Lewis — 15 May 2008 @ 11:07 AM

  57. I know climate science is complex but thinking about warming of a block of ice in a glass, the temperature increase will stall for a while at 0deg.C while the ice melts before taking off again. It could just be that the same thing is happening on a global scale.

    Comment by Mark Sharkey — 15 May 2008 @ 1:11 PM

  58. Mark Sharkey–Yes, the temperature IN THE VICINITY OF THE ICE stops rising. However, I would be reluctant to attribute a cold winter in Baghdad to melting ice at the poles. This is weather. The skeptics will continue to crow that warming stopped in 1998, just like they did in 1996 and 1993 and 1991… They will do so until the next big El Nino knocks us up to another record year, and when the following year is cooler than the record, they’ll say global warming stopped them. Hell, I’m surprized they don’t claim warming stops every winter just for the practice!

    Comment by Ray Ladbury — 15 May 2008 @ 1:44 PM

  59. #36, #11 etc. I’m not sure what your point is. Hearing the phrase “over 3%” in Boulder yesterday doesn’t contradict Gavin’s assertion: [Response: Emissions are rising 3% a year, concentrations at just over 0.5% a year (~2ppm). - gavin]

    You can easily discern the correct numbers with google.

    These numbers confirm that Gavin’s 3% for the emissions rate is correct.

    http://www.earth-policy.org/Indicators/CO2/2006_data2.htm

    This site gives the growth rate in ppm:

    http://www.esrl.noaa.gov/gmd/ccgg/trends/

    Typical annual increase is about 2 ppm/year.

    The CO2 concentration is about 380ppm. Thus the fractional increase is 2/380 = .005 = .5% as Gavin stated.

    Comment by John E. Pearson — 15 May 2008 @ 2:17 PM

  60. The April numbers are in from GISS and HadCRU.

    GISS: .51 anomaly. Dropped .17 from March. 2008 so far the coolest year globally since 2001.
    HadCRU: .25 anomaly. Dropped .18 from March. 2008 so far the coolest year globally since 1997.

    In addition, 2008 has been the coldest year in the U.S. since 1993.

    Comment by Jared — 15 May 2008 @ 3:41 PM

  61. > 3%, Richard Ordway
    It’d be interesting to know what source you were relying on when you wrote “evidence shows” — where did you get that? Link or cite? If it’s an error somewhere it’s worth correcting. If it was misread, that’d be useful to know.

    Comment by Hank Roberts — 15 May 2008 @ 4:00 PM

  62. I am an amateur at this subject but I keep up with this website and I admit I’m a partisan pro-climate changer. But I wanted to bring up a previous bet by a few russian scientists a few years ago claiming that there will be a pause as well (global cooling briefly) and then roaring back heating. Whatever happened to that bet ?

    Thanks :-P

    Comment by Nick dePalma — 15 May 2008 @ 4:09 PM

  63. Sir Gilbert Walker’s (“discoverer” of the Southern Oscillation) words seem apposite here with respect to short term predictions of “climate” and their value and the dangers of making predictions on unsubstantial grounds:

    Speaking (of the monsoon) at the 1930 meeting of the Royal Meteorological Society, Walker stated:

    “In general the object of prediction is to assist the layman, and it is the opinion formed by him that decides whether they will suceed or fail. Hence I regard it foolish to issue a prediction except in years when the indication for an excess or deficit [of rainfall] are so strongly marked as to give a 4:1 chance of success….and as the claim to “forecast” the seasons arouses the expectation of an annual precipitation, I advocate the word “foreshadow” as expressing a smaller ambition”

    Do Keenlyside consider their prediction to be a “forecast”….. or a “foreshadow”….?

    [Walker quotation from J. Madeleine Nash "El Nino: Unlocking the Secrets of the Master Weather-Maker" AOL-Time Warner 2002, p 45.....which is a very good read]

    Comment by Chris — 15 May 2008 @ 6:18 PM

  64. Gosh, Jared has discovered weather. Next think you’ll know, he’ll discover climate.

    Comment by dhogaza — 15 May 2008 @ 6:30 PM

  65. Nick:
    http://julesandjames.blogspot.com/2005/08/bet.html

    (I Googled: climate Russian scientists bet cooling
    and it popped right up.)

    Comment by Hank Roberts — 15 May 2008 @ 7:03 PM

  66. #60. Golly, Jared, thanks for the weather report. Maybe there’s a domain name “realweather” and somebody will care there.

    Comment by Ray Ladbury — 15 May 2008 @ 8:05 PM

  67. Hank Roberts Says:
    15 May 2008 at 4:00 PM
    > 3%, Richard Ordway

    [[It’d be interesting to know what source you were relying on when you wrote “evidence shows” — where did you get that? Link or cite? If it’s an error somewhere it’s worth correcting. If it was misread, that’d be useful to know.]]

    Hank, I’ll get their source…I need to know myself. I was out of the office today. It was from an in house presentation from a visiting scientist. Thank’s for reminding me.

    If I mistated it, I will gladly post that too. Like I said, any of the moderators can look up one of my two IP addresses and know where the source was. Speaking of which, finding out where I heard the original presenter speak, would probably take you about two minutes if you really wanted to.

    Comment by Richard Ordway — 15 May 2008 @ 10:56 PM

  68. Hank Roberts wrote:
    “where did you get that?”

    You could also look at the acknowlegements section of the book “Climate Change” by Bob Henson :)

    Comment by Richard Ordway — 15 May 2008 @ 11:12 PM

  69. Unless I missed something, I’m not seeing anything as to whether your bet has been accepted. What’s the status?

    If nothing else, it would be nice if Keenlyside et al would come by here and post a response – I hope they are taking this in good spirit.

    This is turning into a nice demonstration of how blogs like this one can supplement comments and replies in the published literature – it’s fast, informal and more public.

    Comment by tharanga — 15 May 2008 @ 11:40 PM

  70. Ray:

    You know, when somebody introduces themselves as “veritas” or Mr. Friendly the used automobile salesman, I reflexively reach for my wallet.

    Reach for a bat instead.

    Responding to gavin’s response:

    This begs a question. Should you lose the bet, what ramifications does that have for AGW theory? How many years of cooling will it take before AGW theory is debunked? Let’s see a commitment from RC staff on this. How many years of continued cooling will it take for AGW theory to be rejected? You like bets, then place one on that.

    [Response: None. About 20. Like I said. Lot’s of bets have been offered - few taken. - gavin]

    Respectfully, I disagree. If we see — call it 3 to 5 years — a period of cooling that isn’t predicted by the same people predicting warming, any progress on reducing emissions will be lost and the consequences will be worse. After several warm winters and summers, most people I know that I talk to causally about global warming were “convinced”. Now, with two regular winters, a mild summer, and what looks to be another mild summer, the “it was a scam” drumbeat is growing.

    It’s like the stupid “Gasoline Tax Holiday” ideas being floated here in the States. The most direct measure we have of scarcity is cost, and cost needs to accurately reflect scarcity or people will forget it is “scarce”. Dropping the tax will increase consumption, and then when the poop really hits the propeller, things will be even worse.

    Comment by FurryCatherder — 16 May 2008 @ 12:01 AM

  71. dhogdzha – March was initially 0.81 when first added 4 weeks ago but the Mrch figure decreased to 0.68 when the April data was added. I was talking March only, not the change from Feb to March.

    Comment by Peter Johns — 16 May 2008 @ 2:00 AM

  72. #55 (Gavin response): If photosinthesis is not the cause, why does it happen that the years in which CO2 concentration increases the most are years which are colder than the year before, independently of the changes in emissions? Also, why do you think that the ocean’s absorption of CO2 has reduced so much? We didn’t change too much the rate of increased emissions, but the rate of increase of CO2 concentration has raised a full 25% from the 90′s. Another thing, you make reference to O2 changes and d13C published somewhere. Is there a link I can follow to read that information?

    Thanks a lot.

    Comment by Nylo — 16 May 2008 @ 2:15 AM

  73. Furrycatherder, While a few years of cooling might change the urgency in the collective mind of the great unwashed, it will not change the science. Hell, the public mind changes with the weather–literally. Ultimately, it will come down to education. I am hoping that as climate models improve we’ll have a better fix on the realistic risks. I really believe that one of the things driving opposition to the science is uncertainty over what actions will be required to limit damage from climate change. Most people envision going back to the horse and buggy days, and they are understandably loathe to do that. I think that if we can come up with a concrete plan of action and show that it does not destroy the economy, we will win a lot more converts.

    Comment by Ray Ladbury — 16 May 2008 @ 10:10 AM

  74. Ray #73, I agree with your post and the need to act without destroying the economy. One of the problems is that there are proposals from various state legislatures (US)and other organizations to reduce emissions by 80 percent by 2050 to stabilize CO2 levels. If you account for population growth between the baseline year of 1990 and 2050, you end up in 2050 with a per capita carbon footprint that gets us back to where we were in colonial times. So the horse and buggy days fear is not unfounded.

    Comment by B Buckner — 16 May 2008 @ 11:33 AM

  75. B. Buckner, To claim that because we cannot burn fossil fuels, we cannot consume energy is a fallacy. With oil becoming ever more scarce, our energy consumption will have to change in any case. Adding climate to the equation eliminates coal as an option, but that is about all. I would claim that this is a problem that could have a technical solution–and technical solutions often have a way of finding applications that make the economy grow.
    The main problem is that we don’t know how close we are to various tipping points, so it makes sense to try to conserve as much as possible in order to buy time. The goal has to be sustainability, and sustainability is not incompatible with growth, as long as the growth comes via technological advance.

    Comment by Ray Ladbury — 16 May 2008 @ 1:21 PM

  76. #72 Nylo,

    If photoynthesis is the cause then why the change in isotope composition?

    A large part of the CO2 we emit is absorbed by the ocean and land biological processes. Any changes in either ocean (Weather/El Nino’s, circulation changes, etc) or land, (warmer/cooler or wetter/dryer years) will impact how much is taken up. That means the amount added to the atmosphere would vary even if we were emitting a constant amount each year. Actually we’re rapidly increasing emissions on a global basis.

    And on the subject of warm/cool or wet/dry years: The article by David Archer that I linked to discusses cases where average wind conditions have changed and this, not primarily temperature, has reduced CO2 uptake by the oceans.

    With regards an explanation of isotopes and how we know the CO2 increase is down to humans: Just click on Index at the top of this page, and scroll down to “Greenhouse gases:”, you need the second link down, entitled “How do we know that recent CO2 increases are due to human activities?”. It is not a coincidence that the article explains how we know the CO2 increase is due to human activity.
    ;)

    #74 B Buckner,

    So the horse and buggy days fear is not unfounded.

    I think it is unfounded, personally I consider it a straw man.

    Based on those I know at work and socially, I consider it inherently improbable that you could get people to vote for a government that proposes such austerity. There are 2 reasons I have reduced my emissions: Because it’s the right thing to do and because it saves me money.

    Comment by CobblyWorlds — 16 May 2008 @ 1:42 PM

  77. > finding out where I heard the original presenter speak
    Richard, that doesn’t matter, I’m just asking for a source for the number — ‘reference librarian’ not ‘private investigator’ question.
    Next time I see the number in someone’s blog, I’d like to point to a cite for it, not trying to blame it on anyone (grin).

    Comment by Hank Roberts — 16 May 2008 @ 1:46 PM

  78. Hi Hank,

    Here is the peer-reviewed reference from the National Academy (PNAS) on CO2 rising more than 3% per year:

    “CO2 emissions from fossil-fuel burning and industrial processes
    have been accelerating at a global scale, with their growth rate
    increasing from 1.1%/y for 1990–1999 to >3%/y for 2000–
    2004.

    The emissions growth rate since 2000 was greater than for
    the most fossil-fuel intensive of the Intergovernmental Panel on
    Climate Change emissions scenarios developed in the late 1990s.

    ‡‡CO2 data are available at http://www.cmdl.noaa.gov/gmd/ccgg/trends.”

    Raupauch et al. PNAS 2007. “Global and regional drivers of accelerating
    CO2 emissions”
    http://www.pnas.org/cgi/reprint/0700609104v1

    Comment by Richard Ordway — 16 May 2008 @ 3:17 PM

  79. 77 Ordway’s original comment was bizarre: “Evidence shows that CO2 is going up at over 3% per year”

    since he doesn’t actually say what it is that he’s talking about. “CO2 is going up”? What is that supposed to mean? Up into the sky? Up in concentration? Up in rate of emission? In none of his subsequent remarks did he acknowledge that his original post was incoherent.

    if you want a source for Gavin’s numbers you can click on the links that I posted in 59 and you’ll find all the numbers you need to get an estimate that is in accord with Gavin’s claim of emissions rate increasing at 3%/year and concentration increasing at 0.5%/year.

    Comment by John E. Pearson — 16 May 2008 @ 3:26 PM

  80. There we go, it’s _emissions_ not _atmospheric_level_ going up at three percent, which does make sense.

    Illustrating why to state units when quoting digits (grin).

    Comment by Hank Roberts — 16 May 2008 @ 4:47 PM

  81. Hi,

    Re #6,

    ‘RealClimate needs to be read by the whole world. You are often too mathematical for almost everybody. Your concepts are mathematical. Nonetheless, RealClimate should be what everybody reads directly for themselves, if they can.’

    I am about to set up a web site that, amongst other things, will report such things as Realclimate articles (with citation). The idea is that it will be aimed at a slightly less educated audience
    than this site. The web site exists but is currently private.

    Comment by John Bartlett — 16 May 2008 @ 6:50 PM

  82. Re 31: I assume that 20 years includes the previous 10 that has shown a flat temperature change, so on Jan 1, 2019 and the world has not heated up you will declare AGW theory false, right?

    Ok, so let’s add others to the mix. How many years of there not being any acceleration in the rate of sea level rise would it take to declare AGW theory false? To accommodate the IPCC the rate would have to increase 3-5 times the current 1.33mm/yr, the same rate it’s been for at least the last 110 years. Some of the more extreme increases would call for a rate increase of 30 to 40 TIMES the current rate. So, how many more years of flat rate will it take to abandon AGW theory?

    Comment by Richard Wakefield — 17 May 2008 @ 7:46 AM

  83. Richard Wakefield, What is it with the anti-science crowd and “falsification”? A failure of models to predict correctly does not necessarily mean the model is completely wrong. More likely, the model is incomplete. It neglects a factor that is important during the period under question. This factor may counter the anthropogenic hypothesis, or it may merely mask it for awhile. A Grand Solar Minimum, as many in the denialosphere are blogviating (btw, thanks to the RC folks for this term), does not mean that CO2 is unimportant, as it will kick in with a vengeance when the minimum ends. You guys really need to look into how science actually is done. There’s more to it than Karl Popper.

    Comment by Ray Ladbury — 17 May 2008 @ 9:29 AM

  84. Assuming, for the purposes of this question, that the Keenlyside et al paper is right so that there will be a pause in the rise of land and sea surface temperatures, am I right in thinking that this does not indicate a pause in global warming in that, during the pause in the rise in surface temperatures, the temperatures in the ocean below the surface layers would be increasing?

    If so, would such rises be very small compared with surface temperature rises? I’m thinking that they would be because of the huge thermal capacity of the ocean.

    Again if so, are ocean temperature measurements made with sufficient accuracy that such rises could be detected reliably?

    Comment by Ed Davies — 17 May 2008 @ 10:53 AM

  85. Re Richard Wakefield @82: What 10 year flat temperature change?
    http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/
    I don’t see a ten year flat temperature change anywhere on that graph.

    Nor on this one
    http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

    As for your 1.33 mm/yr rate of sea level rise, you are woefully behind in your reading:
    http://www.sciencemag.org/cgi/content/abstract/sci;294/5543/840
    Even if entirely due to thermal expansion the current rate is almost double that.

    Not only do you guys really need to look into how science is actually done, you need to look into what the science actually says.

    Comment by Jim Eager — 17 May 2008 @ 11:13 AM

  86. Ed Davies, I think you are basically correct. The heat does not leave the system. However, the extent of the warming in the ocean depends on how much mixing (e.g. to what depth) occurs.

    Comment by Ray Ladbury — 17 May 2008 @ 12:24 PM

  87. > falsification

    The physical theory and data collection can be falsified — that’s the individual pieces.

    A whole model can’t be falsified. Willy Ley once famously remarked that analysis is all very well, but you can’t figure out how a steam locomotive works by melting it down and analyzing the mess. You have to look at the pieces and test each one.

    Same thing when airplanes fall out of the sky. That doesn’t falsify aviation, or the particular airplane design, or flight in general.

    A repeated problem can falsify one component:

    http://www.promotex.ca/articles/cawthon/2005/2005-06-15_article.html

    “… The testing took months but finally identified the problem. The stresses caused by thousands of takeoffs and landings were causing the plane’s aluminum skin … to crack …. Eventually the metal would completely fail, causing immediate depressurization of the cabin and catastrophic structure failure….”

    That falsifies one design element, not the whole idea of flight.

    If a problem once identified fails to be understood, yes, later designs will have the same kind of failure:

    http://www.ec.erau.edu/cce/centers/edwards/SF335/CaseStudy1Pres.htm

    “… As the airplane leveled at 24,000 feet, both pilots heard a loud “clap” or “whooshing” sound followed by a wind noise behind them. The first officer’s head was jerked backward, and she stated that debris, including pieces of gray insulation, was floating in the cockpit. The captain observed that the cockpit entry door was missing and that there was blue sky where the first-class ceiling had been….”

    There is no such thing as a fail-safe design:

    http://peanuts.aero/low_cost_airline_news/airline/8661//Southwest+Airlines+provides+Testimony+to+US+House+of+Representatives+Committee+on+Transportation+and+Infrastructure
    “The Boeing 737 Classic was designed with a ‘fail-safe structure’…”

    Current aircraft use far more modeling in the design than the older ones. No one claims to be able to “falsify” computer models per se, or even individual models at a particular point in time.

    Well, no one who uses or understands them.

    So, see someone claiming some one fact can falsify a model, or modeling?

    Check their cites.

    Comment by Hank Roberts — 17 May 2008 @ 1:05 PM

  88. Re: 74

    To add to the other comments, the “horse and buggy” logic seems to go like this:

    1. Before fossil fuels, quality of life was lower (horse and buggy).

    2. Fossil fuels increased quality of life.

    3. Therefore, a strong move away from fossil fuels will return us close to (1).

    Problem is, in the horse and buggy days, we didn’t really have a great ability to capture wind and solar energy, among other things. There wasn’t the option of nuclear power. There was no such thing as EV or plug-in hybrids. Carbon sequestration wasn’t a possibility in the near future. There wasn’t a range of other options to make us more energy-efficient.

    Some technologies are already economically viable:

    http://news.yahoo.com/s/ap/20080512/ap_on_go_ca_st_pe/wind_energy

    Comment by gmb — 17 May 2008 @ 1:58 PM

  89. #83 “A failure of models to predict correctly does not necessarily mean the model is completely wrong.”

    That’s the best you got? Kidding aside, I know it’s not your best, but you have to admit that statement is a fair distance removed from “an overwhelming scientific consensus has determined humans are responsible for most of the global warming in the last xx years.” I appreciate the honesty, and it’s good to see some healthy scientific caveats emanating from the insistosphere.

    Comment by wmanny — 17 May 2008 @ 8:06 PM

  90. #32 Ray Ladbury,
    The 500 kg CO2 gorilla’s dad in the room is the 4000 kg H20 that also slows the rate of heat loss from the surface to space. (In and of themselves, the gorilla family would block about 1% of out-going infra-red radiation. Feedbacks, both positive and negative, are well known to climate science – much of the uncertainty revolves around the net effects of clouds which exhibit both forms). A slowing rate of heat loss means cooling more slowly than before, not warming. Surface temperature equilibrium is reached when the sum of the energy absorbed by the surface from the sun and the from atmosphere equals the energy it radiates to space. At equilibrium, changes to either the sun’s or the atmosphere’s radiation fluxes would determine whether the surface begins to warm or continues to cool. The changes need be only small to switch the temperature from equilibrium. We know from geology that the surface temperature periodically reaches equilibrium, switching between ice ages and inter-glacial warm periods. We know from the laws of physics and astronomy about the cyclical fluctuations on an increasing trend in the sun’s radiation. We know, from the same laws, about cyclical fluctuations in the sun’s magnetic field and, consequently, in the entry into the atmosphere of cosmic rays, a form of energy. We know from ice-core analysis about the cyclical variability in atmospheric concentration of CO2. We can find correlations between temperature on the one hand and both sun’s radiation and atmospheric concentration of CO2 on the other. We know that the latter correlation is time-shifted, temperature leading CO2 concentration. We ought, therefore, to agree that pre-human, or more precisely, pre-industrial climate change was caused by changes in solar activity; that these effects continue today; and that past changes in the atmospheric concentration of CO2 remain to be explained. We ought also to agree that fossil fuel burning industrialisation pumps increasing quantities of CO2 (plus water vapour and sensible heat – I wonder whether the models include these?) directly into the atmosphere. This is where questions and disagreements begin. The IPCC argues that these effects completely swamp solar ones, on two main grounds: first, the rate of warming in the latter half of the 20th century exceeds all previous experience; and second, otherwise their models don’t make sense. Well, the latter sounds a bit chicken and egg-ish to this layman. As to the former, the Central England temperature record contains a period of warming three times as much in two- thirds of the time. On the other side of the Atlantic, unpublicised revisions to the US temperature record reveal that six of the hottest ten years occurred in the first half of the 20th century. What I would like the climate models to tell me is when, in the absence of AGW, average global surface temperature would reach its zenith before beginning descent into the next ice age. I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation. A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?

    Comment by John Millett — 18 May 2008 @ 2:21 AM

  91. Re 85:

    James, did you not read that abstract on sea level change?

    Science 26 October 2001:
    Vol. 294. no. 5543, pp. 840 – 842
    DOI: 10.1126/science.1063556
    Prev | Table of Contents | Next

    Reports

    Sea Level Rise During Past 40 Years Determined from Satellite and in Situ Observations
    Cecile Cabanes, Anny Cazenave, Christian Le Provost

    The 3.2 ± 0.2 millimeter per year global mean sea level rise observed by the Topex/Poseidon satellite over 1993-98 is fully explained by thermal expansion of the oceans. For the period 1955-96, sea level rise derived from tide gauge data agrees well with thermal expansion computed at the same locations. However, we find that subsampling the thermosteric sea level at usual tide gauge positions leads to a thermosteric sea level rise twice as large as the “true” global mean. As a possible consequence, the 20th century sea level rise estimated from tide gauge records may have been overestimated.

    Twice 3.2 is 1.7 mm/y.

    As for your ref http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/. Nice try, but do you not see the downward last 10 years? Best to see it in a tighter perspective:

    http://atmoz.org/blog/2007/10/22/no-global-warming-signal-in-sea-surface-temperature-data/

    [edit]

    [Response: You need to look at the same groups updates ie. Lombard A, Cazenave A, DoMinh K, Cabanes C, Nerem RS, GLOBAL AND PLANETARY CHANGE 48 (4): 303-312 OCT 2005. And please stay on topic. - gavin]

    Comment by Richard Wakefield — 18 May 2008 @ 7:40 AM

  92. ” I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation. A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?”

    I’m able to confirm that CO2 will absorb far more than 0.04% of the IR emitted from the surface, more like 10%.
    The absorbed energy will initially raise the rotational and vibrational temperature of the CO2 molecules which within less than a microsecond will raise the temperature of the surrounding molecules.

    Comment by Phil. Felton — 18 May 2008 @ 8:49 AM

  93. Re John Millett @90: “We ought, therefore, to agree that pre-human, or more precisely, pre-industrial climate change was caused by changes in solar activity”

    Sorry, John, but changes in solar activity has never been the only and not always the dominant driver of climate change. Google “Milankovic cycles”, “Paleocene-Eocene Thermal Maximum”, “Permian-Triassic”, and “snowball Earth”, for example.

    John: “We ought also to agree that fossil fuel burning industrialisation pumps increasing quantities of CO2 (plus water vapour and sensible heat – I wonder whether the models include these?) directly into the atmosphere.”

    Water vapour from direct human activity does not need to be included–google “relative humidity.” Atmospheric water vapour content can not be permanently increased unless either atmospheric temperature or pressure is increased first, otherwise the addition simply rains or snows out in a matter of days. That said, increased water vapour as the atmosphere warms is included in the models. Sensible heat from human activity has been discussed and quantified here repeatedly, it is negligible.

    John: “The IPCC argues that these effects completely swamp solar ones, on two main grounds: first, the rate of warming in the latter half of the 20th century exceeds all previous experience; and second, otherwise their models don’t make sense. Well, the latter sounds a bit chicken and egg-ish to this layman.”

    It’s not only the models that do not make sense without including the effect of increasing CO2, John, observed reality doesn’t make sense without including it either.

    John: “On the other side of the Atlantic, unpublicised revisions to the US temperature record reveal that six of the hottest ten years occurred in the first half of the 20th century.”

    You’re falling prey to deliberate disinformation here, John.
    See: http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt

    You have to go to the hundredth of a °C to break the tie between 1934 and 1998 for highest annual mean temperature anomaly (1.25 vs 1.23), and the following 23 ranked years, all above .50, are: 2006 (1.15), 1931 (1.00), 2005 (.99), 1999 (.94), 1953 (.90), 2001(.89), 1990 (.88), 2007 (.84), 1987 (.84), 1954 (.84), 1939 (.80), 1938 (.78), 1986 (.74), 1946 (.71), 1991 (.69), 2002 (.67), 1933 (.66), 2000 (.65), 2003 (.65), 1981 (.65), 1941 (.61), 2004 (.54), 1900 (.52).

    That’s only two years from the first half of the century in the top 10, not six, and 15 of the above 25 are since 1980.
    You might want to double check stuff like this that is easy enough to look up before you post next time.

    Comment by Jim Eager — 18 May 2008 @ 9:20 AM

  94. #93

    CO2 in the 1930′s was ~303 ppm.

    CO2 in the 90′s and 00′s is ~370 (currently ~380).

    Yet temperatures are only slightly higher now than 1930′s.

    Why?

    Comment by Jim Cross — 18 May 2008 @ 10:28 AM

  95. 1. An alternative approach. (Not really serious). One bet based on probability may not be decisive in determining the superior type of model. The trouble is that each model is consistent with a range of outcomes with different probabilities. Just for the sake of argument consider instead a couple of betting shops using different advisors to offer the public a range of bets with different odds. One shop would base its offers on the set of IPCC models and the other would use Keenlyside et al (perhaps supplemented by some more runs). The better modelling would be converted into a profit.

    2. Does the proposed bet suggest that the group are betting against the relevance of Schlesinger and Ramankutty ,1994. Nature,367,723 who looked at unforced oscillations of period 65-70 years period? They ended with the warning:

    “Accordingly, it is prudent not to expect continued year-after-year warming in the near future and, in so doing, diminish concern about global warming should global cooling instead manifest itself again.”

    Perhaps they really meant decade on decade. (Incidentally the German defeat in the 2nd world war has been partially attributed to the prolonged cold about 65 years ago). Its difficult for a non expert to judge the importance of individual papers.

    3. Coupling shocks. I suspect I have missed something. The green curve appears to have unphysical looking kinks at about 2000 and 2010; are these symptoms of coupling shocks? If so, what about the kink in the black curve at about 2010?

    Comment by Geoff Wexler — 18 May 2008 @ 10:52 AM

  96. Re 84. In regard to Ed’s comment, I want to follow up with a related question.

    If there is a pause in surface warming because of cooler water being brought to the surface of the oceans, would this not lead to an increase in the energy imbalance, and thereby increase the rate of heat accumulation at the earth’s surface? The cooler ocean surface would radiate less IR back to space. Maybe the effect is negligible, or maybe there would be an offsetting negative feedback due to changes in clouds. I am asking.

    Comment by Ron Taylor — 18 May 2008 @ 11:24 AM

  97. > Jim Cross, temperatures

    Which ones, Jim?
    http://cdiac.ornl.gov/trends/temp/jonescru/graphics/nhshgl.jpg

    PS, I really appreciate your blog post on “How To Create a Major Software Outage”

    Comment by Hank Roberts — 18 May 2008 @ 11:47 AM

  98. wmanny, “insistosphere” good! we need a screech name to counter all the labels laid on us skeptics. Makes the debate healthy.

    Comment by Rod B — 18 May 2008 @ 1:41 PM

  99. Re: Several comments on falsification.

    Just as current models can be verified by successfully reproducing the observed climate of the recent past century or so( the ones that include anthropogenic effects anyway), so can models be falsified by say, using orbital parameters such as the tilt of the Earth’s axis, and not being able to reproduce seasonal variations. Such a model would wrong.

    If a models have successfully shown the effects of sizable volcanic eruptions, as a number have, they’ve been verified, if a model could not, it’s been falsified. At least that’s my take on it.

    If this were not true, science counterparts of Elmer Gantry, could spout all kinds of nonsense, which may happen anyway, but it could not be shown to be wrong.

    Comment by Lawrence Brown — 18 May 2008 @ 2:25 PM

  100. John Millett, You make a lot of assertions with zero attribution. Some are true, some half true and some blatantly false.

    To correct the most blatant false notions:

    Each warming and cooling epoch in the paleoclimate has its own causes. In some cases these were based on solar variations, but in others volcanism, greenhouse warming and other factors were dominant.

    Then you say: “I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation.”

    Where the heck does that come from? Are we talking IR energy or IR photons?

    and

    “A supplementary question: Would the absorbed energy raise the molecule’s temperature or increase its velocity or are these one and the same thing?”

    This sort of thing has been discussed repeatedly. First, how do you get a temperature for a single molecule? Second,

    Read:
    http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/

    and
    http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/

    Comment by Ray Ladbury — 18 May 2008 @ 3:41 PM

  101. First post on Realclimate from me. Very good site. Thank you for helping me form opinions on the science (I’m a lapsed Geologist/Biologist so i can follow a lot of it, but have not kept up to date since the early 90′s)

    you are right to be concerned about media coverage of this. The New Scientist in the UK is reporting this in a misleading way:

    “The controversy is unlikely to go away. A study in Nature this month (vol 453, p 84) led by Noel Keenlyside of the Leibniz Institute of Marine Sciences in Kiel, Germany, forecasts that this cyclical warming would soon abate. “There could be some cooling in Europe and North America over the coming decade as the natural cooling offsets the warming from human activities,” Keenlyside says.”

    – that’s at the end of an article on the Rosenzweig et al study published recently in Nature on the impact of climate change on plants and animals. Presumably New Scientist have put this in as a counterpoint. It is very misleading though. No “this is only an experiment” or “not everyone agrees with this result” etc.

    and i always thought New Scientist was a good magazine. just goes to show how messages can get distorted very easily.

    http://environment.newscientist.com/channel/earth/mg19826564.400-life-feels-the-effects-of-a-changing-climate.html

    Comment by Jari Worsley — 18 May 2008 @ 4:34 PM

  102. I like to think for myself and hypothesize what would the Earths climate be like if Mankind did not exist.

    Assuming that was so. :-

    We are in a warmer interglacial period would I therefore expect the climate to be warming, to be stable, or to be cooling?

    Would I expect Glaciers and ice coverage to be reducing, to be stable, or to be increasing?

    The information I would really need to know, I think, is whether, the non mankind influenced, inter glacial period had reached its maximum or not and was now in decline.

    Does anyone know for certain?

    Therefore, when you put mankind back into the equation how can anyone postulate that mankind is having any influence either way?

    Comment by Alan Millar — 18 May 2008 @ 6:43 PM

  103. Alan, if you want “for certain” you need either the mathematics department or a religion — they’re the ones who can prove statements beyond any doubt, as long as you accept their basic assumptions.

    Science doesn’t offer that kind of certainty.

    Do you ever gamble? Fly on an airplane? Use a device with a semiconductor in it, like a laser, CD player, phone, or computer?

    Those are all matters of probability, not certainty.

    If you’ll accept the level of likelihood we use day to day in using science and what’s developed from it, you can have a very good likelihood of an accurate answer.

    Interested? Read more. Try the “Start Here” link at the top of the page. Put any term or name you read about elsewhere into the Search box.

    Oh, and consider just looking at the pictures.
    Here’s one:
    http://svs.gsfc.nasa.gov/stories/greenhouse_20020103/images/figure1m.gif

    Remember chlorofluorocarbons? hair spray? refrigerants? the ozone hole? Those also are greenhouse gases.

    So, yes, it IS possible to do what you ask, figure out what difference human contribution makes.

    And, yes, it IS possible to do something about it. We already have.

    Comment by Hank Roberts — 18 May 2008 @ 7:05 PM

  104. Hi Hank

    So what would your guesses be for the Earths current climate if Mankind didn’t exist?

    Comment by Alan Millar — 18 May 2008 @ 7:56 PM

  105. 103. Careful. Paradigm shifting. Dichlorine peroxide break-down rates not as previously understood. Science consensus being called into question, as invariably happens throughout the history of science. TBD whether Montreal has proven to have changed much.

    [Response: The recently reported revisions to the rate constants are inconsistent with clearly observed shorter time variability. Many people more directly involved in ozone chemistry than I do not expect them to stand up. - gavin]

    Comment by wmanny — 18 May 2008 @ 8:59 PM

  106. Hank, the relative/historical forcings set me back abit. A question out of right field: what happened to the 30-50years it takes (took?) for a CFC moleculae to make it to the stratosphere?

    Comment by Rod B — 18 May 2008 @ 9:40 PM

  107. Rod, if you would check your own beliefs before posting them as assumed truths, it would save me a lot of unnecessary typing. I’m trying to teach you how to be a good skeptic, you know. Trust me on this. You -can- get there. I’ve got to go spend time helping inlaws with a sick kid for a few weeks starting soon.

    You’re ready to solo. Go for it. Last time, let’s do the exercise:

    Standard question — what’s your source? Why do you believe the number? Where did you get it?

    I did a Google search for “30-50 year” and — lo, are we surprised? — find that in posts from the people still claiming “the ozone hole is a fiction” on blogs.

    Nothing in any science sites I found — got any other source for the notion you have?

    Let’s try Google Scholar:

    http://www.sciencemag.org/cgi/content/abstract/272/5266/1318
    That suggests five to seven years would be about right, though it’s an early and optimistic post, things didn’t work out that well.

    A little more searching (you can figure out the terms, the minus sign rules out terms you don’t want, like “ocean” in searching).

    “… stable and reach the stratosphere unchanged over a five to seven year period following release into the atmosphere. CFC and HCFC. molecules are then …”
    http://www.uneptie.org/outreach/wssd/docs/sectors/final/refrigeration.pdf

    OK? Three minutes. You _can_ do this.

    Now, the thinking part. Dang “wisdom” button still not programmed.

    What was that graphing? Global warming potential. How big is the GHG potential of chlorofluorocarbons?

    You can look it up. I trust you.

    Thinking it through, where do greenhouse gases operate? “Whevever they want to sit.” As they say about the 800 pound gorilla. The time lag getting to the stratosphere has no relation to the greenhouse warming potential of the chlorofluorocarbons.

    Yes, they persist, they do over time (not that long either) reach the stratosphere where they also catalyze ozone breakdown, that changes ozone levels, and that has a greenhouse forcing effect — but that’s a different aspect of their chemistry/physics than greenhouse gas-ing.

    Comment by Hank Roberts — 18 May 2008 @ 10:44 PM

  108. Alan, if mankind didn’t exist — or if we’d invented something better than burning coal and hadn’t started the current experiment? Well, look at the past.
    This may help, look at the cited papers and the citing (subsequent) papers with the links in the sidebar:
    http://www.sciencemag.org/cgi/content/abstract/240/4850/293

    This may help; the black line goes vertical at the right margin, note the arrow labeled “2004″ pointing to where it was at that time. The last 200 years are in the tiny little bit of the chart right of the tickmark.
    http://www.globalwarmingart.com/images/b/bb/Holocene_Temperature_Variations_Rev.png

    Comment by Hank Roberts — 18 May 2008 @ 10:52 PM

  109. What kind of function line (equations) are they using that is rendering their probability outcomes within their programming that is being used in their varying computer models
    and what did they base that, or those, functions and or equations on?

    All computers,computer modeling included, are subject and constrained to the limits of programmer and program itself. The math go to string inputs contained within the programming.

    Comment by Cheska — 19 May 2008 @ 12:04 AM

  110. Hi

    I’m new here. Have only been folowing the AGW debate for a little while so please excuse me if my question has been answered already. I’m definitely on the fence. It sure is fasinating!

    My question: Does RC believe that increases in C02 leads or follows increased temps?

    Thanks.

    [Response: The carbon cycle is both affected by climate and, through the greenhouse effect, affects climate. Therefore the answer is both. If climate changes through some other factor (say Milankovitch forcing), the carbon cycle will follow and amplify the change. If you add carbon to the system (i.e right now or at the Paleocene-Eocene Thermal Maximum), climate will follow. You might as well ask whether chickens or eggs lead or follow. - gavin]

    Comment by Toby — 19 May 2008 @ 1:42 AM

  111. re 97

    http://en.wikipedia.org/wiki/Image:Instrumental_Temperature_Record.png

    The five year average at the end of the 1930′s and the five year average in the mid 1990′s is only around .2 degrees different but CO2 is up over 20% between those times.

    I’m not saying it was as warm as it is now in the 1930′s and I’m not denying that the difference right now is closer to .4 degrees from the 1930′s. I am just asking for an explanation of why raising CO2 over 20% didn’t create more warming than it did.

    Comment by Jim Cross — 19 May 2008 @ 5:47 AM

  112. re #93

    Google and climate change. You have done a good job replying to #90. Just one comment. You have advised John to use Google and your examples may have been good ones for doing that. The trouble is that he may have started with Google as his main source anyway. He might come back at you with ‘Google solar changes’ or some such. Using Google with discrimination is a skill which needs to be learned and is perhaps hard to teach. I am beginning to despair about Google when it comes to this subject. When Channel 4′s Great Global Warming Swindle came out in the UK I was surprised to receive enquiries from graduates who decided to check up on the programme by using Google and immediately found it to be confirmed. This is of course one of the arguments for the existence of Realclimate but some people (especially those who don’t like authority) end up by being completely confused.

    Whereas the world wide web used to be mainly a means of sharing science and other academic material it has become joined at the hip with the media in general and is now open to purchase by those with money to spend. Since Google Scholar may be too technical it might be possible to use more specific suggestions like giving the whole link,Googling for the subject + Wikipedia,or + the Met Office etc. or Googling for a named person or group. If this sounds like censorship I would argue that I am not arguing for anything as absurd as a ban, just a bit of guidance. No one would recommend say the UK’s Telegraphs (Daily and Sunday) as sources for information about climate even though the Telegraphs do report on the subject in between articles by Christopher Monckton. No criticism of #93 intended.

    Comment by Geoff Wexler — 19 May 2008 @ 5:56 AM

  113. John Millett writes:

    plus water vapour and sensible heat – I wonder whether the models include these?

    Of course they do.

    The IPCC argues that these effects completely swamp solar ones, on two main grounds: first, the rate of warming in the latter half of the 20th century exceeds all previous experience; and second, otherwise their models don’t make sense.

    The second “argument” is something you made up. The IPCC doesn’t say anything of the sort. Have you actually read the AR4 report? Why don’t you do that before telling us what it says?

    unpublicised revisions to the US temperature record reveal that six of the hottest ten years occurred in the first half of the 20th century.

    What “unpublicized revisions?” Are you making stuff up again? And what makes you think US continental temperature records, or central England temperature records, reflect what’s true for the whole world? Do you understand what an ‘average’ is?

    I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation.

    No climate scientist in his right mind is going to “confirm” something that just isn’t true. CO2 accounts for 26% of the clear-sky greenhouse effect according to Kiehl and Trenberth (1997):

    http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf

    Comment by Barton Paul Levenson — 19 May 2008 @ 6:40 AM

  114. Jim Cross posts:

    I’m not saying it was as warm as it is now in the 1930’s and I’m not denying that the difference right now is closer to .4 degrees from the 1930’s. I am just asking for an explanation of why raising CO2 over 20% didn’t create more warming than it did.

    Well, let’s find out. The radiative forcing approximation for carbon dioxide under near-present conditions is:

    RF = 5.35 ln (C/C0)

    where C is present or end concentration and C0 is reference concentration. (C/C0) according to you is 1.2 for the period in question. 5.35 ln 1.2 = approximately 0.98. Using a climate sensitivity of 0.75 K/W/m2, that translates to 0.73 K. The actual rise was 0.4 K.

    I suggest that the discrepancy is probably due to the massive release of anthropogenic aerosols which caused the cooling in the ’40s and has created a negative temperature feedback since. You would only need a cooling of 0.33 K over 70 years to match.

    Comment by Barton Paul Levenson — 19 May 2008 @ 6:50 AM

  115. #92Thank you, Phil Fenton. I have difficulty with the notion that any matter making up a proportion “x” of a medium can intercept a proportion “250x” of waves passing through the medium. All waves would pass through an atmosphere comprising only N2 or O2. No waves would pass through an atmosphere comprising only CO2. But, you imply, less than half the waves (much less, perhaps zero)would pass through an atmosphere of half CO2 and half N2 or O2. Why is this so? On the other part of your answer to my query, I take it that heat would be transferred from CO2 molecules to N2 and O2 by conduction? And that this would raise the intensity of radiation from the atmosphere to the surface?

    Comment by John Millett — 19 May 2008 @ 7:32 AM

  116. Re #115

    “#92Thank you, Phil Fenton.”
    That’s Felton.

    “I have difficulty with the notion that any matter making up a proportion “x” of a medium can intercept a proportion “250x” of waves passing through the medium.”

    Perhaps you should read up on light absorption and spectroscopy then! Ever heard of an emerald?
    It’s a gem composed of the transparent mineral beryl, it looks green because all the blue and red light is absorbed by an impurity, chromium, which is present at less than 1%.

    “All waves would pass through an atmosphere comprising only N2 or O2. No waves would pass through an atmosphere comprising only CO2. But, you imply, less than half the waves (much less, perhaps zero)would pass through an atmosphere of half CO2 and half N2 or O2. Why is this so?”

    No because only those wavelengths between ~13 and 17 microns will be absorbed by CO2, in that band almost all will be absorbed within a few meters.
    http://webbook.nist.gov/cgi/cbook.cgi?Spec=C124389&Index=1&Type=IR&Large=on

    “On the other part of your answer to my query, I take it that heat would be transferred from CO2 molecules to N2 and O2 by conduction?”

    By collisions.

    Comment by Phil. Felton — 19 May 2008 @ 8:13 AM

  117. John Millett, I find it more illuminating to think of it this way. Imaging a photon of wavelength roughly 15 microns propagating upward through the atmosphere. If it encounters a CO2 molecule during its ascent, it is likely to interact with it and excite the vibrational state, right? So what is the probability that it will encounter a CO2 molecule?
    CO2 constitutes 385 ppmv, which is about 600 ppm by mass. A COLUMN OF AIR 15 MICRONS IN RADIUS weighs roughly 7.2 mg. That means there are roughly 59 trillion CO2 molecules encountered by every 15 micron photon on a straight-line path out of the atmosphere. The photon is, effectively, a sitting duck. Moreover, the lifetime for radiative decay of the corresponding excited vibrational state is of order microseconds, so the state is much more likely to decay collisionally than radiatively. It thus imparts energy to N2 and O2, Ar–the whole atmosphere.
    Thus, the chances of an IR photon in the CO2 energy band are pretty slim until the radiation occurs high in the atmosphere.
    As to radiation transfer–within the atmosphere there are many ways energy can be transferred to the surface. It’s not just radiation.

    Comment by Ray Ladbury — 19 May 2008 @ 8:21 AM

  118. Re #116

    (In case Phil Fenton misses #116 )
    “I have difficulty with the notion that any matter making up a proportion x of a medium can intercept a proportion 250x of waves passing through”

    Experiment: Try a mixture of one part of potassium permanganate and 250 parts of water.

    Theory. Since the oxygen and nitrogen are transparent to infra-red they might as well be ignored, at least for the first absorption. That would still leave a large number of closely spaced CO2 and H2O molecules.

    “On the other part of your answer to my query, I take it that heat would be transferred from CO2 molecules to N2 and O2 by conduction? And that this would raise the intensity of radiation from the atmosphere to the surface?”

    If you are thinking of radiation from oxygen or nitrogen that would be negligible because a zero absorber is also a zero radiator.This is an application of laws discovered by Kirchoff, Angstrom (the older one) and I believe Rayleigh.

    Comment by Geoff Wexler — 19 May 2008 @ 8:41 AM

  119. Re Geoff Wexler @ 112:
    Geoff, I would strongly agree with your comments about being careful when using google, but since I was suggesting that John Millett use it to look up something as uncontroversial as relative humidity I wasn’t too worried. But you are right when it comes to more controversial subjects such as the PETM, the end Permian, snowball Earth, and even the Milnkovic cycles. In fact I recently had someone try to refute Milankovic forcing by citing strenuous arguments made by a proponent of ‘intelligent’ design. :)

    Comment by Jim Eager — 19 May 2008 @ 10:35 AM

  120. Hank, Carl Sagen, of global warming and global winter fame (among other stuff) said 50 years. I recall reading also a number of years back as much as 100 years for CFCs to make it to the stratosphere. I assume the science and our understanding have improved since then, as opposed to, say, burying it as “downright embarrassing: ;-). It still seems a little tough for the very heavy CFC molecules to get to the top of the troposphere and then through the narrow gate of the tropopause in a half-dozen years. But, as you say, it’s just a thought; I have no studied reason to dispute it.

    Actually the answer to my ill-posed (as it turns out) question was the transit time to the stratosphere has little to do with CFC greenhouse gas potential. Though that potential blew me away (new news for me).

    Good luck with your helpful sojourn.

    [Response: Look up "age of air". For the polar stratosphere you get mean numbers like 4 or 5 years (though the tail of age distribution can be quite long). You can deduce this from estimates of SF6 concentrations, Radon measurements (both ground sources with 'clocks' attached), or from the decay of bomb 14C for instance. Rind et al 1999 has a good discussion. - gavin]

    Comment by Rod B — 19 May 2008 @ 10:36 AM

  121. Ray (117) good analysis that I will explore thoroughly with your start. But you left me hanging with, “…As to radiation transfer–within the atmosphere there are many ways energy can be transferred to the surface. It’s not just radiation.” Which might be true, but my long-standing question is what is the source of the massive IR radiation from atmosphere to surface?

    Comment by Rod B — 19 May 2008 @ 10:58 AM

  122. # 120 Usually when a scientist asks for a reference they don’t mean an unsubstantiated claim that some famous person said it. They mean a published result in the literature. Having such a source (like the one Gavin provided) doesn’t in and of itself mean that the number is correct. What that really does is provide a hook into the literature that one can use to ascertain whether a particular result is in the right ballpark by looking to see if the result in question is pretty well accepted in the literature or if there is substantial dispute within the literature. The time for CFC’s to reach the upper atmosphere seems like a relatively straightforward thing to measure. It is unlikely that it is in dispute. I expect that in all probability you are misquoting Sagen and incorrectly remember your reading from “a number of years back”.

    Comment by John E. Pearson — 19 May 2008 @ 11:28 AM

  123. Alan Millar (102) — The peak of the Holocene interglacial is long past. Without humans the climate would be slowly cooling towards the next attempt at a stade (massive ice sheets) in about 20,000 years.

    Comment by David B. Benson — 19 May 2008 @ 1:42 PM

  124. Rod, I know you hear this over and over, but:

    It will _really_help_ you to read Spencer Weart’s book, first link under Science, right hand side of the RC page.

    You’ll ask better questions, knowing the basics. The effect of the CFCs is among those discussed there.
    http://www.aip.org/history/climate/othergas.htm

    Comment by Hank Roberts — 19 May 2008 @ 2:39 PM

  125. The wiki link in post #14 didn’t work exactly right for me, although it seems to be the same as the page on which I eventually landed:

    http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change

    However, if you go there and it still doesn’t work, use the search that they suggest and you will quickly come to the right page. I will keep this link in mind for skeptics who try to tell me that there’s no global warming because “even scientists don’t agree.”

    I just want to thank everyone who works to keep RC up and running – it’s a wonderful resource!

    Comment by Maya Chase — 19 May 2008 @ 2:55 PM

  126. Rod, I didn’t mean to imply that there is no radiation from the atmosphere to the surface, merely that that is not the only energy transport mechanism. CO2 or H2O molecules near the surface can and will radiate at their blackbody temperature–again equilibrium. However there are other transport mechanisms for energy to make it back to the surface.

    Comment by Ray Ladbury — 19 May 2008 @ 4:37 PM

  127. #93 Thank you, Jim Eager. Apart from the abnormal climate change events you mention, the numerous oscillations between ice ages and inter-glacial warming periods also express natural causes (most likely related to solar impacts of one kind or another – if not, what else?) making the case for AGW dependant solely on the unprecedentd rate of current warming. Suitably chastened, I looked at the revised US data you helpfully posted and found they make an interesting pattern. The hottest 25 years in the record occurred over 107 years from 1990 to 2007 and show a slight warming trend. Trimmed of the three observation greater than an anomaly of 1.00 and the two less than 0.6, the remaining 20 span the 76 years from 1931 and show an even slighter warming trend. That there is a warming trend in an inter-glacial period is unsurprising: that it is so slight, given the AGW hypothesis and the rapid increase in CO2 emissions over the period, is surprising.

    Comment by John Millett — 19 May 2008 @ 6:40 PM

  128. John, the USA has been on the low side — that fits what the climate models suggest will happen, given the ocean and atmospheric circulation.

    http://hadobs.metoffice.com/hadcrut3/diagnostics/monthly/anomaly.png

    Look at the global data. This is helpful:

    http://bp3.blogger.com/_7NrAt8xGd0E/SCXfzDRcsJI/AAAAAAAAAts/JNe5Nuf0A9o/s1600-h/20080429.gif

    News article about it here:
    http://www.sciencedaily.com/releases/2006/12/061218130705.htm

    Comment by Hank Roberts — 19 May 2008 @ 8:05 PM

  129. Re: 100

    Then you say: “I would also like a climate scientist to confirm that, in and of itself, CO2 would block no more than 0.04% of out-going infra-red radiation.”

    Where the heck does that come from? Are we talking IR energy or IR photons?

    I believe it was misquoted by a factor of 10 from an old study of Arrhenius that I learned of in the beautiful work of Spencer Weart that I learned of from Hank Roberts in #124:

    http://www.aip.org/history/climate/co2.htm#N_7_

    “These measurements and arguments had fatal flaws. Herr Koch had reported to Ångström that the absorption had not been reduced by more than 0.4% when he lowered the pressure, but a modern calculation shows that the absorption would have decreased about 1% — like many a researcher, the assistant was over confident about his degree of precision.(8a) But even if he had seen the1% shift, Ångström would have thought this an insignificant perturbation. He failed to understand that the logic of the experiment was altogether false.”

    Comment by John E. Pearson — 19 May 2008 @ 10:05 PM

  130. Barton Paul Leveson writes (114)

    Well, let’s find out. The radiative forcing approximation for carbon dioxide under near-present conditions is:

    RF = 5.35 ln (C/C0)

    where C is present or end concentration and C0 is reference concentration. (C/C0) according to you is 1.2 for the period in question. 5.35 ln 1.2 = approximately 0.98. Using a climate sensitivity of 0.75 K/W/m2, that translates to 0.73 K. The actual rise was 0.4 K.

    I suggest that the discrepancy is probably due to the massive release of anthropogenic aerosols which caused the cooling in the ’40s and has created a negative temperature feedback since. You would only need a cooling of 0.33 K over 70 years to match.

    If I understand the science behind climate sensitivity correctly, with a climate sensitivity of 0.75 K/W/meter squared there’s approximately 0.4 to 0.6 K of warming in the pipeline. That extra warming would become apparent if the climate were allowed to reach equilibrium without further forcing.

    So the observed rise of 0.4 degrees coupled with the warming in the pipeline (of at least 0.4 degrees) would be more than enough to equal the amount due to greenhouse gas forcing, even with some of the temperature rise masked by aerosols, wouldn’t it?

    Ken

    Comment by Ken Feldman — 19 May 2008 @ 10:31 PM

  131. Sorry if its slightly OT, but tab between say http://manati.orbit.nesdis.noaa.gov/ice_image21/D08136.NHEAVEH.GIF
    And
    http://manati.orbit.nesdis.noaa.gov/ice_image21/D08139.NHEAVEH.GIF
    and have a look at the way the remaining multi-year sea ice of the Arctic is peeling away from the Canadian Archipelago. Bets? A sure thing, more likely!

    Comment by Nigel Williams — 20 May 2008 @ 12:23 AM

  132. #100 Thank you, Ray Ladbury. I’ve got the message on the abnormal climate change events from Jim Eager, as well (#93 and my response #107 (awaiting moderation)). “Are we talking IR radiation or IR photons?” Ray, I thought they were much the same thing; but if not, I don’t think I want to go there – it’s bound to be too complicated. “How do you give a single molecule a temperature?” Courtesy of #92, by placing it in the path of a particular wave length of IR radiation. Chastened again, I’ve gone to “CO2 in 6 easy steps” where step 1 made me wonder, unmasking a simple (and ancient) engineering background, whether a water reservoir was analagous to the atmoshere? Pumping water into a reservoir at a faster rate than it is draining out results in the reservoir overflowing. What happens to all those watts accumulating in the atmosphere as the surface pumps in energy at 1.6 times the rate at which it escapes to space?

    #117 Ray, what you didn’t tell me is that as well as the 59 trillion photon-gobbling CO2 molecules in the air column there are 98 quadrillion photon-friendly molecules of N2 and O2. The probability of the photon escaping to space is 0.9994, no?

    Comment by John Millett — 20 May 2008 @ 1:44 AM

  133. #114 Barton Paul Levenson:

    … that translates to 0.73 K. The actual rise was 0.4 K.

    Mostly correct, I think. Note that 0.73K represents equilibrium warming; what we want is transient warming, only about half of that, the rest going into long term ocean warming. I don’t think we need aerosols here to make the books close (and the large aerosol cooling effects are mostly for the period 1940-1975 anyway).

    Comment by Martin Vermeer — 20 May 2008 @ 3:41 AM

  134. Ken and Martin — good point. I had forgotten that the RF in the Myhre et al. equation was for equilibrium warming, and that some warming is still coming.

    Comment by Barton Paul Levenson — 20 May 2008 @ 6:57 AM

  135. Is it possible for the ice cap/sheets to melt (completely) in the north and build in the south?

    What effect could this have on earths orbit/rotation/climate?

    Comment by paulm — 20 May 2008 @ 7:55 AM

  136. Re: #135 (paulm)

    Yes, it’s possible. Right now the far north is warming faster than any other region of the planet, but the far south only very slowly.

    I doubt there’d be any effect on our orbit, but I recall (don’t recall where) seeing statements that the re-distribution of mass due to ice melt can affect earth’s rotation. If I recall correctly, it’s expected that mass will be transferred equatorward, which will slow earth’s rotation but only by a tiny amount. Again, I doubt that the miniscule change in rotation rate will have a noticeable climate effect. This is all speculation on my part.

    Comment by tamino — 20 May 2008 @ 8:46 AM

  137. John (132), a quicky minor clarification. A photon absorbed into vibration energy of CO2 does not raise its temperature. Though this is mostly academic as it turns into higher temperature when it collides with another air molecule. Two, I don’t think you can call N2 or O2 photon friendly.

    Comment by Rod B — 20 May 2008 @ 9:12 AM

  138. Re John Millett @127: “the numerous oscillations between ice ages and inter-glacial warming periods also express natural causes (most likely related to solar impacts of one kind or another – if not, what else?)”

    Natural, yes, and initiated by changes in solar insolation, yes, but not as a result of variations in solar output, rather as a result of changes in Earth’s orbit, tilt and wobble of axis. See Milankovic Cycles from my post 93. But CO2 (and methane) emitted by thawing permafrost and tundra bogs, and CO2 emitted by a slowly warming ocean then amplifies the insolation induced warming.

    John: “making the case for AGW dependant solely on the unprecedentd rate of current warming.”

    Not at all. The case for AGW rests on multiple lines of evidence, but most fundamentally on the known radiative physics of CO2 and other greenhouse gases. If CO2 from a warming ocean naturally causes more warming, then CO2 added directly to the atmosphere from fossil fuels will cause more warming. Add to that the fact that fossil fuels have a low ratio of carbon 13 to carbon 12, and that the ratio of 13C to 12C in atmospheric CO2 is dropping as CO2 concentration is rising, means that the increase must be from burning fossil fuels.

    John: “Trimmed of the three observation greater than an anomaly of 1.00 and the two less than 0.6, the remaining 20 span the 76 years from 1931 and show an even slighter warming trend.

    Sorry, dropping any of them is not an option. But even if you do, those 20 may span 76 years, but 12 of them are still from the last 27 years (since 1981). See Hank’s linked graph of ranked global anomalies here: http://www.metoffice.gov.uk/corporate/pressoffice/2008/pr20080429.html

    John: “That there is a warming trend in an inter-glacial period is unsurprising: that it is so slight, given the AGW hypothesis and the rapid increase in CO2 emissions over the period, is surprising.”

    Why? First, the increase in temp from increasing CO2 is not linear, it is logarithmic. Second, a very large and massive heat sink covers 70% of Earth’s surface, meaning much of the added heat is not in the atmosphere. Third, look up ‘global dimming’ caused by aerosols, and ‘Asian brown cloud.’

    And @132 John asked Ray: “whether a water reservoir was analagous to the atmoshere? Pumping water into a reservoir at a faster rate than it is draining out results in the reservoir overflowing.”

    Not necessarily overflowing, but definitely rising. Yes, a reservoir (or bucket, or bathtub) with different outlet levels is a useful analogy. When the water level (temperature) reaches a new outlet or hole the outflow will once again equal the input, but the level (temperature) will be higher.

    John: “What happens to all those watts accumulating in the atmosphere as the surface pumps in energy at 1.6 times the rate at which it escapes to space”

    The elevation at which IR photons are more likely to escape to space than to be absorbed rises, the atmosphere warms, the warmer atmosphere and back radiation warms the surface and ocean.

    John: “Ray, what you didn’t tell me is that as well as the 59 trillion photon-gobbling CO2 molecules in the air column there are 98 quadrillion photon-friendly molecules of N2 and O2.

    The N2 and O2 molecules are transparent to the photons, but they are energised through collision with the excited CO2 (and H2O) molecules.

    Comment by Jim Eager — 20 May 2008 @ 9:30 AM

  139. Thank you for taking the time to answer my question. I’m starting to see just how complex this issue really is.

    Comment by Toby — 20 May 2008 @ 11:58 AM

  140. John Millett, Not to bring back unpleasant memories ;-), but remember back to you modern physics class–an atom or molecule can only absorb radiation with an energy equivalent to the difference between two states of the atom/molecule. O2 and N2 being diatomic, do not have any rotational states or vibrational states that will absorb in the IR. Far from being IR “friendly,” they don’t even wave as the photon goes whizzing past. Ah, but you will ask, what about water vapor? A wonderful greenhouse gas, but 1)water vapor content of the atmosphere has not changed significantly (CO2 has increased by 38%) and 2) water vapor peters out at the cloudtops, while CO2 is well mixed (and continues to work as a ghg and absorb IR) up into the stratosphere.
    My point about whether you were talking about photon numbers or energy is not that complicated–the energy is just the integral of photons at a given energy times the energy integrated over the range of interest–that is, the first moment wrt energy.
    And your instincts are pretty good–the mathematics are similar to the “hole in my bucket, dear Liza, dear Liza” problem. As long as energy in=energy out, you have equilibrium (by definition). Now if you stop some of that energy leaving (and the only way it leaves is as blackbody radiation peaking in the IR range), things have to warm up, and they will continue to warm up until the energy of the outgoing radiation (mainly that outside the absorption bands of the greenhouse gasses) is equal to the incoming radiation. Does that make sense?

    Comment by Ray Ladbury — 20 May 2008 @ 12:29 PM

  141. John, look through a pane of glass — it’s almost clear in the visible light range. Look through it edgewise and it’s very green. The CO2 and other greenhouse gases in the atmosphere are trace gases, but between the ground and outer space, any photon will have a very high likelihood of interacting rather than escaping the planet. Only the greenhouse gases near the top of the atmosphere are emitting infrared photons that, if they go up, are likely to escape the planet. (At those elevations you have CO2, chlorofluorocarbons and such; the water is mostly frozen out much lower down.)

    Comment by Hank Roberts — 20 May 2008 @ 1:23 PM

  142. Re #140 Ray Ladbury.

    Haven’t you gone a bit too far in downgrading the importance of water vapour?

    You wrote:
    “1)water vapor content of the atmosphere has not changed significantly (CO2 has increased by 38%) and 2) water vapor peters out at the cloudtops, while CO2 is well mixed (and continues to work as a ghg and absorb IR) up into the stratosphere’

    A casual reader might conclude from these remarks that positive feedback from water vapour is of no importance. Since the water vapour ought to go up at a rate of 6% per degree C there must already been an increase in H2O thus contradicting your point 1). I thought that this had also been confirmed by observation. Furthermore at high altitudes the spectra of water vapour and CO2 act as distinct lines which implies that the radiation from the highest H20 molecules ought to reach the top of the atmosphere without further absorption by CO2. Isn’t that right?

    Comment by Geoff Wexler — 20 May 2008 @ 3:53 PM

  143. > water vapour … up at a rate of 6% per degree C

    But the stratosphere is cooling, not warming.

    > at high altitudes … which implies

    What altitude is “high”? What’s your cite on this?

    Comment by Hank Roberts — 20 May 2008 @ 3:55 PM

  144. Geoff, Thanks for correcting any misimpression I might have left. Yes, as temperature rises, water vapor content does act as a feedback. My point was that water vapor could not be the driver. I believe that even high in the atmosphere, there is overlap between CO2 (15 micron band) and water vapor spectra. It does look like it from the spectra I’ve seen, but I’m sure Gavin or somebody else will correct me if I am wrong.

    Comment by Ray Ladbury — 20 May 2008 @ 4:14 PM

  145. Re #137

    ” A photon absorbed into vibration energy of CO2 does not raise its temperature.”

    Sounds like a dubious remark to me. If you plug the original temperature into the standard equilibrium formula it would tell you that the molecule is probably not vibrating i.e. you have made an error. The definition of temperature here is mainly a matter of terminology. From some standpoints it might be convenient to define a raised effective temperature.

    The main point is to keep tabs on where the energy is gone and how it is shared out between the different degrees of freedom.

    Comment by Geoff Wexler — 20 May 2008 @ 4:15 PM

  146. Geoff, this may clarify the overlap:

    http://earthobservatory.nasa.gov/Study/Iris/Images/greenhouse_gas_absorb_rt.gif
    “… what makes carbon dioxide so interesting is that the gas absorbs energy in some small segments of the thermal infrared spectrum that water vapor misses. …”

    Comment by Hank Roberts — 20 May 2008 @ 5:56 PM

  147. reiterating 146′s remark: Weart http://www.aip.org/history/climate/co2.htm writes:

    Improved physics theory and precise laboratory measurements in the 1940s and after encouraged a new way of looking at the absorption. Scientists were especially struck to find that at low pressure and temperature, each band resolved into a cluster of sharply defined lines, like a picket fence, with gaps between the lines where radiation would get through.(24) The most important CO2 absorption lines did not lie exactly on top of water vapor lines. Instead of two overlapping bands, there were two sets of narrow lines with spaces for radiation to slip through. So even if water vapor in the lower layers of the atmosphere did entirely block any radiation that could have been absorbed by CO2, that would not keep the gas from making a difference in the rarified and frigid upper layers.

    Comment by John E. Pearson — 20 May 2008 @ 9:59 PM

  148. my uncle sent me this.
    is this global cooled 0.7C in 2007 ..is this number real or relevant or meaningful?
    – lorax73
    =====================================

    —-Original Message—–
    From: Jack Perrine
    Sent: Sun, 18 May 2008 7:09 pm
    Subject: SORRY TO RUIN THE FUN, BUT AN ICE AGE COMETH

    [ I find this particularly amusing. In the late 70's I had a friend
    who was an editor at the National Climate Center in Boulder Coloado.
    He pointed me at a few books on the coming glacial age. Then all of
    a sudden he was pointing me at books on Global warming. What was so
    amusing at the time was they both seemed to be the same books if one
    looked carefully: a large part of the text was the same while the indexes
    and title pages had been changed. But now below you can see a very good
    article on a coming ice that could come close to destroying civilization
    ......and yet our stupid politicians are still working on bankrupting
    the world with their funny CO2 and Global Warming

    Jack ]

    OPINION: SORRY TO RUIN THE FUN, BUT AN ICE AGE COMETH

    The Australian, 23 April 2008
    http://www.theaustralian.news.com.au/story/0,25197,23583376-7583,00.html

    Phil Chapman

    [edit]

    [Response: No. In the same way that a drop of 10 deg C from one day to another can't be extrapolated to a cooling of 100 deg C in ten days, month-by-month temperature changes (associated in this case mainly with La Nina in the Pacific) can't be extrapolated to decades. This was neither unusual nor exceptional, and will disappear as the La Nina does. I suggest keeping the email and showing it to your uncle in a year's time and asking him about his predictive skill. - gavin]

    Comment by lorax73 — 20 May 2008 @ 10:18 PM

  149. Re #144

    Try http://www.spectralcalc.com/spectralcalc.php
    Run it for CO2 & H2O between 600-700 cm^-1 at a pressure of 10mbar.

    Not too much overlap.

    Comment by Phil. Felton — 20 May 2008 @ 10:39 PM

  150. For those who want global warming to increase temperatures every year, do you think the average temperature every year would be constant without an external impulse?

    If not, you have to consider how a long-term warming trend would look if you superimposed it on short-term variations.

    My approach to this was to look for a period in the temperature record where there was no discernible long-term trend, the first 50 years of HadCRUT3 (1850-1899). If you look at this data, you will see that the variation between the maximum and minimum annual average is over 0.5°C with variations of over 0.4°C in as little as 2 years. A linear regression shows a trend of warming of 0.08°C per century with r2 = 0.0124.

    What would have happened if you had superimposed today’s level of CO2 forcing onto that situation? You would have had a long-term trend of increasing temperature and the odd patch where the trend was flat or even down. See http://opinion-nation.blogspot.com/2008/04/why-doesnt-it-get-hotter-every-year.html for more detail (comments and corrections welcome as always).

    Given that I artificially forced this trend onto data which didn’t have a significant warming trend before, this is some indication of why you shouldn’t expect to see a monotonic increase in temperatures under today’s conditions. The only way I would expect that to happen would be if the warming signal was above inter-annual natural variability. Given that we are talking about a trend which is accelerating to around 3°C per century, or only 0.03°C per year, it’s not surprising that every year is not warmer than the last.

    Comment by Philip Machanick — 20 May 2008 @ 11:40 PM

  151. #113 Thank you, Barton Paul Leveson. An average, as I understand it, is a statistical artefact derived by dividing the sum of a set of numbers, each weighted according to purpose, by the count of the set. What interests me, is why two statisticians get different averages from a common data set. This is relevant to the current “cooling equals warming” dialogue. GISS and UKmet presumably use the same raw thermometer readings and the same area-based weights. However, the former says that, on average from 2001 to 2007, the planet warmed while the latter said it cooled (the difference being 1.5 degrees C/decade http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001425how_to_make_two_deca.html). Would this measurement uncertainty not warrant climate scientists requiring the statisticians to agree a “data cleansing” methodology (to account for heat island effect, for example – what else could explain the difference?)and to remove this measurement ambiguity before proclaiming the science to be settled. Moreover, spare a thought for the hapless modeler looking into the distant future starting now. How does he handle the ambiguity – toss a coin, halve the difference or play favourites?

    [Response: An average is just a mathematical operation - not an artifact. Since we don't have perfect information, all global mean averages are estimates. And like with all estimates there are uncertainties. For short time periods those small changes can lead to large swings in trends - because a linear trend is not a good fit for such periods. People in the future will be looking at much longer timeseries and so the ambiguity will be less. Not too hard to understand surely? - gavin]

    Comment by John Millett — 21 May 2008 @ 12:13 AM

  152. #138 Thanks,Jim Eager.
    Jim, following your first response I changed language from “solar activity” to “solar impacts” meaning that this would include variability in the earth’s orbit and behaviour. Despite the CO2 amplification of a warming originating in such variability, the system periodically reverses from warming to cooling. Those natural dynamics are still in play in the current warming period. I have no difficulty with relating increasing atmospheric concentrations of CO2 to man burning fossil fuels. And I can accept the radiative physics of CO2 (understanding it is another matter, particularly its quantitative effect). But while our understanding of the radiative physics of CO2 has only recently been acquired, the physics itself has been in play from the start. This is why I reject the scientific discovery as a peg to hang the AGW hat on, leaving the rate of temperature increase (related to the atmospheric concentration of CO2) as the only basis for the AGW hypothesis.

    Jim, Winston Churchill famously said: “There are lies and damned lies. Then there are statistics”. Outliers in a data set can make trends unrepresentative of the body of data. Statisticians routinely trim outliers, not permanently, but to get a better understanding of what the data are telling us. They also play around with raw data; Churchill was on to something.

    Jim, the oceans covering 70% of the planet’s surface not only contain most of the heat in the climate system but also contribute 70% of the average global surface temperature. Would it not be more plausible to see the lower than expected warming as natural causes dominating man-made ones?

    Jim, to stabilise the system we have to either reduce the inflow rate or increase the outflow rate, irrespective of the elevation at which the outflow occurs. Since the backward radiation from the atmosphere to the surface tends to increase the inflow rate, there is an urgent need to increase the photon escape rate. The need is urgent because in a column of air one metre square energy is accumulating at the rate of 150 watts per second, according to step 1 of CO2 in 6 easy steps. It must be that as the atmospheric temperatures increases photons escape at a faster rate as well as from further up in the atmosphere?

    Comment by John Millett — 21 May 2008 @ 2:52 AM

  153. #140 Thank you, Ray Ladbury.
    As a photon leaving the surface with escape to space on my mind and confronted with a whole bunch of N2 and O2 molecules in my path I don’t really care whether they give me that permanent “have-a-nice-day” smile or ignore me. What I do care about is avoiding those H2O and CO2 guys – not many of them, but each with evil intent towards me. I take comfort from the laws of probability. For each baddie there are “n” good guys where “n” is a large number. I’m gonna make it!

    Ray, I see a problem. “Energy in = energy out” at the top of the atmosphere would imply “energy in > energy out” within the atmosphere. This means that the surface temperature has to fall from an energy level of 390 W/m2 to 240 W/m2 to reach equilibrium. But back radiation from a warming atmosphere will prevent this.

    Comment by John Millett — 21 May 2008 @ 4:29 AM

  154. Geoff, The definition of temperature is not at all ambiguous: It is the partial derivative of energy wrt entropy. What is dubious is the idea of applying “temperature” to a single molecule.

    Comment by Ray Ladbury — 21 May 2008 @ 6:37 AM

  155. re #154 Ray Ladbury.

    Ray Ladbury Says:

    “It is the partial derivative of energy wrt entropy”…

    Agreed and to finish off your point the energy has risen so the temperature has gone up even if there is no translational energy involved. But as far as definitions are concerned, you have just shifted the problem from defining temperature to defining entropy and as far as I remember (I’m a bit rusty now) that depends on whether there is equilibrium, or if not, whether you can imagine that there is.

    I am not sure that you need to bring in single molecules. Remember that the point was raised in connection with very short times before the excited CO2 had time to undergo collisions. To discuss this regime it might be good enough to consider a slightly different system i.e. a large uniform set of CO2 molecules in a box with the same total energy and interacting with infra-red photons and nothing else. This slightly hypothetical system would reach thermodynamic equilibrium with a well defined entropy and temperature. This argument is not perfect because some energy might eventually leak into the translational modes because of the photons’ momentum, but its only a thought experiment.

    Comment by Geoff Wexler — 21 May 2008 @ 9:11 AM

  156. Re 153. You can take comfort from the laws of probability but your reasoning is utterly flawed. The probability that “you” get absorbed by N2 or O2 is zero. If you’re an infrared photon the N2 and O2 might as well not be there. N2 and O2 play no role in the process. The chance that “you” get absorbed by CO2 or some other GHG is much closer to 1.

    Comment by John E. Pearson — 21 May 2008 @ 12:03 PM

  157. #156 Thank you John E. Pearson. The probability of my dying in a plane crash is the product of a number of independent events occurring: one, that I am in a plane; two, that the plane crashes; and three, that the rash kills me. The probability that a crash would kill me is close to 1 but that doesn’t mean that I’m virtually certain to die in a plane crash because the probability of a plane crashing is very low as is the probability of my being in that plane rather in some other plane or none is also low. The product of these probabilities is very low indeed. Similarly, the probability of a photon “dying” in its passage through the atmosphere is the product, first of it being intercepted by a GHG, which is a function of GHG concentration (no?) and therefore low, and second of it being “killed” by the capturing GHG, which as you suggest is close to 1. The product of the two probabilities is low. However, other posts indicate that the word “similarly” is inappropriate. I would be grateful to be told why.

    Comment by John Millett — 21 May 2008 @ 6:31 PM

  158. Gavin, with respect you haven’t got to the nub of my concern. An average, which is the end result of a mathematical process, is not an estimate with attached uncertainties unless the data being processed are estimates with attached uncertainties. Neither thermometer readings nor the areas of which they are deemed to be representative are estimates. The only part of the process involving estimates and attached uncertainties must be data cleaning. This uncertainty would be eliminated if statisticians employed the same methodology.

    [Response: You forget that spatial sampling is not complete and it is mainly the decisions on how to to infill missing data that cause the differences in the products. And frankly you don't want everyone to employ the same methodology. Different groups making different (but reasonable) assumptions tell you what is and what isn't robust. - gavin]

    Comment by John Millett — 21 May 2008 @ 6:44 PM

  159. Re 157:

    Your logic is still flawed: Similarly, the probability of a photon “dying” in its passage through the atmosphere is the product, first of it being intercepted by a GHG, which is a function of GHG concentration (no?) and therefore low, and second of it being “killed” by the capturing GHG, which as you suggest is close to 1.

    I am not a climate scientist so I don’t know the numbers. I do know the logic and your’s is incorrect.

    NOTATION: [GHG] = concentration of the greenhouse gas under discussion
    PA([GHG],f) = probability that the GHG present at concentration [GHG] absorbs a photon of frequency f

    Given that PA([0],f]=0.

    So far we’re good. then you fall into incoherency.

    You are comparing the concentration of GHG’s to that of O2 and saying since [GHG]

    [Response: use & l t ; for the less than sign - gavin]

    Comment by John E. Pearson — 21 May 2008 @ 7:36 PM

  160. I didn’t quite follow John E. Pearson’s comment 159 — I suspect he used a less than or greater than sign that the blog has interpreted as HTML — and perhaps he has expanded it in comments not published at the time of this writing, but the missing piece in John Millett’s thought-computation is simple. The concentration of CO2 in the atmosphere is indeed quite small, so if the photon encounters a molecule on its ascent through the atmosphere that molecule is very likely to be, say, N2 or O2 and have no effect. However, there is quite a lot of atmosphere that a photon must travel through: we need an additional factor for the number of molecules the photon can expect to meet, and this factor is very, very large, far more than adequate to bring our probability near to 1.

    This was already explained by Ray Ladbury in comment 117 and Hank Roberts in comment 141 (and perhaps elsewhere?), but perhaps the third time will be sufficient?

    Comment by JBL — 21 May 2008 @ 8:05 PM

  161. John Millett, So you really think the probability of being absorbed by any of the 59 trillion CO2 molecules you encounter would be small, huh? Because that is the only event that stands between you and escape. The O2 and N2 are only relevant because they increase the range of wavelengths the CO2 can absorb. The only molecules you see as a 15 micron photon are the CO2–and 59 trillion between you and space doesn’t give you good odds. We know this is true, John, because we know CO2 is responsible for 20-25% of the greenhouse warming that keeps Earth from being an inhospitable ice-ball. We’ve just increased the CO2 by 38%, and there’s no reason to expect the physics to change at 280 ppmv (the preindustrial value).

    Comment by Ray Ladbury — 21 May 2008 @ 8:21 PM

  162. John, if the probability of any single IR photon being intercepted by a CO2 or H2O molecule before reaching space is so low, then pray tell why satellite photos of Earth in the infrared bands absorbed by CO2 are opaque, i.e. the surface can not be seen?

    Oh, and is this pdf file http://tinyurl.com/5d4llo your submission to the Garnaut Climate Change Review?
    http://www.garnautreview.org.au/domino/Web_Notes/Garnaut/garnautweb.nsf

    Comment by Jim Eager — 21 May 2008 @ 10:37 PM

  163. Re # 152 John Millit:

    “lies, damn lies, …statistics”

    That observation predates Churchill by several decades, at least. It is often attributed to Mark Twain, though he cited Disraeli as the source. The true source is not clear.

    http://www1c.btwebworld.com/quote-unquote/p0000149.htm

    Comment by Chuck Booth — 21 May 2008 @ 11:05 PM

  164. Gavin, I take it that the term “robust” implies reliability of the data and confidence for users of the data. Using different technologies to measure temperature – instruments, balloons and satellites – provides a basis for assessing reliability, the closer the measurements are to each other, the more confidently can the data be used. But, within the instrument technology, how does giving statisticians discretion in the processes of cleaning data and extrapolating to unsampled areas – and consequently confronting their customers with the widely divergent results displayed for the period 2001-07 – improve users’ confidence? Isn’t there a scientific “best practice” for these processes?

    [Response: You are confusing the extreme sensitivity of a trend estimate through a small number of points with the reliability of the points themselves. The correlation between HadCRU and GISTEMP is extremely high. - gavin]

    Comment by John Millett — 22 May 2008 @ 7:04 AM

  165. #160 Thank you JBL. I think you may be hinting that the probability of interception is also a function of transit time? Perhaps that’s what John E. Petersen is in the process of telling me. Let’s wait and see.

    Comment by John Millett — 22 May 2008 @ 7:33 AM

  166. John Millett, No. The probability of absorption has nothing to do with transit time. It has to do with the probability of absorption by each molecule encountered and the number of molecules encountered. Since N2 and O2 do not interact with IR photons (except when distorted), that leaves H20 and CO2, mainly.
    Yes, climate science is complex. However, the basics of anthropogenic causation of current warming are fairly simple. CO2 traps radiation, generating about 20-25% of the 33 degrees C of known greenhouse warming on Earth. This is virtually indisputable. Increassing CO2 traps more radiation, so Earth must heat up until Energy out=energy in again (definition of equilibrium).
    The anthropogenic hypothesis explains the trends we are seeing in terms of known physics–something no competing hypothesis does. That is essentially the argument–and if you don’t accept it your really have a lot of ‘splaining to do, Lucy.

    Comment by Ray Ladbury — 22 May 2008 @ 8:56 AM

  167. Sorry I didn’t know that I couldn’t use a less than sign. I’ll try again.
    First my confusion with the “less than” sign, then a power outage, and dead internet kept me from fixing this earlier.

    NOTATION:

    [x] = concentration of whatever x is

    [O2] = oxygen concentration

    [GHG]=greenhouse gas concentration

    PA([GHG],f) = probability that the GHG present at concentration [GHG] absorbs a photon in the infrared portion of the spectrum and converts to heat via collisions

    Given that PA([0]]=0.

    You are comparing the concentration of GHG’s to that of O2 and saying since

    [GHG] < < [O2] that it then follows that PA([GHG]) < < < 1

    The value of PA([GHG]) has nothing at all to do with how the concentration of greenhouse gases compares to the concentration of [O2] and [N2]. I believe, but might be wrong about this, that the probability of an IR photon getting absorbed by GHG’s and captured into heat is only slightly increased by a doubling of CO2. After all, we’re only talking about changes in the forcing of a few W/m^2 in comparison to the forcing which is a few hundred W/m^2. I would think that the change in the probability of absorption with increasing CO2 wouldn’t need to be enormous.

    [Response: you also need to remove the spaces... - gavin]

    Comment by John E. Pearson — 22 May 2008 @ 9:04 AM

  168. Gavin, shoot for perfect corelation; eliminate one layer of uncertainty before the economists add several more.

    [Response: r^2=0.97 since 1955, isn't that good enough? - gavin]

    Comment by John Millett — 22 May 2008 @ 5:56 PM

  169. #162. yes, Jim, that’s me – requesting more time for scientists to sort out their widening set of differences before economists are let loose on the project.

    Comment by John Millett — 22 May 2008 @ 6:21 PM

  170. John Millett, As far as peer-reviewed work that gets cited in subsequent papers–and that is what matters–scientists do not differ on what is causing climate change. Nor do they differ particularly on the basic approach toward mitigation, since it is unlikely anything will work in the near term except cutting greenhouse gas emissions. The only aspects where there is still uncertainty–and some controversy, it is true–are how serious the effects will be–disastrous or catastrophic.

    Comment by Ray Ladbury — 22 May 2008 @ 7:57 PM

  171. #166. Cussed lady that she is, Lucy argues thusly. Ray, you posit that the absolute number of GHG molecules in a parcel of air is the sole determinant of the probability of absorption by a GHG molecule of a photon passing through the parcel; and that the very much larger number of non-GHG molecules are irrelevant. That is, for the purposes of the exercise these molecules can be eliminated and, in effect, replaced by space. Imagine a column of air horizontally thinly sliced, say one molecule thick. Each layer would contain a small fraction of the total number of GHG molecules in the air column, and the distance between the molecules would be very much greater than their diameters. On your premise, the probability of capture of a photon passing through a layer would be a small fraction of the overall probability. Your premise therefore requires that the probabilities of capture in each slice be additive which, I would venture to suggest, would give an overall probability greater than 1 and must be rejected. QED, Lucy.

    Ray: “….Earth must heat up until Energy out=energy in again (definition of equilibrium)”.
    I see a problem. “Energy in = energy out” at the top of the atmosphere would imply “energy in > energy out” within the atmosphere. This means that the surface temperature has to fall from an energy level of 390 W/m2 to 240 W/m2 to reach equilibrium. But back radiation from a warming atmosphere will prevent this.

    [Response: John, you're getting silly, and I don't feel inclined to let this pointless discussion go on much longer. Regarding your first remark, as Ray no doubt would have told you the absorption is proportional to the number of molecules encountered only when the total absorption in a layer is small. Each layer takes out photons from what would be absorbed by the next layer; when you multiply (1-epsilon) by itself, to lowest order the absorption is 2epsilon, but when you multiply enough of these together, the absorption approaches 1. Simple stuff. By the way, ih saying that the other gas molecules didn't count, Ray probably didn't want to confuse you by giving too much information at once, but actually the others do count in the sense that collisions increase the absorption by the GHG molecules, so it does matter that the other molecules are there. Your second point is just plain wrong. In equilibrium, energy in = energy out at the top of the atmosphere, and also energy in = energy out at the bottom. However, at the bottom of the atmosphere, the energy budget includes not only radiative terms (both solar and infrared), but also turbulent heat fluxes of latent and sensible heat. --raypierre]

    Comment by John Millett — 23 May 2008 @ 1:53 AM

  172. Gavin, r^2=0.97 since 1955 is impressive and begs an explanation for the negative correlation this century.

    [Response: There isn't a negative correlation this century: r^2=0.81 for 2000-2007 (annual means). - gavin]

    Comment by John Millett — 23 May 2008 @ 1:59 AM

  173. Re John Millett @169: “yes, Jim, that’s me – requesting more time for scientists to sort out their widening set of differences before economists are let loose on the project.”

    John, It seems quite clear that you are doing rather more than that in your submission, and that you are using a good many unsubstantiated, ill-informed, and just plain wrong assertions and arguments, many of them repeated in this very discussion here at RealClimate, all of them repeated elsewhere on RC.

    - that It will be cheaper to adapt than to mitigate [with no mention of economic studies arguing the opposite, such as Stern's]
    - that mitigation [by reducing dependence on carbon-based fuels] will not work because climate change is caused by natural phenomena
    - that ocean circulation (ENSO, PDO) drives climate change [never mind conservation of energy]
    - that the greenhouse gas hypothesis itself can not be correct since the gases are ‘trace’ components of the atmosphere [the dilution argument]
    - that climate sensitivity to burning fossil fuels is a contested hypothesis [never mind the well-established physics]
    - that the hypothesis of anthropogenic forced climate change “can only be tested by the predictive reliability of computer models derived from [the hypothesis]”
    - that the temperature record is flawed, biased, and inconsistent
    - that temperatures in the 1930s were just as high or higher, supported by Australian temperature records and the flat out wrong US figures that you used here earlier

    John, far from striving to understand the science of climate change, as you state in your opening paragraph, you are actively seeking out evidence–no matter how slim or how incorrect–to refute the science of climate change. I see no point in indulging you further.

    Comment by Jim Eager — 23 May 2008 @ 11:03 AM

  174. “yes, Jim, that’s me – requesting more time for scientists to sort out their widening set of differences before economists are let loose on the project. …” – John Millett

    Widening differences? I’m curious to learn more. Name the climate scientists and what it is about which you think they are having this widening disagreement.

    Comment by JCH — 23 May 2008 @ 11:35 AM

  175. Inactivists would rather pass the costs of adaptation on to the next generation rather than paying for prevention themselves.

    Comment by Arch Stanton — 23 May 2008 @ 2:33 PM

  176. Raypierre: I have no desire to outstay my welcome. Before signing off, I need to clarify a few things. I am not an activist (#175) seeking to refute the science of climate change (#173). Rather, I am a loner lacking competence to refute received wisdom (as evidenced here over recent days) but attracted to those who aren’t so constrained (#173). Coming to RC, the centre of the AGW universe, was meant as a counter to that innate tendency. The differences (#174) among the scientific community, as I read the situation, are about the relative climate sensitivities to natural and man-made behaviour, not about the fact of greenhouse warming. AGW is the front runner offering us the choice between catastrophe or mere disaster (#170). The peer-review process (#170) – the thing that did for Galileo but not his science – left competing hypotheses trailing the field. Will peer-review of the current cooling and experiments relating to the cosmic ray hypothesis bring AGW back to the field? Getting a better fix on relative climate sensitivities is highly desirable since it determines how well we allocate resources between adapting to climate change and mitigating it.

    What have I learned?
    That the proportion of LW radiation absorbed by GHGs may be 38% (CO2 in 6 easy steps); or 26% (CO2 only, #113); or 10% (CO2 only, #92); or approaching 100% (…any photon will have a very high likelihood of interacting rather than escaping the planet, #141). That only those wavelengths between ~13 and 17 microns will be absorbed by CO2, in that band almost all will be absorbed within a few meters (#116). This implies that other bands in LW radiation escape directly to space; and that CO2 in the atmosphere above this height is largely redundant, no?

    Any offered reconciliation of these inconsistencies would be helpful and gratefully received.

    There is one other point. I visualise the atmosphere as a thin spherical shell with a heat source at its centre and under the variable influence of the distant sun. What influence does the internal heat source have on the temperature of the inside surface of the shell and on climate?

    Comment by John Millett — 24 May 2008 @ 8:05 AM

  177. Just a simple question from a laymen: Why has the term “global warming” been dropped in favor of “climate change”?

    Comment by SteveStip — 24 May 2008 @ 7:15 PM

  178. Re #76 Cobblyworlds:

    Here you have the data from Mauna Loa (txt) and a graph I personally created from those data:

    ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt
    http://www.elsideron.com/MaunaLoaCO2.png

    I will explain the interesting point that I want to remark with that graph, and which supports the increase of the photosinthesis in the NH as the main cause for the discrepancies between our carbon emissions and its effects on the Mauna Loa CO2 concentration measurements.

    In the linked graph, with cyan squares, you have how much the CO2 concentration dropped during the NH summer (approx June to October), for every year on record. Do you notice something special about it? Yes, that’s it. It shows absolutely no trend. How can it be? No trend means that, during the NH summer, the ammount of carbon emissions minus the CO2 absorption by natural causes has remained stable since the 50′s. But we know that carbon emissions during the summer didn’t remain stable, did they? This necesarily means that natural processes have improved the earth’s capability to absorb CO2 during the summer. That’s OK, we had already agreed on that, the only difference is that I said it was because of photosinthesis, and you claimed it was because of ocean absorption.

    Here is the data that gets us out of any doubt: in the same graph, in purple triangles, you have the ammount of CO2 concentration increase that took place every year on record, in winter (approx October to June). Hey! That really shows a trend! An increasing trend, indeed. The trend it shows is the reason why there is a trend in how much the CO2 concentration increases every year. So what this data says is that, in winter, nature is not being able to counter our increase in emissions. It does in the summer, and quite perfectly, but it doesn’t in winter.

    What would you expect, if it was the ocean acidification the main cause for nature’s improved response? Well, you should see more CO2 uptake by the sea in winter, for 1 main reason: the sea is colder, and it is able to hold more CO2. Do we see that? The answer is no.

    Does this mean that ocean is not increasing the CO2 it is absorbing? No, of course, CO2 absorption by the oceans is taking place. It is part of nature’s response. But it is not the main response. The main response is improved photosintesis in the NH because of increased temperatures.

    Now, the final proof: look again at the cyan squares. Although, in general, there is no trend, if we go to more reduced time frames, we can easily distinguish an increasing trend between 1970 and 1998, followed by a decreasing trend later on. Now, what was happening between 1970 and 1998, for the planet to be able to increase the ammount of CO2 concentration that was taken from the atmosphere in the summer, in spite of our always increasing carbon emissions? Right. The planet was warming. Photosintesis was improving. What has happened AFTER 1998? Right. The planet is no longer warming. As a result, photosinthesis is not improving. Because carbon emissions continue to increase, the overall result is a reduction in the ammount of CO2 taken from the atmosphere in the summer.

    Comment by Nylo — 26 May 2008 @ 7:20 AM

  179. I’d like to correct myself (#178): Ocean is colder in NH summer because most of the oceans’ surface is in the SH. Still the oceans’ uptake of CO2 is not as seasonally driven as photosinthesis. If oceans acidification was the most important thing going on, one would expect both the observed increase of CO2 in winter and a lower CO2 reduction in the summer. But CO2 reduction in the summer is stable.

    Comment by Nylo — 26 May 2008 @ 9:24 AM

  180. Nylo,
    I refer you to the counsel of H. L. Mencken: “Explanations exist: they have existed for all times, for there is always an easy solution to every problem — neat, plausible and wrong.”

    First off, we know that there is more plant growth in the summer, but you will know notice that the summer reduction is not trending significantly upward, while the winter decrease is definitely trending upward. I don’t see evidence supporting your hypothesis.

    Comment by Ray Ladbury — 26 May 2008 @ 9:32 AM

  181. Nylo, have a look here for a regional but significant report on ocean acidification.

    http://seattletimes.nwsource.com/html/nationworld/2004433462_acidoceans23m.html

    Comment by Ron Taylor — 26 May 2008 @ 10:05 AM

  182. Re #180: That’s exactly my point. Although emissions are increasing, also in the summer, the CO2 reduction in the summer remains the same. There is only one posible explanation for that: IN THE NH SUMMER, photosinthesis is improving as much as our emissions are increasing. And of course it doesn’t happen in winter. In winter there is little photosinthesis to increase, because there is less land in the SH, and also, because SH temperatures are not raising as much as NH temperatures. So this constant CO2 reduction in the summer with growing CO2 increase in winter is consistent with overall increased emissions and increased photosinthesis happening almost only in the NH summer. It’s the fingerprint that blames photosinthesis for the reduction of the increase ratio of CO2 concentration between the 80′s and the 90′s.

    Comment by Nylo — 26 May 2008 @ 10:45 AM

  183. Re #181 Ron: I’m glad that you provided that link, I was looking for it. I would like to mention the abuse of the term “acidification”, when it is a WRONG term. More alarming, but wrong. Any pH value over 7 is not acidic. It is alkaline. And the most so-called acidic value they found was 7.5, therefore alkaline. So we could only say that the sea is turning, regionally, less alkaline. If the trend continued and it became less than 7, then it would begin to “acidify”.

    Also about that article, it has to be absolutely false and profoundly misleading to claim that “the scientists found regions where the water was acidic enough to dissolve the shells and skeletons of clams”. First, because the water was NOT acidic. And as long as the water is ALKALINE, any “acid” you add will counter the alkaline substances already disolved in the water, making the water less alkaline, but without affecting the shells within.

    You can tell me that the clams depend on an alkaline sea to grow better, and therefore if the sea gets less alkaline, they grow less. Fine, I could buy that. But you cannot persuade me that an acid ocean is disolving them. No way. For the sea to start to disolve the shells and skeletons of clams, it would first need to be pH

    [Response: please use & l t ; (with no spaces for a < symbol). Plus your logic is flawed. Think of the analogy with warming or cooling - even if it is -40 deg an increase of a couple of degrees is still warming, even though that temperature is not considered 'warm'. Acidification (or de-alkalinisation) is a statement about the direction of change, not the state. And there are plenty of places in the ocean where carbonate dissolves even without a ph < 7 (look up lysocline). - gavin]

    Comment by Nylo — 26 May 2008 @ 11:12 AM

  184. Nylo, start with any comprehensive review article, for example
    http://www.nature.com/nature/journal/v437/n7059/abs/nature04095.html
    Also click there on the links for:
    more articles like this
    see also
    Articles in CrossRef citing this article

    Don’t rely on other people to convince you of anything. Read the science.
    Convince yourself. Then point other people to the published science.

    If you’re reading something contrary elsewhere, tell us where you’re reading what convinces you and why you trust that source over the science journals.

    Comment by Hank Roberts — 26 May 2008 @ 1:34 PM

  185. Nylo, what astonishes me is that you are accusing the scientists quoted in the article of incompetence or dishonesty. Are you genuinely qualified to make such a judgement? If not, then perhaps you should follow Hank Robert’s suggestion and try to find out why the scientists are concerned.

    Comment by Ron Taylor — 26 May 2008 @ 2:51 PM

  186. SteveStip (177) — The changes to the climate (and the biosphere) are more extensive than just warming. But IMO either phrase will do.

    Comment by David B. Benson — 26 May 2008 @ 4:26 PM

  187. Nylo, think about this. The term “denialist” comes up on this site, usually in a rather perjorative sense. But I think it is often more accurate use the term to apply to someone who is “in denial,” rather than someone who is trying intentionally to be damaging.

    I knew a vibrant young woman who was diagnosed with childhood diabetes as a young girl. She craved sweets and carbs (as do all diabetics) and she could not see that they were doing any particular harm. She felt fine, so simply refused to listen to her doctor and follow her diet. Total denial. She would not accept that what she was doing was setting in motion terrible long-term damage to her body. She died in a nursing home last month, at age 36, blind, on dialysis, unable to walk. Long before she died, she realized she had been terribly wrong. But it was too late. Lethal damage was already in the pipeline.

    AGW is very much like this, but on a longer timescale. If you remain in denial, by the time there is overwhelming evidence that even you can no longer deny, it may be too late to avoid extremely serious, even catastrophic consequences. Remember, temperatures will continue to increase for decades after we put a cap on emissions.

    Stop grasping at any straw to argue for inaction. Study the problem, get informed, think. And if you refuse to trust the climate scientists, then so be it. But you will be taking the same approach to life as the young diabetic who refused to trust her doctors.

    Comment by Ron Taylor — 26 May 2008 @ 6:34 PM

  188. Re #184 Hank: Only the summary is available for me about that article. Anyway I notice that they claim acidification to be a problem by 2050, not earlier. Then there is the report that was linked before, about scientists finding acidified water right now, “ahead of time”. What I am missing in that report is 1) did they only go to that specific location or did they take measures everywhere? 2) What were the results in the measures of other parts of the ocean? Did they find any excess of alkalinity anywhere? 3) Do we have a history of the acidity state of that specific part of the ocean that they claim to be unusually acidic? 4) Was it an upwelling part of the ocean, with cold water coming from below and getting warm and, as a result, having a temporary excess of CO2? 5) Why haven’t they published a peer-reviewed paper?

    As for the article you link, I would like to know 1) How much was the “notable dissolution” experienced by the pteropods? 2) At which level of acidity? 3) We know what happened after two days, but what happened to them in the longer term, say, 1 month? I guess that if you make reference to that article is because you read it and can answer those questions.

    Comment by Nylo — 27 May 2008 @ 1:09 AM

  189. Oh, I forgot, do we have any prehistorical data about acification of the oceans? If this acidification is real, is it unprecedent? If it is not, did pteropods survive to the last acidification? I’m just guessing that during any ice age, the CO2 content of the sea must have been quite higher, and this means it got more acidic, am I right?

    Comment by Nylo — 27 May 2008 @ 1:21 AM

  190. Climate Science has posed a set of questions in response to your “bet” postings [see “Challenge to Real Climate On The IPCC Global Climate Model Predictions Of Global Warming“. We look forward to your reply.

    Comment by Roger A. Pielke Sr. — 27 May 2008 @ 5:54 AM

  191. “each time starts again close to the observed climate, because it is initialised with observed sea surface temperatures. So by construction it cannot get too far away, in contrast to the “free” black scenario.”

    If the Keenlyside model is used without this re-initialisation, what would it come up with? Would the coupling effect send it off course? and would the course shift up or down between 1960 and 1990?

    Comment by naught101 — 31 May 2008 @ 5:36 AM

  192. #32 – “Since such radiation is the only way energy escapes the climate system, that has to heat things up.”

    Not completely true. The energy does NOT all have to radiate from the surface. When water condenses into clouds at altitude it releases the energy that evaporated it at the surface. Therefore, the energy that evaporated the water at the surface was not ~only~ radiated back up, whatever went into evaporation was first physically transported up several thousand feet and THEN radiated. Therefore, the energy that goes into the heat of evaporation is transported up through, and unimpeded by, any concentration of CO2 below the altitude of cloud formation, (where most of it exists). It is my understanding that IPCC models do not account for that mode of heat energy transport.

    [Response: Your understanding is wrong. You must have gotten it from some really rotten source. IPCC models, indeed even the simple radiative-convective models going back to Manabe' work in the 1960's, account for, and indeed rely on, this mode of heat transport. --raypierre]

    Comment by Mike M — 5 Jun 2008 @ 5:02 PM

  193. Even Keenlyside et al.’s green line shows a global (? or just North Atlantic? That seems a bit unclear) warming of around 0.8 degrees C in the next fifteen years or so (until 2025). So why are they talking about global cooling? Re #13 “media in comfortable lockstep with AGW proponents”: As far as I read the media thats pure nonsense. They give the impression that there exists a great scientific debate among IPCC and the so-called “climate scepticists” (this expression is silly, since it has no more meaning “to be sceptical to the climate” than to be sceptical to the sun. The better expression would be “the global warming deniers” for some and “the greenhouse warming scepticists” for others, even if the two groups are normally almost identical). This media impression is pure propaganda, and some of it has been proven to be paid for by fx. ExxonMobil. The main reason for the global warmning denial/ridiculization industry (as I find it reasonable to call most of the media coverage) is of course not bribery but rather a weak spot in human nature which led fx. the guatemalian president in 1902 to proclaim: “There are no active volcanoes in Guatemala” – just in the middle of a big eruption and even while a city was being destroyed by it! Some human beings will unfortunately do whatever it takes to deny for themselves the parts of reality they don’t like, often because they believe this reality prohibit their business and/or leisure activities, their so-called beliefs etc. etc.

    Comment by Karsten J — 26 Jun 2008 @ 9:44 AM

  194. Re # 176

    I want to put it on the record that I agree with John Millett, albeit only on one tiny point:

    John says: “I am a loner lacking competence to refute received wisdom (as evidenced here over recent days) but attracted to those who aren’t so constrained.”

    However I would like to see John put a bit more effort into distinguishing between “those who aren’t so constrained” and those who, as it turns out, are. It would save everyone contributing to and (gratefully, like me) using this site a lot of time and effort.

    Garry.

    Comment by Garry S-J — 21 Jul 2008 @ 8:28 PM

  195. I have not posted on RealClimate before, so I thought I could add something to this thread to “get my feet wet” without causing needless disruption if I haven’t quite got the hang of posting here. Let me add some comments on one of the main subthreads.

    John Millett (#90 et seq.) demonstrates a common difficulty with problems involving conditional probability: the inability to formulate the problem correctly as a sequence of conditional events rather than a single event.

    Millett (mis)formulates the probability of an IR photon radiating into space as the probability of “getting past” a *single* molecule, despite talking of an air column, as in #132:

    “#117 Ray, what you didn’t tell me is that as well as the 59 trillion photon-gobbling CO2 molecules in the air column there are 98 quadrillion photon-friendly molecules of N2 and O2. The probability of the photon escaping to space is 0.9994, no?”

    The proper way to formulate the problem is inductive: the probability of “getting past” the first N molecules in the air column is the probability of not being absorbed by the Nth molecule, given that the photon was not absorbed by the previous N-1 molecules. This conditional probability, for these sequential and (assumed) independent events, becomes the *product* of the probabilities of not being absorbed by the N molecules individually.

    Now the probability of not being absorbed by a non-GHG molecule is, by definition, unity, and if the probability of not being absorbed by a GHG molecule is (1-x), then the conditional probability of not being absorbed by the first N molecules is (1-x)^n, where “n” is the number of GHG molecules in the N molecules. Since x is non-zero by definition, letting n increasing to 59 trillion leads to an escape probability of essentially zero.

    The non-GHG molecules (N2, O2, etc.) have no effect on this conditional probability product, since for these molecules we have x=0. This is clear from the product formulation, a point that Millett has not yet understood.

    Comment by Brian Brademeyer — 10 Aug 2008 @ 9:32 AM

  196. You probably know this already, but if not, worth following up.

    The Sun is very quiet indeed at present — no sunspots. This has been the case for quite a while. In the past, such low solar activity has been associated with cold spells on Earth, like the Little Ice Age of the 17th century. It could be that (i) the greenhouse effect is stopping the Earth cooling now and (ii) the solar effect is partly canceling the greenhouse effect which is why global warming has slowed. The implication is that when “normal service” resumes on the Sun the world will get hotter, quicker.

    Comment by John Gribbin — 26 Aug 2008 @ 2:40 AM

  197. John Gribbin,
    The question is this: What is the mechanism by which a quiet sun cools Earth. If total solar irradiance has not changed, if the globe is not appreciably cloudier, then what possible mechanism could there be? Certainly, we cannot judge by the past year–a very deep La Nina year. What is more, the current solar cycle is not grossly out of the normal range of variability just yet.
    Have you seen Tamino’s analysis?

    http://tamino.wordpress.com/2007/10/13/solar-cycle-24/

    http://tamino.wordpress.com/2008/07/13/dalton-gang/

    I agree there are (seeming) correlations between grand solar minima and cooling (Usoskin 2007), and that such cooling lasts at most a few decades. So if we do enter a cool spell, it provides at best, temporary relief.

    Comment by Ray Ladbury — 26 Aug 2008 @ 8:05 AM

  198. Was there any follow-up on #190?

    Comment by Richard Sycamore — 26 Aug 2008 @ 10:14 AM

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