Nature article on ‘cooling’ confuses media, deniers: Next decade may see rapid warming

The Nature article that has caused so much angst about the possibility we are entering a decade of cooling — “Advancing decadal-scale climate prediction in the North Atlantic sector” (subs req’d) — has, in fact, been widely misreported. I base this in part on direct communication with the lead author.

In fact, with the general caveat from the authors that the study as a whole should be viewed in a very preliminary fashion, and should not be used for year-by-year predictions, it is more accurate to say 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 “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.

Before explaining where the confusion came from — mostly a misunderstanding of how the Nature authors use the phrase “next decade” — let’s see how the media covered it:


The UK Telegraph says “Global warming may ‘stop’, scientists predict” — “… Researchers studying long-term changes in sea temperatures said they now expect a ‘lull’ for up to a decade.”

National Geographic News blares, “Cooler Climate May Hit N. America, Europe Next Decade.”

Revkin at the NYT wonders, “Can Climate Campaigns Withstand a Cooling Test?” and says the Nature study forecast “some Northern Hemisphere cooling in the coming decade.”

No surprise, global warming denier Sen. James Inhofe leaped on this with his own press release: ” ‘Global Warming Will Stop,’ New Peer-Reviewed Study Says: Global Warming Takes a Break for Nearly 20 Years?

But none of these headlines accurately portray what the data presented in the paper actually says. Let’s look at the paper’s key figure, the one that looks at past and (forecast) future global temperatures, “Hindcast/forecast decadal variations in global mean temperature, as compared with observations and standard climate model projections” (click to enlarge)


Let me try to explain this complicated figure (I’ll reprint the authors’ own caption at the very end).

The first thing to know about the figure — indeed, one major source of confusion — is that “each point represents a ten-year centred mean.” That is, each point represents the average temperature of the decade starting 5 years before that point and ending 5 years after that point.

Second, the red line is the actual global temperature data from the UK’s Hadley Center for Climate Prediction and Research. Why does the red line stop in 1998 and not 2007? Again, it is a running 10-year mean, and the authors use data from a Hadley paper that ends around 2003 (I believe), so they can’t do a ten-year centered mean after 1998.

Third, the black line is one of the IPCC scenarios, A1B. It is a relatively high-CO2-growth model — but actual carbon emissions since 2000 have wildly outpaced it (see here).

Fourth, the solid green line is the “hindcast” of the authors — how well their model compares to actual data (and the A1B scenario). It is then extended (in dashes) through 2010 and finally to 2025, where it meets up with A1B, since their model only imposes decadal variability on the inexorable climb of human-caused global warming.

[Fifth, the short purple line is with radiative forcing (i.e greenhouse gas concentrations) frozen at 2000 levels, which, of course, didn’t happen.]

So you can clearly see that the green line rises and then plateaus, repeatedly, until it really starts to take off in the decade of the 2010s. Perhaps the source of much of the media’s confusion is that the authors describe their results in the final line of the abstract this way:

Our results suggest that global surface temperature may not increase over the next decade, as natural climate variations in the North Atlantic and tropical Pacific temporarily offset the projected anthropogenic warming.

But what they mean by that statement is not what a simple reading of that sentence would suggest: They do not mean that “the global surface temperature may not increase over the next ten years starting now.” What they mean is what the lead author, Dr. Noel Keenlyside, wrote me last night when I asked for a clarification:

Thus, based on our results we don’t expect an increase in the mean temperature of the next decade (2005-2015).

They are predicting no increase in average temperature of the “next decade” (2005 to 2015) over the previous decade, which, for them, is 2000 to 2010! And that’s in fact precisely what the figure shows — that the 10-year mean global temperature centered around 2010 is the roughly the same as the mean global temperature centered around 2005.

The authors have not predicted the next 10 years won’t see any warming. They have, however, offered an explanation for why temperatures have not risen very much in recent years, and, perhaps, why ocean temperatures have also not risen very much in the past few years (see here). Dr. Keenlyside continues:

However, as you correctly point out, our results show a pick up in global mean temperature for the following decade (2010-2020). Assuming a smooth transition in temperature, our results would indicate the warming picks up earlier than 2015.

Again, at that point, Dr. Keenlyside reiterates the disclaimer that this analysis can’t be used for year-by year predictions. Indeed, he notes that his main conclusion is not really quantitative, but qualitative:

Given the uncertainties that exist in such kinds of preliminary studies, I believe it is more useful to point out that climate on decadal timescales may be quite different from that expected only considering external radiative forcing (as in the IPCC). This is actually an obvious, but I believe mostly overlooked fact. Our results highlight this.


Before coming to a final conclusion, I would add three points. First, as you can clearly see in the figure — the actual observed runnning average temperatures from the Hadley Center since 1995 have been between the IPCC scenario projection and Dr. Keenlyside’s forecast, which does suggest that his model may be underestimating warming. Indeed, the lack of agreement between the model’s “hindcast” and actual temperatures since 1995 should remind us again to view this only as a very preliminary analysis with predictive ability that is much more qualitative than quantitative.

Second, since carbon emissions since 2000 have been racing past all projections, and been accompanied by soaring CO2 concentrations, (see “NOAA: Atmospheric Carbon Dioxide, Methane Rise Sharply in 2007“), we would again naturally expect actual temperatures to be slightly higher than Dr. Keenlyside’s forecast (just as frozen concentrations yield results below his forecast).

Third, this general prediction — internal variability leading to slower than expected warming in recent years through 2010, followed by accelerated warming — is almost exactly the same prediction that the Hadley Center made last summer in Science (see here). They concluded:

… at least half of the years after 2009 predicted to exceed the warmest year currently on record.

… [2014 will] “be 0.30° ± 0.2°C warmer than the observed value for 2004.”

So I take both these admittedly preliminary short-term forecasts to suggest that warming is going to be a roller coaster ride, with much short-term variation, but we are probably going to get quite hot quite fast early in the 2010s.

One final caveat: After reading the first draft of this post (which I have since revised), Dr. Keenlyside writes me this morning, “All our figures are decadal means, and it is hard to say (due to high frequency internal variability) at which point [after 2010] a rapid increase will occur.” That is, his study does not necessarily predict the rapid warming will actually start, in say, 2011, though his results are not inconsistent with that possibility. He reiterates that his paper is not designed to make such detailed year-by-year predictions. Indeed, the paper was designed to show that any such predictions are complicated by decadal-scale climate factors.


Here is the authors’ own caption for the figure:

Model projections are twentieth century-RF [radiative forcing] followed by A1B scenario simulations (’20C-RF/A1B’); ‘Stabilization’ forecasts assume greenhouse gas concentrations fixed at year 2000 levels. Each point represents a ten-year centred mean; vertical bars indicate ensemble spread; verification and forecast periods are indicated (dark shading begins 2008, indicating the start of the true forecast period). Three additional decadal means (joined by a dotted line) show the evolution of the initialized and un-initialized 2005 predictions extended till 2030. Correlation of both hindcasts and climate model projections with observations are given in brackets. Correlation of the twentieth century-RF simulation with observations is greater than that of the hindcasts, but only marginally at the 5% significance level. Observed global mean temperature anomalies are from HadCRU3


66 Responses to Nature article on ‘cooling’ confuses media, deniers: Next decade may see rapid warming

  1. Andy says:

    This post is great. It shows very well why those who are plotting the IPCC global temperature forecasts against actual global temps on a yearly or even monthly basis are simply herding cats. It also points out how the media’s obsession with providing 24 hour news updates doesn’t mesh with our real world which changes on a much longer time scale.

    I’d love to see journalists help explain the latest studies to the public instead of simply “keeping score”. Surely they can find ample sources to such as yourself to explain the subtleties of these works.

  2. Cliff says:

    Right on, Andy, and thanks again, Joe, for clarifying scientific complexity at least enough to reveal the truth behind it. Terms like “decadal mean” are probably as much over the heads of almost all journalists as they are over the head of this Internet specialist. But maybe we’d better get more familiar with them, eh?

  3. Gestur says:


    Thanks for this great explication of the Keenlyside et al. Nature article, and for discussing its policy implications so well. There’s a relatively minor error in your discussion of the first point in “What This Study Tells Us”, namely your statement:

    “First, as you can clearly see in the figure — the actual observed running average temperatures from the Hadley Center since 1995 have been between the IPCC scenario projection and Dr. Keenlyside’s forecast…”

    As the authors note in their caption to Fig. 4, “Observed global mean temperature anomalies are from HadCRU32”, and of course their (i.e. observed global mean temperature anomalies) placement with regard to the plots of the Hindsight /Forecast and the IPCC scenario projections is determined by the properties of the scale on the right hand side of this figure, namely for anomalies. Thus there isn’t enough information provided here to make the point that observed is between these two forecasts, although we can’t rule that out. [The slope of the Hindsight /Forecast is negative and the anomalies are still positive and high from 1995, so they are going in opposite directions; but the slope of the IPCC scenario projection is positive and looks from the figure to be around +0.2, and this looks to be less than the average of the anomalies, which appears to be around +0.3. Again, however, you can’t determine relative positions of all three in the absolute scale of mean temperatures.]

    As you declared, this is a complicated figure!

    Keep up your excellent posts!


  4. jturner says:

    You AGW zealots are hilarious. I love the way you label anyone who doesn’t buy into the AGW religion as a “denyer”. And the way you love the press when their headlines mirror your “the sky is falling” partyline, but when they dare report anything that deviates from the partyline, they are “confused” and “too stupid to understand what the study really says”. You guys will never admit that science doesn’t work by concensus, but by the scientific method. And the scientific method says when the observed data doesn’t fit the hypothesis, you discard it. But nooooooo – when the AGW data doesn’t fit the hypothesis, you simply cook (so to speak) the data – as Dr. Hansen has been busily doing with the NOAA data for years. In ten years we shall see who’s right and who’s wrong. But a decade from now, when AGW hasn’t panned out, I expect to see yet another “model” explaining why it hasn’t happened, but wait, it’s just around the corner, and when it happens, look out, the sky is really gonna fall then.

  5. Joe says:

    Gestur — you may be right. This figure is a toughie to unscramble.
    I was influenced by this statement in the figure caption:

    “Correlation of the twentieth century-RF simulation with observations is greater than that of the hindcasts, but only marginally at the 5% significance level.”

    I took that to mean that the figure portrayed the fact that the IPCC forecast was in fact slightly closer to reality than the hindcast.

  6. Pahbs says:

    If you have a valid scientific point to make, THEN MAKE IT. If it is to the contrary of what the majority of the scientific community is saying, THEN LET YOUR DATA AND ANALYSIS SPEAK FOR ITSELF.

    Otherwise, do not continue the banter about how scientists are “cooking” data, because then you bring the same type of rhetoric that you accuse your so-called opponents of purveying.

    Let’s all let the data do the talking and let those who understand the science do the explaining. Not all data is going to correlate with everything else, and not all the data is easily digested be interested onlookers (and scientists). It takes time, patience and objectivity to sort through everything.

  7. David B. Benson says:

    jturner — You will be better informed after you read “The Discovery of Global Warming”, linked here:

  8. ice says:

    thanks for the explainations. I had come to the same conclusions as to what the author meant by “no warming till 2015”. But then this prevision is not specially linked to their initialization/hindcast model, since the black line (standard “IPCC version” echam5 model with SRES scenario AIB) shows the same plateau over the 2005 and 2010 points…

  9. exusian says:

    Note to Jturner and others of the same ilk:

    I usually stop reading as soon as I get to phrases like “AGW zealots” and “AGW religion.”

    They are sure signs that you have nothing what so ever to say about the science.

  10. jturner says:

    Mr Benson,
    Dr Weart’s book and web site are interesting for a historical perspective. But just because he is a scientist doesn’t mean he doesn’t have an agenda. That is made clear in his personal note, when he says “we can conclude (with the Intergovernmental Panel on Climate Change in its 2007 report) that it is very likely that significant global warming is coming in our lifetimes. This surely brings a likelihood of harm, widespread and grave (see this summary of expected impacts). The few who contest these facts are either ignorant, or so committed to their viewpoint that they will seize on any excuse to deny the danger.” Hmm. Let me paraphrase that: “The sky is falling and if you don’t believe it you’re an ignorant denyer.”

  11. John McCormick says:


    tell us: what is your agenda?

    You said of Spencer Weart:

    [But just because he is a scientist doesn’t mean he doesn’t have an agenda.]’

    Are you a scientist? Are you a parent? Give us a glimpse of your motivation to join this discussion.

    John McCormick

  12. jturner says:

    Mr McCormick, I have no agenda, other than to champion the free exchange of ideas. I am a parent and I have a degree in Physics, though I do not work in the field of science. Quite frankly, I posted here just to see what reaction I would get. As long as the AGW “debate” remains a debate, I have no problem. But when AGW is seen as dogma, and heretics are figuratively burned at the stake, then I have a big problem.

  13. exusian says:

    You open with the phrases “AGW zealots” and “AGW religion” and you have no agenda.

    But there is no debate on the science, the debate is on what to do with the science, or on policy.

    To be sure, plenty of scientists have questioned the science, as well they should, but none of them have been able propose an alternate hypothesis that can both explain the observed and measured effects AND negate the known physics of greenhouse gases.

  14. Brian D says:

    Jturner, as a fellow physicist, I can assume that your training included the tacit understanding of falsifiability. Before we go any further, let me ask you: What would convincing evidence look like on either “side” of this ‘debate’? Without defined goalposts, it’s easy to move them, which doesn’t help anyone (well, with one exception).

  15. David B. Benson says:

    jturner — AGW is seen as the best explaination of the facts observed in the field, the laboratory experiments, and the known physics.

    Dogma is for religions:

  16. Lou Grinzo says:

    I love how often discussions about how A the observed GW is turns to this “I just want to see an open debate” meme.

    This always prompts me to ask: At what point do we draw a line and say, “OK, it’s time to assume there is a very significant human contribution to GW and focus all the debate on what to do to save our collective neck.”

    I am not, by any means, trying to stifle debate. I run my own blog and I’ve worked for years as a writer, so I’m about as militant a supporter of free speech as you can find. But how would we treat someone who wanted to have an open debate about whether the CIA invented AIDS, whether the US really staged the 9/11 attacks, whether the earth is flat, or any of a few dozen other notions of similar ilk? I’m not for a second saying that debating AGW is the same as debating those issues, but I often wonder where the line is that lets us say one group (like those who believe the offensive and ludicrous examples I mentioned) are fruit loops and others aren’t.

    Not to be overlooked, of course, is the risk assessment in herent in this situation. If we continue to debate much longer and the Romms and the Hansens of the world are right, we’re in trouble beyond all comprehension.

  17. John McCormick says:


    Hmm. Let me paraphrase your paraphrase that read as follows: “The sky is falling and if you don’t believe it you’re an ignorant denyer.”

    My paraphrase:

    “The Arctic sea ice melted, in 2007, to an extent never witnessed in recorded history and if you don’t believe it you’re not honest; if you do believe it you and your children will have to live with the consequences of repeated Arctic ice meltback of similar and likely greater extent.”

    John McCormick

  18. exusian says:

    But John, it doesn’t matter what you, me or jturner believes, it mets regardless of belief. It melts because physics causes it to melt. It’s not belief in physics that makes it do what it does.

  19. David B. Benson says:

    Lou Grinzo — Good points.

    But are you sure you don’t want to debate “why the sea is boiling hot and whether pigs have wings”? :-)

  20. jturner says:

    Gentlemen, thank you for your instructive replies to my posts. I believe I have made my point. Obviously, no one is going to change anyone’s mind in blog responses. I’m sure you are concerned about your children’s future, and so am I. In my opinion, we would be better served to buy them extra sweaters for the future, rather than swimsuits, because I believe natural forces, primarily the sun and ocean circulation, will trump any AGW contribution by CO2. I hope we live long enough to see who’s right.

  21. David B. Benson says:

    jturner wrote “…I believe natural forces, primarily the sun and ocean circulation, will trump any AGW contribution by CO2.” Why should you ‘believe’ that?

    Here are the 10-year average global temperatures:

    Here is the excess CO2 added by humans to the air:

    Now re-read about CO2 as a global warming (so-called greenhouse) gas.

  22. Lamont says:

    “I believe natural forces, primarily the sun and ocean circulation, will trump any AGW contribution by CO2.”

    Well, you’re just wrong about the sun and it doesn’t matter what you believe, the science doesn’t bear you out.

    As far as ocean circulation goes, the oceans are just a big heat sink. There’s no net loss or gain of cooling there over decadal timescales, but heat can be temporarily transfered away from the atmosphere or returned.

  23. Roy says:

    Superb analysis and discussion.

    Joseph Romm, you are the Go to Guy!

    Thanks you,

    Roy in Santa Clara

  24. exusian says:

    jturner, ocean circulation moves a tremendous amount of heat around, but it can not generate it. And while it’s true that all of earth’s energy budget does come from the sun, how come all solar proxies diverge from the temperature trend after the late 1970s?

  25. Kiashu says:

    See now, this is why I think all BSc should have to do a unit or two of some Arts course, so that they’re able to express themselves clearly.

    Clearly enough for journalists, even. Because when I read that paper I get muddled messages, I’m not sure what they’re really trying to say – and I’ve got some basic science education, am reasonably well-versed in the various climate change causes and effects, and so on.

    If it left me muddled, then your average journalist would be hopelessly confused.

    Perhaps as part of the peer review process, the papers should have to go to people who are not specialists in the field to see if they can understand them. That was always the guideline we were given in essay writing – write as though your reader is intelligent, interested in the topic, but not a specialist in it. Given that these days scientific issues – not just climate change – are so much in the media, perhaps scientists ought to take that as their guideline, too.

    Write clearly.

  26. Sean says:

    “The Arctic sea ice melted, in 2007, to an extent never witnessed in recorded history and if you don’t believe it you’re not honest; if you do believe it you and your children will have to live with the consequences of repeated Arctic ice meltback of similar and likely greater extent.”

    – John McCormick

    Allow me to point out, in all honesty, that the statement above is true only if you date the dawn of recorded history to 1979. That’s the year Margaret Thatcher was elected Prime Minister of Great Britain (which many conservatives believe to be the beginning of recorded political history) and the year that the Clash released “London Calling” (to which many fans of punk rock date the beginning of musical history — specifically to the moment that Nicky “Topper” Headon smashed his guitar on the floor of New York’s Palladium on Sept. 29, 1979, which is featured on the cover of London Calling, but I digress. It’s also the year that Nasa satellite measurements of the polar ice cap began.

    But if you believe that there was sea ice variation before satellites could measure it, you’ll find some interesting “records” in the era before the Iron Lady.

    Here’s an interesting observation from 57 B.C. (before the Clash):

    “The Arctic ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the water too hot, according to a report to the Commerce Department yesterday from Consul Ifft, at Bergen, Norway.

    “Reports from fishermen, seal hunters and explorers, he declared, all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met with as far north as 81 degrees 29 minutes. Soundings to a depth of 3,100 meters showed the gulf stream still very warm.

    “Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared. Very few seals and no white fish are found in the eastern Arctic, while vast shoals of herring and smelts, which have never before ventured so far north, are being encountered in the old seal fishing grounds.

    – State Department report, 1922 A.D.

    By the way, on the subject of ocean currents, the Arctic Oscillation, generally positive since 1979, turned negative in about 2003. With a three to four year lag in effect, we should expect to see Arctic ice returning to pre-1990 levels over the next several years.

  27. Ron Taylor says:

    JTTurner – Apparently your degree in physics did not include any study of thermodynamics, especially conservation of energy. You seem to believe that ocean circulation can offset a radiative energy imbalance of the earth, where the incoming radiation is greater than the earth’s radiation to space.

    It reminds me of an old fighter pilot friend in aerospace engineering who was fond of saying, “It is not the ignorant cane cutters who are dangerous to our society, but the ill-educated intelligentsia.”

  28. Joe says:

    Sean: “By the way, on the subject of ocean currents, the Arctic Oscillation, generally positive since 1979, turned negative in about 2003. With a three to four year lag in effect, we should expect to see Arctic ice returning to pre-1990 levels over the next several years.”

    Wanna bet? Real money, that is, on this absurd claim of yours. Or do you just post comments you don’t really believe.

  29. Joe Hunkins says:

    Hmm – of course the media got it wrong. They also report catastrophes are now looming from AGW which is absurd, but too rarely debunked by responsible scientists. A key point of contention is the degree to which natural variations swamp out the AGW effects, and the study lends considerable support to those who have suggested that the near term impacts of human generated CO2 have been exaggerated by models. What exactly will we have to see in the real world for true believers to begin a more robust study of alternative modelling scenarios? Will these models just keep pushing effects out so far that nobody can be held accountable for being….wrong?

  30. mauri pelto says:

    The first global warming related conference I went to was at Northwestern in 1983, and at it a scientist, sorry I cannot recall who, made an analogy that has panned out well…. Climate warming and cooling period develop a sawtooth pattern in history, but global warming is going to dampen the cooling and heighten the warming leading to a staircase. This seems to be fairly accurate for the last 100 years. It is true that a sharp warming in 1976-77 for the globe followed a rearrangement in the North Pacific Ocean circulation. If the current switch back is robust than it will dampen the warming trend. However, this is ignoring the other building feedbacks in the system, such as more open water in the Arctic etc.

  31. Lamont says:

    Can anyone explain where this stupid conservative meme came from about solar forcing? There seem to be an awful lot of anti-AGW people who “believe” that it all has to do with solar cycles and that we’re about to enter a period of cooling. The “science” of this approach seems to be composed of taking a graph of sunspot activity and going “look its going to cool off”. This is broken in so many different ways — but isn’t the solar forcing one of the best understood areas of the modeling of the Earth’s climate? Isn’t it pretty easy to take satellite measurements of the solar flux over time hitting the earth and figure out how the variability of the sun’s output over time contributes to variability in climate? Why cant someone write a quick paper to shut these idiots up?

  32. rando says:

    ….finally something begins to bring balance to the Force. My concern has always been with the concept that the science behind global warming had somehow been settled. Other areas I like to think about: the sunspot/climate correlation is compelling; as is a cascade of feedbacks in response to elevating levels of atmospheric C02, which has already contributed to globally enhanced vegetative biota. Initial lab studies (Keppler et al. 2006, and others) are suggesting that methane may result from live vegetation, a field still actively being investigated. If there is a significant contribution determined, any C02 enhanced increase in biota will also enhance methane production, which is a very powerful GHG. Just in case, I’m going out to cut down some trees in my yard later this afternoon to do my bit to reduce atmospheric methane. I’ll likely need the wood to heat my house next winter anyway – I won’t be able to afford heating oil, and if our winter next year is anything like the one we’re just getting over, I’m going to need all the free heat I can get.

  33. JD says:

    Well here is a nice AGW choir singing to itself. World measured temperature using the accepted measurement indices hasn’t risen since 1998. See for example:

  34. Joe says:

    Sorry, JD, that denier talking point has long since been debunked on this blog and elsewhere. So much so, that I don’t typically bother responding to it, but you’re a newbie.

    You can try here:

  35. Anshuman says:

    This is too dissapointing, I’d just read the newspaper article, and was going about with a new hope kind of feeling, now that I read this, and see what it actually means, it’s too depressing.

  36. Lamont says:

    1998 was an extremely strong el nino year.

    try graphing the yearly temperature of the past century. don’t label it. take it to a technical analyst at a hedge fund and tell them its a stock chart and ask if they think the stock is overbought, oversold, or a buying or shorting opportunity.

    i’m pretty sure they’d tell you that the uptrend channel has not be violated and that the stock is oversold and is due for a bounce and would advise strongly against shorting it.

    and in the case of the climate we know it got “overbought” in 1998 because of the unusual el nino year and the pacific ocean being extremely warm. currently there’s a moderate la nina year with a cold pacific. if you connect up only la nina years there’s still a clear uptrend. so unlike a stock price, there’s fundamental reasons behind the consolidation in climate temperature from 1998-2008.

    going back to 1998 is also cherry picking a start year. if you go back to 2000 (more valid because that is a la nina year), there’s still a clear uptrend.

    this is bad because the ENSO is an oscillation and the fact that we’re in a la nina year this year is not an indication of climate change — it is decadal varaiation in weather — and when moderate-to-strong el nino years happen again the temperature will be much warmer.

  37. David B. Benson says:

    JD — Here is a correct way to see the statistics: the 10-year average global temperatures since 1850 CE.

  38. Sean says:

    Hi Joe,

    Yes, I think a bet would be a good idea and I propose we bet on the September (i.e. annual minimum) sea ice extent data from NOAA.

    Raw data here:

    The September 2007 reading was 4.28mm square kilometers. The September, 1990 reading was 6.24 million square kilometers.

    I bet sea ice increases every year for the next ten years, at a rate that would put it back at the 1990 level in ten years.

    The progression would look like this:

    4.28 2007
    4.48 2008
    4.67 2009
    4.87 2010
    5.06 2011
    5.26 2012
    5.46 2013
    5.65 2014
    5.85 2015
    6.04 2016
    6.24 2017

    Every year that sea ice extent is less than the number in the table above, I will pay you $100. You pay me $100 every year that sea ice extent is greater than the table value. Settlement within, say, a week of the September number being published (usually in the first two weeks of October)

    So you win (and keep winning) if sea ice keeps shrinking (which is what I presume you believe will happen), if it stays the same, and even if it grows at a fair clip (approx. 4% per annum if I did my math right).

    I win only if sea ice grows at a rate that increases its extent by nearly 50% over the next decade. Sound like a fair bet?

    I clearly start at a disadvantage:

    University of Colorado at Boulder (2008, May 2). Three-in-Five Chance Of Record Low Arctic Sea Ice In 2008, According to New Forecast.

    Even if sea ice is the same this Sept. as last Sept. I lose (and even lose if it grows a bit), so your odds in the first year should be even higher than 3 in 5.

    If you agree to the bet, we could ask the website adminstrator to share our email addresses with each other, then we could email phone numbers and real addresses to put it in writing.

    Looking forward to your reply,


  39. John McCormick says:

    Oh, thanks Sean, you reminded me and all that:

    [specifically to the moment that Nicky “Topper” Headon smashed his guitar on the floor of New York’s Palladium on Sept. 29, 1979].

    Now, I feel silly thinking that the 1979 to 2008 satellite images of the Arctic Sean Ice meltback gives a true repesentation of the September Arctic sea; at least since the galactic era of Nicky “Topper” Headon. Prior to 1979 was known as the pre-Headon era…..I think….help me here Sean. Or, was it known as the pre-Headon-istic era?

    So, I am wrong and there really is nothing to the massive and rapid ice meltback of the Arctic Sea ice.


    Now, I can sleep without having those scary thoughts about the earth’s temperature rising and causing warm air and water into the Western Arctic Ocean to melt that ice.

    John McCormick

  40. Wadard says:

    The most effective thing you can do to ramp up the fight against climate change is to go and take on a AGW denial propagandist, on their own astroturf.

  41. Jay Alt says:

    Sean writes:
    Allow me to point out, in all honesty, that the statement above (sea ice extent) is true only if you date the dawn of recorded history to 1979.

    Even now, the top ‘non-scientific science experts’ (CEI, Marshal Institute and assorted Climate Clowns) toil on a fallback fable. They already have more versions than the Brothers Grimm but they may need a new one soon –

    Arctic muds (will) reveal sea ice record

    Regarding to Arctic warming early in the 20th century –
    The Arctic is the most sensitive region and more likely to exhibit warming. That is true now, when AGW is evident globally. It was also true in the 1920s, when despite lower greenhouse gas levels the period of modern warming was beginning.

    GHG concentrations aren’t the only thing that affects Arctic climate. There have been additional
    human-caused factors.

    Man-made Soot Contributed To Warming In Greenland In The Early 20th Century

  42. Erik Hammerstad says:

    Sean, that State Department report you quoted is from Spitsbergen, it really has very little relevance to Arctic ice conditions. And yes, it was warm on Spitsbergen in that year

  43. Joe says:


    You have made me an offer I can’t refuse. While I can always use the money, how about if goes to the nonprofit (501c3) of the winning side’s choice?

    I am mostly the site administrator on a day-to-day basis. I will email you Monday.


  44. Sean says:

    Hi Joe,

    I like the idea of having the money go to a non-profit. I used the email address I check most frequently for this post.

    Looking forward to hearing from you Monday,


  45. Sean says:

    Erik says:

    Sean, that State Department report you quoted is from Spitsbergen, it really has very little relevance to Arctic ice conditions.


    It’s actually quite relevant. Sptizbergen is at the edge of the polar ice cap, and is largely surrounded by Arctic sea ice in years of high ice extent.

    Here’s a map of Arctic sea ice extent exactly 60 year after the report (Oct,1982):

    Also, the report says that the Arctic was ice free to 81′ 29″ N. Since the Northern coast of Svalbard is approximately 80′ N, that’s about 15% of the distance to the Pole. If you look at the map, you’ll see that whether that stretch of water is covered by ice or ice free is directly relevant to the question of Arctic sea ice extent.

  46. Sean says:

    To my point about the Arctic sea ice extent data starting in 1979, Jay Alt writes:

    Even now, the top ‘non-scientific science experts’ (CEI, Marshal Institute and assorted Climate Clowns) toil on a fallback fable.

    Jay, I don’t even know what those institutions are, and I don’t know why they would be “toiling” to point out that the Arctic sea ice data is only available for the past 30 years. It took me about 5 minutes on Google to discover that.

    Nor could I guess why their toils would be relevant to the fact in my post: when someone says that Arctic sea ice melted “to an extent never witnessed in recorded history” it’s helpful to know that recorded history in this case is the last thirty years. If it was 3 years, it wouldn’t tell you anything at all, and if it was 3,000 years it would establish a very high degree of statistical certainty for long-term sea ice decline. The period, therefore, is relevant to the claim.

    By the way, the article you linked was right on point to our discussion. Here’s an excerpt:

    “The satellites show the sea ice retreat in summertime from 1979, but before then there’s virtually no record at all.”

  47. Bob Webster says:

    Reading these comments, it is clear that the AGW believers base their climate “history” on very little of Earth’s history. Do any of you AGW believers actually understand that Earth is currently in an Ice Era that began roughly 60 million years ago? Do you understand that Earth is also in an Ice Epoch? But, thanks to cycles in the Ice Ages, Earth is now in an Interglacial of an Ice Age. So humans are doing their thing while the planet is in an interglacial of an ice epoch within an ice era. When Earth is NOT in an ice Era (about 93% of its history), global temperatures are vastly warmer (think age of dinosaurs) and there is NO permanent ice anywhere on the planet at sea level (that includes the poles). So humans have NEVER experienced Earth’s typical (normal?) climate … which is MUCH warmer than present.

    Beyond all that, I would like just one educated AGWer to read, objectively, Dr. Howard C. Hayden’s book, “A Primer on CO2 and Climate” and then explain to us how CO2 can possibly, from ANY source, human or otherwise, be a significant force for climate CHANGE. Then read Dr. Roy W. Spencer’s new book, “Climate Confusion” and think about the contribution of weather (especially precipitation) to regulating Earth’s temperature.

    Considering the IPCC’s reports are laced with “probably” “likely” “most likely” “unlikely” etc., terms that statisticians use when they have no idea what is really going on, and the IPCC’s use of climate models that have no concept of how to treat precipitation or clouds properly … or even water vapor … it is hard to get excited about a theory (AGW) that flies in the face of observation and for which there are numerous contradictions. Those who bother with scientific method know that any theory becomes bunk when it a single contradiction to its basis is found. In the case of AGW, there are many contradictions. Yet the train plows ahead.

    When does reason take over from emotion?

    I am a mathematician with many years experience as a physical science analyst, computer model developer and analyst and a life-long interest in meteorology and climatology. I have no interest in any business that produces CO2 emissions. However, I do have a high regard for common sense, the scientific method, reasonableness, logic, and historical evidence. I also know when computer models are being misused (and why some people do that deliberately … it was always a problem trying to avoid the misuse of data generated by computer simulations).

    I will look forward to reading anyone’s scientific basis for finding Drs. Hayward & Spencer wrong in their assessment of the climate change issue.

  48. John McCormick says:

    Bob Webster, you ask a good question;

    Applied to yourself: [When does reason take over from emotion?] I sense your emotion. I question the source of your reason.

    Have you put all of your faith in Dr. Spencer. He is one peristent voice running against the tide of an international community of scientists too busy to have formed a cabal to fraud the science and even hoodwink the Chinese government.

    Come on, Bob; do some serious work and challenge your comfort zone.

    John McCormick

  49. Lamont says:

    “Reading these comments, it is clear that the AGW believers base their climate “history” on very little of Earth’s history. Do any of you AGW believers actually understand that Earth is currently in an Ice Era that began roughly 60 million years ago?”

    Actually, I do.

    The Earth has seen dramatically higher temperatures and CO2 levels in the past. We are “merely” going back to an earlier time. The Earth will go on spinning.

    However, on a large scale it seems obvious to me that what we’re doing is reversing millions of years of natural carbon sequestration. As the carbon was captured underground it was taken out of the atmosphere and we’re now in a very cool period which has been punctuated by ice ages every 100,000 years or so.

    We are now reversing that natural capture of carbon and going back towards to a climate which was prevalent during the Jurassic period. This is one of the reasons why I don’t support drilling in ANWR and other arguments that we can just drill more or exploit more oil shale in order to get out of the current oil crunch. We need to be leaving more carbon in the ground. The more of it we burn, the more we turn the clock back.

    And the big problem is the rate of change of the climate. We’re currently changing the climate quickly on a geographic timescale. The rate of change is analogous to the paleocene-eocene thermal maximum which was although thought to be GHG related (but natural release of methane clathrites, not anthropogenic) and caused mass extinctions.

    Even though its within the ‘natural’ parameters of the Earth, its still not something that we should be leaving for the next generation. It is also “natural” for the Earth to get hit by 10km asteroids, but we understand that would be viewed in human terms as a catastrophe.

  50. David B. Benson says:

    Bob Webster — I encourage reading physicist Weart’s historical “The Discovery of Global Warming”, linked here:

    Next, you need to understand that Homo spaiens only evolved under ‘ice age’ conditions. As a species, we prefer the climate on the cool side. Then think about leaving the comfort zone of the Holocene and leaving agriculture behind…

  51. Lamont says:

    Weart’s page has a great article on solar activity:

    Its what I expected. The influence of the sun on the climate is a very old idea, and the AGW deniers have recently rediscovered all the old mistakes that were made…

    “However, rough limits could be set on the extent of the Sun’s influence. Average sunspot activity did not increase after 1980, and overall solar activity during the period since 1950 looked little different from earlier periods. The satellite measurements of the solar constant found it cycling within narrow limits (less than one part in a thousand). As for cosmic rays, they had been measured since the 1950s and likewise showed no long-term trend. Yet the global temperature rise that had resumed in the 1970s was accelerating at a record-breaking pace. It seemed impossible to explain that using the Sun alone, without invoking greenhouse gases. For one thing, the stratosphere was cooling, which was exactly what models predicted would result from the greenhouse effect, but was the reverse of what should result from a solar influence.”

  52. exusian says:

    Bob Webster said: “So humans have NEVER experienced Earth’s typical (normal?) climate … which is MUCH warmer than present.”

    That’s exactly the point, Bob. Everything we know as human history and development, including agriculture and civilization itself, has developed not just in the current epoch, but in the current interglacial. All of our infrastructure has been built based on the current climate regime and physical geography.

    Paleoclimate and geologic history teach us much about how Earth’s climate system and energy budget behaves, but few, if any, past epochs match the exact circumstances of the present, and it is the present climate system that we are altering.

    You’ve given us a couple references to read, now here are a few for you to read:

    The Discovery of Global Warming, by Spencer Weart, available on-line at the web site of the Center for History of Physics of the American Institute of Physics here:

    The Climate Book, by Ray Pierrehumbert, and in-progress textbook and accompanying workbook and downloadable data sets on the physics of climate, available as a pdf here:

    Global Warming, understanding the Forecast, by David Archer; sample chapter 4 on greenhouse gases available as a pdf here:
    and the on-line models are available here:

  53. Nylo says:

    For every 100.000 molecules in our atmosphere, mankind-related activities are doing the terrific job of adding 1 (one) molecule of carbon dioxide every 2 years. We are doomed.

    Sean, Joe already made a public bet on Arctic Sea Ice extension, you may want to join this one as well. It seems even easier to win that the one you propose:

  54. exusian says:

    Nylo resorts to a favourite slight-of-hand argument of global warming skeptics and deniers, namely the argument of dilution.

    When he uses that argument he’s hoping that you don’t think about the inconvenient fact that all but a few of those 100,000 molecules are ordinary oxygen and nitrogen, which are transparent to infrared light, yet it is exactly those few molecules per 100,000 that are greenhouse gasses, which are opaque to infrared, make Earth’s average surface temperature 33°C (almost 34°C now) warmer than it otherwise would be, and that we have single-handedly increased one of them, CO2, by almost 38%, and another of them, methane, by almost 150%.

    But hey, never let inconvenient facts get in the way of a perfectly useful slight-of-hand.

  55. Nylo says:

    Actually, there is 50 times more water vapour than CO2 in average, and H2O is three times as powerful as CO2 as a greenhouse gas. Multiply.

  56. Nylo says:

    I forgot to add that water vapour is not uniformly distributed like CO2. Water vapour exists mostly where temperatures are higher and, therefore, its effects as a GHG are maximised. In the tropics, for example, where the Green House effect reaches its maximum because of the higher emisivity of the Earth, the concentration of water vapour can reach up to 5% of the air. 5% is 50.000 ppm. Compare it to the 380 ppm of CO2, whose effects as a GHG are also lesser (a given mass of CO2 absorbs less infrared radiation than the same mass of water vapour). Adding or substracting 100 ppm of CO2 has a similar effect to adding or substracting 40 ppm of those 500.000 ppm of water vapour. And that number is very very far below natural variability of the concentration of water vapour.

    If climate sensitivity to GHG was as big as they are trying to persuade us it is, it would be enough to have 1 year 0.5ºC hotter or colder, because of any natural causes, to trigger a trend very difficult to stop, because of the concentration change of water vapour that would immediately follow (it has a very quick response time to temperature changes), a positive feedback both for warming and cooling trends, with or without CO2. As such a thing has not happened in millenia, it is unlikely that the climate sensitivity is as high as AGW followers claim.

  57. exusian says:

    Nylo’s sill sticking with the dilution argument, and now throwing in the “water vapour overwhelms CO2” argument to boot.

    Except we aren’t adding water vapour, Nylo. We couldn’t even if we tried.

    Unless we warm the atmosphere first, that is. That’s why it’s called a feedback.

    Oh wait, we ARE warming the atmosphere first. Silly me.

    Moreover, the amount of water vapour drops rapidly with elevation as both temperature and pressure drop, while CO2 remains well mixed into the stratosphere, so that CO2 comes to dominate H2O well below the stratosphere. Its here that increasing CO2 raises the elevation at which energy can escape to space and cool the atmosphere, which means that that energy remains in the atmosphere longer before escaping, which means the atmosphere warms.

    It’s really not that hard to understand

  58. Nylo says:

    Your comment about the distribution of the gasses with altitude is irrelevant. Yes, CO2 can beat water vapour as a GHG “3-0” near the stratosphere, especially in the poles, but if water vapour beats CO2 “200-1” in the lower troposphere, especially in the tropics, where most of the total GH effect takes place, then water vapour is still by far the dominant gas in the GH effect. Even pro-AGW scientists agree on this.

    You didn’t get the point. The point is that the 100 ppm rising of CO2 levels compared with the total ammount of GH effect we already had before, and comming primarily from water vapour in the atmosphere, calls to a really minimal change in the total warming because of CO2’s GH effect. Maybe 0.2ºC, at most, without additional feedbacks. The models believe in H2O immediately joining the party in the form of water vapour and causing the remaining 0.5ºC increase.

    But that is very stupid. First, because the response in water vapour content in the atmosphere for a temperature increase at sea level is VERY quick. A matter of a few hours. So, if an increase of 0.2ºC leads to extra water vapour adding an extra 0.5ºC increase, it happens a very short time later. So that if natural events led to a month being especially warm, say +0.2ºC in average, worldwide, and the kind of feedback AGWers expect from water vapour was true, we would have an additional +0.5ºC bias for the next month, and then +1.2, and +2ºC, and the very hell in a year.

    But this doesn’t happen, therefore either the positive feedback of water vapour is not that strong, or it comes together with aditional strong negative feedbacks too, or both. But a permanent addition of +0.2ºC because of CO2 cannot lead to additional +0.5ºC of forcing by positive feedbacks, because 0.2ºC is very little compared to the natural variability of the Earth’s climate. If a +0.2ºC forcing could cause positive feedbacks bigger than the initial forcing itself, the Earth would not be enjoying the rather stable climate it has had for millenia. We would rather be exchanging ice ages and hellfire every other decade. The water vapour feedback cannot be bigger than the initial forcing. And the initial forcing caused by CO2 alone is very small.

    So yes, we have had a +0.7ºC increase, but no, it’s not just because of CO2. CO2 causes about 0.2, then “something else” may have been adding +0.3 and water vapour feedback may have raised the resulting +0.5 into +0.7. When the “something else” forcing disappears or lowers down, we will cool, like we did between 1940 and 1970. And if it turns negative, we will reverse all the previous warming. But fortunately, thanks to CO2 we will still be a little warmer than in 1750.

  59. Sean says:

    Hi Joe,

    I haven’t received your email. No rush, but wanted to let you know in case there was some error in the address you used, and you are waiting for me to reply.


  60. leebert says:


    The canonical logarithmic formula for CO2-driven warming is more like 1.2 degrC from 280 – 560 ppm increase in CO2 level. It’s been covered over at climateaudit. That’d fit your 0.7 degrC current temp increase since 1880, but most of it ascribed to CO2. I tend to suspect that soot’s playing a big role here & I might bring that CO2 value down a bit, maybe down to 0.45 degrC, discounting for tropospheric soot’s net heating effect (40% over the Pacific alone) and the largely soot-driven boreal thaw (about 20% of total AGW).

    Here’s a thought: In favor of your argument is the 1998 el Nino. It burped a huge amount of heat into the atmosphere and the next year, not only did the heat dissipate, in 1999 temperatures fell in the exact opposite trend, leveling out to temperatures reflecting a negative mini-PDO from 2000 – 2004.

    So, where did all the el Nino heat in 1998 go in 1999? It didn’t get swept under the rug in some temporal pipeline, the Argo data do not show this (AFAIK). Likewise, where did all the coolth from Pinatubo go? It was all gone in two years as well (except for a residual trace that naturally sank, being cooler).

    So what happened to the heat from el Nino? It went away! But how. Maybe it got cycled out of the system using one of the solar system’s biggest heat-exchange systems there are: The Earth’s ocean surface & rain clouds.

    What’s a hydrological cycle without some energy to drive it and speed it up? The atmosphere is dynamic, this can be readily observed in the difference between spring showers and summer thunderstorms: The hotter the system runs, the faster it runs, the more heat differential gets cycled (pumped) out of it.

    There’s more than thermal inertia at play here in the oceans, there’s a natural heat-exchange role that is just now being modeled in models that couple air & ocean.

    The 1998 el Nino was a shift-over event that put the Pacific (& Earth with it) into a different cycle. When it belched out 0.2 degrC of warmth GST, the planet disgorged a fair amount of energy, externalizing it into space through more massive thunderheads.

    That energy flux did in fact go somewhere, nor did it lead to a runaway greenhouse (as you mention). If it got swept back under the rug, we would’ve seen it by now. But that sudden injection of heat into the atmosphere was instead externalized, and not back into the oceans.

    This isn’t to exculpate CO2, but to characterize what the atmosphere is up to. It somehow self-regulates. The Aqua data appear to indicate that warmer temperatures simply invoke a vaster hydrological cycle, with taller convective cloud structures (cooling) and more rain (cooling) that offset the increased energy input.

    Will it always work this way? It is canonical, as I mentioned before, that CO2’s additional effects will start to level off, in a leveling slope. Since the trend line plateau we have now would jibe with the basic CO2 curve, then it appears the heat we have now is not heat we have to deal with 12 years from now.

    And then we have the question of our spotless sun….

  61. MeltyMan says:

    Joe: thanks for an outstanding explanation and clarification. This is a very nice blog.

  62. Bob Webster says:

    Been gone for awhile. Refreshing to see the spirited exchanges on my return. With the exception of John McCormick, who added nothing to the discussion, the rest have made serious attempts at intelligent discussion. Naturally, I find Nylo and Leebert the most convincing, but I will follow the suggested links provided by Benson and Exusian.

    I would hope both would also take a little time to pick up Dr. Hayden’s book at a library and give it a read.

    What strikes me further is the AGW believers acceptance that GHG warming can be climate altering or any great significance in scope. Pending a read of the materials suggested, I haven’t yet come across anything yet that can positively point to a human signature in the climate record with any degree scientific validity. There seems to be a grand assumption that greenhouse gases work in Earth’s atmosphere as an actual greenhouse does to warm plants. That, of course, is a flawed analogy and the term “greenhouse” is more misleading than not when used with respect to heat retention in Earth’s atmosphere. Greenhouses on Earth keep their space warm because they are a closed system. The atmosphere is not and weather is the great spoon that stirs the pot. The dynamics of weather (cloud formation, precipitation, advection, convection) are massively involved with the stabilization of Earth’s atmosphere, yet those factors are the least understood and most poorly represented (when at all) in GCMs.

    Frankly, it’s hard to get worked up over a theory that claims rising CO2 levels from humans are going to overwhelm a system that the present and historic record indicates is relatively insensitive to CO2 as a driving mechanism. Chart the rise in CO2 over the past 100 years with the change in global temperature. There is no correlation whatsoever. Then chart variability of solar magnetism, sunspot cycles, and radiation over the same period. A remarkable correlation emerges. The slow response time of ocean temperatures to forces that control global temperature changes produces a delayed release and absorption of atmospheric CO2. When looked at over a just the right scale of 100’s of thousands of years, their appears to be a correlation (pointed out by Mr. Gore) that might suggest that CO2 drives temperature changes. Yet, when looked at over either a longer time frame (millions of years) or a vastly shorter time frame (100s or 1000s of years), the apparent correlation vanishes. Even when the correlation appears, it is only valid with a delay of 100s of years (which is why it cannot be seen over shorter time periods). Unless one is prepared to believe in retroactive causality, it’s time to acknowledge that the CO2 demon in climate change theory needs to reflect on the phrase, “we’ve got a problem here.”

    Nylo and Leebert nail the problem skillfully.

    Now to check out those links.

  63. A. D. says:

    More stuff on non-Global Warming from the U.S. Congress:

    Full Comments by Scientists:

    1) Dr. Roger A. Pielke, Jr. Professor in the Environmental Studies Program at the University of Colorado reacted to this study in the journal Nature by declaring: “Climate models are of no practical use.” Pielke, who is not a climate skeptic, said on April 30, “There is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun. This means that from a practical standpoint climate models are of no practical use beyond providing some intellectual authority in the promotional battle over global climate policy.” (LINK)

    [JR: I deleted the rest of this post, since he is just a repetition of long-debunked denier talking points. But it is interesting that the first “scientist” you pick as an example of non-Global Warming is 1) a political scientist and 2) someone who has repeatedly said on this blog and elsewhere that he accepts the IPCC findings. Says a lot, no?]

  64. Sean says:

    I agree with JR. The fact that Pielke accepts the IPCC findings does say a lot. It says that that Pielke is not a climate skeptic

    Which is not really much of a surprise because A.D., in the bit of his post that we can read, says that Pielke … “is not a climate skeptic”.

    Maybe some things are worth repeating?

  65. msn nickleri says:

    Which is not really much of a surprise because A.D., in the bit of his post that we can read, says that Pielke … “is not a climate skeptic”.

    I agree with JR. The fact that Pielke accepts the IPCC findings does say a lot. It says that that Pielke is not a climate skeptic

    Maybe some things are worth repeating?

  66. Walt Bennett says:

    I am looking for one good science blog that does not allow itself to get bogged down “defending” AGW from those who insist on arguing from ignorance.

    I would like to see the moderator snip those posts and point the poster to useful links, and I would like to see the rest of the group ignore such posts entirely.

    I’ll check back from time to time to see if this otherwise excellent blog gets any better at that.