George Will's Crack Fact-Checkers Continue Their Nap

By Carl Zimmer | July 23, 2009 10:24 am

There is no way to keep up with all the bad reporting on science these days, but I cannot resist certain egregious cases. As Loom readers know, George Will writing about global warming is one. This morning brings fresh evidence of his trouble with the facts–and, more importantly–the empty claims of the Washington Post‘s editorial page that they respect the time-honored art of fact-checking.

In a nutshell, George Will wrote some columns starting in February in which he claimed that scientific evidence shows that all the heat-trapping carbon dioxide we’re putting in the atmosphere is having no effect on the planet. He claimed as proof that global ice levels had not changed in thirty years and that in fact there has been no global warming since 1998, just to name two.

giss440.jpgThe Loom and many other blogs pointed out why these claims were in error. Will ignores the fact that climate change is a noisy, long-term process. Today it is cooler at my house than it was yesterday. That does not mean that next week I will wake up to find snow on my doorstep. If you look at the annual mean temperature of the planet, you can cherry-pick one year, such as 1998, in order to make the false claim that there is no global warming. Of course, you could just as easily pick 1999, in which case the same logic would force you to conclude that there has been a staggering increase in temperature. But that’s not how climate scientists actually study global warming. They look at long term patterns, such as the red line in this graph from NASA, which represents the five-year mean since 1880. And when they do, they recognize a long-term trend of rising temperatures.

This somehow slipped through the multiple levels of fact-checking carried out by the editorial page staff at the Washington Post. Nor could they catch the other errors Will made on the science. So my fellow blogger Chris Mooney and the secretary general of the World Meteorological Organization made it easy for them, by writing a column and a letter respectively, to set things straight. The Post even saw fit to run both.

They did not, however, issue any correction on Will’s claims. Ombudsman Andrew Alexander, who claimed that there had been fact-checking on multiple levels, did acknowledge things might have been handled a wee bit better, and then offered this sunny thought for the future:

On its news pages, it can recommit to reporting on climate change that is authoritative and deep. On the editorial pages, it can present a mix of respected and informed viewpoints. And online, it can encourage dialogue that is robust, even if it becomes bellicose.  [Emphasis mine]

As far as I can tell, Alexander’s wish is being ignored. Today Will has published a column about recent negotiations on controlling carbon emissions. He considers them a bunch of empty promises, which seems to be just fine with Will, because there is no global warming to control anyway. Here’s how Will closes his latest piece:

When New York Times columnist Tom Friedman called upon “young Americans” to “get a million people on the Washington Mall calling for a price on carbon,” another columnist, Mark Steyn, responded: “If you’re 29, there has been no global warming for your entire adult life. If you’re graduating high school, there has been no global warming since you entered first grade.”

Which could explain why the Mall does not reverberate with youthful clamors about carbon. And why, regarding climate change, the U.S. government, rushing to impose unilateral cap-and-trade burdens on the sagging U.S. economy, looks increasingly like someone who bought a closetful of platform shoes and bell-bottom slacks just as disco was dying.

In earlier days, Will liked to claim the World Meteorological Organization as an authority when he wrote that there has been no global warming since 1998. Now that the World Meteorological Organization has set things straight, he’s claiming a columnist at National Review as his authority. That’s quite an upgrade.

The most urgent question today’s column raises is not about Will, but about how media organizations decide how to present science to the public. If the Post’s editorial page editors really do believe in fact-checking and in “respected and informed viewpoints,” I can only conclude that they slept in very late this morning.

Update: A commenter below accuses me of intellectual dishonesty for not showing a graph with a longer time-scale, which, I guess, would show that there’s no link between between carbon and climate. Ummm…like this one? (CO2 levels as black curve, temperature grey. Source pdf.)


Comments (67)

  1. Eric

    This is inexcusable intellectual dishonesty on Will’s part. I see you’re putting the onus on the Post, but actual *thinking* has to start somewhere.

  2. Mike Lemonick

    To paraphrase a statement I wish I had been the first one to make, Will is entitled to his own opinion, but he isn’t entitled to his own facts.

  3. Mike Lemonick

    Oh, and just for the record, here’s one of those opinions George Will is entitled to: men should stop wearing those trashy blue jeans, and aspire to dress like Fred Astaire. It’s a paraphrase, but he really did say it.

  4. I am confused by George Will. He’s not obviously a lobbyist. He’s certainly a right wing apologist, but this needn’t be structured by such painful twisting of facts. He’s not exactly an intellectual slouch. I am at a loss to understand his motivations. It can’t honestly believe that being a shill for the anti-global-warming head-in-the sands types is automatically in his best interests. I can only believe that somewhere, deep back in time, he was embarrassed by a science teacher for faulty reasoning, or alternatively, that he’s seeking a more lucrative role as a petrochem spokesperson now that his media place has become so marginalized. I used to like listening to his reasoned (however wrong) take on the American political landscape. Now though, unless dementia has crept in, he seems to be driven by something terribly perverse. Either way, I am certain even Will doesn’t believe his own words. Intellectual dishonesty at its height.

  5. dennis p

    By putting up a 100-year graph and then saying “climate change is a noisy, long term process”, you exhibit the same kind of intellectual dishonesty Will does. Is 100 years really “long term” in terms of global climate shift patterns? Why not extend your graph back to include the Medieval Warming and Little Ice Ages, and put some “geological time” context around it? From what I’ve seen, I think you’ll be surprised at how that changes your Y-axis and your perception.
    I don’t dispute the reality of climactic changes, including the recent cooling trend. But I remain unconvinced of the strength of the nexus between really significant climate change and carbon emissions in light of intervening factors such as natural cycles in ocean temperature regimes, sunspot activity, volcanic eruptions, and the like. This natural and valid skepticism is the reason why national leaders around the earth (except Obama) are backing away from draconian commitments on reducing emissions.

    Carl: Dennis, you might have noticed that instead of cherry-picking years, I simply reproduced a graph that has been generated over many years by NASA scientists. So if you’re accusing me of intellectual dishonesty, you’re really accusing them. Now, why might they have chosen to track climate on this time scale and with this five-year averaging? Well, for one thing, it’s as far back as this particular kind of climate measurement can be extended. For another, it’s not long after industrial production of carbon dioxide really took off. And on these time scales, the signal of climate change starts to emerge from the noise, thanks to the sensitivity of the climate system. For more on climate sensitivity, you can read this pdf. And if you want graphs, check out the one I’ve reproduced from the pdf at the end of my post. Finally, I don’t recall any national leaders talking about sunspot activity. Got any evidence to share with us?

  6. JMW

    Evidently when the Post wishes to print “respected and informed” opinion, it isn’t required that every opinion be both – one or the other will do for each opinion, as long as the aggregate of the opinions are both…

  7. Pete

    I think the motivation might be as simple as he just doesn’t want it to be true. I think naturally we dislike to believe in future harm, and it might help us to rest more easy if we convince ourselves its just not true. Add to this the fact the government action will force some inevitable sacrifices on our part.

    Frankly, I don’t want it to be true. I hope we learn later that it is not or the consequences are less then we feared. But I don’t get a vote on what it reality.

  8. Barry

    mark siddall Says:

    ” He’s not exactly an intellectual slouch.”

    Since when was he *not*? Remember, way back when, Doonesbury slagged him for using ‘quote-finders’ to find witty quotes to make him look intellectual.

  9. Sam Simple

    If Mr. Will has any doubt about the toxicity of what is coming out of his car, I have a simple experiment for him. Have him connect a garden hose to the tail pipe of his car and run the other end into his living room. Then, start the car and let it idle for a half hour or so. Then, let Mr. Will assert that we have nothing to worry about with regard to pollution. What these numbskulls don’t seem to get is that we are poisoning ourselves by doing nothing and that global climate change is just one of mnay negative outcomes.

  10. Dave X

    I’m amazed that the deniers can be so obtuse about noisy time series like these. If CO2 and temperature were stock prices on Yahoo Finance, then they would miraculously understand 5-year averages and trends in noisy data. Saying there is no “warming” in the S&P500 (or S&P500, if that link doesn’t work) would be laughable and ridiculously easy to check.

  11. Update: A commenter below accuses me of intellectual dishonesty for not showing a graph with a longer time-scale, which, I guess, would show that there’s no link between between carbon and climate. Ummm…like this one? (CO2 levels as black curve, temperature grey. Source pdf.)

    A mere 350 ka? Stop cherry picking, Carl! Why don’t you show CO2 and temperature out to 800 ka?

    ; )


    Carl: D’oh! My cunning deception has been exposed…Thanks for a window into deep(er) time!

  12. Enkidu

    George Will did not research the evidence then form an opinion. He started with an opinion, then went looking for evidence. We can know this as surely as we know rain makes grass grow. When the World Meteorological Organization refuted his position, he didn’t reasses his opinion, he found another, far inferior source.

  13. JThompson

    I think people are being far too kind to climate change denialists by assuming they’re arguing in good faith.

    There are pretty much three kinds of denialists:
    1: People with a financial interest in fighting reform. e.g. oil/coal companies
    2: People with a personal interest in fighting reform. (If AGW is real, they’ll take away my SUV that gets 6mpg!)
    3: People that will automatically oppose anything a scientist or liberal says, simply because it’s a scientist or liberal saying it. The “You elitists think you know it all.” crowd.

    I don’t know which one Will is, and it probably doesn’t matter. The first two are dishonest and the third is irrational. None of them are going to accept evidence of any sort.

    The irony of the situation is they all claim to be “skeptics” when dismissing the conclusions of the world’s top scientists, yet accept uncritically the charts and graphs of a man whose PhD in “Whetherology” is written on a Wendy’s napkin in green crayon.

  14. Kyle

    I haven’t dug into it much, but this might be the sunspot thing mentioned above:

    I must admit to being somewhat frustrated with the global warming debate in that I think it’s missing (and indeed drawing focus away from) the point, which is that we need to focus on long-term sustainability in our interactions with the planet. If we spend all of our time arguing about whether or not humans are causing global warming, we’re wasting time and energy. Reducing our reliance on (obviously finite and in all likelihood dwindling) fossil fuels is only a part of how we should be moving forward. To see so many otherwise intelligent people fighting over whether or not global warming is a good reason to reduce said reliance makes me lose some of what little remaining faith I have in humanity.

  15. nichole

    An evangelical christian once told me that one reason she was opposed to gay marriage was that if gay couples were accorded all the legal rights and tax breaks as normal couples, we would all have to pay more taxes. And she is correct, as far as I can tell.

    The point of my story being that fanatics = smarter than they look & act. Devious little suckers, they are. Hard to guess at their motives, but I’ll bet there’s more than 3, JT.

  16. “But I remain unconvinced … in light of intervening factors such as natural cycles in ocean temperature regimes…

    The interesting thing about natural cycles is that we see them oscillate for hundreds of thousands of years in core samples. When we see massive spikes in temperatures and carbon emissions like we do today, we can say that there’s something more at work than a natural cycle.

    sunspot activity…

    The supposed link between sunspots and global warming is so tenuous and has so many problems in its science, any effect sunspots have on our planet are likely to be very weak:

    volcanic eruptions, and the like.”

    Volcanic eruptions would actually cool the Earth over the short term as fine ash lingers in the stratosphere, reflecting sunlight. We’d need huge lava flows like the Siberian and Deccan Traps to significantly raise the planet’s average temperature.

  17. Bob

    It’s unfortunate that people like JThompson believe that anyone who disagrees with human induced warming is an elitist or has some financial stake in fighting the disasterous cap and tax effort. How about a disagreement with the science itself? I fully accept there has been a warming of the climate but reject the idea that humans have caused it. Proof of warming is not proof that CO2 or other “greenhouse gases” have caused it. There is plenty of valid scientific data (ice cores) showing that temperature increases preceed CO2 increases, not the other way around. Satellite data shows no overall warming since 2001. Actual temperature data has proven that the models all predict far more warming than has actually occurred so something is missing. There is no greenhouse signature, no C02 fingerprint. Carbon doesn’t seem to have driven temperaturs before; probably isn’t doing it now; things are not getting warmer and computer models can’t predict the weather.

    Carl: Bob, Can we see some citations of published scientific studies in which you find this “valid scientific data”?

  18. JJ

    Bob?, Bob?………..Bob?

    What are all these crickets doing here?

  19. not a gator

    So Bob doesn’t believe in el Nino/la Nina, I take it?

    And those hurricane season forecasts are done with entrails of a young goat, eh, eh?

  20. PaulG

    It appears from the first graph that the warmest year on record is not in fact 1998, but 2005? Am I misinterpreting the data? And if not, how long have this been known? (I admit, when these graphs get thrown up, they all look the same and I don’t bother to look too closely. I don’t know why I bothered this time.)

  21. DonK

    The “long term trend” is unfortunately marred by the fact that for the
    first half of the evidence tree, many scientists didn’t have indoor
    plumbing, let alone instruments truly capable of measuring a hundredth
    of a degree.

  22. MadScientist

    Hang on, that Figure 3-1 really doesn’t make things any clearer. To me it appears that the temperatures have been swinging up and down by about 3 degrees over the past 10,000 years and it’s still cooler than it was ~130,000 years ago.

    Carl: I’d suggest you read the book chapter from which the figure comes (see the link). The temperature certainly has been swinging up and down long, long before there were coal-fired plants or cars. The pattern is linked to the rising and falling levels of carbon dioxide in the air, which traps heat. There are also complex feedbacks involved in the process. There certainly have been times in the past when the Earth was warmer than it is now, but climate scientists project that we’re only at the start of a warming response to the CO2 that’s already in the air (not to mention all the additional CO2 that will be going into the air in years to come.) And this graph also shows that the rate of CO2 increase is far faster than anything the Earth has seen for a long time.

  23. Jay K.

    Paul G is right, the first graph is either incorrect or is using the unfiltered giss data that includes the stations with high Urban Heat Indexes. But I’m only guessing that PaulG is talking about the first graph, not the second. The second shows that 2005 has the highest CO2 ppm (dark black) and that the 2001-2007 region is hovering around some value (actually is slightly climbing during those years, if you blow it up).

    Can Carl please address the first graph, though? We have enough issues with denialists when we use the right data, and that doesn’t appear to be the right data.

    [Carl: I'm on deadline on another story this afternoon. For now, you can click on the graph to go to the NASA site from whence it came. I'll try to get back to it next week.]

  24. Francis Manns

    The anti-deniers have become deniers. I guess that is why cooler weather is called climate change. The minus 22 degree celsius recently in Pretoria (that is in the southern Hemisphere at 25 degrees south latitude must be denied! That cannot have happened in Africa. It must be fact-checked and denied! Unless the new El Nino developes and solar wind picks up, next winter should be a doozie in both Washington, D.C., and Washington, the state.

    Yes the climate changers are still using the corrupt database, but lies became facts for them. The first rule of science is, “The minute you begin to believe your own hypothesis, you are a dead duck as a scientist.” You may, however, qualify for the House of Representatives. Senate vote on ‘Bait and Switch’ is yet to come. Want to bet Pelosi and Boxer will rush it throuh before the climate changes any more.

  25. Francis Manns

    Most of the above is ad hominem. Interesting to tabulate too!

  26. Francis Manns

    Demand Debate!

  27. Larry Oliver


    I think they’re all waiting for you to figure out that your comments are incoherent, your references unfounded in reality, and that you look like nothing so much as a troll…

    Or they may simply be ignoring you… I just found your post, and I’ll be ignoring you as well.

  28. I really wish I could find a way to give George Will the benefit of the doubt. I have enjoyed reading him (even when I disagreed with him) over many years.

    I am still not inclined to say he is a “liar.” But something is very wrong with his writing, and I have no idea why that should be so.

  29. Marion Delgado


    What’s wrong with what you say is, global warming is the biggest deal.

    Speaking for myself, I have always been very involved with environmental issues. When I was a teenager I was helping people prepare and transmit southern hemispheric ozone depletion data, for instance. But every year in the 1980s the climate change issue became more pressing. We wanted things to change early enough so we wouldnt be accused of being erious if we didnt accept tons of nukes or put other issues on hold, etc. I was fooled by the success with ozone. My guess was by 2009 we’d be seeing the peak and a huge world program would already be in place. Bush I wasn’t the environmental president, or even Nixon, but he was not that bad. Little did I know we’d have 8 years of worse-than-Reagan and worse-than-Goldwater running the largest polluter.

    People are going to ask, what’s the biggest problem, and we’re going to have to say climate change. Clearly, the underlying problems of overconsumption and population growth have to be addressed, but everything we do now for carbon reduction is 100 things we don’t have to do in 10 years.

  30. J Thomason

    It’s interesting that now, in 2009, you decided to post a graph that ends in… 2005. Now THAT’s some cherry picking. How about posting an up-to-date temperature graph? How about this one that shows that June 2009′s temperature anomaly was …. +.001 C:

    So George Will could have truthfully said that temperature has FALLEN dramatically from 1998, and given as his source one of the major authorities on global temperature measurements.

    Then, in response to someone who asks you to show a longer graph of temperatures, you do … but add CO2 measurements as well. Unfortunately, this does not establish what you think that it establishes. First, of course, on the longer scale we are able to see that current temperatures are well within the same range as they have been the last several thousand years. Also, it clearly shows that CO2 LAGS temperature – in other words it has historically increased (or decreased) in RESPONSE to changes in temperatures, not the other way around – yet you and other global warming alarmists insist that the tail wags the dog.

    PS And of course, past temperature records have a strange habit of being lowered in the NASA records, making current temperatures appear :

    Maybe because a global warming nut (Hansen) is in charge? Strange how he stopped updating NASA’s annual global temperature graph (as already mentioned) as of 2005, isn’t it? Now why oh why would he do that?

    PPS You yourself provided the “proof” regarding what commenter “Bob” mentioned. Did you not bother to look at your own graph?

    [Carl: Follow these simple steps. Go to the site where I got the graph from and read the caption.

    Global Annual Mean Surface Air Temperature Change
    Fig A2

    Line plot of global mean land-ocean temperature index, 1880 to present. The dotted black line is the annual mean and the solid red line is the five-year mean. The green bars show uncertainty estimates. [This is an update of Fig. 1A in Hansen et al. (2006)]

    Figure also available as large GIF, PDF, or Postscript. Also available are tabular data.

    (Last modified: 2009-01-09)

    Check out the tabular data, and you will find that the graph actually goes up to 2008, the last full year of readings.

    To paraphrase your own comment, did you not bother to look at the graph before accusing me of cherry-picking?

    As for the graph you point readers to, it is a record that only goes back 30 years, less than a quarter of the record in the graph I showed. The NASA graph does certainly have some uncertainties, but those are marked in the graph itself. The fact that the satellite record ends a few months later than the NASA one at the moment is irrelevant.]

  31. Canadian

    Thomas Friedman’s house.

    There is no need to post one of Al Gore’s.

    Listen not to what the climate cultists say.

    Watch what they do.

  32. Aaron Durst

    Thanks for having the intellectual honesty to show the graph with the long term relationship between carbon dioxide levels and temperature change. Now, please have the intellectual honesty to point out that as the graph shows (but may not be clear), the increase in temperature precedes the increase in carbon dioxide by nearly 800 years.

    [Carl: The latest paper on the timing of temperature changes and carbon dioxide that is this one (open access). The authors make some corrections to the record from Antarctic ice cores and reject the 800 year lag identified in earlier papers. They write, "If this correction is valid throughout the last glaciation the CO2 deglacial increase may have started simultaneously or even with a lead of the CO2 rise over Antarctic temperature."

    The picture that emerges from the climate record is a complex set of factors that feed back on each other. The wobbling of the planet changed how the Sun warmed the Earth periodically, which appears to have triggered complex feedbacks that may have released carbon dioxide from the ocean or other sinks, which, in turn, further increased the planet's temperature. See, for example, this 2008 paper.

    So, there doesn't seem to be a lag of the sort you say I should divulge, and if you think that brings global warming into question, papers like thoe ones I've cited demonstrate why that's not so.]

  33. Lasorda

    I dunno, that graph you show in the update doesn’t seem to help your argument as far as temperatures are concerned. I think the commenter who demanded it had a point.

  34. AST

    I agree that “There is no way to keep up with all the bad reporting on science these days.” I decided to quit subsidizing it, which is why I canceled my subscription to Discover Magazine after 20+ years.

    If I wanted environist agitprop, I’d join the Sierra Club.

  35. Leigh Williams

    Francis Mann, can you construct an argument rather than throwing out some random facts and some political insults? I don’t follow this issue closely, so don’t assume I know what the heck you’re talking about. I do know, however, that the big majority of climate scientists are seriously alarmed about this issue, and frankly, calling them all liars doesn’t make you look too rational.

    So, I’m taking your suggestion and Demanding Debate. Debate requires an argument and evidence. Where is yours? I’m willing to be convinced, so give it your best shot.

    p.s. Peer-reviewed evidence is what I need to see, not political talking points.

  36. Aaron Durst

    The graph you provided clearly shows the 800 year lag. If the lag does not exist, as you seem to suggest, please correct the graph to eliminate the lag. I am betting you can’t do it, because the best scientific evidence available is that the lag exists. It is intellectually dishonest of you to pretend something does not exist when the best scientific evidence shows that it exist.

    Furthermore, in regards to this comment “if you think [800 year lag] brings global warming into question, papers like thoe ones I’ve cited demonstrate why that’s not so”, that is nonsense. Not only does the temperature start increasing 800 years before the carbon dioxide increases. It reaches its peak 800 years before the carbon dioxide reaches its peak, and starts declining. If you and others were correct, several times in the past as carbon dioxide continued to rise, global temperatures should have continued to rise. They didn’t. They had already fallen to normal levels and stayed there throughout the continued increase in carbon dioxide levels.

    [Carl: "The best scientific evidence available is that the lag exists," you claim. What is that best evidence? The 2007 paper comes from the same EPICA ice core project that gave us the earlier 800 year lag in the first place. I'm showing you the latest scientific literature. If you have a paper that shows why this analysis is wrong, show us. As for your other argument, climate scientists have long taken into account many other factors that can influence the climate, and which can change, such as ocean-atmopshere oscillations, the albedo of advancing and retreating glaciers, changing levels of incoming radiation. So the argument you present is a straw man. If you're describing an argument that's been presented in recent scientific literature, perhaps you can share it.]

  37. Aaron Durst

    Your own graph shows the lag. Why? If the lag is wrong, please take the lag out of your graph.

    Your argument is basically, this graph proves that I am intellectually honest because it shows a historical connection, but we should not trust the graph because it is inaccurate in the sense that it does not show the historical connection accurately, but I can not provide a better graph.

    Yeah, that makes sense.

  38. Aaron Durst

    “climate scientists have long taken into account many other factors that can influence the climate, and which can change, such as ocean-atmopshere oscillations, the albedo of advancing and retreating glaciers, changing levels of incoming radiation”

    That is basically, the climate change skeptics argument in a nutshell. I am glad that you have adopted it when it is convenient for you (i.e., because you can not present historical evidence conclusively showing carbon dioxide increases preceding global warming trends, and instead desperately need to refute the historical evidence which shows global warming trends predating and peeking possibly 800 years prior to carbon dioxide increases and peeking).

  39. Aaron Durst

    Provide a scientifically accurate graph without the lag. Until then, you are intellectually dishonest.

  40. Aaron Durst

    As one last addendum until you respond, you are also being intellectually dishonest in how you are reporting the finding of the study that disputes the lag. The authors of that study were far more hesitant to make the strong conclusions that you are implying they made.

  41. J Dubb

    We’re doomed. I don’t know how they’ve done it, but the republicans have tapped into the caveman brain inside of people and made them say black is white, up is down. How can people fight so vigorously against policies that would help them? How can they suspend reality and just choose to believe the world works in ways that back up their pre-existing ideology?

    This Aaron guy, I guarantee he doesn’t have any background in climate research. I also guarantee he decided to deny climate change because it fits his ideology — Republican, Ayn Rand B.S.

  42. Robert Eaton

    The major problem with George Will and his republican apoligists is their “belief” system concerning science. Science simply is. Backed by data and properly assesed facts it transcends anything remotely connected with “belief”. Will’s repuglican friends refuse to accept anything which pushes on the status quo. If it was good enough for my granddad, it’s good enough for me and anything else is heresy. Let’s massage the data to make it match our beliefs, it’s more comfortable that way. It’s like the alcoholic being in denial, can’t face the facts, but it’s there just the same.

  43. Aaron Durst

    Nice ad hominem attack. I am sorry that it bothers you that Carl Zimmer would post a graph that shows temperatures rising followed 800 years later by carbon dioxide emissions rising as proof as a historical connection carbon dioxide emissions increases leading to global warming, and then when challenged on this point, can not update the graph to show the carbon dioxide emissions predating global warming.

    [Carl: According to climate scientists, we are in a situation where a rapid injection of carbon dioxide is leading to a rise in global average temperature. But the paleoclimate record indicates that a somewhat different series of events--which is still not fully understood--caused the periodic warming of the planet. In 1990, almost 20 years ago, scientists proposed the following hypothesis (pdf): small changes in the Earth's orbit could lead to a weak warming. This warming then caused the planet to release more greenhouse gases, like carbon dioxide and methane, into the atmosphere, possibly because warmer oceans give off extra gases.

    "Changes in the CO2 and CH4 content have played a significant part in the glacial-interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing," the authors of the 1990 study wrote.

    These gases, which are known to trap heat in the atmosphere, were able to raise the temperature far more than the orbital variations could on their own. They may have helped trigger other feedbacks, such as the melting of ice sheets, changing the ocean circulation and the reflectance of the planet.

    When scientists later used ice cores to tease out the pattern of temperature and CO2 changes over the past few hundred thousand years, they got the sort of pattern you'd expect from the 1990 hypothesis (here's another graph). They expected a lag, but they also expected a fairly strong correlation between rising CO2 and rising temperature. And that's what they find. So demanding that CO2 records always precede warming in the climate record is a strawman argument.]

  44. Eric R.


    You’re hopeless and, yes, that’s ad hominem. Regarding your denialist claptrap link above.

  45. Aaron Durst

    “According to climate scientists, we are in a situation where a rapid injection of carbon dioxide is leading to a rise in global average temperature. But the paleoclimate record indicates that a somewhat different series of events–which is still not fully understood–caused the periodic warming of the planet.”

    I think you should re read what you just wrote. You just made the case for those who are skeptical of anthropomorphic climate change. You should apologize to George Will and Mark Steyn for stealing their argument.

    J Dubb and Eric R, you might want to direct your ad hominem attacks against Carl Zimmer. It appears that he has embraced anthropomorphic climate change skepticism.

  46. Chris L.

    He forgot to say “statistically significant” in “no statistically significant warming since 1998″. (The error bars claimed on the data you cite are +/- .1C, which is significantly larger than the difference between higher subsequent temperatures and 1998′s temp.)

    Shortening “no statistically significant” to “no” is not dishonest, still less is it misunderstanding the science involved.

  47. Aaron Durst

    “So demanding that CO2 records always precede warming in the climate record is a strawman argument.”

    That is a strawman because I never demanded any such thing. I would settle for you being able to point to 1 instance in the climate record where a significant peak in carbon dioxide increases preceded a significant peak in global warming.

  48. Aaron Durst

    “They expected a lag, but they also expected a fairly strong correlation between rising CO2 and rising temperature. And that’s what they find.”

    An 800 year lag? Yes the correlation is strong, but it is from lagging temperatures 800 years (i.e., temperatures changes occured 800 years prior to changes in carbon dioxide emissions). It seems to me that would suggest temperatures are the causal factor and not carbon dioxide emissions.

    (I understand there is a study that “disputes the lag”, but that study would require rewriting the record, and the authors are unsure if their conclusions are correct, and if they are correct how to apply them.)

  49. Aaron Durst

    “In 1990, almost 20 years ago, scientists proposed the following hypothesis (pdf): small changes in the Earth’s orbit could lead to a weak warming. This warming then caused the planet to release more greenhouse gases, like carbon dioxide and methane, into the atmosphere, possibly because warmer oceans give off extra gases.”

    Please point to anywhere in the record such an occurence can be seen?

    Furthermore, I don’t think you understand how this would affect the statistics and your aforementioned strong correlation. Such a feedback mechanism would make the relationship non-linear, and no linear statistical analysis would be able to determine the true relationship between the two variables.

  50. Peter


    Stop trying, they’re not interested. This is politics for Zimmer and the rest of them – not really about science at all. They would much prefer to think those that question their theory are stupid or morally compromised rather than argue.

  51. Dave McRae

    Aaron, Peter – if indeed you’re new to this topic and your question is genuine, then please Google “Climate Denialist Crock of the Week youtube Temp leads carbon” and you will be presented with a video that addresses this concern.

    The probable reason your question is not being addresed is because it’s come up so often and knocked on it’s head many times before it’s getting beyond a joke. Please see that video if you’re not the typical denialist recycler of FUD.

  52. LogicallySpeaking

    “An 800 year lag? Yes the correlation is strong, but it is from lagging temperatures 800 years (i.e., temperatures changes occured 800 years prior to changes in carbon dioxide emissions). It seems to me that would suggest temperatures are the causal factor and not carbon dioxide emissions.”

    If it had happened before, prior to any possible anthropogenic causes, that would be evidence that what we are seeing now is natural. Your fallacy lies in trying to compare a natural (or closed) system with one that is open to the causal influence of humans. Consider the following thought experiment:

    Imagine you have a farm with a bunch of chickens on it. Each generation you count the number of eggs and the number of chickens. Over sufficient time, you’ll see the population oscillate up and down due to random fluctuations, but everytime you’ll see that the number of eggs increases before the number of chickens increase (since chickens can lay extra eggs, but a single egg can’t — or almost never — gives rise to multiple chickens). Now suppose that at some point in time, you start buying chickens from your neighbor. Suddenly, in this generation, the population of chickens increases before the number of eggs increases.

    Do we deny that the increase in eggs is (at least partially) caused by the farmers adding more chickens to the system? Do we say, “Hey, EVERYONE knows that the number of eggs affects the number of chickens and not the other way around!”

    And that’s why this obsession with the past climate record is so moronic. Really, really, REALLY basic science tells us that carbon dioxide (and other greenhouse gases) will, all other things being equal, cause temperatures to rise. There are only two reasons skeptics/denialists even mention the lag: 1) they’re really stupid; 2) to confuse a scientifically ignorant public. Now, of course, all other things AREN’T equal — there are feedback loops in the clouds, oceans, biosphere, to name a few. So it could very well be the case that the expected increase in temperatures from increased GHGs will be compensated for by other natural processes. That said, there is really no room for doubt whatsoever that carbon dioxide concentration affects temperature.


    “Today it is cooler at my house than it was yesterday. That does not mean that next week I will wake up to find snow on my doorstep.”

    So, this analogy only works one way??????


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.


See More

Collapse bottom bar

Login to your Account

E-mail address:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »