Much truth is spoken in jest.
Much truth is spoken in jest.Courtesy Meredith P.

We've all heard about global warming, the undeniable fact that the Earth's temperatures rose (dramatically / sharply / noticeably – take your pick) from 1980 to 1998. (We've heard considerably less about the equally undeniable fact that from 1999 to present temperatures have held steady or even dropped, but never mind.)

We've all heard that carbon dioxide, released into the atmosphere when we burn coal, gas or other fossil fuels, is the (only / primary / most important) source of the warming. (The Earth also warmed during Roman and Medieval times, when fossil fuel consumption was vanishingly small. But never mind.)

And we've all heard how this warming is going to bring about floods, drought, storms, extinctions and other ecological disasters if we don't reduce out carbon output by (the end of the century / 2020 / tomorrow afternoon).

Those first two points can be tested through observation and experiment. The last one cannot. It's a prediction about the future, and you cannot observe something that hasn't happened yet. But you can always bolster your position by accurately predicting the past.

Now, that may seem like a waste of time – I mean, it's the past. We know what happened. But that's what makes it such a great laboratory. Y'see, scientific predictions are based on models. Scientists take all those observations and experiments, put them in a computer, and see where the trends lead. You can test the model by taking observations from some point in the past, crunching the numbers, and seeing if the results match what we know happened next.

And that's exactly what Richard Zeebe, James Zachos and Gerald Dickens did. In an online article published by the journal Nature Geoscience, these three scientists took the model used by climate researchers to predict future global warming and applied it to an episode of past global warming. Specifically, they looked at a well-studied period 55 million years ago when the Earth's temperature rose dramatically. They plugged the data from that warming into the model used to predict current warming, and they found....

It didn't work. The climate models being used today were unable to duplicate known conditions from the past. They weren't even close – the results were off by about 50%.

Emily Latella, call your office.

Your Comments, Thoughts, Questions, Ideas

JGordon's picture
JGordon says:

Do you know if the model was just based on CO2?

I was looking at Wikipedia's page on the Paleocene-Eocene Thermal Maximum (I know, Wikipedia, whatever), and it seems like the main theories as to what caused that warming episode mostly involve methane. Do you suppose that necessarily means that our recent warming was not caused by CO2?

I don't really know anything about this model, but I wonder how dependent it is on the particulars of the current geological period. I mean, global climate is to a large extent determined by the behavior of ocean currents, and I expect that the currents today are pretty different than those during the Eocene, considering that the continents hadn't quite reached their current positions.

I suppose the study was more detailed than that article had space for. It goes to show, though, whatever position you might want to take, climate is complicated.

posted on Thu, 07/23/2009 - 12:24pm
Anonymous's picture
Anonymous says:

Gene, I believe your interpretation the Zeebe et al paper misses the mark if you are suggesting that their study casts doubt on the results of IPCC-class climate models that project significant 21st century warming.

Check out the comments of the lead author, Richard Zeebe at
Zeebe is quoted as saying...


"The question is still open by how much the global temperature will increase until the end of the century, depending how much carbon dioxide we put into the atmosphere," Zeebe said.

"The important message is we believe there are other mechanisms that contribute significantly to warming when we release CO2," he said. "That's why we're concerned about future warming. If we do not precisely understand those mechanisms, warming could be stronger than people believe now."

posted on Tue, 07/28/2009 - 2:58pm
Gene's picture
Gene says:

I believe I detect a contradiction. You argue that the study does not "cast[] doubt on the results of IPCC-class climate models." Yet you then quote one of the authors saying, "The question is still open by how much the global temperature will increase until the end of the century." Which sounds very much like doubt to me.

posted on Sat, 08/01/2009 - 9:21am
JGordon's picture
JGordon says:

But the scientist does say "Current and future warming is almost entirely due to carbon emissions. There is no doubt about this."

That's sort of the opposite of doubt. Unless the authors are picking and choosing what parts of the model they have doubts about.

Or are we doing that? It's remarkable how subjective this study turned out to be.

posted on Sun, 08/02/2009 - 2:23am
Gene's picture
Gene says:

Of course, Karl Popper would consider "There is no doubt" to be a most unscientific statement. But let us not go down Epistomology Avenue ( a profoundly boring and tedious drive).

As I see it, the authors accept the notion that emissions cause warming, but find that the IIPC model based on that notion does not match the historical record. I leave it to them to resolve this contradiction.

posted on Sat, 08/08/2009 - 2:50pm
bryan kennedy's picture

I was about to post the same thing as Anonymous. Maybe I'm missing the thrust of your point, Gene. What point are you trying to make about the use of modern climate models to forecast current warming trends?

Should we avoid using models to help understand how inputs to our climate system affect the future? I'm befuddled by the context in which you are presenting this research.

posted on Tue, 07/28/2009 - 4:09pm
Gene's picture
Gene says:

I thought the context was clear. We are told that the Earth will warm in the future, based on the models. We are told this warming will lead to all kinds of natural and ecological disasters, based on the models. We are told we must change our lifestyles and habits, based on the models. We are told we must skupper our national economy, based on the models.

Then we are told, the models don't work.


posted on Fri, 07/31/2009 - 12:04pm
DU's picture
DU says:

gene, first it seems you may have not read the article you cite closely enough. Second, ice cores from the Greenland ice sheet show that atmospheric carbon dioxide was stable until the early 19th century when the level start to increase and dthe rate of increase has accelerated since then. In other words a new element (man and his industril revolution) has been introduced that was not present before so it would be difficult to retrofit some of therecent models to prior warmups.

posted on Fri, 07/31/2009 - 3:59pm
Gene's picture
Gene says:

If your assertion is correct -- that modern conditions are too different to permit comparison with earlier periods -- then that means no model can ever be tested. Which means we have no way of knowing if they have any predictive power at all. I don't know if I accept that, but it certainly is a provocative thesis.

posted on Sat, 08/01/2009 - 9:15am
Gene's picture
Gene says:

Before we go too far down ad hominem road (a scenic but extremely uncomfortable journey), remember: this is not “Gene’s interpretation” of the report. Rather, it is the interpretation offered by journalists from outlets as diverse as USA Today, Reuters, the notoriously partisan PhysOrg.com, even the Wall Street Journal (third item).

This is – dare I say it – the consensus opinion. And we know there’s no arguing with that.

posted on Sat, 08/01/2009 - 9:14am
JGordon's picture
JGordon says:

Just double checking here, but, Gene, you are being sassy about the consensus thing, right?

Without inflection, this Internet double-talk makes my head spin. Thank goodness we have news outlets to help me figure out what's right. And what makes a good headline.

(I guess that was a little sassy, but I'm applying it to the popular press' take on most stories, not just this one.)

posted on Sun, 08/02/2009 - 2:43am
Gene's picture
Gene says:

Sassy? Moi? Heaven forfend!

posted on Sat, 08/08/2009 - 2:33pm
phamilton's picture
phamilton says:


Yes, successful backcasting of past conditions by climate models provides rigor that they will generate good forecasts of future climate conditions. But backcasting can only be performed when a good instrumental record of past conditions is available, as is the case for the past 100 years. Numerous climate models now do a good job of backcasting conditions over the past 100 years which helps generate confidence that they can do a reasonable job of forecasting potential conditions looking forward a few centuries into the future.

Zeebe, Zachos and Dickens were not performing a backcasting experiment to validate a climate model. Far too little is known about the PETM (56 million years ago!) for it to serve this purpose. The researchers made numerous approximations about PETM atmospheric and ocean conditions based on proxy data because of course no instrumental records exist.

The researchers were not attempting to validate climate models but to investigate whether the PETM might represent a possible analogue for the future. When they plugged a contemporary climate model into their approximations of past PETM conditions, their outputs under predicted the degree of global warming suggested by proxy data sources. The researchers use this result to point to two potentially fruitful areas of future research:

One is that the Earth during the PETM might be just too different from contemporary conditions for the PETM to serve as a useful analogue for future anthropogenic warming. The other is that existing climate models are not “wrong” but possibly conservative in their estimates of the amount of global warming that might be expected under future elevated levels of atmospheric CO2.

Zeebe, Zachos and Dickens do not doubt that increasing levels of atmospheric CO2 will lead to global warming. Rather, they raise the alarming idea that the temperature increase might be much more severe than currently imagined.


Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Fri, 08/14/2009 - 1:52pm
Gene's picture
Gene says:

As I understand the articles, PETM was chosen precisely because it is fairly well understood.

Backcasting 100 years is good. Backcasting 1,000 or 1,500 would be better. That would encompass the Little Ice Age and the Medieval Warm Period, two climate fluctuations as great (if not greater) than the current warming, and yet clearly not caused by human-produced carbon. A computer model that can recreate the 12th and 18th centuries as accurately as the 20th would show that science has gone a long way in understanding climate dynamics.

(Though that still leaves unresolved the mystery of the 21st century, when carbon emissions went up by leaps and bounds, but global temperatures remained flat or even dipped slightly.)

posted on Sat, 08/29/2009 - 12:09am
Patrick Hamilton's picture
Patrick Hamilton says:

PETM was not chosen because it is fairly well understood. Nowhere in the article is this claim made. Rather, the PETM is posited as “a possible analogue for the future and thus may provide insight into climate system sensitivity and feedbacks” because this period of global warming was induced by a large and in geologic terms rapid influx of carbon dioxide into the atmosphere.

According to the IPCC, evidence from mountain glaciers does point to increased glaciation in a number of regions around the world outside Europe prior to the 20th century. The timing of maximum glacial advances in these regions differs considerably, however, suggesting regional climate changes, not a global increase in glaciation. Thus the current scientific evidence does not support globally synchronous periods of anomalous cold or warmth over the past 1,000 years, and the terms "Little Ice Age" and "Medieval Warm Period” have limited utility in describing trends in global mean temperature changes in past centuries. So while it would intrinsically interesting scientifically to better understand the mechanisms that induced these regional variations of past warmth and cold, the current limited ability to do so does not cast into doubt the evidence that large-scale global increases in atmospheric carbon dioxide induces global warming.

We are only eight years into the 21st century. The atmosphere will not behave in lockstep with carbon dioxide concentrations. The vast majority of the additional thermal energy being retained by the Earth is going into the global ocean since water has a far higher specific heat than air. Look to the oceans and you will find the increasing global temperatures you find wanting in the atmospheric record. You will also find ocean chemistry being dramatically altered as carbon dioxide dissolves into the surface waters, forms carbonic acid, and converts carbonate into bicarbonate – ocean acidification.

Patrick Hamilton
Director of Environmental and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Tue, 09/15/2009 - 5:03pm
Gene's picture
Gene says:

Thank you! I’ve been waiting for someone to acknowledge that carbon and climate do not march in lockstep.

The global warming debate in general revolves almost entirely around carbon: carbon emissions, carbon footprints, carbon taxes, carbon, carbon, carbon. And yes, humans have been pumping carbon into the atmosphere in ever-increasing amounts since about 1800. Yet, we have had:

cooling until about 1860
warming 1860-1880
cooling 1880-1910
warming 1910-1940
cooling 1940-1980 (with some periods of stasis)
warming 1980-2000
stasis 2000-present

(All dates approximate.)

Seems to me that there’s more going on here than just “carbon bad.” Even Dickens, co-author of the article in question, acknowledges, "[t]here appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models."

A brave admission. So, let’s study it. Let’s find out exactly how carbon and climate and atmosphere all work. But until we do, we could all do with fewer definitive assertions, such as “the science is settled” and “we have ten years to save the Earth.” (Not a reference to this specific conversation, but to the larger debate.) Such statements clearly fall on the far side of Occam’s razor.

As for warming oceans, some people find them. Others, not so much.

Finally, our inability to understand small-scale climate change does not breed confidence in our ability to understand large-scale climate change.

posted on Sun, 09/20/2009 - 6:18pm
phamilton's picture
phamilton says:

I think that you are presenting a straw man argument. I cannot think of a single, respected climatologist that would argue that atmospheric carbon dioxide concentrations and climate march in lockstep.

As you acknowledge, humans have been pumping carbon into the atmosphere in ever-increasing amounts since about 1800. Since the mid 18th century, about 321 billion tons of carbon have been released into the atmosphere from fossil fuels and cement production alone and half of these emissions have occurred in just the past 35 years.

One would expect that the inherent inertia in the climate system (due to 70 percent of the Earth being covered with liquid water) combined with the very recent loading of the bulk of human-generated carbon dioxide into the atmosphere would result in the human fingerprint on climate appearing later rather than immediately with the onset of the industrial revolution.

You suggest through your qualitative description of temperature trends since the 1860s that temperatures have bounced around some sort of mean. This is simply not the case. Despite ups and downs, the instrumental record shows an increase in Northern Hemisphere temperatures over that period of time, with a pronounced increase in recent decades.

The “science is settled” statement is shorthand for the fact that the big climatological challenge up to a few years ago was trying to identify a human signal in climatological data. A large scientific consensus now exists that human-induced changes to the global climate system are now discernable above the natural background noise of climate variability to a high degree of statistical confidence.

The focus now is moving away from the question of “Are humans impacting global climate?” to “What might be the changes we should anticipate in coming years." Significant efforts now are underway to develop models that resolve small-scale (regional) climate systems because policymakers increasingly want to know to what degree they need to anticipate changes in temperature and precipitation regimes. Different questions require different types of models.

Yes, Dickens states, “There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models." But he is not advocating that existing global circulation models be discarded. Rather, he is suggesting that “Some feedback loop or other processes that aren’t accounted for in these models… caused a substantial portion of the warming that occurred during the PETM.

You imply that these statements will be received with horror by the climatological community. But there already has been much discussion in the community in recent years that feedbacks (e.g. changes in Arctic albedo) and other processes (e.g. meltwater speeding the outflow of Greenland glaciers) may be too conservatively specified in models since both Arctic warming and Greenland icecap ablation are both occurring much faster than originally anticipated.

Finally, NOAA’s National Climate Data Center released a report earlier this month noting that the world’s ocean surface temperature was the warmest for any August on record, and the warmest on record averaged for any June-August (Northern Hemisphere summer/Southern Hemisphere winter) based on records dating back to 1880. What is your source of information indicating otherwise?

And one other point. I see that you choose not to address the topic of ocean acidification which I raised at the end of my last post. Do you accept the evidence that large amounts of carbon dioxide from the atmosphere are dissolving into the oceans and reducing ocean pH?

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Tue, 09/22/2009 - 10:49pm
Gene's picture
Gene says:

I do not raise the straw man argument. Rather, it is Al Gore, Henry Waxman, the popular media, and the "environmental movement" at large who have oversimplified climate to the equation "carbon = bad." Glad to hear there are scientists who appreciate the complexity of the system we are dealing with.

Yes, one would expect that inertia would mean that temperatures rise after CO2 levels rise. Except, they don't. Examining the geologic record, it turns out that global temperatures rise on average800 years before CO2 levels rise. Plays havoc with cause and effect.

Yes, the Earth has generally been warming since 1860. It's been generally warming for over 10,000 years. We are, after all, coming out of an Ice Age. (Or in the midst of an interglacial period, if you prefer.)

A large consensus with hundreds of dissenters. That's cool.

Models may not need to be discarded, but clearly they need to be drastically revised, perhaps to the point that they will no longer be recognizable. Which is pretty much the same thing. In any event, attempts to anticipate future changes will be of minimal use until new models are developed, and any actions taken based on our current inadequate knowledge would be profoundly premature, to say the least.

My previous post contained links to articles citing ocean cooling / lack of warming.

I did not respond to the acidification argument because I am not familiar with any link between ocean pH and global temperatures. Can you elaborate?

posted on Fri, 09/25/2009 - 6:43pm
phamilton's picture
phamilton says:

“Carbon = bad” is your terminology. I have not seen anyone else use it. So take credit for it if you wish but don’t attribute it to others.

You claim in one of your earlier posts that an article cites ocean cooling and a lack of warming. Your interpretation of what this article states is incorrect. It says in the lead paragraph, “These diving instruments suggest that the oceans have not warmed up at all over the past four or five years.” The scientists interviewed are not saying that the oceans have not warmed since historic recordkeeping began in the 1880s, but rather that they did not detect an increase in temperature over the past few years. The article you cite, furthermore, is 15 months old. Scientific research does march on and apparently the upward trend in ocean temperatures has resumed.

The only geologic record with a resolution approaching 800 years that you refer to your previous post is carbon dioxide data from ice cores going back several hundred thousand years so I guess that you are referring to the most recent Ice Age. Strong evidence exists that the driving mechanism for the ice ages over the past two million years are variations in the Earth’s orbit that alter the timing and distribution of solar energy across the Earth’s surface. But these tiny changes in insolation are insufficient to generate the large temperature swings that occur between glacial maxima and minima. Feedback mechanisms (e.g. terrestrial plants) amplify the insolation changes by driving large changes in the carbon dioxide concentration of the atmosphere.

So let me ask you a cause and effect question: Do you accept the scientific evidence that carbon dioxide is a greenhouse gas?

Actually no, we are not coming out of an Ice Age. We are in an interglacial. And no, global temperatures have not been generally warming over the past 10,000 years. They instead reached a peak at between 9,000 and 5,000 before present and then trended downward (until recently).

I am not concerned about the quantity of dissenters but rather the quality of their arguments. If dissenters think that they really have compelling alternative explanations for the large-scale and accelerating global changes now underway, I look forward to seeing their arguments in peer-reviewed scientific journals, such as Science, Nature and others.

You do not make the case for why existing models need to be drastically revised unless you are referring to one scientific study that indicated that contemporary climate models were able to replicate only 50 percent of the global temperature increase that occurred during an event that took place over 55 million years ago. You are betting a lot on one study of a geologic event that may or may not be a good analogue for contemporary conditions. By the way, a bad scientific model is one that does not explain any variability. A model that explains 50 percent of variability to a high degree of statistical confidence is a good model – one that shows promise for being further developed with the goal that it explain even more.

Let me clarify the issue of ocean acidification for you. It is another large-scale global change now underway because human activities are releasing large quantities of carbon dioxide into the atmosphere. Ocean acidification is undesirable because if left unchecked it will profoundly alter ocean chemistry and therefore ocean ecology in coming decades. Ocean acidification is far easier to model than global climate change.

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Wed, 09/30/2009 - 10:39pm
Gene's picture
Gene says:

Evidence suggests that the Medieval Warm Period was a wide-spread phenomenon.

posted on Sun, 12/06/2009 - 11:33am
Gene's picture
Gene says:

“Carbon = bad” was not meant as a direct quote. I thought that was obvious, but I erred. I apologize for any confusion this terminology may have caused. However, it is an accurate summary of the over-simplified version of climate change we hear time and again in the media. It is therefore legitimate to attribute it, in meaning if not verbatim, to any writer, politician or scientist who reduces complex climatological phenomena to human-produced-carbon-is-warming-the-Earth-and-we’re-all-gonna-die! (Please note the absence of quote marks.)

I also stand by my interpretation of the articles on ocean cooling. I never said, nor meant to imply, that the oceans have never warmed. Of course ocean temperatures have gone up and down over time; that’s what temperatures do. My point—and again, forgive me for not being sufficiently explicit—is that these temperatures are not responding to increases in atmospheric carbon in ways we have been led to believe. The fact that ocean temperatures rise, fall and stagnate, while carbon concentrations only go up, tells me that something fairly complicated is going on here. And while the study may be from last year, we cannot throw out inconvenient data just because it’s old. We certainly cannot throw out four or five years’ worth of data just because the latest measurement shows an uptick.

Thank you for the clarification on ocean acidification. It’s pretty much what I had thought. It does not, however, seem to have any connection to global warming – unless you are committing the minor fallacy, which would be a major mistake. ;-)

I said “interglacial.” I used “Ice Age” in the vernacular sense of glaciers extending far below the Arctic, carving out lakes and such; wooly mammoths and saber-toothed tigers running around; that sort of thing. It is interesting to learn that over the past 10,000 years, temperatures have risen and fallen naturally. My point is, during an Ice Age (scientific or vernacular), Earth’s temperatures are far cooler than normal. When an Ice Age ends (or goes into an interglacial reprieve), we should expect temperatures to naturally regress toward the mean; i.e. get warmer.

I suspect dissenting scientists hold the same attitudes toward quantity and quality as you express. As for peer-reviewed scientific papers posing questions to anthropogenic global warming, here’s a list. (There is apparently an earlier list with 300 additional names. I was unable to locate it readily.)

And here’s another. I did not check for overlap. Yes, these lists were compiled by people out to support a particular view. That does not negate the fact that the articles themselves were published in the sort of peer-reviewed journals you mention. I’m not sure if any of these papers offer “compelling alternative explanations,” but then, I’m not sure the null hypothesis needs to be published.

“Accelerating” does not seem to accurately describe the last ten years of more-or-less stagnant temperatures.

I feel the case for better models makes itself. A model that accounts for 50% of climate change at one point in history is an important step for science. But it is not nearly robust enough to justify the sorts of social and economic changes we are told are necessary to combat global warming. From the relatively mild goals of the Kyoto accord, to some of the more draconian proposals I’ve seen floated (one called for reducing global carbon emissions by 90%!), any effort to deal with global warming will have real-world consequences. And I’m not willing to accept wrenching social changes unless the evidence is much, much stronger. And even then, as Bjorn Lomborg points out, we’re probably much better off learning to live with global warming than trying to stop it.

As I noted earlier, a model that accurately back-casts the known historical record would be a tremendous step in the right direction. (Just because the Little Ice Age and the Medieval Warming were not global phenomena doesn’t mean they didn’t happen.)

Yes, carbon dioxide traps heat. However, scientists such as Richard Lindzen and Leighton Steward have questioned whether it has any noticeable impact on climate. Given the extremely low concentrations of CO2 in the atmosphere, they argue that the effect is minimal to negligible. It is entirely possible that they may be proven wrong. I’m just not seeing it yet.

posted on Fri, 10/09/2009 - 10:54pm
phamilton's picture
phamilton says:

My original argument with you was over your misinterpretation of a research article published by Richard Zeebe, James Zachos and Gerald Dickens, but your recent rant about the media has me confused. You castigate the mass media and others over their alleged oversimplifications of the science of global warming and then you use the oversimplifications that you attribute to them to question the science.

An example – you said in your last post that, “…these [ocean] temperatures are not responding to increases in atmospheric carbon in ways we have been led to believe.” Regardless of what the media does or does not say, do you really believe that they should move in lock step? I am not aware of any peer-reviewed scientific articles that make the argument that ocean temperatures and carbon dioxide levels in the atmosphere should do so.

By the way, the article “Global hydrographic variability patterns during 2003–2008,” by K. von Schuckmann, F. Gaillard, P.-Y. Le Traon in the September 4, 2009 issue of the peer-reviewed Journal of Geophysical Research – Oceans analyzes ocean temperatures down to 2,000 m (other recent papers has focused on only the top 700 m). Guess what – the trend of ocean heat from 2003 through 2008 has been upward.

You say in your last post, “we should expect temperatures to naturally regress toward the mean; i.e. get warmer.” No, the Earth does not regress to some sort of mean temperature. The average global temperature of the Earth is determined by the balance between incoming solar radiation and outgoing thermal radiation.

Your second link to scientific articles is actually a list of quotations from scientists or excerpts from articles or statements made in non-peer reviewed publications (i.e. Grist magazine, Washington Post). I will focus on the first link to a list of scientific articles published in peer-reviewed scientific journals that are about Dansgaard-Oeschger cycles.

The concern about global warming is that human releases of greenhouse gases are changing global mean temperature by altering the global heat budget, a climate change of the first kind. Changes of the second kind are due to changes in heat transport in the atmosphere or ocean. Dansgaard-Oeschger cycles are of the second kind because a key signature of these cycles is that Arctic temperatures increase while Antarctic temperatures decrease. Dansgaard-Oeschger are interesting climatological phenomena but do not cast doubt on current anthropogenic global warming because temperatures are presently rising in both polar regions – something that should not occur in a Dansgaard-Oeschger cycle.

The Little Ice Age and the Medieval Warming also are climate changes of the second kind. (No one is implying they never happened). They were regional and asynchronous events which is evidence that they likely were due to changes in heat transport in the atmosphere or ocean and not a change in the total global heat budget. So I appreciate your interest in these events but they are not particularly relevant to the larger question of the changes underway to the heat budget of the entire planet.

I guess that I just keep reiterating it. Current global circulation models were not developed to model the energy budget of the planet 56 million years ago. Nonetheless, the models were able to account for 50 percent of the global warming at that time, meaning that current global circulation models may very well be under forecasting future temperature increases.

You contend that efforts to address global warming will have wrenching social consequences. I argue that failing to do so will have wrenching social consequences. I accept the evidence that it is not possible to change the chemical composition of the atmosphere and not change climate. I also know that societies around the world have made tremendous investments in vast human infrastructures predicated on existing climate conditions. I guess that I am the conservative in being concerned that these investments are being placed at great risk by altering the conditions for which they were designed.

I trust that Lindzen and Steward do not really dismiss CO2 because of its low concentration in the atmosphere as this would be a peculiarly unscientific statement to make. It would be comparable to saying that a blood alcohol content of 0.08 could not possibly impair judgment or motor skills because blood is composed overwhelming of water. 99.8 percent of the atmosphere is composed of gases (nitrogen, oxygen, argon) that play no significant role in mediating incoming solar radiation or outgoing thermal radiation.

You say in your last post, “Thank you for the clarification on ocean acidification. It’s pretty much what I had thought’. Well, what do you think about it? Is it not a problem? Do you find it acceptable? And if yes, why?

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Fri, 10/16/2009 - 10:32pm
Gene's picture
Gene says:

Wrenching social consequences is pretty much the whole point. I mean, temperatures go up, temperatures go down, and no one really cares too much -- unless it impacts our lives. And what that impact will be, and what if anything we can/should do about it, are as much a part of the global warming debate as the science. Hence my so-called "rant" joining the two. Even if the science of anthropogenic causes for global warming is correct (and the theory has its skeptics), the question of what this means for our future is much murkier.

It is my understanding that most scientists have backed off -- if they ever even supported -- the more catastrophic climate scenarios (e.g An Inconvenient Truth, The Day After Tomorrow, etc.) and predict much more modest effects from global warming. But even those modest impacts will affect infrastructure, as you say.

And what is "infrastructure"? It is cars and planes, factories and farms, schools and hospitals, power grids and computers -- all the stuff of modern life, and almost all of it running on carbon-emitting fossil fuels. Many who argue that carbon causes warming also argue that cutting warming will require us to cut carbon emissions. I have seen estimates as high as 90% for 50 years -- a price tag of some 2.5 quadrillion dollars! This would basically shut down the world economy for half a century and consign billions of people to lives of famine, disease, war and death.

I find myself concurring with Bjorn Lomborg of the Copenhagen Consensus, and Steven Levitt and Stephen Dunbar of SuperFreakenomics (all of whom, BTW, accept human carbon emissions as the driving force behind global warming) when they note that, for a tiny sliver of that cost, we can build better sea walls, create better emergency response and evacuation systems, develop better storm tracking, and simply learn to live with a warmer world. This would be less wrenching by an order of magnitude or two.

But whatever we choose to do, we will do it based on predictions, based on models. And this, at last, brings us back to the original study. It applied a current climate model to a warming episode which I now understand happened a very long time ago, and is not as well-understood as I originally thought. (Those errors are on me.) Regardless, the model could only account for half of the ancient warming. You see that as pretty good -- a sort of glass half-full view. I guess I see it as half empty. But before we go off spending billions, trillions, quadrillions of dollars on anything, I think we need to be a heck of a lot more confident than just 50%.

That's all I'm sayin'.

posted on Sun, 10/25/2009 - 9:21pm
Gene's picture
Gene says:

Evidence suggests the oceans are cooling.

posted on Sun, 12/06/2009 - 11:37am
bryan kennedy's picture

Actually that looks like two different interpretations of the situation--one by a group of bloggers and one by Australia's chief scientist.

posted on Sun, 12/06/2009 - 1:51pm
Anonymous's picture
Anonymous says:

Gene, I've followed Science Buzz almost since its inception and always look forward to your posts. At the risk of overstepping my bounds, though, I feel like the often sarcastic tone that you take toward others (even if they contract themselves, etc.) makes it harder for may people to follow what you're saying and may even unfairly bias them against your points, no matter how sound they may be. Sometimes making your case matter of factly, withot the parenthetical chides, makes it easier for others to understand what you're saying. Peace.

posted on Sun, 10/18/2009 - 12:35pm
Gene's picture
Gene says:

Thank you for your kind words. You are right -- while sarcasm can be fun, it all too easily slides into the "cheap shot," which is uncalled for. I don't think I've been egregious in this regard in the current exchange -- I certainly didn't mean to be -- but if I have stepped on any toes, I do apologize.

I'd also like to take a moment to thank Pat for participating in this exchange. Everyone should know that, even though he and I disagree on this point, we otherwise get along just fine. Pat is one of the pleasantest people I have ever known, let alone ever argued with, and if anything I have said has given a different impression, then I am truly and deeply sorry. And that is no sarcasm.

posted on Sun, 10/25/2009 - 9:29pm
Anonymous's picture
Anonymous says:

I like all of the above points about the value of peer-reviewed arguments as opposed to arguments made in isolation or in journals that lack a peer-review process. Thanks for this important reminder!

posted on Sun, 10/18/2009 - 12:47pm
Maggie E's picture
Maggie E says:

Journals are very important to keep with you. You should always have it in a secret place so people would not sneak it out of your nose

posted on Tue, 10/27/2009 - 11:17am
JGordon's picture
JGordon says:

This is absolutely true for some kinds of journals.

Others are better if everybody reads them.

posted on Tue, 10/27/2009 - 11:47am
phamilton's picture
phamilton says:

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Wed, 11/04/2009 - 10:46am
phamilton's picture
phamilton says:

You are not correct in your October 25 posting that scientists now are predicting much more modest effects from global warming. The scientific consensus is exactly the opposite.

An October 22 letter to the U.S. Senate signed by the leaders of 18 major U.S. scientific organizations (e.g. American Geophysical Union, American Meteorological Society) states that “ongoing climate change will have broad impacts on society, including the global economy and on the environment… The severity of climate change impacts is expected to increase substantially in the coming decades.”

Oh sure, there are global warming skeptics. But these individuals lack peer-reviewed scientific information to support their positions and lack the support of major U.S. scientific organizations.

Your estimate of 2.5 quadrillion dollars as the cost of moving away from carbon fuels is pure scare tactic. That number is 41 times the dollar value of all global economic activity for the entire planet for 2008. That number is not supported by any scientific peer-reviewed analysis of the cost of developing and implementing a non-carbon based energy economy. It is conjured up out of thin air by opponents to action on global warming in an attempt to shut down discussions about how to develop a new energy economy.

The position by Lomborg and Dunbar that we can adapt to the climate changes that humans are instigating without doing anything to limit the severity of future climate change has serious inconsistencies. Climate models apparently are robust enough to inform adaptation to climate change but insufficient to justify taking action to mitigate climate change.

Climate change will accelerate if we continue to put carbon dioxide into the atmosphere. The new sea walls, better emergency response and evacuation systems, etc. that you, Lomborg, and Dunbar advocate would quickly become obsolete (talk about stranded economic costs!) if we did nothing to mitigate the forces pushing up sea levels, changing the timing and patterns of precipitation, increasing the frequency and severity of heat waves, etc.

I see that you assiduously avoid the issue of ocean acidification caused by human releases of carbon dioxide into the atmosphere. I understand this reticence. Ocean acidification threatens the whole climate skeptic position and thus must be ignored.

The observational data of ocean acidification are irrefutable, the computational models are readily verifiable, and predictions of future acidification are easy to calculate. So if human actions are changing the chemistry of the vast global ocean, then is it really plausible that human actions are not also be substantially changing the thin envelop of air around the planet? And the only solution to ocean acidification is to reduce dramatically human releases of carbon dioxide into the atmosphere.

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Wed, 11/04/2009 - 10:49am
Gene's picture
Gene says:

My apologies. The total cost of eliminating global warming should not be 41 times the total world GDP. It should be 45 times. For environmentalists tell me it would take a 90% reduction in carbon output for 50 years to bring CO2 back to "natural" levels.

I have already provided lists of peer-reviewed science which questions aspects of anthropogenic global warming.

I am not avoiding the issue of ocean acidification so much as I am ignoring it as irrelevant. As I understand your explanation, it is neither a cause nor an effect of global warming; it is at best an epiphenomenon.

Scientists are now predicting more extreme effect from global warming? Somebody should alert the media, and quickly!

posted on Fri, 11/20/2009 - 4:45pm
phamilton's picture
phamilton says:

So let me get this right. You have no evidence, no peer-reviewed studies that buttress your contention that it will take the entire global economic output for close to the next half century to switch to low-carbon energy systems. In fact, you just decide off the top of your head that it will take not 41 but 45 times total world GDP to achieve this conversion. You are blogging on Science Buzz and just making up ‘facts’ as you go along?

No, you have not provided a list of peer-reviewed science that question aspects of anthropogenic global warming. I have already explained why the Hudson Institute’s list of scientific articles about Dansgaard-Oeschger cycles are not about global changes in temperature but rather hemispheric.

Here is another issue I have with your Hudson Institute list: It seeks to imply that the scientists who produced those research studies question the existence of anthropogenic global warming. I know several of the scientists on the list and I know that they are concerned about global warming. In particular, I know that Dr. Dan Engstrom of the Museum’s St. Croix Watershed Research Station accepts the scientific evidence for anthropogenic global warming. I will let him know that his research in the Arctic is being mischaracterized by the Hudson Institute when I see him next week. I anticipate that he will be disappointed but not surprised.

I see that you are uncertain about the connection between global warming and ocean acidification. Perhaps an analogy will help – A heavy smoker goes to his doctor. The doctor says that the patient is exhibiting evidence of incipient emphysema and heart disease due to his smoking habit. Did the emphysema or the heart disease cause the other? No, they are both caused by the patient’s cigarette smoking. Would the patient conclude that one disease was serious while the other was merely an ‘epiphenomenon’? No, both have the capacity to cause him great bodily harm. What is the doctor’s recommendation? Quit smoking. (Of course, the patient may choose to ignore the doctor’s advice – even call him a quack – because he does want to accept the situation).

It took millions of years for Earth’s fossil fuel reserves to accumulate. They have been sequestered away in the Earth for millions, tens of millions and even hundreds of millions of years. We are in the process of returning them to the atmosphere in the form of carbon dioxide, a known greenhouse gas, in the span of a few centuries. Yet you have convinced yourself that nothing deleterious will occur.

Patrick Hamilton
Department of Environmental Sciences and Earth-system Science
Exhibits Division
Science Museum of Minnesota

posted on Thu, 12/03/2009 - 11:21pm
Gene's picture
Gene says:

I make up nothing. According to this article:

[E]nvironmentalists like Lester Brown and George Monbiot have argued that we need to cut CO2 current emissions by 80% by 2020 and by 90 percent by 2030.

(President Obama is reported to be pegging the number at 83%.)

Since almost all economic activity on earth is powered by fossil fuels, then they are indeed talking about reducing global economic output by some 80% or so.

As for the time it takes for excess carbon to leave the atmosphere through natural processes, this NAS-funded journal says 50 years.

Crunch the numbers, and yes, reducing carbon emissions will require us to forfeit an amount of money equal to 35 to 45 times the annual economic output of the entire world. And that's just to get carbon levels back to "normal." To prevent their future rise, we would have to stay at this reduced level of economic activity...forever.

I do not know where any of them got their figures, but you have convinced me – I will never trust an environmentalist again.

I’m afraid your analogy does not stand up. Though emphysema is almost always related to smoking, heart disease has many causes. It is possible that a smoker could have these two diseases for two different reasons. Nevertheless, a doctor would undoubtedly tell the patient to stop smoking—the link between smoking and these illnesses, and between these illnesses and death, is well established. On the other hand, the link between C02 and both global warming and ocean acidification, and the link between those events and future catastrophe, is much weaker.

In light of recent revelations coming out of the University of East Anglia, Pennsylvania State University, NASA, Queens University, etc., I feel it best to withhold comment on peer-reviewed research and computer-generated climate models. Which is pretty much this whole thread.

posted on Fri, 12/04/2009 - 7:37pm
jerseyboychet's picture
jerseyboychet says:

You say you make up nothing Gene but you make up your mind without getting all the facts. This might help.

posted on Sat, 12/05/2009 - 5:45pm
Molly P's picture
Molly P says:

I like your analogy to the smoker who won't (or can't) accept that cigarette smoking is the cause of his or her smoking related health problems. The climate change skeptics often remind me of the evolution deniers in their arguments.

As a former paleoclimatologist (one who studies past climate) I remember reading a few peer-reviewed papers by those who denied the human impact on climate change, and they were usually funded by oil companies.

With regard to the cost of mitigating our CO2 input into the climate system. It is not as if that $ will go into some black hole. It will provide jobs and work for lots of people and could ensure that life as we know actually continues to be viable on the earth.

posted on Fri, 12/04/2009 - 10:54am
Gene's picture
Gene says:

This raises a crucial point. The arguments of climate-change skeptics (we don't deny anything; we merely refute) are nothing at all like those of creationists.

Science looks for natural causes for natural phenomena. Creationists propose a supernatural cause for the natural phenomenon of evolution. This is not science.

Climate-change skeptics propose natural causes for global warming--solar activity, or cycles of ocean circulation. Or, they critically investigate the natural causes proposed by AGW supporters. This is science. (Whether the science is as strong as that supporting AGW is, of course, the entire subject of this debate.) They never, so far as I know, propose supernatural causes.

You are correct: the cost of mitigating CO2 will not "go into some black hole." The money will never be made in the first place. Reducing carbon emissions by the amounts being proposed will require the near-complete shut-down of the world economy.

posted on Fri, 12/04/2009 - 7:21pm
phamilton's picture
phamilton says:

I do not have a dispute with the estimates for the amount of carbon dioxide reduction necessary to avoid dangerous anthropogenic climate change. These estimates have been vetted in a number of peer-reviewed scientific journals.

What I question is your calculation that it will take every single dollar of global annual economic output for decades to revise our fossil fuel-based economies (by the way, do you expect these finite resources to last indefinitely?) Please find me a peer-reviewed journal article that supports your calculations. I have never come across any scientific paper that remotely comes close to your estimates.

The link between CO2 and ocean acidification is quite strong. Again, I ask you to find a peer-reviewed scientific article that questions the link between CO2 and ocean acidification and that questions the future acidification that will occur if atmospheric CO2 concentrations continue to rise. This original strand of debate began with you trumpeting a scientific study of the Paleocene-Eocene thermal maximum, which was based in part on evidence of carbonate dissolution in sediments thousands of feet below the surface because high concentrations of atmospheric CO2 had acidified the oceans.

Yes, climate-change skeptics propose natural causes for global warming – the same ones over and over again despite the cumulative scientific evidence refuting solar activity, ocean circulation, etc. I think that the analogy is not between climate-change skeptics and creationists but rather between climate-change skeptics and creation scientists - the careful and selective interpretation of scientific evidence to support a certain set of beliefs.

I suspect that what climate-change skeptics do not really like is not the science of global warming and ocean acidification but the perceived implications of these problems. It seems they fear that acknowledging global warming and ocean acidification would violate strongly held views about the world or force them to accept unacceptable solutions.

Too bad, because the world could badly use innovative conservative ideas about how to address global warming and ocean acidification. But so far, most conservatives (but not all!) have opted instead to sit out the debate about policy solutions to these problems.

Patrick Hamilton
Director of Environmental Sciences and Earth-system Science
Science Museum of Minnesota

posted on Wed, 01/20/2010 - 10:49pm
DO's picture
DO says:

Excellent summary of the case against the deniers. They are certainly short of citations but usually refer to "X articles on the web" or something similar.

posted on Fri, 01/22/2010 - 5:32pm

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