Sunday, April 29, 2007

Bjorn Lomborg gets confused about global warming

Bjorn Lomborg styles himself as the "skeptical environmentalist." The one thing that he seems most skeptical about is that environmental problems such as global warming are of paramount importance. He recently laid out his thinking in an interview on The News Hour with Jim Lehrer.

Lomborg's main point was that global warming is just one among many problems that we face in the 21st century. Since we can't address all of those problems with equal attention, we should prioritize. So far, so good. But instead of putting global warming near the top of his list, Lomborg places it far below other problems such as the spread of AIDS and malaria, malnutrition, agricultural research and strangely, free trade. (Lomborg, incidently, doesn't see free trade as causing some of the problems we face, but rather as a solution to those problems.)

Now, most doctors know that to cure an illness, one should treat the cause of the disease rather than merely addressing the symptoms. But even though Lomborg acknowledges that global warming will be a leading cause of the problems he seeks to address--problems such as reduced harvests and the spread of disease--he opts for focusing on the symptoms rather than the cause.

His reasoning is that it is far too expensive with current technology to reduce greenhouse gas emissions and that further research may help reduce the costs of doing so. His solution is to invest some money in research and see what happens. He also tosses out the disingenuous red herring that the Kyoto Protocol will do little to affect the trajectory of global warming even if everyone--including those currently opting out such as the United States--meets its targets. In this he is correct. But someone in his position certainly knows that the protocol will be renegotiated in 2012 and that all serious proposals now on the table call for far deeper cuts--as much at 80 percent--in greenhouse gas emissions by mid-century.

Lomborg, who is a political scientist by training and fond of using statistics to make his point, seems to know just enough math to make him dangerous. What he assumes is that the gently sloping temperature curves implied by some models of global warming mean that world society will be able to adapt over time and that this adaptation will be less costly than addressing the problem directly. (Even if these curves are accepted as correct, the idea that it will be cheaper to address symptoms only is strenuously in dispute.) But what Lomborg doesn't seem to know is that natural systems such as climate are not as well-behaved as we'd like to believe. To use the mathemetician's term, such systems are nonlinear.

That means that climate could change abruptly. Even if abrupt climate change is considered a low probability, it would likely be a high-severity event. And, the most severe nonlinear outcome would be runaway global warming which could not be stopped by human action once it begins. Lomborg's proposed priorities simply don't take such possibilities into account. Keep in mind that many scientists who discuss such possibilities believe that if they come to pass, they will severely disrupt and possibly even destroy modern civilization over a period of just a few decades. Lomborg's priorities seem all the more confused given this context.

A third confusion seems almost laughable. Lomborg assumes that even as global warming proceeds, there will be far more wealth in places such as Bangladesh--an impoverished, low-lying country that could suffer greatly from rising oceans and reduced food harvest. Lomborg assumes that other great natural systems such as fisheries and water will not decline greatly even though they are declining precipitously in the present. He also assumes ample energy supplies to power economic growth worldwide over the next century despite the necessity to reduce fossil fuel usage and despite the peaking of oil and natural gas that even the most optimistic experts expect no later than mid-century. It short, he assumes that the disruptions caused by global warming and resource depletion will not greatly affect global economic growth. These are hardly surefire assumptions even if they reflect the wisdom of some unnamed economists at the United Nations which he cites.

Lomborg has organized a group called the Copenhagen Consensus to push his priorities. Perhaps, you may say, the people who participate in the group's various analyses know something we don't about the Earth's natural systems. Alas, no. They are all economists who seem to know little or nothing about natural systems and their dynamics. Beyond this, something seems awry when such economists simultaneously insist that the world economy will experience rapid economic growth in the coming decades, but also act as if we are living in a zero-sum economy that will severely limit resources available to address critical environmental and public health problems.

So what makes Lomborg's ideas so compelling? First, few people would disagree that we need to address AIDS, malaria and malnutrition. And, few people would disagree that we are currently not doing enough about each. In addition, Lomborg is a compelling messenger. He's articulate (in English as well as his native Danish), personable and good-looking.

For all of this Lomborg seems like a captain who, as his ship is being tossed in dangerously unstable seas, focuses on addressing the widespread problem of sea-sickness among the passengers rather than charting a course away from a storm that threatens to capsize his vessel. The reasoning he gives is that the medication for sea-sickness is readily available and cheap, while charting an uncertain detour away from the storm might result in costly delays for the shipping line.

Such logic on its face ought to make us exceedingly skeptical of the skeptical environmentalist and his methods.


Anonymous said...

Hi Kurt
Alexander Cockburn wrote an interesting article in Counterpunch claiming Global Warming is a natural phenomenon, using Dr. Martin Hertzberg's theory, that water vapor is the culprit and not CO2. The position of the Earth with respect to the Sun and the fact that we are close to the end of an Ice Age are the main reasons. Hertzberg's writing appears in an old article. Have you heard of such a theory?


Kurt Cobb said...


I am a reader of The Nation where Cockburn's Counterpunch article on global warming also appeared. I respect his work, but in this case he seems to have uncritically swallowed Hertzberg's conclusion without doing his own digging. Hertzberg is a serious scientist, but he is an expert in combustion and not a climatologist. Given that he is a serious scientist, it is surprising that he has been so careless in his analysis.

The role of solar radiation in the periodic warming and cooling of the Earth is well-known. But precise data from satellites have only been available for the past 25 years and the conclusion from that data is that observed increases in solar radiation are "not enough to cause notable climate change." The Goddard Institute scientist who evaluated the data, Richard Willson, does say that if such a trend continued over a century or more, it would then become "a significant component of global warming."

Notice that he said component, not sole cause which he clarifies in this article on In the article Willson says that even though anecdotal evidence prior to satellite data suggests that solar radiation has been increasing since the end of the 19th century, this does not mean that industrial pollution has not also been a major factor in climate change. In essence, he is saying that until we have a way of more precisely measuring solar radiation prior to the satellite data, we won't know whether such radiation has actually played a significant role in global warming.

That said, if hypothetically speaking, increases in solar radiation were responsible for 25 or even 50 percent of the warming, wouldn't it be all the more urgent for us to reduce or eliminate greenhouse gasses since this would be the one driver of global warming that we humans could affect? See my references in the post above concerning abrupt climate change and runaway global warming to understand why human society should consider embarking on such a strenous task even if factors beyond greenhouse gases are significant contributors to global warming.

With regard to water vapor as a greenhouse gas, Hertzberg is technically correct in saying this. But he is apparently unaware of the difference between what's called a "forcing" and a "feedback." Increased water vapor in the atmosphere is a feedback due to increased warming. As the site RealClimate explains, the Earth attempts to maintain a constant relative humidity on average across the globe. Atmospheric temperature determines how much water the atmosphere can hold. As the atmosphere warms, it can hold more water vapor. The question is, what gets the warming trend started in the first place? Water doesn't just decide to put more of itself into the atmosphere one day. The answer is another "forcing" such as increasing carbon dioxide levels which then reflect more heat back to the Earth and warm the atmosphere which then results in the "feedback" phenomenon of increased water vapor. In short, no "forcing" means no increased water vapor. Cockburn asserts that climate modelers do not take into account water vapor in their models. In this he is just plain wrong. What the modelers do is treat water vapor as a feedback which amplifies the effects of increased greenhouse gases.

Cockburn also quotes Hertzberg that the geologic record shows that increases in atmospheric levels of carbon dioxide actually lag increases in temperature. Again, he is technically correct. But as RealClimate explains here, in comparison to the total interval of warming (usually around 5,000 years) the lag of about 800 years is relatively short. What this means is that the first 800 years of warming can be attributed to other factors, but that the next 4200 years of warming are heavily influenced by carbon dioxide levels. And, the role of carbon dioxide in trapping heat is not in dispute.

No genuine climate scientist will tell you that global warming has one and only one cause. The alarm raised by climate scientists has to do with their ability to isolate the various causes and assign relative weight to the contributions. The overwhelming weight of the evidence shows that greenhouse gases, primarily carbon dioxide, are driving global temperature gains and that the largest new source of such gases is human activity. (Scientists can tell via a chemical signature in the carbon that this is true.)

Finally, Cockburn cites Hertzberg's observation that even though the rate of carbon emissions dropped precipitously during The Great Depression of the 1930s (because of decreased industrial activity), carbon dioxide levels in the atmosphere continued to climb when, he claims, they should have dropped. This is such a simpleminded error that it's surprising that someone like Cockburn or Hertzberg would make it. Even during The Great Depression, as they both admit, society continued to emit large (though declining) amounts of carbon into the atmosphere. Since carbon dioxide is long-lived in the atmosphere--it takes about a century for it to finally leave--it makes perfect sense that the build-up would continue, albeit at a lower rate. This is precisely the problem with carbon dioxide emissions. They persist and build up and thereby add heat to the Earth over time. If carbon dioxide dissipated within a matter of weeks or months, we might still have a global warming problem, but it would be much, much less pronounced and not nearly so urgent to address. But, alas, carbon dioxide has a mind of its own and sticks around on average for more than a century.

Alex Smith said...

FYI for you and your readers...

My piece on Alexander Cockburn, Climate Denier can be found in my blog here:

This is actually a script for my radio production of the same name, a 23 minute piece (which includes a clip from Sonali of KPFA interview George Monbiot in late May, asking him about Cockburn)

which is here:
(22 MB mp3 file)

This will be broadcast twice this week on CFRO FM in Vancouver, Canada, and then rebroadcast on a series of college and community stations.

Alex Smith
Radio Ecoshock

harry said...

You write: 'Lomborg, who is a political scientist by training and fond of using statistics to make his point, seems to know just enough math to make him dangerous.'

This is not true. Lomborg is a statistician by training. Therefore when he speak math - PARTICULARLY stats math - you should spend more time listening to what he says and less time writing disingenous BS.

Kurt Cobb said...


I'm always happy to be corrected when I'm wrong, but in this case one needs only to read what Lomborg writes in his biography on his own website: M.A. in political science, 1991 and Ph.D. at the Department of Political Science, University of Copenhagen. 1994. He is currently an associate professor in the Department of Political Science. True, he has taught statistics, but then I've taught English composition at the college level. That doesn't make me an expert in English literature, however. Nor even a composition specialist. He may have learned about statistics on his own, but as I pointed out, he is not trained as a statistician. For an excellent catalog of the mistakes (some of them elementary) in the way he uses statistics and also what appear to be deceptive tactics, look at the Lomborg Errors website.

Anonymous said...

"Bjorn Lomborg is associate professor of statistics in the Department of Political Science at the University of Aarhus, Denmark. His formal education is political science. He earned his Ph.D. in game theory. From 2002 - 2004 he was head of the Environmental Assessment Institute. In 2004, following the Copenhagen Consensus, he resigned the post to return to academia. [1]

Game Theory, my dear chap, is statistics.

A PhD requires, I think you will agree, domination of the statistics field.

I rst my case.