Cooler Heads and Climate Change

By Judith Curry
Wednesday, October 10, 2007; 6:55 PM

In his Outlook essay "Chill Out," Bjorn Lomborg rightly notes that skepticism about climate change is no longer focused on whether it the earth is getting warmer (it is) or whether humans are contributing to it (we are). The current debate is about whether warming matters, and whether we can afford to do anything about it.

In this debate, Lomborg has positioned himself squarely in the skeptics' camp. But he has some of his facts wrong -- and he fails to appreciate the risks that global warming bring to us all.

On the facts, Lomborg writes that the Kangerlussuaq glacier in Greenland is "inconveniently growing," somehow undercutting the argument that the world is getting warmer. But NASA research shows that Greenland's Kangerlussuaq glacier is not growing; it is simply spilling into the sea.

Lomborg also misrepresents some conclusions of the U.N.'s Intergovernmental Panel on Climate Change. He is skeptical about the claim that polar bears "will be decimated by global warming as their icy habitat melts." But the report shows that, even under the best-case scenario, about two-thirds of the current polar bear population will be lost by 2050.

Lomborg's attitude toward risk is also troubling. He focuses only on the middle range of the panel's projections, dismissing the risk from the higher end of the range. But if the risk is great, then it may be worth acting against even if its probability is small. Think of risk as the product of consequences and likelihood: what can happen and the odds of it happening. A 10-degree rise in global temperatures by 2100 is not likely; the panel gives it a 3 percent probability. Such low-probability, high-impact risks are routinely factored into any analysis and management strategy, whether on Wall Street or at the Pentagon.

The rationale for reducing emissions of carbon dioxide is to reduce the risk of the possibility of catastrophic outcomes. Making the transition to cleaner fuels has the added benefit of reducing the impact on public health and ecosystems and improving energy security -- providing benefits even if the risk is eventually reduced.

In his cost-benefit analysis, Lomborg considers only one policy option for reducing carbon emissions -- the Kyoto Protocol -- and says its worldwide cost would be about $180 billion per year. But the debate over the economics of global warming is more wide-ranging than Lomborg would have it. More than a dozen different studies have examined the economic impact of Kyoto-level controls. Some have concluded that it could have relatively small negative effects, such as those cited by Lomborg. Others have predicted small positive effects. Moreover, by focusing only on the Kyoto Protocol, Lomborg ignores potentially better policies that could cost far less than Kyoto and deliver higher economic growth worldwide.

Lomborg gets it right when he calls for an ambitious public investment program in clean-energy technologies. But he mistakenly assumes that existing technologies and strategies can't make a big dent in carbon emissions at an affordable price. We're developing hybrid and electric cars, building wind farms and ocean wave energy stations. New batteries, fuel cells and solar panels are smaller, better and cheaper than they were just a few years ago. I am in awe of the new technologies that I see being developed at Georgia Tech, and such research is happening at the nation's major research universities and in the private sector.

As scientists continue to challenge and improve the quality and understanding of climate records and models, skepticism by scientists conducting such research is alive and well. But oversimplifying the situation, using misleading information and presenting false choices is not useful in the public debate over global warming.

Lomborg seems to have missed it, but a sensible debate has begun on how to best respond to global warming -- in national and local governments, universities and the private sector -- in the U.S. and around the world. There is no easy solution to this problem; the challenge is how best to develop options that are feasible, efficient, viable and scalable. Lomborg is correct to be concerned about the possibility of bad policy choices. But I have yet to see any option that is worse than ignoring the risk of global warming and doing nothing.

Judith Curry is chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.

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