Bjorn LomborgBjorn LomborgBjorn Lomborg, the Danish climate skeptic, is back in the news. The headlines say he has changed his position on global warming. According to the Guardian, a leading British newspaper, Lomborg is now calling for an annual investment of $100 billion to “resolve the climate change problem by the end of the century,” in an alleged “U-turn that will give a huge boost to the embattled environmental lobby.”

But the Guardian, and other news outlets worldwide, should not have been so easily misled by this latest salvo in the climate debate. Lomborg now wants to have it both ways, calling climate change real, but not really urgent. In his forthcoming book, the source of his supposed reversal, Lomborg does say that “it is vital to emphasize the consensus on the most important scientific questions” about global warming, and “we have long moved on from any mainstream disagreements about the science of climate change.”

But Lomborg also writes that “drastic carbon cuts would be the poorest way to respond to global warming,” and claims that policy makers have become unwisely “fixated on cutting carbon in the near term as the chief response to global warming.” Arguing against cuts in carbon dioxide emissions, Lomborg’s position for more than a decade, is the opposite of what climate scientists have been urging the world to do in response to climate change.

It’s nice to see that a much-quoted skeptic has given up his attempts to rebut all of modern climate science. But that just means that his core position — don’t cut emissions — now rests on economic errors alone. Lomborg opposes steep CO2 cuts that would keep average global warming below 2 degrees C (3.6 F), a target recommended by many scientists, because, as he writes in the new book, “it would reduce annual world GDP by a staggering amount,” around “$40 trillion in 2100,” which “would be about fifty times [the cost] of the avoided climate damage.”

Both costs and benefits at the end of this century are, of course, unknown at this time. Our best guesses about future economic impacts depend on our assumptions about how the economy will evolve over decades to come. Lomborg assumes that the damages from unchecked climate change would be trivially small, while assuming costs of emission reduction drastically higher than most economists studying the problem.

On the damage side, Lomborg projects that the climate-related losses we could avoid by reducing emissions would be only a fraction of 1 percent of world GDP by 2100. This is completely out of scale with the warnings of serious disruption of our way of life that are emerging from climate science. The Stern Review, a comprehensive analysis in 2006, projected that uncontrolled climate change could causes losses of 5 to 20 percent of world GDP, and the outlook has only grown more ominous since then.

On the cost side, serious long-range economic modeling has often projected the need to spend 1 to 3 percent of world output to stabilize the climate. A few economists have projected much higher costs. Why the big difference?

Over the long run, the cost of protecting the earth’s climate is the cost of creating new technologies and industries that run on renewable energy and avoid carbon emissions. The costs in question include the costs of commercializing solar energy, developing vehicles that run without petroleum, and deploying these industries around the world. That will take real money — but it will also create real jobs, making things that we desperately need.

The question of the long-run costs of controlling climate change comes down to our ability to launch new low-carbon industries. If you assume failure, then the only way to control emissions is to turn off the lights; that’s the implicit assumption in the economic models that Lomborg relies on. If you assume success, then our investment in research, development, and retooling will lead to new ways to keep the lights on, simultaneously creating jobs and protecting the earth.

Suppose that it does cost 1 to 3 percent of GDP to solve the climate problem, as many economic models suggest. Can we afford to give up that much current spending, for the sake of long-run goals? We already do. In both the United States and China, the top two emitters of greenhouse gases, military spending is more than 4 percent of GDP. Many other leading economies spend 2 to 3 percent of GDP on the military. If we can back away from the arms races and the imaginary threats (remember Iraq’s weapons of mass destruction?) that drive our military expenditures, we can spend the money that’s needed to protect against the real threat to our long-run security.