Penser plus intelligemment le changement climatique

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Des réductions drastiques d'émissions feront plus de mal que de bien au combat contre le changement climatique, soutient Bjørn Lomborg, auteur de l'"Ecologiste sceptique" et de 'Cool it", directeur du Centre du consensus de Copenhague et professeur à la Business School de Copenhague.

La contribution suivante a été rédigée par Bjørn Lomborg,auteur de l'"Ecologiste sceptique" et de 'Cool it", directeur du Centre du consensus de Copenhague et professeur à la Business School de Copenhague.


"Politicians and commentators are understandably pessimistic about the chances of an international deal on carbon cuts emerging from the United Nations summit in Mexico this December. Nothing has been resolved since the Copenhagen climate talks fell apart last year.

Fortunately, recent research points to a smarter way to tackle climate change. There is no longer any mainstream disagreement about the reality of global warming. The crucial questions concern the economics of our response. But this debate can be just as heated.

Ever since I published The Skeptical Environmentalist in 2001, I have always acknowledged that man-made global warming is real. Yet activists have repeatedly labelled me a 'climate-change denier'. This is not because I have ever suggested that the basic science of global warming is wrong. Rather, it reflects anger and frustration over my insistence on pointing out that drastic carbon cuts make no sense.

The Copenhagen Consensus Centre – a think-tank where I serve as director – recently asked a large group of top climate economists to explore the costs and benefits of different responses to global warming.

At the same time, we convened a second, equally stellar group of economists, including three Nobel laureates, to examine all of the research and rank the proposals in order of desirability. Cambridge University Press is publishing their research and findings this month, under the title Smart Solutions to Climate Change.

The book includes a chapter by prominent climate economist Richard Tol, who has been a contributing, lead, principal and convening author for the United Nations' Intergovernmental Panel on Climate Change. In his chapter, Tol shows why grand promises of drastic, immediate carbon cuts are such a flawed strategy.

Tol found that trying to keep temperature increases under 2°C, as the G-8 industrialised nations have promised to do, would require emissions reductions of about 80% by mid-century. Based on conventional estimates, this would avoid total climate damages of about $1.1 trillion across the century. However, it would cut economic growth by around $40 trillion a year. In other words, we would effectively be spending $40 trillion every year by the end of the century to do just over $1 trillion worth of total good.

In fact, this estimate is wildly optimistic. The calculation assumes that over 100 years, politicians everywhere in the world will consistently enact the most efficient, effective laws imaginable to reduce carbon emissions. Dump that far-fetched assumption and the cost could jump by a factor of ten or even 100."

To read the op-ed in full, please click here.

(Published in partnership with Project Syndicate.)

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