Overselling the benefits of methane and black carbon mitigation threatens long-term climate protection

In recent years the idea that aggressive near-term action to mitigate short-lived climate forcing agents such as methane and black carbon is a necessary and desirable part of climate protection policy has gained considerable currency. This notion has been promoted by the United Nations Environment Program, and has spawned an advocacy organization, the Climate and Clean Air Coalition. In this talk, I will show why this notion is fundamentally misguided, and is likely to have serious adverse consequences for the Earth's future climate if put into practice. In a world of limited resources, incentives to control short-lived forcing agents almost inevitably will detract from mitigation of carbon dioxide; the resulting diversion of effort buys a trivial reduction in near-term warming at the expense of considerably greater CO2-induced warming a few decades later, which will persist for millennia. The short time horizon used in most analyses of short-term forcing mitigation strategies conceals this simple truth. So far as climate protection is concerned, far better results can be obtained by ignoring short term forcing agents for a century or so, and bringing them under control only after reductions in CO2 emisions are well underway. I will also discuss the fundamental flaws in Global Warming Potentials as metrics for comparing the climate impacts of short-lived greenhouse gases with those of CO2.




15:15 Uhr


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Raymond T. Pierrehumbert, The University of Chicago, Department of Geophysical Sciences


Jochem Marotzke

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