News Center

Elsewhere Online twitter Facebook SLS Blogs YouTube SLS Channel Linked In SLSNavigator SLS on Flickr

Is A Popular Carbon-Offset Method Just A Lot Of Hot Air?

Publication Date: 
June 01, 2009
Scientific American
Madhusree Mukerjee

Professor Michael Wara is quoted in the Scientific American in a story discussing the effectiveness of carbon off-sets:

A convenient way of cutting industrial gases that warm the planet was supposed to be the United Nation’s clean development mechanism (CDM). As a provision of the Kyoto Protocol, the CDM enables industrial nations to reduce their greenhouse gas emissions in part by purchasing “carbon offsets” from poorer countries, where green projects are more affordable.


Many CDM projects, however, do not appear to be offsetting carbon output at all. The Berkeley, Calif.–based organization International Rivers discovered that a third of the CDM’s hydropower projects had been completed before they were accredited. Lambert Schneider of Germany’s Institute for Applied Ecology judged two fifths of the world’s CDM portfolio to be of similarly questionable additionality. Climatologist Michael Wara of Stanford University guesses the figure could be much higher, but, he says, “we have no way of knowing.”


Some observers think the CDM is too far gone to salvage. No amount of tinkering will repair such a “fundamental design flaw” as additionality, Wara contends. Last November the U.S. Government Accountability Office warned that carbon offsets “may not be a reliable long-term approach to climate change mitigation.” In January the European Commission determined that the CDM should be phased out for at least the more advanced developing countries, which would instead be pressured to accept binding commitments to limit emissions. Another proposal would replace the CDM with a fund for developing countries to build green projects without generating credits—thereby eliminating the entire concept of additionality.