A Mechanism of Hot Air; June 2009; Scientific American Magazine; by Madhusree Mukerjee; 2 Page(s)

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. The scheme, which issued its first credits in 2005, has already transferred the right to emit an extra 250 million tons of carbon dioxide (CO₂), and that could swell to 2.9 billion tons by 2012. Offsets will "play a more significant role" as emissions targets become tighter, asserts Yvo de Boer of the U.N. Framework Convention on Climate Change.

But criticism of the CDM has been mounting. Despite strenuous efforts by regulators, a significant fraction of the offset credits is fictitious "hot air" manufactured by accounting tricks, critics say. As a result, greenhouse gases are being emitted without compensating reductions elsewhere.