By Janet Raloff

Web edition: December 18, 2009

COPENHAGEN One major schism between negotiating blocs at the United Nations climate change meeting is over which nations should face a mandate to reduce their greenhouse-gas emissions. Just the industrial powers that have historically spewed most of the carbon dioxide responsible for today’s climate troubles? Or that group and the newly emerging industrial leaders – especially China, who for several years has reigned as the world’s greenhouse-gas king? The deadline for resolving this dilemma is ostensibly quite imminent. As in today.

During the development of the Kyoto Protocol, the current climate treaty, developing countries such as China and India got a bye. The idea was that since they weren’t responsible for most of the emissions-related pollution that had triggered climate instability, they shouldn’t have to pay economically for addressing current mitigation efforts.

But that was a dozen years ago, when China was not the global industrial and economic powerhouse it is today. And India is now following close on its heels. These may still be developing countries, but perhaps only for a short while longer. They’re really nations in transition to becoming global industrial – and pollution – leaders. Toward that end, many Western industrial countries feel it only smart climatologically to ask such transitional economies to also shoulder some responsibility for reining in their increasingly copious greenhouse-gas emissions.

Both China and India have volunteered to do so. But not as aggressively as many Western powers would like to see. Moreover, noted Jo Leinen, chairman of the European Parliament's delegation to the climate-change meeting, yesterday, the robust industrial prowess of some of these transitional nations warrants their being asked to assume binding limits on emissions – not just voluntary ones, which at a minimum would not be enforceable.

How much of a commitment to ask from such transitional economies threatens to prove yet another stumbling block to completing the draft of a successor treaty to the Kyoto Protocol, many of whose provisions are due to expire in 2012. And the deadline for the draft of the successor treaty? Today, while world leaders are in town to sign off on it – from Barack Obama and China’s Premier Wen Jiabao (a geologist and engineer by training) to little Tuvalu’s Prime Minister Apisai Ielemia.

See also: Climate: China defends its reputation