A deal among nearly 200 countries to take modest steps to fight global warming could help political efforts to fight emissions in the United States, Washington's top climate envoy said this afternoon.
"None of us knows exactly what the shape of climate activity is going to be next year; there will be important things going on in the executive side and the legislative side," Todd Stern told reporters in a sunrise press conference after the conclusion of the UN deal negotiated in two weeks of talks.
"I think that it's a positive thing to see a worldwide agreement, one that includes all of the major economies," said Stern.
US president Barack Obama helped broker the Copenhagen Accord last year. While the UN talks there failed, both developed and developing countries pledged in the accord to take actions to fight climate change.
The deal in Cancun basically binds those pledges to the UN climate process. The world's top emitter China, for instance, pledged to cut its emissions intensity, or the amount of carbon emitted for every unit of economic output, though developing countries would not be penalized for failing to hit their targets.
Mr Stern said China's willingness to take on an emissions commitment and to do so in a transparent manner could help ease concerns in the United States about what rapidly developing countries are doing to fight climate change.
It will not lead to passage of a US climate bill right away, he said, but "it's a generally helpful development."
The climate deal, reached at Mexico's Cancun beach resort, did not require developed countries to take on binding cuts beyond the Kyoto Protocol, which runs out in 2012.
The United States, the world's top greenhouse gas emitter after China, is the only rich country that never ratified the Kyoto pact.
The United States faces tough odds of meeting its Copenhagen pledge of a 17 per cent cut in emissions from 2005 levels by 2020. A climate bill failed in July, and prospects for passing a measure are even dimmer next year when Republicans take control of the House of Representatives from Democrats.
The US Environmental Protection Agency is taking steps to fight carbon emissions from both tailpipes and smokestacks, but those efforts face legal hurdles. Additional rules on mercury and other pollutants from coal plants are expected to close older, inefficient power plants.