An international panel on climate change said if global temperatures rise by more than 2 degrees Celsius, it could lead to serious environmental consequences. Rising sea levels brought on by temperature increases of more than a few degrees could mean disaster for some island nations.
Todd Stern, the U.S. special envoy for Climate Change, said during a news briefing from Durban, South Africa, that the 2-degree limit was a good suggestion.
"I think that we look at 2 degrees as an important and serious goal which ought to guide what we do, which ought to guide the action that we take in order to try and attain it," he said. "It's important, it's serious, and it's a guidepost I would say."
He went on to say that was different, however, than viewing it as some sort of "operational cap" that would be used for mandatory obligations regarding the environment.
"We don't see it as akin to a national target," he said.
Participants at Durban are reviewing parts of the greenhouse gas-limiting Kyoto Protocol, parts of which expire next year.
The United States in 2001 abandoned Kyoto and major economies like Japan, Russia and Canada said they might not accept new mandated emission targets.
European delegates said they wanted to extend parts of Kyoto but not without commitments from major emitters like the United States and China.