U.N. climate treaty seeks ways to entice U.S

By Alister Doyle, Environment Correspondent - Analysis

BONN, Germany (Reuters) - Hoping to encourage the next U.S. president to sign up, negotiators of a new U.N. climate treaty might simply wipe the slate clean for judging greenhouse gas emission curbs.

Some want to reset the benchmark for rating performance by developed nations to current levels from the 1990 base year of the U.N.'s Kyoto Protocol, despite criticisms this would water down curbs in a new global pact due to be agreed in late 2009.

The 1990 benchmark is a hard standard for the United States, Canada or Japan as their emissions have risen in the past 18 years, but easy for former Soviet bloc nations where emissions have plunged after the 1990s industrial collapse.

"If you stick to a 1990 baseline the gap becomes too large to be sold as fair to all," Elliot Diringer, a director of the Pew Center on Global Climate Change, a think-tank in Washington, said on the sidelines of June 2-13 climate talks in Bonn.

He said there was a growing awareness at the 170-nation talks of a need to start over with a clean slate.

Japan, for instance, favors shifting the goalposts and indicated on Monday that it could make deep cuts of 14 percent by 2020 from 2005 levels. But under Kyoto's current rules that would only be about a puny 4 percent cut below 1990.

Diringer said that resetting the clock would make it easier for the next U.S. president, likely to be either Democrat Barack Obama or Republican John McCain, to sign up for a new U.N. treaty after President George W. Bush snubbed Kyoto.

U.S. emissions are about 14 percent above 1990 levels.