G8 nations, papering over deep differences, said on Tuesday they would work toward a target of at least halving global greenhouse gas emissions by 2050 but emphasised they would not be able to do it alone.
In a communique released during a summit in northern Japan, the Group of Eight leaders also agreed that they would need to set interim goals on the way to a "shared vision" for 2050 although they gave no numerical targets.
Mention of mid-term goals was an advance from last year when the G8 agreed at Heiligendamnn, Germany, only to "seriously consider" a goal of halving emissions by mid-century.
But calling on countries involved in U.N. negotiations on climate change to also "consider and adopt" the 2050 goal satisfies the United States, which has said it cannot agree to binding targets unless big polluters such as China and India rein in their emissions too.
Dan Price, assistant to U.S. President George W. Bush for international economic affairs, said the statement reflected that "the G8 alone cannot effectively address climate change, cannot effectively achieve this goal, but that contributions from all major economies are required".
Critics outside the rich nations' club slammed the deal, although many had already predicted that chances for bold steps were slim until a new U.S. president takes office next January.
"The G8 are responsible for 62 percent of the carbon dioxide accumulated in the Earth's atmosphere, which makes them the main culprit of climate change and the biggest part of the problem," environmental group WWF said in a statement.
"WWF finds it pathetic that they still duck their historic responsibility."
DEVELOPING NATIONS WANT MORE
Five big emerging economies including China, India and South Africa also panned the G8 and called on rich nations to slash their greenhouse gas emissions by 80-95 percent below 1990 levels by 2050, and make cuts of 25-40 percent by 2020.
South African Environment Minister Marthinus van Schalkwyk said he feared this year's communique was a step backward.
"While the statement may appear as a movement forward, we are concerned that it may, in effect, be a regression from what is required to make a meaningful contribution to meeting the challenges of climate change," van Schalkwyk said.
The Group of Five, which also includes Brazil and Mexico, met in the northern city of Sapporo before joining talks with the G8 on Wednesday.
The European Union and Japan had been pressing for this year's summit to go beyond just "considering" the 2050 goal, and Brussels had wanted clear interim targets as well.
Prime Minister Gordon Brown praised the agreement.
