By David Fogarty and David Ljunggren
Climate change has been the most contentious topic at this year's Group of Eight summit in Japan, which the heads of big emerging economies such as China, India and Brazil were invited to join on the third and final day.
The statement by leaders of 16 countries, including top emitters China and the United States, came a day after the G8 rich nations endorsed a target of halving global emissions by 2050 while stressing they could not achieve that goal alone.
Tuesday's G8 statement papered over deep gaps, with the United States opposed to committing to firm targets without assurances big emerging economies will act too.
Developing countries, along with the European Union and green groups, say rich countries must take the lead and specify interim targets for how to reach the mid-century goal, which scientists say is the minimum needed to prevent dangerous global warming.
European Commission President Jose Manuel Barroso said Wednesday's meeting had been constructive.
"We have to get real," Barroso said in a statement.
"It is quite wrong to see this in terms of a confrontation between developed and developing countries. Of course we accept the lion's share of responsibility but this is a global challenge, which requires a global response."
But environmentalists immediately blasted the agreement, which represented no changes from an earlier draft agreed on in late June by negotiators from the same countries in Seoul.
"It's the stalemate we've had for a while," Kim Carstensen, director of the WWF's global climate initiative, told Reuters.
"Given the lack of willingness to move forward, particularly by the U.S., it hasn't been possible to break that."
Climate experts are sceptical that any significant advance on steps to combat global warming can be made until a new U.S. president comes to office in January 2009.
MID-TERM GOALS, BUT NO TARGET
On Wednesday, the 16 countries' leaders agreed major developed economies would set mid-term goals, but set out no specific numbers. The group also said poorer countries would act to rein in rapid growth in their emissions.
The stance of emerging nations is important. The G8 nations emit about 40 percent of mankind's greenhouse gas emissions. China and India together emit about 25 percent of the total, a proportion that is rising as their coal-fueled economies boom.
A Japanese government official told reporters that only Indonesia, Australia and South Korea had supported the G8 call to share their vision of halving global emissions by 2050. The others arguing that advanced countries that are responsible for the bulk of historical emissions must act first.
"China is a developing country and is in the process of industrialization and modernization," China's state Xinhua news agency quoted President Hu Jintao as saying.
"People's living standards are still not high, and China's core task at present is developing its economy and improving people's welfare."
The G8 summit on the northern Japanese island of Hokkaido brings together the leaders of Japan, Britain, Canada, Germany, France, Italy, Russia and the United States.
Climate change was not the only bone of contention at Wednesday's talks. Emerging nations are suffering more than rich countries from soaring fuel and food prices and have bristled at the suggestion that their rising demand is to blame.
"The emphasis was that rising food prices was hurting the poor and that it was important to increase food production to deal with this," a Japanese official said after a meeting of five big emerging nations with G8 leaders.
"There was concern about rising oil prices and many emerging countries stressed the factor of speculative trade."
(Additional reporting by Chisa Fujioka and William Schomberg; Writing by Linda Sieg; Editing by Sonya Hepinstall)