But soon after, some leaders began back-peddling on the goals. A Russian official said the 80 percent goal was unachievable for Russia. And Canada's Environment Minister Jim Prentice said the goal was aspirational and fit Canada's target of cutting emissions by 60 percent to 70 percent below 2006 levels by 2050, according to Reuters.
"This hasn't given me a huge rush of adrenalin," said Yvo de Boer, the United Nations' top climate change official, of the outcome of the G-8 summit, Reuters reported.
"Generally this is careful but useful step forward towards Copenhagen," he said of the U.N. climate pact to be agreed upon in mid-December. "I'm still confident that the deal can be done."
U.N. Secretary-General Ban Ki Moon said progress on climate change at the G-8 was "not enough" so far, reported the Associated Press. "This is politically and morally (an) imperative and historic responsibility ... for the future of humanity, even for the future of the planet Earth."
The G-8 nations of Britain, Canada, France, Germany, Italy, Japan, Russia and the United States also failed to persuade China and India and other developing nations to sign up for the goal of reducing by half global emissions by 2050. The G-8 leaders also stopped short of calling on developing countries to set specific targets.
The nations did acknowledge, however, that temperature rises should be limited to 2 Celsius (3.6 Fahrenheit), which would force deep cuts in greenhouse gas emissions.
"This is an important step," said German Chancellor Angela Merkel of the 2 Celsius goal, adding that "We still have a lot to do."
President Barack Obama, speaking at the conclusion of the G-8 summit in L'Aquila, Italy, said the global recession makes it harder to strike an international climate agreement but that leaders must "fight the temptation toward cynicism" and press forward, according to the AP.
The debate over global warming dominated the opening of the summit meeting, but the G-8 leaders also discussed the global economic downturn, Middle East peace, the war in Afghanistan and development in Africa, according to media reports.