"We have a moral obligation towards future generations," said Prime Minister of Denmark Lars Lokke Rasmussen.
UK Prime Minister Gordon Brown described the stake in apocalyptic terms Thursday.
"Without common action, extreme temperatures will create a new generation of poor with climate change refugees driven from their homes by drought, climate change evacuees fleeing the threat of drowning, the climate change hungry desperate for lack of food," Brown said. "Hurricanes, floods, typhoons and droughts that were once all regarded as the acts of an invisible god are now revealed to be also the visible acts of man."
ABC News' Karen Travers, Kirit Radia and Viviana Hurtado contributed to this report.