President Barack Obama on Wednesday pledged that the United States "will do more" to tackle the threat of climate change and said the world must do likewise before it is too late.
"Our generation must move towards a global compact to confront a changing climate before it is too late, that is our job, that is our task," Obama said in a speech in Berlin.
Speaking on a blistering hot day at Brandenburg Gate, Obama said that "peace with justice means refusing to condemn our children to a harsher, less hospitable planet".
He said Germany, which is fast building up solar, wind and other renewable energies, and Europe, had led in efforts to battle a warming planet, melting ice caps and rising seas.
He said the United States had also doubled renewable energies, boosted fuel efficiency in cars and brought down carbon emissions, but added: "We know we have to do more and we will do more."
With a view to developing giants such as China and India, he added: "With a global middle class consuming more energy every day, this must now be an effort of all nations, not just some.
"For the grim alternative affects all nations. More severe storms, more famine and floods, new waves of refugees, coastlines that vanish, oceans that rise."