Barack Obama says climate change will "define the contours" of the next century unless all countries play a role in reducing greenhouse gas emissions.
Speaking at the United Nations climate summit Tuesday afternoon, the U.S. president said his country will meet its Copenhagen commitments and set a new target next year. The U.S. agreed in 2010 to reduce greenhouse gas emissions by 17 per cent from 2005 levels, by 2020.
He said no country can stand on the sidelines on the issue and called for other countries to do more to reduce emissions.
Mr. Obama's speech was highly anticipated at the UN summit, which was convened by UN Secretary General Ban Ki-moon to galvanize political momentum for ongoing climate negotiations. More than 120 heads of government are attending the day-long event, making it one of the best-attended meetings on climate change.
However, several high-profile leaders did not attend the event, including Indian Prime Minister Narendra Modi and Chinese President Xi Jinping. Canadian Prime Minister Stephen Harper and the leaders of Germany and Australia also did not attend.
Mr. Obama said he met with China's vice premier ahead of his talk at the summit and said that as "big countries," both have a special responsibility to lead. He added the U.S. would make climate change a consideration in all future international development projects.
He said he recognizes that his country has contributed to climate change and said he is willing to play a role – as the world's second-biggest emitter of greenhouse gases – in tackling the issue.
Mr. Obama noted that the U.S. has felt the effects of climate change in all regions and said the current generation is probably the last that would be able to address the issue.
World leaders are gathering in New York for a General Assembly that is likely to be dominated by crises such as the spread of Ebola in West Africa and Islamic State extremism.
"There is one issue that will define the contours of this century more dramatically than any other," Mr. Obama said. "That is the urgent and growing threat of a changing climate."