BBC News reports that key states have reached what they call "a meaningful agreement" at the Copenhagen climate summit. In the press conference, President Obama called the agreement a "historic step forward". But no one, including the leaders involved, believe it's enough to halt global warming.
Obama said the US, China, Brazil, India and South Africa had "agreed to set a mitigation target to limit warming to no more than 2C and, importantly, to take action to meet this objective". Its not at all clear if any other states are party to the deal.
As part of the deal's terms, countries are committed to aim for targets to cut harmful emissions and provide information for international analysis.
With no firm target for limiting the global temperature rise, no commitment to a legal treaty and no target year for peaking emissions, critics immediately condemned the declaration as watered-down and meaningless.
But US officials insist the deal will act as the foundation for a legally binding treaty to be signed in Mexico in 2010.