In February 2009, Stern said that the US would take a lead role in the formulation of a new climate change treaty in Copenhagen in December 2009. He made no indication that the U.S. would ratify the Kyoto Protocol in the meantime. US Embassy dispatches subsequently released by whistleblowing site WikiLeaks showed how the US 'used spying, threats and promises of aid' to gain support for the Copenhagen Accord, under which its emissions pledge is the lowest by any leading nation.