When president Barack Obama arrived in Copenhagen for the Summit of chiefs of government, Congress was still discussing a comprehensive climate and energy bill. Expectations were set too high for COP15. Most delegates and environmentalists hoped that Obama would lead the way towards a global climate agreement. EPA administrator Lisa Jackson explained on a side event her agency would soon start regulating carbon emissions.

The Copenhagen Accord fell short of expectations, but Obama’s last minute deal with the leaders of the emerging powers was pivotal to its approval. The Cancun Agreements would not be possible without the groundwork done in Copenhagen. One of its major achievements was to make core elements of the Copenhagen Accord official. The most important were