It's being called a failure and a betrayal by many developing nations and environmentalists, but Barack Obama, the US president, says it's an unprecedented breakthrough.
At the Copenhagen Summit, President Obama brokered an agreement between China, India, Brazil and South Africa, backed by some European leaders.
But it fails to set specific targets for cuts in greenhouse gas emissions and it isn't legally binding.
Many smaller countries have denounced the agreement, furious that they were excluded from negotiations.
Alan Fisher reports.
Source: Al Jazeera