All international climate change meetings, like all political careers, end in failure.

In a sense, it cannot be otherwise. Climate science has become much more certain in recent years, with a growing consensus that global greenhouse gas emissions must peak by between 2015 and 2020 to avoid the worst effects of warming. Yet such a level of action is next to impossible for governments to agree, especially given the atmosphere of suspicion that prevails between rich and poor nations over the course to pursue.