Paris climate talks: the real test is whether countries will keep their word | Lenore Taylor

The emissions pledges are in and the world's leaders are in town - but there is a risk that progress will be smothered by old sticking points

At the Copenhagen climate summit in 2009 world leaders arrived at the end and could not save it from failure. In Paris, 150 leaders came at the beginning and were confident of success.

That is partly because the negotiators have reset what qualifies as a success - and not just to allow the leaders to pat themselves on the back. They decided that, counter-intuitively, they might achieve more by demanding less. But the new plan comes with a risk.