Both economic and environmental problems are increasingly global, and so have to be solved globally. The United Nations is crucial to this. Over its three and a half decades of life, UNEP has been at the heart of forming an array of international environmental laws, enabling governments to cooperate across a wide range of issues, from saving the ozone layer to controlling trade in hazardous wastes, from the deserts to the seas. But the greatest test of all – bringing global warming under control – has yet to be met, and this year will be crucial in deciding whether it is.