Climate change is gathering pace — and so is the global drive to fight it. This week the World Meteorological Organisation said human alteration of the atmosphere had passed an unwelcome milestone as levels of carbon dioxide, the greenhouse gas most responsible for warming the world, exceeded 400 parts per million; that is 40 per cent above the pre-industrial figure and the highest for several million years. More tangibly, 2016 is turning into the hottest year on record, with a global temperature at least 1C above the long-term average.