Two analyses of the Copenhagen Accord and its pledges, by Dr Sivan Kartha of the Stockholm Environment Institute, and by the Climate Action Tracker website, suggest that, with the cuts that are currently promised under Copenhagen, the world will still warm by 3.5C by 2100. Such a rise would be likely to have disastrous effects on agricultural production, water availability, natural ecosystems and sea-level rise across the world, producing tens of millions of refugees.

A month ago, in its annual State of the Climate report, published in conjunction with the UK Met Office’s Hadley Centre, America’s National Oceanic and Atmospheric Administration (NOAA) listed 10 separate indicators of a warming planet, seven of them rising – ranging from air temperature over land and humidity to sea level – and three of them declining: Arctic sea-ice, glaciers, and spring snow cover. “The scientific evidence that our world is warming is unmistakable,” NOAA said.