This is the end of the world news, brought to you by the Intergovernmental Panel on Climate Change: catastrophic climate change is now inevitable. If all fossil-fuel emissions ceased tomorrow, temperatures would still rise by at least 2°C this century, the ‘maximum safe upper limit’ adopted at the Copenhagen summit in 2009. Two degrees of anthropogenic warming would be disastrous enough: we would see hundreds of millions of ‘climate refugees’, low-lying countries inundated, unprecedented heat waves, massive crop failures. The IPCC isn’t (yet) allowed to use words like ‘catastrophic’ in its executive summaries, but the consensus among the hundreds of climate scientists who compiled its latest reports is that if we carry on burning fossil fuels at the current rate, temperatures will increase by at least 4°C, perhaps as soon as 2060. 

Despite the best efforts of the environmentalists (notably Bill McKibben, who has inspired a global survival movement), climate change still ranks very low in surveys of voters’ concerns in North America, the UK and Australia. If you happen to live in Alice Springs, four degrees of warming sounds pretty grim,