I am hugely grateful to all those readers who responded to my suggestion that they ask their MPs how, in practice, we can cut our “carbon” emissions by 80 per cent in less than 40 years, without closing down almost all of our fossil-fuel dependent economy. This quixotic quest is pursued in the name of saving the planet from global warming, though the UK’s contribution to global man-made CO2 emissions is only 1.6 per cent. China’s emissions increase every year by more than this amount. Many readers pointed out in their letters that the target cannot be met by building more windmills: these currently supply barely 3 per cent of our electricity, and more than once last week they were providing only 0.5 per cent.