This year, the world will spend $US162 billion ($230bn) subsidising renewable energy, propping up inefficient industries and supporting middle-class homeowners to erect solar panels, according to the International Energy Agency. In addition, the Paris Agreement on climate change will cost the world from $US1 trillion to $US2 trillion a year by 2030. Astonishingly, neither of these hugely expensive policies will have any measurable impact on temperatures by the end of the century. Climate campaigners want to convince us that not only should we maintain these staggering costs, but that we...