In polite society, we are required to pretend that the Earth faces an existential crisis because of increasing levels of atmospheric CO2; that global warming will destroy the planet, that the oceans will rise and storms will batter the sea coasts; that fossil fuels are the devil’s spawn, and in a short time–by 2050, say–all civilized societies will have banned their use, and we will be living in a solar- and wind-powered Nirvana.