“The chemistry of this is more than a century old… The basic physics of carbon dioxide and other greenhouse gases has been known for a very long time. In fact some back-of-the-envelope calculations were made then which more or less stand the test of time a century later.” A few weeks back I met Mark Lynas in Oxford to talk about his book, Six Degrees: Our Future on a Hotter Planet, shortly before the book won this year’s Royal Society Science Book Prize. The book looks degree by degree at the consequences for the Earth, its biodiversity and its inhabitants, as average global temperatures continue to rise throughout this century. The book is alarming without being alarmist, sobering without being defeatist. As the Royal Society recognized, the book represents a magnificent achievement on Mark’s part, who sifted through a huge amount of scientific data in order to construct such readable and readily comprehensible scenarios. Average rises in global temperature of up to two degrees have serious consequences; above that, the consequences range from the dramatic …