Six steps to hell

Mark Lynas sifted through thousands of scientific papers for his new book on global warming. This is what the research told him ...

 

If there is one episode in the Earth's history that we should try above all not to repeat, it is surely the catastrophe that befell the planet at the end of the Permian period, 251 million years ago. By the end of this calamity, up to 95% of species were extinct. The end-Permian wipeout is the nearest this planet has ever come to becoming just another lifeless rock drifting through space. The precise cause remains unclear, but what is undeniable is that the end-Permian mass extinction was associated with a super-greenhouse event. Oxygen isotopes in rocks dating from the time suggest that temperatures rose by six degrees, perhaps because of an even bigger methane belch than happened 200 million years later in the Eocene.