Guardian: Life on Earth is in trouble. That much we know. But how bad have things become and how fast are events moving? How soon, indeed, before the Earths biological treasures are trashed, in what will be the sixth great mass extinction event? This is what Gerardo Caballos of the National Autonomous University of Mexico and his colleagues have assessed, in a paper that came out on Friday.
These are extraordinarily difficult questions. There are many millions of species, many elusive and rare, and inhabiting...