DON’T read this if you’re a worrier. This year we discovered that life on Earth is more precarious than we thought, and not just because we’re doing a good job of destroying the environment and devising fresh ways to kill en masse (see “Despite all the talk, real change is as elusive as ever” and “Bioterror takes centre stage”).
While astronomers downgraded their estimate of how often to expect a city-levelling asteroid strike – from once every 250 years to once a millennium – geologists claimed this was a mistake. Their evidence, which includes car-sized rocks tossed over 40-metre…
