All things must pass. That includes life on Earth, which will surely be wiped out eventually. But how long does it have?
The fossil record tells us that life on Earth has lasted at least 3.5 billion years. In that time it has survived being frozen, clobbered by rocks from space, mass poisoning, and even lethal radiation. Clearly, it’s hard to completely sterilise the planet.
But there’s no shortage of potential apocalypses. Which of them will finally render the Earth barren?
Probably the nearest life has come to ultimate destruction was 250 million years ago, during the end-Permian mass extinction. The event obliterated perhaps 85% of all species living on land – and 95% of all ocean-dwelling species. Back then, Siberia experienced such a large and sustained period of activity that lava smothered an area eight times the size of the UK. Volcanic activity on that scale is rare, but not unheard of.