Earth is overdue a mass extinction by 30m years

DOOMSDAY scenarios are usually the subject of Hollywood blockbusters.

But experts believe they are more scientific fact than science fiction – with Earth overdue a mass extinction event for more than 30million years.

They have worked out that catastrophic global incidents come roughly every 27million years.

And with the last mass extinction 66million years ago – when dinosaurs were wiped out by an asteroid or comet – they reckon Earth could be on borrowed time.

Catastrophic events such as meteor strikes and eruptions can follow a cycle.

With new statistical analysis, US researchers concluded extinction comet showers occur every 26 to 30million years when they pass through the galaxy.

If they hit Earth, the cataclysmic impacts could create widespread dark and cold, wildfires, acid rain and ozone depletion.

These would potentially kill off land and marine life.

The scientists also found all eight of the coinciding mass extinctions on land and in the oceans matched times of flood-basalt eruptions – where an enormous amount of lava flows on to the Earth’s surface. This would create lethal greenhouse heating and less oxygen in the ocean.

Any threat is down to how our planet orbits the Milky Way, they say. The study’s author, Professor Michael Rampino from New York University’s Department of Biology, said: ‘It seems that large-body impacts and the pulses of internal Earth activity that create flood-basalt volcanism may be marching to the same 27million-year drumbeat as the extinctions, perhaps paced by our orbit in the galaxy.

‘These new findings of coinciding, sudden mass extinctions on land and in the oceans, and of the common 26 to 27million-year cycle, lend credence to the idea of periodic global catastrophic events as the triggers for extinctions.

‘In fact, three of the mass annihilations of species on land and in the sea are already known to have occurred at the same times as the three largest impacts of the last 250million years, each capable of causing a global disaster and resulting mass extinctions.

‘The global mass extinctions were apparently caused by the largest cataclysmic impacts and massive volcanism, perhaps sometimes working in concert.’

The findings are published in the journal Historical Biology.

‘Annihilation of species’