Doubt that environmental tipping points can change the Earth’s climate in a geologic blink of an eye? Doubt no more.

Using unprecendented fine-scale measurements from a mud core taken from an Irish lake, researchers have found evidence that the Younger Dryas mini-ice age — which started about 12,800 years ago and lasted some 1,300 years — came on within just 12 months or less. The rapid and dramatic cooling essentially shifted Ireland to an Arctic climate in less than a year.

The Younger Dryas, blamed for the dieoff of the ancient North American Clovis culture, was set off when a glacial lake in Northwest Canada burst its banks, flooding the North Atlantic and Arctic oceans with cold fresh water. The sudden influx put the brakes on the Gulf Stream, an ocean current that keeps parts of Europe much warmer than they would otherwise be at their latitudes.

The University of Saskatchewan’s William Patterson and his research team based their findings on carbon isotope measurements taken from thinly sliced layers of the mud core. Each layer — just 0.5 to 1 millimetre in thickness — represented about three months’ worth of sedimentation.

The researchers hope to provide even finer detail in future studies, aided by a robot that can slice through samples at a thickness of just 0.05 micometres. That level of resolution could provide a single day’s worth — or less — of climate data.

“We can get you mid-July temperatures from 400 million years ago,” Patterson told New Scientist this week.

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