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That calculation is based on the last time Yellowstone erupted, around 630,000 years ago, which cast a volcanic ash cloud over the globe and led to a massive decrease in temperatures worldwide.
Two separate eruptions 170 years apart each reduced the global temperature by three degrees celsius, according to a new study.
According to the report, which was presented at the Geological Society of American’s annual meeting, a team of geologists from the University of California Santa Barbara (UCSB) analysed two layers of volcanic ash found in seafloor sediments off the coast of California.
These layers have the unique fingerprint of a Yellowstone eruption and also allow scientists to analyse climate records from the time.
UCSB geologist Jim Kennett said: “We discovered here that there are two ash-forming super eruptions 170 years apart, and each cooled the ocean by about three degrees Celsius.”
The researchers say the volcanic winters were caused by ash and sulphur dioxide reducing the amount of sunlight which hit the land and seas of Earth.
Professor Kennett said the eruptions must have happened at a particularly sensitive time for Earth’s climate as the winters lasted longer than they should have done.
He said: “It was a fickle, but fortunate time.
“If these eruptions had happened during another climate state we may not have detected the climatic consequences because the cooling episodes would not have lasted so long.”
If the volcano were to erupt it would kill an estimated 87,000 people immediately and make two-thirds of the United States immediately uninhabitable.
The massive eruption could be a staggering 6,000 times as powerful as the one from Washington’s Mount St Helens in 1980 which killed 57 people and deposited ash in 11 different states and five Canadian provinces.
If the volcano explodes, a climate shift would ensue as the volcano would spew massive amounts of sulphur dioxide into the atmosphere, which can form a sulphur aerosol that reflects and absorbs sunlight.
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