If we were to burn all of the planet's fossil fuel reserves, we would be kissing Antarctica goodbye.
A new study has revealed that the planet's remaining fossil fuel resources would be sufficient to melt nearly all of Antarctica if burned, leading to a 50- or 60-meter (160 to 200 foot) rise in sea level.
Because so many major cities are at or near sea level, this would put many highly populated areas where more than a billion people live under water, including Kolkata.
Carnegie's Ken Caldeira said "the findings show that if we do not want to melt Antarctica, we can't keep taking fossil fuel carbon out of the ground and just dumping it into the atmosphere as CO2 like we've been doing."
Caldeira added that the study demonstrates that burning coal, oil, and gas also risks loss of the much larger East Antarctic Ice Sheet.
Although Antarctica has already begun to lose ice, a complex array of factors will determine the ice sheet's future, including greenhouse gas-caused atmospheric warming, additional oceanic warming perpetuated by the atmospheric warming, and the possible counteracting effects of additional snowfall.
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Explaining all the contributing factors for which the team's models had to account, lead author Ricarda Winkelmann said that it is much easier to predict that an ice cube in a warming room is going to melt eventually than it is to say precisely how quickly it will vanish.
Co-author Anders Levermann said that the West Antarctic ice sheet may already have tipped into a state of unstoppable ice loss, whether as a result of human activity or not, but if "we want to pass on cities like Tokyo, Hong Kong, Shanghai, Calcutta, Hamburg and New York as our future heritage, we need to avoid a tipping in East Antarctica."
The team found that if global warming did not exceed the 2 degree Celsius target often cited by climate policymakers, Antarctic melting would cause sea levels to rise only a few meters and remain manageable.
But greater warming could reshape the East and West ice sheets irreparably, with every additional tenth of a degree increasing the risk of total and irreversible Antarctic ice loss.
The study is published in Science Advances.