Melting polar ice due to global warming poses an existential threat to humanity.

New research on the melting of Antarctic ice sheets has suggested a dramatically faster pace of melting than is currently believed to be occurring — projections which, if they play out at the median level, could submerge land that is today home to nearly four times the combined population of Mumbai, Delhi, Bengaluru and Hyderabad, as per Census 2011.

A “Plain Language Summary” of the research, which employs complex models of projection, says it links “new Antarctic model results into a sea-level rise projection framework to examine their influence on global and regional sea-level rise projections and their associated uncertainties, the potential impact of projected sea-level rise on areas currently occupied by human populations, and the implications of these projections for the ability to constrain future changes from present observations”.

In a summary of the research in the nonprofit online environment magazine Grist, the meteorologist Eric Holthaus wrote the study’s results pointed to two possible roadmaps: “1) a relatively steady but substantial rise in sea levels even if we sharply reduce global emissions, flooding 100 million people’s homes worldwide by the end of the century, and 2) a wild-card world that could jeopardise civilisation itself if fossil fuels continue to dominate”.

As per the study’s projection, “under a high greenhouse gas emission future”, the median global mean sea level could rise from ~80 cm to ~150 cm. “…Without protective measures, by 2100 (rising seas will) submerge land currently home to more than 153 million people.”

The study’s mid-range estimate in the second scenario projects an almost 5-foot rise in sea levels by 2100. This was the worst-case scenario in a similar study by the same authors three years ago. At the high end, the new study estimates there’s a 10% chance that seas will rise more than 8 feet this century, enough to flood nearly every coastal city on Earth.

Melting polar ice due to global warming poses an existential threat to humanity. Enormous chunks of ice have broken off from the Antarctic ice shelf in recent years, and massive swathes of the Arctic have melted, with the meltwater raising sea levels

Source: December 15, 2017, The Indian Express