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Record Heat Threatens Greenland's Ice Sheet

A majority of Greenland's ice sheet is experiencing above-freezing temperatures this week, which could cause record melting and raise global sea levels.
The terminus of Kangerlugssuup Sermerssua glacier in west Greenland.

The terminus of Kangerlugssuup Sermerssua glacier in west Greenland.

Last week's record-breaking heat wave in Europe has shifted north to the Arctic. Now, a "heat dome" is threatening the second-largest ice sheet on the planet. Meteorologist Eric Holthaus said on Twitter that the heat over Greenland this week could result in the loss of 40 billion tons of ice, enough to measurably raise global sea levels.

"We are in a climate emergency," Holthaus tweeted on Monday. Another climate researcher, Xavier Fettweis, said this week's potential melt is what worst-case scenario climate models have projected for 2050, reaffirming what many scientists are finding: that we're closer to the catastrophic predictions for climate change than previously thought.

Greenland's 2.4 million-year-old ice sheet covers most of the island and would raise global sea levels by 23 feet if it melted away entirely, submerging cities like Boston, Sacramento, and Miami—and that's just in the United States.

This week's Arctic heat wave will likely result in the second-largest melting of the ice sheet since 1950 (when record-keeping began). The ice sheet had its worst melt year just seven years ago, in 2012. Clare Nullis, a spokeswoman for the United Nations World Meteorological Organization, said in a briefing on Friday that it was still unclear whether this week's events would break the 2012 record level of melt. "But it's close," Nullis said, according to Reuters.

Whether or not this week's heat wave breaks any records for the ice sheet, it's already been an unusual summer for melt. Ruth Mottram, a climate scientist with the Danish Meteorological Institute, told CNN that 2019's melt started earlier than expected, in May, and is different from what occurred in 2012 because it has been a persistent melt throughout the summer, rather than occurring in quick bursts.

A study earlier this year found that Greenland's ice sheet is currently melting six times faster than it was in the 1980s, and a press release from NASA last month stated that, unless global emissions change, the ice sheet is expected to melt completely in the next 1,000 years. The same NASA research shows that, at the current melt rate, the ice sheet will contribute nearly six feet to global sea-level rise in the next 200 years.

According to Mottram, Greenland's ice loss has added 180 billion tons of water to global sea-level rise since July 1st, which amounts to about half a millimeter.

"That is quite a lot higher than usual," she told CNN. She said the expected average would be roughly a third of that at this time of year. What's become increasingly clear is that, when it comes to arctic ice melt, the days of average are gone.