Greenland’s ice sheet melt may raise the world’s sea level by up to 12.6 cm by 2100
Temperature increases on land and high-pressure weather patterns are producing a big melt of Greenland’s ice sheet, a new study confirms.
By 2100, the melting of the Greenland ice sheet is likely to result in up to 12.6 centimetres (nearly five inches) in global sea level rise, researchers predict.
That’s in line with estimates from previous studies, but Danish Meteorological Institute climatologist Ruth Mottram told Nunatsiaq News that there is a risk that “we underestimate the rate at which the ice sheet will melt.”
Mottram and her fellow researchers looked at almost 30 years of scientific data on the melting of the Greenland ice sheet.
In doing so, they were able to establish a link between the change in the last 30 years’ summer temperatures in Greenland and the ice sheet loss.
During 1991 to 2019 there was “significant overall warming in Greenland” of 4.4 C in winter, 2.7 C in spring, and 1.7 C in summer, generally in areas away from the extreme south, according to their study, published this week in the International Journal of Climatology.
Some climatologists say the melting of the Greenland ice sheet, which could contribute as much as seven metres to global sea level rise, is irreversible. (Image from Polar Portal)
The greatest warming was in west and northwest Greenland, of up to 6.5 C in winter.
The researchers found that for every increase in summer temperatures by 1 C, there was a surface mass loss of ice equivalent to about 91 billion tonnes per year on the ice sheet.
Based on this, they were able calculate how much the melting of Greenland’s inland ice will contribute to the global sea level.
Greenland’s ice sheet alone contains enough water to eventually raise global sea levels by as much as seven metres.
Global temperatures are on a path to increase by another 4 C to 6.6 C by 2100, and that increase will be felt even more in the polar regions, Mottram said.
But for the Greenland ice sheet, and “more or less any Arctic glacier,” it’s not just the absolute temperature, but also the weather pattern that is important, she told Nunatsiaq News.
“When there is a big blocking high pressure over the ice sheet, this can give relatively sunny and stable weather with clear skies,” she said. “If these conditions persist a long time, as they did last year, then a large amount of melting can happen, which led directly to the very high melt record.
“This is a weather pattern that climate models often seem to find … hard to get right, and therefore there is a risk that we underestimate the rate at which the ice sheet will melt.”
The Canadian Arctic is likely to experience warming similarly to Greenland, Mottram said.
“The Arctic is warming pretty rapidly in general, so while you won’t necessarily see the same weather, the climate trends will certainly be the same,” she said.
It’s clear that the glaciers in the Canadian Arctic have already lost a lot of ice in the last few decades, she said.
“And the break-up of the ice shelf on Ellesmere Island is very much part of that pattern,” she said.
https://news.google.com/__i/rss/rd/articles/CBMia2h0dHBzOi8vbnVuYXRzaWFxLmNvbS9zdG9yaWVzL2FydGljbGUvdGVtcGVyYXR1cmUtaW5jcmVhc2VzLWluLWdyZWVubGFuZC1mdWVsaW5nLWljZS1zaGVldHMtbWVsdC1uZXctc3R1ZHkv0gEA?oc=5
2020-08-21 14:30:00Z
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