Follow for more talkers

Ice melting in Greenland MUCH faster than scientists feared

It could contribute up to six times more to global sea level rise by the end of the century.

Avatar photo

Published

on
Piece of ice in water
(Greens and Blues via Shutterstock)

By Mark Waghorn via SWNS

Greenland's ice sheet is melting much faster than previously feared, according to new research.

It could contribute up to six times more to global sea level rise by the end of the century than climate models predict.

The study is based on an analysis of the Northeast Greenland Ice Stream (HEGIS) that extends 372 miles into the interior.

It could add a half-inch or more of water to sea levels by the end of this century, which is equivalent to the entire Greenland ice sheet’s contribution during the past 50 years.

An international team combined satellite images and numerical modeling with GPS data collected over the past decade.

In 2012, the intrusion of warm ocean currents caused the floating extension of the NEGIS to collapse.

It has accelerated ice flow and triggered a wave of rapid ice thinning that has spread upstream.

The researchers found this thinning stretches inland from the Greenland coast as far as 124 to 186 miles. Other glaciers on Greenland may be suffering the same fate.

(MATLAB R2021a via Nature)

Co-author Professor Mathieu Morlighem, of Dartmouth College in New Hampshire, said: "Many glaciers have been accelerating and thinning near the margin in recent decades.

"GPS data helped us detect how far inland these changes happening near the coast propagate.

"The Greenland ice sheet is not necessarily more unstable than we thought, but it may be more sensitive to changes happening around the coast.

"If this is correct, the contribution of ice dynamics to overall mass loss on Greenland will be larger than what current models suggest."

NEGIS connects the interior of the ice sheet to two marine-terminating glaciers Nioghalvfjerdsfjord Gletscher and Zachariae Isstrom which drain about 12 percent of the Greenland ice sheet.

(MATLAB R2021a via Nature)

Over the past decade, it's been speeding up. But uncertainties over the flow rate have hampered the detection of ice flow acceleration upstream from the glacier terminus.

The study in the journal Nature indicates from 2011 to 2021 NEGIS thinned by up to ten feet. This will continue at an accelerated rate throughout this century.

First author Professor Shfaqat Abbas Khan, of the Technical University of Denmark, said: "We can see the entire basin is thinning and the surface speed is accelerating.

"Every year, the glaciers we've studied have retreated farther inland, and we predict this will continue over the coming decades and centuries.

"Under present-day climate forcing, it is difficult to conceive how this retreat could stop."

Although winter 2021 and summer 2022 were particularly cold, the NEGIS glaciers have kept retreating.

Northeastern Greenland is an Arctic desert where precipitation is less than an inch a year in places.

Frontal position from 2000 to 2021 based on Landsat 5–8 optical satellite imagery. (MATLAB R2021a via Nature)

This means the ice sheet is not regenerating enough to offset melt. However, estimating how much ice is lost and how far into the ice sheet the process occurs is not easy.

The ice sheet's interior moves less than three feet per year. It's difficult to monitor - which limits the ability to make accurate projections.

Khan said: "Models are mainly tuned to observations at the front of the ice sheet, which is easily accessible, and where, visibly, a lot is happening.

"Our data show us what we see happening at the front reaches far back into the heart of the ice sheet."

As more precise observations are included in models, it's likely estimates of global sea-level rise such as the eight to 38 inches by 2100 projected by the UN Intergovernmental Panel on Climate Change will need to be corrected upwards.

Coauthor Professor Eric Rignot, of California University in Irvine, said: "We foresee profound changes in global sea levels, more than currently projected by existing models.

"Data collected in the vast interior of ice sheets, such as those described in our research, help us better represent the physical processes included in numerical models and in turn provide more realistic projections of global sea-level rise."

Stories and infographics by ‘Talker Research’ are available to download & ready to use. Stories and videos by ‘Talker News’ are managed by SWNS. To license content for editorial or commercial use and to see the full scope of SWNS content, please email [email protected] or submit an inquiry via our contact form.

Top Talkers