A current slowdown within the melting of Iceland’s glaciers is probably going brought on by a patch of unusually chilly water within the North Atlantic Ocean, in accordance with a brand new research revealed within the AGU journal Geophysical Analysis Letters. Credit score: Finnur Pálsson
Chilly seawater might gradual ice loss on the island till 2050, then warming and melting might speed up.
A area of cooling water within the North Atlantic Ocean close to Iceland, nicknamed the “Blue Blob,” has seemingly slowed the melting of the island’s glaciers since 2011 and will proceed to stymie ice loss till about 2050, in accordance with new analysis.
The origin and explanation for the Blue Blob, which is positioned south of Iceland and Greenland, remains to be being investigated. The chilly patch was most distinguished in the course of the winter of 2014-2015 when the ocean floor temperature was about 1.4 levels Celsius (2.52 levels Fahrenheit) colder than regular.
The brand new research revealed in Geophysical Analysis Letters makes use of local weather fashions and subject observations to indicate that the chilly water patch chilled the air over Iceland sufficiently to gradual ice loss beginning in 2011. The mannequin predicts cooler water will persist within the North Atlantic, sparing Iceland’s glaciers till about 2050. Ocean and air temperatures are predicted to extend between 2050 and 2100, resulting in accelerated melting.
Whereas cooler water within the North Atlantic presents a brief respite for Iceland’s glaciers, the authors estimate that with out steps to mitigate local weather change, the glaciers might lose a 3rd of their present ice quantity by 2100 and be passed by 2300. If the nation’s 3,400 cubic kilometers (about 816 cubic miles) of ice soften, sea degree will rise by 9 millimeters (0.35 inches).
The researchers verified the outcomes of their fashions utilizing depth measurements from Iceland’s glaciers, collected by colleagues on the College of Iceland for the reason that Nineties. Credit score: Finnur Pálsson
“In the long run, the message remains to be clear,” stated lead creator Brice Noël, a local weather modeler who focuses on polar ice sheets and glaciers at Utrecht College. “The Arctic is warming quick. If we want to see glaciers in Iceland, then we have now to curb the warming.”
The paper is revealed within the AGU journal Geophysical Analysis Letters, which publishes high-impact, short-format stories with fast implications spanning all Earth and area sciences. Its findings might assist scientists to raised perceive the oblique results of the ocean on glaciers.
“It’s essential to have an concept of the attainable feedbacks within the Arctic as a result of it’s a area that's altering so quick,” Noël stated. “It’s necessary to know what we are able to anticipate in a future hotter local weather.”
The warming Arctic
Nowhere on Earth has warmed as rapidly because the Arctic. Current research report the world is warming 4 occasions sooner than the worldwide common. Iceland’s glaciers steadily shrank from 1995 to 2010, dropping a median of 11 gigatons of ice per 12 months. Beginning in 2011, nevertheless, the pace of Iceland’s melting slowed, leading to about half as a lot ice loss, or about 5 gigatons yearly. This development was not seen in close by, bigger glaciers throughout Greenland and Svalbard.
Noël and his colleagues investigated the reason for this slowdown by estimating the glaciers’ mass stability — how a lot they grew or melted yearly from 1958 to 2019. They used a high-resolution regional local weather mannequin that works on the small scale of Iceland’s glaciers to estimate how a lot snow the glaciers obtained in winter and the way a lot ice was misplaced from meltwater runoff in summer season. The researchers discovered that cooler waters close to the Blue Blob are linked to observations of decrease air temperatures over Iceland’s glaciers and coincide with the slowdown of glacial melting since 2011.
A number of researchers have proposed that the Blue Blob is a part of the conventional sea floor temperature variability within the Arctic. Notably, particularly chilly winters in 2014 and 2015 led to file cooling, which brought about upwelling of chilly, deep water, at the same time as ocean temperatures across the area warmed as a result of local weather change.
Earlier than the Blue Blob, a long-term cooling development in the identical area, referred to as the Atlantic Warming Gap, diminished sea floor temperatures by about 0.4 to 0.8 levels Celsius (0.72 to 1.44 levels Fahrenheit) over the last century and will proceed to chill the area sooner or later. A attainable rationalization for the Warming Gap is that local weather change has slowed the Atlantic Meridional Overturning Circulation, an ocean present that brings heat water up from the tropics to the Arctic, thus lowering the quantity of warmth delivered to the area.
The tip of Iceland’s glaciers?
Noël projected the longer term local weather of Iceland by combining the identical regional local weather mannequin with a worldwide local weather mannequin to foretell how North Atlantic ocean temperatures would have an effect on the glaciers’ destiny till 2100, below a state of affairs of fast warming. The fashions predicted that the North Atlantic close to Iceland will keep cool, slowing — and even perhaps briefly stopping — ice loss from the glaciers by the mid-2050s.
The authors verified that the fashions precisely reconstructed the mass of the glaciers utilizing virtually 1,200 measurements of snow depth collected between 1991 and 2019 by colleagues on the College of Iceland and satellite tv for pc measurements of the elevation and extent of glaciers taken from 2002 to 2019 by co-authors on the Delft College of Know-how.
“I believe their evaluation may be very thorough,” stated Fiamma Straneo, a bodily oceanographer on the Scripps Establishment of Oceanography who was not concerned within the research. “They've a very state-of-the-art regional atmospheric mannequin for trying on the variability of glaciers.” Straneo thinks this strategy may very well be used to know modifications in different glaciers that happen over land, akin to within the Himalayas and Patagonia. “There's very energetic analysis in land terminating glaciers as a result of they're one of many largest contributors to sea degree rise proper now.”
Reference: “North Atlantic Cooling is Slowing Down Mass Lack of Icelandic Glaciers” by Brice Noël, Guðfinna Aðalgeirsdóttir, Finnur Pálsson, Bert Wouters, Stef Lhermitte, Jan M. Haacker and Michiel R. van den Broeke, 24 January 2022, Geophysical Analysis Letters.
DOI: 10.1029/2021GL095697
Post a Comment