According to a new study, an area of cooling water in the North Atlantic Ocean close to Iceland named the “Blue Blob,” has likely decelerated the melting of the island’s glaciers since 2011 and may continue to thwart ice loss until approximately 2050.
A recent slowdown in the melting of Iceland’s glaciers is likely caused by a patch of unusually cold water in the North Atlantic Ocean, according to a new study published in the AGU journal Geophysical Research Letters. Image Credit: Finnur Pálsson.
The origin and cause of the Blue Blob, which is situated south of Iceland and Greenland, is still being analyzed. The cold patch was most noticeable during the winter of 2014-2015 when the temperature of the sea surface was around 1.4 °C (2.52 °F) colder than usual.
The new research employs climate models and field observations to demonstrate that the cold water patch chilled the air over Iceland adequately to decelerate ice loss beginning in 2011. The model estimates cooler water will continue in the North Atlantic, sparing Iceland’s glaciers until approximately 2050. Ocean and air temperatures are estimated to increase between 2050 and 2100, leading to faster melting.
While cooler water in the North Atlantic provides a temporary break for Iceland’s glaciers, the authors predict that without steps to alleviate climate change, the glaciers could lose a third of their existing ice volume by 2100 and vanish by 2300. If the country’s 3,400 cubic kilometers (roughly 816 cubic miles) of ice melts, the sea level will increase by 9 millimeters (0.35 inches).
In the end, the message is still clear. The Arctic is warming fast. If we wish to see glaciers in Iceland, then we have to curb the warming.
Brice Noël, Researcher and Study Lead Author, Utrecht University
Noël is a Climate Modeler who studies polar ice sheets and glaciers.
The article has been published in the AGU journal Geophysical Research Letters, which showcases all high-impact, short-format reports with instant implications covering all Earth and space sciences. Its findings may help researchers to properly comprehend the indirect effects of the ocean on glaciers.
It’s crucial to have an idea of the possible feedbacks in the Arctic because it’s a region that is changing so fast. It’s important to know what we can expect in a future warmer climate.
Brice Noël, Researcher and Study Lead Author, Utrecht University
The Warming Arctic
No other place on Earth has warmed as rapidly as the Arctic. Fresh studies report the area is warming four times faster than the worldwide average. Iceland’s glaciers progressively shrank from 1995 to 2010, losing an average of 11 gigatons of ice per annum.
Beginning in 2011, however, the speed of Iceland’s melting decelerated, resulting in nearly half as much ice loss, or approximately 5 gigatons per annum. This trend was not witnessed in adjacent, larger glaciers across Svalbard and Greenland.
Noël and his colleagues explored the cause of this deceleration by guesstimating the glaciers’ mass balance — how much they grew or melted per annum from 1958 to 2019. They employed a high-resolution regional climate model that is effective at the small scale of Iceland’s glaciers to predict the amount of snow the glaciers received in winter and the amount of ice lost from meltwater runoff in summer.
The scientists learned that cooler waters close to the Blue Blob are connected to observations of lower air temperatures over Iceland’s glaciers and correspond with the deceleration of glacial melting since 2011.
Several scientists have suggested that the Blue Blob is part of the regular sea surface temperature variability in the Arctic. Particularly, cold winters in 2014 and 2015 resulted in record cooling, which resulted in an upwelling of cold, deep water, even as ocean temperatures around the area warmed because of climate change.
Prior to the Blue Blob, an enduring cooling trend in the same area, called the Atlantic Warming Hole, decreased sea surface temperatures by approximately 0.4 to 0.8 °C (0.72 to 1.44 °F) during the last century and may carry on cooling the region in the future.
A likely explanation for the Warming Hole is that climate change has decelerated the Atlantic Meridional Overturning Circulation, an ocean current that supplies warm water up from the tropics to the Arctic, thus decreasing the amount of heat delivered to the area.
The End of Iceland’s Glaciers?
Noël estimated the future climate of Iceland by incorporating the same regional climate model with a worldwide climate model to forecast how North Atlantic ocean temperatures would impact the glaciers’ destiny until 2100, under a situation of rapid warming.
The models forecast that the North Atlantic close to Iceland will remain cool, slowing — and maybe even momentarily stopping — ice loss from the glaciers by the mid-2050s.
The authors confirmed that the models correctly reconstructed the mass of the glaciers using nearly 1,200 measurements of snow depth made between 1991 and 2019 by co-workers at the University of Iceland and satellite measurements of the elevation and extent of glaciers captured from 2002 to 2019 by co-authors at the Delft University of Technology.
“I think their analysis is very thorough,” said Fiamma Straneo, a physical oceanographer at the Scripps Institution of Oceanography who was not involved in the research. “They have a really state-of-the-art regional atmospheric model for looking at the variability of glaciers.”
Straneo thinks this method could be used to understand variations in other glaciers that occur over land, such as in Patagonia and the Himalayas.
There is very active research in land terminating glaciers because they are one of the largest contributors to sea-level rise right now.
Fiamma Straneo, Physical Oceanographer, Scripps Institution of Oceanography
Journal Reference:
Noël, B., et al. (2022) North Atlantic Cooling is Slowing Down Mass Loss of Icelandic Glaciers. Geophysical Research Letters. doi.org/10.1029/2021GL095697.
Source: https://agu.org