“Blue masses” near Iceland can delay glacier melting

Researchers have validated the model’s results using depth measurements from Iceland’s glaciers collected by colleagues at the University of Iceland since the 1990s. Credit: Finnur Pálsson

A region of cooling water in the North Atlantic near Iceland, called the “blue mass,” could delay the melting of glaciers on the island after 2011 and continue to curb ice loss until around 2050, according to new research. there is.

The origin and cause of the Blue Blob, located south of Iceland and Greenland, is still under investigation. Cold patches were most prominent in the winter of 2014-2015. Sea surface temperature About 1.4 degrees Celsius (2.52 degrees Fahrenheit) was colder than usual.

New research will use Climate model Field observations showing that the cold water patch has cooled enough air over Iceland to slow down Loss of ice Models predict that colder waters will persist in the North Atlantic and save Iceland’s glaciers until around 2050. Seas and temperatures are projected to rise between 2050 and 2100, accelerating melting.

The colder waters of the North Atlantic provide a temporary rest for Icelandic glaciers, but the author estimates it without steps to mitigate. Climate changeBy 2100, glaciers will lose one-third of their current ice volume and may disappear by 2300. When the country’s 3,400 cubic kilometers (about 816 cubic miles) of ice melt, sea level rises 9 millimeters (0.35 inches).

“After all, the message is still clear,” said Bryce Noel, the lead author of the Utrecht University’s polar ice sheet and glacier-specialized climate modeler. “The Arctic is warming rapidly. If you want to see glaciers in Iceland, you need to control it.”

The paper is published in the AGU journal Geophysics Research Letter, It publishes a short, high-impact report with immediate impact across all earth and space sciences. The findings may help scientists better understand the indirect effects of the ocean on glaciers.

“The Arctic is a very rapidly changing region, so it’s important to think about possible feedback in the Arctic,” Noel said. “It’s important to know what we can expect in the future Mild climate.. “

Warming Arctic Circle

Nowhere else is the Earth warming as rapidly as the Arctic Circle. Recent studies show that the region is warming four times faster than the world average. Iceland’s glaciers steadily shrank between 1995 and 2010, losing an average of 11 gigatons of ice annually. However, since 2011, Iceland’s melting rate has slowed, resulting in ice losses of about half, or about 5 gigatons per year. This trend was not seen in the large glaciers near Greenland and Svalbard.

Noël and his colleagues investigated the cause of this slowdown by estimating the glacier’s mass balance (annual glacier growth or melting from 1958 to 2019). They estimated using a high-resolution regional climate model that works on a small scale of glaciers. The amount of snow the glacier received in winter and the amount of ice lost due to the outflow of meltwater in summer. Researchers have found that cold water near the blue blob is associated with observations of lower temperatures in Iceland’s glaciers, consistent with slower glacier melting since 2011.

Some researchers have suggested that blue blobs are part of normal Arctic sea surface temperature fluctuations. In particular, the particularly cold winters of 2014 and 2015 provided record cooling, causing cold and deep upwelling despite climate change raising seawater temperatures around the region.

Before the Blue Blob, the sea surface temperature dropped by about 0.4 to 0.8 degrees Celsius (0.72 to 1.44 degrees Fahrenheit) in the last century due to the long-term cooling tendency of the same area called the Atlantic Warming Hall, which is the future area. A possible explanation for the hole in warming is that climate change has slowed the Atlantic meridional overturn. This is an ocean current that brings warm water from the tropics to the Arctic, reducing the amount of heat supplied to the region.

The end of Iceland’s glaciers?

By combining the same regional and global climate models, Noel predicts how North Atlantic seawater temperatures will affect glacial fate by 2100 under rapid warming scenarios. , Predicted the future climate of Iceland. Models predicted that the North Atlantic Ocean near Iceland would be cool, delaying the loss of ice from glaciers by the mid-2050s, and perhaps temporarily stopping it.

The authors have taken approximately 1,200 snow depth measurements collected by colleagues at the University of Iceland between 1991 and 2019, as well as jointly obtained glacier elevation and range satellite measurements from 2002 to 2019. We used the values ​​to confirm that the model accurately reconstructed the glacier mass. Author of Delft University of Technology.

“I think their analysis is very thorough,” said Fiammetta Straneo, a physical oceanographer at the Scripps Institution of Oceanography who was not involved in the study. “They have a truly state-of-the-art regional atmospheric model for investigating glacier variability.” Straneo uses this approach to understand changes in other glaciers on land, such as the Himalayas and Patagonia. I think I can do it. “There is very active research on the end of the land. Glacier Because they are currently one of the biggest causes of sea level rise. ”

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For more information:
Bryce Noel et al., North Atlantic cooling delays the mass loss of Icelandic glaciers, Geophysics Research Letter (2022). DOI: 10.1029 / 2021GL095697

Quote: “Blue mass” near Iceland may delay glacier melting (February 15, 2022) Obtained from February 15, 2022

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“Blue masses” near Iceland can delay glacier melting

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