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HomeScienceThe Disappearance of a Previously Stable Glacier in Greenland is Happening Quickly

The Disappearance of a Previously Stable Glacier in Greenland is Happening Quickly


Steenstrup website. a Location and speed of KIV Steenstrup Nordre Bræ. The color scale indicates the 2016 average velocity from the ITS_LIVE velocity pairs. The colored squares − denote the locations used to sample the velocity time series in Fig. 2, the white line indicates the center line used to derive the profiles in Fig. 3, and the red line indicates the flow gate used to calculate ice discharge. The dotted box indicates the extent of Figure 4, and the dashed box indicates the extent of the panel (B). Background is a composite of Sentinel-2 RGB mean pixel values ​​from May to October 2016. Coordinates are in kilometers from NSIDC Polar Stereographic North. The inset shows the Steenstrup site within Greenland. B Steenstrup forward location change since 2016, determined using GEEDiT82. credit: Nature Communications (2023). DOI: 10.1038/s41467-023-37764-7

One of Greenland’s most stable glaciers is causing ocean temperatures to rise due to climate change, a new study shows, and is now retreating at an unprecedented rate.

A team led by researchers at Ohio State University found that between 2018 and 2021, the Steenstrup Glacier in Greenland retreated about 5 miles, thinned about 20%, doubled the amount of ice it dumped into the ocean, and quadrupled its speed. According to the study, such rapid change is so unusual among Greenland’s ice formations that it now places the Steenstrup in the top 10% of glaciers contributing to total ice discharge in the entire region.

The study was published today in Nature Communications.

Steenstrup Glacier is part of The Greenland Ice Sheet, a body of ice that covers nearly 80% of the world’s largest island, and is also the largest contributor to global sea rise from the cryosphere, a part of Earth’s ecosystem that includes all of its frozen waters. While the region plays a critical role in balancing the global climate system, the region is steadily shrinking as it sheds hundreds of billions of tons of ice each year due to global warming.

Over the past few decades, much of this loss has been attributed to the acceleration of ice discharge from tidal glaciers, the glaciers that connect to the oceans. Many glaciologists believe this recent rise in ice discharge can be explained by the intrusion of warm waters sweeping from the Atlantic into the Greenland fjords—important ocean gateways that can affect the stability of local glaciers and the health of polar ecosystems.

The research team aims to test this theory by examining a glacier in the southeastern region of Greenland called KIV Steenstrups Nordre Bræ, an entity known more colloquially as Steenstrup Glacier.

“Until 2016, there was no indication that Steenstrup was in any way interesting,” said Thomas Chudley, lead author of the study, who completed this work as a research associate at the Byrd Polar Center for Climate Research. Chudley is now a Leverhulme Research Fellow at Durham University in the UK.

“There have been plenty of other glaciers in Greenland that have retreated dramatically since the 1990s and increased their contribution to sea level rise, but this wasn’t really one of them.”

As far as scientists know, not only has Steenstrup been stable for decades, but it’s generally insensitive to the warming temperatures that have destabilized many other regional glaciers, likely due to its isolated location in shallow waters.

It wasn’t until Chudley and his colleagues collected observational and modeling data from previous remote-sensing analyzes on the glacier that the team realized that the Steenstrup was likely experiencing melting due to anomalies in the deep Atlantic waters.

“Our current hypothesis is that ocean temperatures drove this decline,” Chudley said. “The fact that the glacier’s velocity has quadrupled in just a few years opens up new questions about how quickly large ice packs are responding to climate change.”

In recent years, glaciologists have been able to use satellite data to estimate the potential volume of glacial ice stored at the poles and how it might affect current sea levels. For example, if the Greenland Ice Sheet melted, sea levels could rise by about 25 feet. In contrast, if Antarctica’s ice cap collapsed, the oceans could rise by nearly 200 feet, Chudley said.

While Greenland and Antarctica would take centuries to completely collapse, the global cryosphere has the potential to cause sea levels to rise about six feet this century if the West Antarctic Ice Sheet were to collapse.

With about 10% of the planet’s population living in low-lying coastal areas, Chudley said any significant rise in sea level could cause increased risks to low-lying islands and coastal communities from storm surges and tropical cyclones.

In the United States, Chudley said, sea level rise is a particular danger to coastal cities in places like Florida or Louisiana. But this does not necessarily mean that it is too late to prevent such a future. If climate policies evolve quickly, Chudley said, humans may have a chance to halt the worst of sea level rise.

Overall, Steenstrup’s unique behavior reveals that even long-term stable glaciers are subject to sudden and rapid retreat as warmer waters begin to intrude and influence new environments.

While the research says that continued scientific monitoring of the Steenstrup glacier should be a priority, it concludes that other similar glaciers also deserve attention because of their potential to retreat due to warming waters.

Understanding more about these interactions can provide insight into how glaciers thrive in other locations around the world, and can even become an indication of how these environments may change in the future.

“What’s happening in Greenland now is kind of a canary in the coal mine for what might happen in West Antarctica over the next few centuries,” Chudley said. “So it would be great to be able to get into the fjord with real observations on the ground and see how and why Steenstrup changed.”

more information:
TR Chudley et al, Atlantic intrusion causes rapid retreat and regime change in previously stable Greenland glacier, Nature Communications (2023). DOI: 10.1038/s41467-023-37764-7

Provided by The Ohio State University

the quote: A once-stable glacier in Greenland is now rapidly disappearing (2023, April 19) Retrieved April 19, 2023 from https://phys.org/news/2023-04-once-stable-glacier-greenland-rapidly.html

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