by Laura Herrez Borreguero, Alberto Navira Garbato and Jess Melbourne-Thomas, Conversation
Warmer waters are drifting toward the East Antarctic ice sheet, according to our alarming new research, revealing a potential new driver of global sea-level rise.
researchpublished today in nature climate changeshows changing water circulation The stability of the East Antarctic Ice Sheet in the Southern Ocean may be compromised. The ice sheet, about the size of the United States, is the largest in the world.
Changes in water circulation are caused by changes in wind patternAnd linked to including factors Climate change, The resulting warm waters and sea level rise can harm marine life and threaten human coastal settlements.
Our findings underscore the urgency to limit Global warming below 1.5 ℃ to prevent the most catastrophic climate damage.
Ice sheets and climate change
Ice sheets consist of glacial snow that is deposited on land by precipitation. Where the sheets protrude from the land and float on the ocean, they are known as ice shelves.
It is well known that the West Antarctic Ice Sheet is melting and contributing to sea level rise. But until now, little was known about its counterpart in the East.
Our research focused on the offshore sector known as Aurora Subglacial Basin in the Indian Ocean. This area of frozen sea ice is part of the East Antarctic Ice Sheet.
How this basin will respond to climate change is one of the biggest uncertainties in sea level rise projections this century. If the basin were to melt completely, the global sea level would 5.1 m. increase of,
Most of the basin is below sea level, which makes it particularly vulnerable to ocean melting. This is because deep sea water is required low temperature To freeze than in shallow sea water.
what we found
We examined 90 years of oceanographic observations from the Aurora subglacial basin. We found it Sea warming at a rate of 2℃ to 3℃ since the first half of the 20th century. It is equivalent to 0.1 ℃ to 0.4 ℃ per decade.
The warming trend has tripled since the 1990s, reaching a rate of 0.3 ℃ to 0.9 ℃ in each decade.
So how is this warming linked to climate change? The north is related to a band of strong westerly winds over the Southern Ocean. Since the 1960s, these winds have been moving south toward Antarctica during years when the southern annular mode, a climate driver, is in a positive phase.
The East Antarctic Ice Sheet was once thought to be relatively stable and sheltered from warm oceans. it’s partly because it’s surrounded by a lot of Cold water Known as “dense shelf water”.
Part of our research focused on Vanderford Glacier in East Antarctica. There, we saw warm water replacing cold dense shelf water.
The movement of warm water toward East Antarctica is expected to worsen in the 21st century, further threatening the stability of the ice sheet.
Why it matters to marine life
past work On the effects of climate change in the East Antarctic it is generally believed that warming first occurs in the ocean surface layers. Our findings – that deeper waters are warming earlier – suggest a need to re-think potential impacts on marine life.
There is a need for robust assessment work, including investments in monitoring and modeling that can link physical change to complex ecosystem responses. This should include the potential effects of very rapid changes, known as tipping points, that could mean the ocean changes far more rapidly than Marine Life can customize.
East Antarctic marine ecosystems are likely to be highly sensitive to warm waters. antarctic krill, for example, reproduce by immersing eggs in the depths of the deep ocean. Heating of deep water can affect the development of eggs and larvae. This in turn will affect krill populations and dependent predators such as penguins, seals and whales.
Limiting global warming to below 1.5℃
We hope that our results will inspire global efforts to limit global warming to below 1.5℃. To achieve this, global greenhouse gas emissions need to be Fall Around 43% by 2030 and near zero by 2050.
Citation: Disturbing new research shows that warm water is moving toward the world’s largest ice sheet in Antarctica (2022, Aug. 3) Retrieved from -08-world-biggest-ice-sheet-antarctica. .html
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