Science & Technology

Global Warming Could Lead to the Melting of More Than a Third of Antarctic Ice Shelves, Huge Rise in Sea Levels

Larsen C ice sheet. Credit score: ULiège

Knowledge collected utilizing the MAR local weather mannequin developed at ULiège point out that this might occur as early as the finish of this century, and even earlier.

A brand new examine carried out collectively by the College of Liege (Belgium) and the College of Studying (England) means that 34% of the Antarctic ice cabinets may disappear by the finish of the century if the planet warms up by 4°C in contrast with pre-industrial temperatures. This melting could lead on to a vital rise in sea ranges. This examine is revealed in the journal Geophysical Analysis Letters.

Since the early 2000s, scientists have noticed that the Antarctic ice sheet is shedding mass at a price that’s accelerating. The ice sheet is a very thick expanse of ice that may cowl a complete continent. There are solely two ice sheets on Earth: the Greenland ice sheet, which is restricted to the land cowl, and the Antarctic ice sheet, which extends past the continent into the ocean to kind massive floating platforms. “These ice cabinets act like dams and hold the ice on the continent,” explains Christoph Kittel, a researcher at the College of Liege Climatology Laboratory and co-author of the examine revealed in the journal Geophysical Analysis Letters.[1] With out these platforms, big quantities of ice would circulation instantly into the ocean, main to a consequent rise in sea ranges.”

Destruction of the Larsen B platform in Antarctica, photographs from January 31 to April 13, 2002. Credit score: NASA

In summer time, the snow on the floor of these platforms melts and water seeps into the small empty areas in the deep snow layers the place it might probably refreeze and restore the power of the platform. If the soften is just too nice, then the extra water seeps deeper into the ice or varieties lakes on the floor. The seepage and elevated weight of the water as a end result of lake formation tends to fracture the ice. And when the ice soften is bigger than the snowfall, there’s a excessive danger of platform failure. “The break-up and disappearance of the Larsen B platform in 2002 confirmed how delicate these boundaries are to melting,” explains Ella Gilbert, co-author of the scientific paper and a researcher in the Division of Meteorology at the College of Studying. “In a few days, about 3250 km2 of ice has been dumped into the ocean.”

For his or her examine, the researchers used the Regional Atmospheric Mannequin (MAR) developed by the Climatology Laboratory of the College of Liege – one of the finest fashions in the world for learning polar climates. The mannequin allowed them to calculate the evolution of circumstances that lead to platform failures in Antarctica underneath completely different ranges of local weather warming starting from 1.5°C to 4°C. All these situations are potential for the finish of the century.

Projection of the space of Antarctic cabinets that can expertise extra floor meltwater. Credit score: ULiège

“As temperatures rise, intense summer time soften occasions will probably be repeated and, above all, will change into extra intense,” says Christoph Kittel. The meltwater will now not have the opportunity to be absorbed by the snow to refreeze, however will kind lakes and seep deeper into the ice of the platforms, which is able to lead to break-ups.” The examine recognized platforms the place the danger of break-up is excessive. 4 platforms – Larsen C, Shackleton, Pine Island and Wilkins – are subsequently thought of ‘in danger’ as a result of of their location and predicted soften.

“If temperatures proceed to rise at the present price, we may see much more platform collapse occasions in the subsequent few years,” says Gilbert. This echoes a earlier examine by Christoph Kittel, not too long ago revealed in the journal The Cryosphere,[2] which means that local weather change in Antarctica might have been underestimated in earlier IPCC reviews for the 12 months 2100. The local weather scientists stress the significance of assembly the targets set by the Paris Settlement as quickly as potential, which might restrict international warming and the dangers of destroying Antarctic platforms. “It is necessary to act rapidly, as a result of we’re speaking about ten years and even 2040 at the very most earlier than the most pessimistic state of affairs stands out. Limiting international warming is not only good for Antarctica, preserving the ice cabinets means decreasing the rise in sea stage and subsequently the influence that this may have on all our lives,” conclude the two researchers.

For extra on this analysis learn .

References:

“Floor soften and runoff on Antarctic ice cabinets at 1.5°C, 2°C and 4°C of future warming” by E. Gilbert and C. Kittel, 8 April 2021, Geophysical Analysis Letters.

“Diverging future floor mass stability between the Antarctic ice cabinets and grounded ice sheet” by Christoph Kittel, Charles Amory, Cécile Agosta, Nicolas C. Jourdain, Stefan Hofer, Alison Delhasse, Sébastien Doutreloup, Pierre-Vincent Huot, Charlotte Lang, Thierry Fichefet and Xavier Fettweis, 5 March 2021, The Cryosphere.

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