Home Science Summer sea ice in parts of Antarctica has decreased by 400,00 square...

Summer sea ice in parts of Antarctica has decreased by 400,00 square miles

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The amount of summer sea ice found in the Weddell Sea area of Antarctica has reduced by 386,102 square miles (1 million sq km) in the past five years.

That is an area twice the size of Spain and will have a significant impact on the marine ecosystem in the area, according to researchers.

Sea ice surrounding Antarctica provides an important habitat for many species including penguins and seals, which rely on it to access food and to breed.

An international team of researchers led by the British Antarctic Survey, examined satellite records of sea ice extent and weather patterns in the area since the 1970s.

The ice loss occurred due to a series of severe storms in the Antarctic summer of 2016 and a large area of open water opening up in between the ice, they found.  

The area in white indicates where sea ice has been lost over the last 5 years and the box shows the Weddell Sea sector where the summer sea ice extent has decreased by one million square kilometres

The area in white indicates where sea ice has been lost over the last 5 years and the box shows the Weddell Sea sector where the summer sea ice extent has decreased by one million square kilometres

Sea ice surrounding Antarctica provides an important habitat for many species including penguins and seals, which rely on it to access food and to breed

Sea ice surrounding Antarctica provides an important habitat for many species including penguins and seals, which rely on it to access food and to breed

Lead author Professor John Turner, a climate scientist at British Antarctic Survey, said the Antarctic sea ice provides constant surprises for researchers.

‘In contrast to the Arctic, sea ice around the Antarctic had been increasing in extent since the 1970s, but then rapidly decreased to record low levels, with the greatest decline in the Weddell Sea,’ he said.

‘In summer, this area now has a third less sea ice, which will have implications for ocean circulation and the marine wildlife of the region that depend on it for survival.’

The ocean around Antarctica freezes and doubles the size of the continent in the winter, with the sea ice extent reaching over 7 million sq miles by late September. 

Through the spring and summer, the sea ice almost completely melts in most parts of the Antarctic, with only the Weddell Sea retaining a significant amount. 

There are few storms around the Antarctic in the austral summer, but in December 2016, a number of intense and unseasonal storms developed in the Weddell Sea and drew warm air towards the Antarctic, melting a large amount of sea ice.

The ice-free ocean absorbed energy from the Sun and then created a warm ocean temperature anomaly that still persists today.

The winter of 2016 also saw the development of a polynya in the Weddell Sea, that is a large area of open water within the sea ice pack.

This contributed to the overall decline in sea ice extent, researchers said.

This polynya was created by the strong winds associated with the storms and unprecedented warm ocean conditions.

This recent rapid sea ice loss is affecting both the Weddell Sea ecosystem and the wider Antarctic wildlife/plants and animals, the team said.

An international team of researchers led by the British Antarctic Survey, examined satellite records of sea ice extent and weather patterns in the area since the 1970s

An international team of researchers led by the British Antarctic Survey, examined satellite records of sea ice extent and weather patterns in the area since the 1970s

The ice loss occurred due to a series of severe storms in the Antarctic summer of 2016 and a large area of open water opening up in between the ice, they found

The ice loss occurred due to a series of severe storms in the Antarctic summer of 2016 and a large area of open water opening up in between the ice, they found

There are few storms around the Antarctic in the austral summer, but in December 2016, a number of intense and unseasonal storms developed in the Weddell Sea and drew warm air towards the Antarctic, melting a large amount of sea ice

There are few storms around the Antarctic in the austral summer, but in December 2016, a number of intense and unseasonal storms developed in the Weddell Sea and drew warm air towards the Antarctic, melting a large amount of sea ice

Many species, ranging from tiny ice algae and shrimp-like crustaceans called krill to seabirds, seals and whales, are highly adapted to the presence of sea ice. 

‘If the drastic changes observed continue, they will have repercussions throughout the food chain,’ according to the British Antarctic Survey.

This will go from affecting nutrients to the reduction of essential habitat for breeding and feeding for vast numbers of animals, such as ice seals and some penguins.

Author and ecologist Professor Eugene Murphy from British Antarctic Survey said it would have a significant impact on the entire marine ecosystem.

‘Understanding these wider consequences is of paramount importance, especially if the decline in ice extent continues,’ Murphy said.

Because of the large year-to-year variability in Antarctic sea ice extent the scientists cannot be sure if the ice in the Weddell Sea will recover in the short-term or whether they are seeing the start of the expected long-term decline of sea ice. 

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