Parts of Antarctica have actually turned ice in the past 20 years, new research shows, despite the continent having suffered significant losses due to: global warming†
Researchers say sea ice, pushed against the ice shelves by a change in regional wind patterns, helped protect these ice shelves from losses.
Ice shelves are floating pieces of ice attached to land-based ice sheets and help protect against the uncontrolled release of inland ice into the ocean.
During the late 20th century, high levels of warming in the eastern Antarctic Peninsula led to the collapse of the Larsen A and B ice shelves in 1995 and 2002, respectively.
These events drove the acceleration of the ice toward the ocean, ultimately accelerating the Antarctic Peninsula’s contribution to sea level rise.
There was then a period when some ice shelves in eastern Antarctica grew in surface area, despite global warming.
Parts of Antarctica have even gained ice in the past 20 years, new research shows, despite the continent suffering significant losses from global warming
During the late 20th century, high levels of warming in the Eastern Antarctic Peninsula led to the collapse of the Larsen A and B Ice Shelves in 1995 and 2002, respectively. There was a period then when some ice shelves in the Eastern Antarctic grew in the area (shown with a +)
However, since 2020 there has been an increase in the number of icebergs breaking loose from the eastern Antarctic Peninsula.
Scientists, who used a combination of historical satellite measurements, along with ocean and atmosphere data, said their observations “highlight the complexity and often-overlooked importance of sea ice variability to the health of the Antarctic ice sheet.”
The team of researchers from the University of Cambridge, the University of Newcastle and the New Zealand University of Canterbury found that 85 percent of the 870-mile-long (1,400 km) ice shelf along the eastern Antarctic Peninsula was “moving uninterrupted” between surveys of the coastline in 2003-4 and 2019.
This contrasts with the extensive withdrawal of the previous two decades.
The research suggests that this growth was related to changes in atmospheric circulation, which caused more sea ice to be carried towards the coast by the wind.
dr. Frazer Christie, of Cambridge’s Scott Polar Research Institute (SPRI) and lead author of the paper, said: ‘We found that sea ice alteration can protect against or trigger the calving of icebergs from large Antarctic ice shelves.
“Regardless of how the sea ice around Antarctica changes in a warming climate, our observations highlight the often overlooked importance of sea ice variability to the health of the Antarctic ice sheet.”
In 2019, Dr Christie and his co-authors were part of an expedition to study ice conditions in the Weddell Sea off the coast of the eastern Antarctic Peninsula.
However, since 2020 there has been an increase in the number of icebergs breaking away from the eastern Antarctic Peninsula
Researchers say sea ice, pushed against the ice shelves by a change in regional wind patterns, helped protect these ice shelves from losses
Expedition chief scientist and co-author Professor Julian Dowdeswell, also of the SPRI, said the expedition noted parts of the ice shelf’s shoreline were in their “most advanced position since the start of satellite records in the early 1960s.”
After the expedition, the team used satellite images dating back 60 years, as well as state-of-the-art ocean and atmosphere models, to examine in detail the spatial and temporal pattern of ice shelf change.
Currently, the jury is out on exactly how the sea ice around Antarctica will evolve in response to climate change, and thus influence sea level rise, with some models predicting large-scale loss of sea ice in the Southern Ocean, while others predict the increase in sea ice.
But icebergs erupting in 2020 could be the start of a change in atmospheric patterns and a return to losses, according to the study.
dr. Wolfgang Rack, of the University of Canterbury and one of the paper’s co-authors, said: ‘It is entirely possible that we will see a transition to atmospheric patterns similar to those observed in the 1990s that reflect marine loss. -encouraged ice and, ultimately, more ice calving.’
The research is published in the journal Natural Geosciences†
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