Parts of Antarctica have actually gained ice over the past 20 years, new research shows, even as the continent has suffered significant losses due to global warming.
Researchers say sea ice pushed against ice shelves by a change in regional wind patterns may have helped protect those ice shelves from loss.
Ice shelves are floating sections of ice attached to land-based ice sheets and they protect against the uncontrolled release of inland ice into the ocean.
During the late 20th century, strong warming in the eastern Antarctic Peninsula led to the collapse of the Larsen A and B Ice Shelf in 1995 and 2002, respectively.
These events accelerated ice toward the ocean, ultimately accelerating the Antarctic Peninsula’s contribution to sea level rise.
There was then a time when, despite global warming, some ice shelves in East Antarctica were growing in area.
Parts of Antarctica have actually gained ice over the past 20 years, new research shows, even as the continent has suffered significant losses due to global warming
During the late 20th century, strong warming in the eastern Antarctic Peninsula led to the collapse of the Larsen A and B Ice Shelf in 1995 and 2002, respectively. There was then a time when some ice shelves in East Antarctica were growing in area (marked with a +).
MELTING GLACIER AND ICE DISCS WOULD HAVE “DRAMATIC IMPACT” ON GLOBAL SEA LEVELS
Global sea levels could rise as much as 3 meters if West Antarctica’s Thwaites Glacier collapses.
Sea level rise is threatening cities from Shanghai to London, low-lying parts of Florida or Bangladesh, and entire nations like the Maldives.
In the UK, for example, a rise of 2 meters or more can cause areas such as Hull, Peterborough, Portsmouth and parts of east London and the Thames Estuary to become submerged.
The collapse of the glacier, which could start decades ago, could also submerge major cities like New York and Sydney.
Parts of New Orleans, Houston and Miami in the southern United States would also be particularly hard hit.
Since 2020, however, more and more icebergs have been breaking off from the eastern Antarctic Peninsula.
Scientists, using a combination of historical satellite measurements along with ocean and atmospheric records, said their observations “highlight the complexity and often overlooked importance of sea ice variability in the health of the Antarctic ice sheet.”
The research team from Cambridge University, Newcastle University and New Zealand’s University of Canterbury found that 85 percent of the 870-mile (1,400 km) long ice shelf along the eastern Antarctic Peninsula “advanced continuously” between coastal surveys. 2003-4 and 2019.
This was in contrast to the extended retreat of the previous two decades.
The research suggests that this growth is related to changes in atmospheric circulation, which resulted in more sea ice being carried to the coast by the wind.
dr Frazer Christie of the Scott Polar Research Institute (SPRI) in Cambridge and lead author of the publication said: “We have found that sea ice alteration can either prevent or initiate the calving of icebergs from large Antarctic ice shelves.
“Regardless of how the sea ice around Antarctica changes in a warming climate, our observations underscore the often overlooked importance of sea ice variability in the health of the Antarctic ice sheet.”
In 2019, dr. Christie and his co-authors are part of an expedition to study ice conditions in the Weddell Sea off the coast of the East Antarctic Peninsula.
Since 2020, however, more and more icebergs have been breaking off from the eastern Antarctic Peninsula
Researchers say sea ice pushed against ice shelves by a change in regional wind patterns may have helped protect those ice shelves from loss
The expedition’s chief scientist and co-author of the study, Professor Julian Dowdeswell, also of SPRI, said that during the expedition it was found that parts of the ice shelf coast were at their “most advanced position since satellite records began in the early 1960s”. were.
After the expedition, the team used satellite imagery going back 60 years and state-of-the-art ocean and atmosphere models to study the spatial and temporal pattern of ice shelf change in detail.
Currently, the jury is out on how sea ice around Antarctica will evolve in response to climate change and thus affect sea level rise, with some models predicting sea ice loss across the Southern Ocean while others predict sea ice gain.
But the breaking off of icebergs in 2020 could signal 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 quite possible that we are seeing a transition back to atmospheric patterns similar to those observed in the 1990s that promoted sea ice loss and eventually more ice shelf calving.’
The research was published in the journal Nature Geoscience.
Antarctica’s ice sheets contain 70% of the world’s freshwater — and sea levels would rise 180 feet if it melted
Antarctica contains a huge amount of water.
The three ice sheets that cover the continent contain around 70 percent of our planet’s fresh water — all to warm the air and oceans.
If all of the ice sheets melted due to global warming, Antarctica would raise global sea levels by at least 183 feet (56 m).
Given their size, even small losses in the ice sheets could have global consequences.
In addition to sea-level rise, meltwater would slow the circulation of the world’s oceans, while changing wind belts could affect southern hemisphere climate.
In February 2018, Nasa revealed that El Niño events are causing the Antarctic Ice Shelf to melt by up to 25 centimeters each year.
El Niño and La Niña are separate events that change the water temperature of the Pacific Ocean.
The ocean periodically varies between being warmer than average during El Niños and cooler than average during La Niñas.
Using NASA satellite imagery, researchers found that oceanic phenomena are causing the Antarctic ice shelves to melt while snowfall is increasing.
In March 2018, it was revealed that a larger French-sized glacier was floating on the ocean in Antarctica than previously thought.
This has raised fears that it could melt faster as the climate warms and have a dramatic impact on sea level rise.