Parts of Antarctica have actually become ice in the past 20 years, new research shows, despite the continent having lost significant amounts 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 +)
GLACIER AND ICE SHEET MELTING WOULD HAVE A ‘DRAMATIC IMPACT’ ON GLOBAL SEASIDES
If the Thwaites Glacier in West Antarctica collapses, sea levels could rise by up to 3 meters worldwide.
Sea level rise threatens cities from Shanghai to London, to low-lying parts of Florida or Bangladesh, and to entire nations like the Maldives.
In the UK, a rise of 2 meters (6.7 ft) or more could cause areas such as Hull, Peterborough, Portsmouth and parts of East London and the Thames Estuary to be flooded.
The glacier’s collapse, which could start with decades, could also flood major cities like New York and Sydney.
Parts of New Orleans, Houston and Miami in the southern US would also be particularly hard hit.
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 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 an enormous amount of water.
The three ice sheets that cover the continent contain about 70 percent of our planet’s fresh water — and all of this is destined for warming air and oceans.
If all the ice sheets melted as a result of global warming, Antarctica would raise sea levels worldwide by at least 56 meters.
Given their size, even small losses in the ice sheets could have global repercussions.
In addition to rising sea levels, meltwater would slow the world’s ocean circulation, while changing wind belts could affect the climate in the southern hemisphere.
In February 2018, NASA revealed that El Niño events cause the Antarctic ice shelf to melt 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 fluctuates between 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 increasing snowfall.
In March 2018, it was revealed that there is more of a giant glacier the size of France in Antarctica floating on the ocean than previously thought.
This has raised fears it could melt faster as the climate warms and have a dramatic impact on rising sea levels.