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 +).
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.