Some Antarctic ice shelves have GROWED in the past 20 years despite global warming

Parts of Antarctica have actually gained ice over the past 20 years, according to new research, although the continent is suffering significant losses due to global warming.

The researchers say sea ice, pushed against the 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 caps and they help guard against the uncontrolled release of inland ice into the ocean.

In 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 caused the ice to accelerate towards the ocean, ultimately accelerating the Antarctic Peninsula’s contribution to sea level rise.

Then there was a period when some ice shelves in East Antarctica grew larger, despite global warming.

However, since 2020 the number of icebergs breaking off from the eastern Antarctic Peninsula has increased.

The scientists, who used a combination of historical satellite measurements, as well as ocean and atmospheric records, said their observations “highlight the complexity and often overlooked importance of sea ice variability for the health of the Antarctic ice cap.

The team of researchers from the University of Cambridge, Newcastle University and the University of Canterbury in New Zealand found that 85% of the 870-mile (1,400 km) long ice shelf along the eastern Antarctic Peninsula “suffered an unbroken advance” between shoreline surveys in 2003-4 and 2019.

This contrasted with the vast decline of the previous two decades.

The research suggests that this growth was linked to changes in atmospheric circulation, which caused more sea ice to be transported to the coast by the wind.

Dr Frazer Christie, from the Scott Polar Research Institute (SPRI) in Cambridge and lead author of the paper, said: ‘We have found that changing sea ice can either protect 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. ‘Antarctic.”

In 2019, Dr. Christie and his co-authors were part of an expedition to study ice conditions in the Weddell Sea off the eastern Antarctic Peninsula.

The expedition’s chief scientist and co-author of the study, Professor Julian Dowdeswell, also from SPRI, said that during the expedition it was noted that some parts of the sea ice coast were at their “most forward position since satellite recordings began 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 atmospheric models, to study in detail the spatial and temporal pattern of sea ice evolution.

Currently, the jury is out on exactly how the sea ice around Antarctica will evolve in response to climate change, and therefore influence sea level rise, with some models predicting large-scale sea ice loss in the Southern Ocean, while others predict sea ice gain.

But breaking up of icebergs in 2020 could signal the start of a shift in atmospheric patterns and a return to losses, the research suggests.

Dr Wolfgang Rack, from the University of Canterbury and one of the paper’s co-authors, said: “It is entirely possible that we are seeing a transition to atmospheric patterns similar to those seen over the of the 1990s that encouraged the loss of sea ice and ultimately more calving on the pack ice.

The research was published in the journal nature geoscience.