The Decline of the Antarctic Ice Shelf: A Comprehensive Examination
New research based on data from satellite missions has revealed alarming findings about the state of Antarctica’s ice shelves. The study, funded by ESA’s Earth Observation Science for Society program and published in the journal Science Advances, used 100,000 satellite radar images to assess the health of the ice shelves. It found that 40% of these floating shelves have significantly reduced in volume over the past 25 years.
Antarctica’s ice shelves are crucial in stabilizing the region’s glaciers by acting as buttresses, slowing the flow of ice into the ocean. However, as the ice shelves get smaller, the rate of ice lost from the ice sheet increases. The research team discovered that 71 out of 162 ice shelves around Antarctica have reduced in volume, releasing almost 67 trillion tonnes of meltwater into the ocean. This addition of freshwater into the ocean could have implications for ocean circulation patterns.
The study also revealed that almost all the ice shelves on the western side of Antarctica experienced ice loss, while most of the ice shelves on the eastern side remained intact or increased in mass. Benjamin Davison, a research fellow at the University of Leeds, explained that that’s due to differences in ocean temperature and currents. The western side is exposed to warm water, which rapidly erodes the ice shelves from below. In contrast, much of East Antarctica is protected by a band of cold water at the coast.
The Getz Ice Shelf and the Pine Island Ice Shelf experienced some of the largest ice losses. The Getz Ice Shelf lost 1.9 trillion tonnes of ice, with only 5% caused by calving (large chunks of ice breaking away). The rest was due to melting at the base of the ice shelf. Similarly, the Pine Island Ice Shelf lost 1.3 trillion tonnes of ice, with around a third of the loss caused by calving.
On the other hand, the Amery Ice Shelf, located on the opposite side of Antarctica and surrounded by colder waters, gained 1.2 trillion tonnes of ice. The researchers were surprised by the steady attrition of many ice shelves, with almost half of them shrinking without signs of recovery. Anna Hogg, from the University of Leeds, emphasized that this is further evidence that Antarctica is changing due to climate warming.
Satellites play an important role in monitoring the remote polar region. The Copernicus Sentinel-1 mission, Europe’s prime radar mission, provides images regardless of day or night, and whatever the weather. ESA’s CryoSat carries a radar altimeter to measure changes in the height of the ice, which helps calculate changes in actual ice volume. Noel Gourmelen, from the University of Edinburgh and Earthwave, highlighted the importance of CryoSat in accurately quantifying and understanding ice shelf loss.
Mark Drinkwater from ESA expressed the significance of satellite missions in monitoring and tracking climate change across Antarctica. He mentioned that the European Copernicus program’s Sentinel-1 mission, along with its predecessors ERS-1, ERS-2, and Envisat, has revolutionized the ability to assess floating ice shelves and understand the health of the Antarctic ice sheet. In the future, three new polar-focused missions (CRISTAL, CIMR, and ROSE-L) will further enhance Antarctic monitoring.
This research sheds light on the rapid decline of Antarctica’s ice shelves and emphasizes the urgent need for global action to address climate change. The findings also highlight the importance of satellite missions in monitoring and understanding the impacts of climate change on remote regions like Antarctica. With ongoing advancements in technology and new satellite missions on the horizon, scientists will continue to gather crucial data to inform conservation efforts and mitigate further ice loss in Antarctica.
