(ORDO NEWS) — In the context of climate change, one usually speaks of melting glaciers, but scientists note that some large accumulations of ice on the Antarctic Peninsula have grown markedly over the past 20 years. The reason may be changes in atmospheric circulation and redistribution of the mass of Antarctic ice closer to the coast.
Huge masses of ice on the southernmost continent store a significant part of all water, and this water is completely fresh. However, against the backdrop of global warming, many Antarctic glaciers are rapidly melting, which causes a rise in the level of the World Ocean.
Scientists have been watching the process of reducing their area with caution since the middle of the 20th century, and since the 1960s, including with the help of satellite images.
To understand how the icy continent works, it is important to take into account that local glaciers are dynamic: they are constantly growing in some parts and melting in others.
Meanwhile, huge masses of ice literally, albeit very slowly, flow from the center to the edges of Antarctica, go beyond the coastline and break off. As a result, the so-called floating ice is formed, which then go on an independent journey. It is curious that in English this process is called “ice calving” – literally “ice calving”.
The outermost and thinnest part of the Antarctic ice sheet, located in the warmest part of the continent (near the coast), are the so-called ice shelves. They are especially important for maintaining Antarctica’s vast ice reserves, as they serve as “props” that limit the movement of the ice mass into the ocean.
Therefore, glaciologists, climatologists and other scientists are closely following the complex dynamics of the Antarctic Peninsula’s glaciers.
This is the northernmost part of the frosty continent, protruding towards South America for 1300 kilometers. The peninsula accounts for almost four percent of the area of Antarctica, and 80% of its territory is occupied by glaciers.
In 1995 and 2002, scientists noted a catastrophic reduction in the area of glaciers called Larsen A and Larsen B. This caused a sharp acceleration in the flow of ice towards the coast and contributed to the rise in the ocean level.
In a new study published in the journal Nature Geoscience, a team of scientists from the UK and New Zealand used satellite imagery data and information about changes in the state of the atmosphere and ocean.
As a result, they were able to obtain a detailed understanding of the state of the Antarctic Peninsula glaciers and their dynamics. Surprisingly, 85% of the ice shelves in this area have noticeably increased in size since the early 2000s.
Some ice hasn’t gone that deep into the sea since the 1960s, that is, since the first satellite observations. All this contrasts sharply with the rapid shrinking of glaciers in the previous two decades, in the 1980s and 1990s.
Researchers attribute these unexpected changes to the dynamics of air circulation – it is likely that the wind now carries more ice from the interior to the coast. The authors concluded that the ice in the sea is also important for protecting the ice cover from rapid destruction.
“We have found that changes in sea ice can both prevent and trigger the separation of icebergs from large ice shelves in Antarctica,” said one of the authors, Dr. Fraser Christie (Frazer Christie) from the Scott Institute for Polar Research at the University of Cambridge (UK).
“Regardless of how the state of the ice around Antarctica changes as the climate warms, our study highlights the critical importance of often neglected marine glacier dynamics to the health of the Antarctic ice sheet.”
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