According to scientists, 71 of the 162 ice shelves surrounding Antarctica have shrunk in volume over the 25 years from 1997 to 2021, releasing a net 7.5 trillion metric tons of meltwater into the oceans. The study was published in the journal Science Advances.

They found that nearly all of the ice shelves on the western side of Antarctica were experiencing ice loss. In contrast, most of the ice shelves on the eastern side remained unchanged or increased in volume.

Scientists estimate that approximately 67 trillion metric tons of ice was exported to the ocean over 25 years, offset by 59 trillion metric tons of ice added to the ice shelf, resulting in a net loss of 7.5 trillion metric tons.

Research scientist Dr. from the University of Leeds, who led the study. Benjamin Davison said: ‘There is a mixed picture of ice shelf degradation and this is linked to ocean temperatures and ocean currents around Antarctica.

“The western half is exposed to warm water that can quickly erode the ice shelf below, while much of East Antarctica is now protected from warm water by a band of cold water near the coast.”

Antarctica is a huge continent, 50 times the size of Great Britain, and the seas on the west coast are subject to different currents and winds than those on the east coast, resulting in warmer waters beneath the ice shelves on the west coast.

Dr. D., an Earth observation expert in polar regions at the School of Earth and Environment. Davison said: ‘We expect most ice shelves to go through cycles of rapid but short-lived shrinkage followed by slow growth. “Instead we see nearly half declining with no signs of recovery.”

He believes human-caused global warming is likely the primary driver of ice loss. If this were due to natural fluctuations in climate patterns, there would be some evidence of ice growth on western ice shelves.

Ice shelves float in the seas surrounding Antarctica and are an extension of the ice sheet that covers most of the continent. Ice shelves act as giant “plugs” at the ends of glaciers, slowing the flow of ice into the oceans. As the ice shelf thins or decreases in size, these plugs weaken, causing the rate of ice loss from the glaciers to increase.

Basic assessment of Antarctica

Researchers analyzed more than 100,000 satellite radar images to make this important assessment of the “health” of glacier ice shelves.

If ice shelves disappear or even shrink, this would have serious negative consequences for the ice system in Antarctica and the global ocean circulation, the giant “conveyor belt” that carries nutrients as well as heat and carbon through this fragile polar ecosystem.

Potential disruption of ocean circulation

The water entering the ocean from ice shelves and glaciers is fresh. Over the 25-year study period, researchers estimated that 66.9 trillion metric tons of freshwater entered the Southern Ocean around Antarctica from ice shelves alone.

In the Southern Ocean, dense salt water sinks to the ocean floor as part of the global ocean transport belt. This sinking of water serves as one of the engines that drives the ocean conveyor belt.

Freshwater from Antarctica dilutes salty ocean water, making it fresher and lighter, which takes longer to sink, which can weaken the ocean circulation system. Another study published in the journal Nature Climate Change suggests this process may already be underway .