Researchers have discovered a “worrying” change deep beneath the surface of the cold Antarctic continent.
While it has long been known that melting ice caps are causing sea levels to rise, researchers have discovered a previously unknown event that may be responsible for accelerating the process.
The problem could directly affect 900 million people living in low-lying coastal cities around the world. So efforts to protect these towns from coastal flooding may need to go faster than previously thought.
Related: An ice shelf the size of half Canberra is breaking off from Antarctica
How is this “alarming” new melting happening?
The British Antarctic Survey (BAS) found that the problem occurs where ice sheets on land meet the sea. These stretches, known as “grounding zones,” are typically several kilometres long and are known to be sensitive to weather and ocean changes.
Here, increasingly warm seawater caused by climate change is accelerating the creation of new cavities in the ice. These holes allow more water to pass from the sea into the space between the ice and the land on which it rests. This lubricates the ice sheet above and accelerates its melting back into the sea.
Alex Bradley, an ice dynamics researcher at the British Temperature Survey, said: “A very small change in ocean temperature could cause a very large increase in the melting of the impact zone, which would lead to a very large change in the flow of ice over it.”
More disturbing changes in Antarctica
Sea level rise projections may be underestimated
Changes in this region are responsible for much of the water leaking into the ocean and causing sea levels to rise. The British survey says the discovery shows a “new and worrying way” the massive ice sheets are melting.
Bradley expressed concern that the impact of warming waters on the impact zones of both Antarctica and Greenland has not yet been taken into account in climate models prepared by the Intergovernmental Panel on Climate Change (IPCC).
“Our predictions of sea level rise may be significantly underestimated,” he warned.
The results were published in the journal Natural Earth Sciences.
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