Large glaciers in East Antarctica, once thought to be stable despite global warming, are losing increasing volumes of ice, a new study by NASA has indicated.
East Antarctica glaciers contain vast amount of ice with the potential to cause sudden and catastrophic rises in sea level, reshaping of the world's coastlines. However, these glaciers are considered to be more stable than glaciers present in the western part of the continent.
In the current study, Catherine Walker, a glaciologist at NASA's Goddard Space Flight Centre in Maryland, analysed detailed maps of ice velocity and surface height elevation currently being created as part of NASA's Inter-mission Time Series of Land Ice Velocity and Elevation (ITS_LIVE) project.
Walker found that a group of four glaciers, located west of the massive Totten glacier, have started to lose significant volumes of ice, a sign of extensive changes in the ocean.
The change doesn't seem random; it looks systematic
These glaciers are located in Vincennes Bay area and span about one-eighth of East Antarctica's coast. The glaciers have lost about 2.75 metres of ice (in height) since 2008, Walker found. Before 2008, no measured changes in the elevation were seen for these glaciers.
Earlier, scientists had warned that Totten Glacier, which covers about 6,144 square kilometres, is shrinking continuously due to warming ocean waters. Totten is the largest glacier in East Antarctica and contains enough ice to increase sea levels by at least 3.35 metres.
Walker also found that the melting rate of a group of smaller glaciers along the Wilkes Land coast has almost doubled since around 2009 and that these glaciers are losing ice by about 24 centimetres each year.
"The change doesn't seem random; it looks systematic," said Alex Gardner, a glaciologist with NASA's Jet Propulsion Laboratory and the lead scientist of ITS_LIVE project. "Now we might be finding clear links of the ocean starting to influence East Antarctica."
Recent changes in sea ice and winds have led to a rise in the amount of heat delivered by the ocean waters to the glaciers
Walker compared ocean temperature simulations from a model with measurements obtained through sensors fitted on marine mammals. The results revealed that recent changes in sea ice and winds have led to a rise in the amount of heat delivered by the ocean waters to the glaciers in Vincennes Bay and Wilkes Land.
"Heightened attention needs to be given to these glaciers. We need to better map the topography and we need to better map the bathymetry," Gardner said.
"Only then can we be more conclusive in determining whether, if the ocean warms, these glaciers will enter a phase of rapid retreat or stabilise on upstream topographic features."
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