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Satellites show acceleration of Antarctic glaciers

Glacier flow and ice loss in an important region of Antarctica has increased only marginally in recent decades, a satellite study has found.

The discovery represents the first detailed assessment of changing glacier flow in a south-western corner of the Antarctic Peninsula, known as Western Palmer Land.

Researchers’ findings are important for monitoring how the area, many of whose glaciers lie well below sea level, is responding to climate change.

Pioneering work

An international team of scientists, led by the UK Centre for Polar Observation and Modelling at the University of Leeds, is the first to map the change in ice speed.

The team, involving Edinburgh researchers, collated measurements from five different satellites to track changes in the speed of more than 30 glaciers between 1992 and 2016.

They found that the flow of most of the region’s glaciers increased by between 20 and 30 centimetres per day.

This equates to an average 13 per cent increase in speed across the glaciers of Western Palmer Land.

Modelling study

The team also combined their satellite observations with a computerised model, enabling a pattern of ice flow to be mapped.

This revealed that the region’s glaciers are losing an additional 15 cubic kilometres of ice into the oceans each year compared with the 1990s.

The findings contradict a recent separate study which reported that the region was losing three times as much ice.

This earlier result was based on measurements of glacier thinning and ice mass loss determined from other satellite measurements.

The latest study casts doubt on that interpretation, because the degree of glacier acceleration is too small.

Glacier insight

The research, published in Geophysical Research Letters and supported by the Natural Environment Research Council, provides the first direct evidence that the peninsula is losing ice because of increased glacier flow.

The greatest increase in flow was seen at glaciers grounded more than 300 metres below the ocean surface, which flow through deep bedrock channels into the warmest layer of the ocean.  

Our findings show that although Western Palmer Land’s glaciers are accelerating and contributing to sea level rise, this is here, unlike at nearby sectors, taking place at a slow rate.

Noel GourmelenSchool of GeoSciences