West Antarctic ice melt rate tripled, finds NASA

A detailed 21-year analysis of the fastest-melting region of Antarctica has found that the melt rate of glaciers there has tripled during the last decade.

The glaciers in the Amundsen Sea Embayment in West Antarctica are haemorrhaging ice faster than any other part of Antarctica and are the most significant Antarctic contributors to sea level rise, the US space agency said in a statement.

"The mass loss of these glaciers is increasing at an amazing rate," said scientist Isabella Velicogna, jointly from University of California Irvine and NASA's Jet Propulsion Laboratory.

For the study, the researchers reconciled measurements of the mass balance of glaciers flowing into the Amundsen Sea Embayment using four observational techniques.

Measurements were available from 2003 to 2009. Combined, the four data sets span the years 1992 to 2013.

The total amount of loss averaged 83 gigatons per year (91.5 billion tonnes).

"By comparison, Mt. Everest weighs about 161 gigatons, meaning the Antarctic glaciers lost a Mt.-Everest's-worth amount of water weight every two years over the last 21 years," Velicogna said.

The rate of loss accelerated an average of 6.1 gigatons (6.7 billion tonnes) per year since 1992.

From 2003 to 2009, when all four observational techniques overlapped, the melt rate increased an average of 16.3 gigatons per year - almost three times the rate of increase for the full 21-year period.

The four sets of observations include NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, laser altimetry from NASA's Operation IceBridge airborne campaign and earlier ICESat satellite, radar altimetry from the European Space Agency's Envisat satellite, and mass budget analyses using radars and the University of Utrecht's Regional Atmospheric Climate Model.

The paper appeared in the journal Geophysical Research Letters.