Ice losses from the Antarctica region have tripled since 2012, increasing global sea levels by 0.12 inch (3 millimeters) within that timeframe alone, according to a major new international climate assessment funded by NASA and ESA (European Space Agency).
According to the study, ice losses from Antarctica are causing sea levels to rise faster today than at any time in the past 25 years.
(Learn More. Antarctica is contributing an increasing amount to global sea level rise, according to new research published in Nature by an international team of scientists led by Professor Andrew Shepherd from Leeds’ School of Earth and Environment. Courtesy of the University of Leeds UK and YouTube. Posted on Jun 14, 2018.)
Results of the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) were published Wednesday in the journal Nature.
“This is the most robust study of the ice mass balance of Antarctica to date,” said assessment team co-lead Erik Ivins at NASA’s Jet Propulsion Laboratory (JPL).
“It covers a longer period than our 2012 IMBIE study, has a larger pool of participants, and incorporates refinements in our observing capability and an improved ability to assess uncertainties.”
It is the most complete picture of Antarctic ice sheet change to date – 84 scientists from 44 international organizations combined 24 satellite surveys to produce the assessment.
(According to research from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE), published today in Nature, the Antarctic ice sheet’s contribution to global sea level was 7.6 mm since 1992, with two fifths of this rise (3.0 mm) coming in the last five years alone. Courtesy of SciNews and YouTube. Posted on Jun 13, 2018.)
The assessment, led by Professor Andrew Shepherd at the University of Leeds and Dr. Ivans at NASA’s Jet Propulsion Laboratory in California, was supported by the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA).
The team looked at the mass balance of the Antarctic ice sheet from 1992 to 2017 and found ice losses from Antarctica raised global sea levels by 0.3 inches (7.6 millimeters), with a sharp uptick in ice loss in recent years.
They attribute the threefold increase in ice loss from the continent since 2012 to a combination of increased rates of ice melt in West Antarctica and the Antarctic Peninsula, and reduced growth of the East Antarctic ice sheet.
Prior to 2012, ice was lost at a steady rate of about 83.8 billion tons (76 billion metric tons) per year, contributing about 0.008 inches (0.2 millimeters) a year to sea level rise.
Since 2012, the amount of ice loss per year has tripled to 241.4 billion tons (219 billion metric tonnes) – equivalent to about 0.02 inches per year (0.6 millimeters) of sea level rise.
West Antarctica experienced the greatest recent change, with ice loss rising from 58.4 billion tons (53 billion metric tons) per year in the 1990s, to 175.3 billion tons (159 billion metric tons) a year since 2012.
Most of this loss came from the huge Pine Island and Thwaites Glaciers, which are retreating rapidly due to ocean-induced melting.
At the northern tip of the continent, ice-shelf collapse at the Antarctic Peninsula has driven an increase of 27.6 billion tons (25 billion metric tons) in ice loss per year since the early 2000s.
Meanwhile, the team found the East Antarctic ice sheet has remained relatively balanced during the past 25 years, gaining an average of 5.5 billion tons (5 billion metric tons) of ice per year.
Antarctica’s potential contribution to global sea level rise from its land-held ice is almost 7.5 times greater than all other sources of land-held ice in the world combined.
The continent stores enough frozen water to raise global sea levels by 190 feet (58 meters), if it were to melt entirely.
Knowing how much ice it’s losing is key to understanding the impacts of climate change now and its pace in the future.
“The datasets from IMBIE are extremely valuable for the ice sheet modeling community,” said study co-author Sophie Nowicki of NASA’s Goddard Space Flight Center.
“They allow us to test whether our models can reproduce present-day change and give us more confidence in our projections of future ice loss.”
“We have long suspected that changes in Earth’s climate will affect the polar ice sheets. Thanks to the satellites our space agencies have launched, we can now track their ice losses and global sea level contribution with confidence,” explained Professor Shepherd.
“According to our analysis, there has been a step increase in ice losses from Antarctica during the past decade, and the continent is causing sea levels to rise faster today than at any time in the past 25 years.”
“This has to be a concern for the governments we trust to protect our coastal cities and communities.”
“The added duration of the observing period, the larger pool of participants, various refinements in our observing capability and an improved ability to assess both inherent and interpretive uncertainties, each contribute to making this the most robust study of ice mass balance of Antarctica to date,” added Dr. Ivins.
The satellite missions providing data for this study include:
- NASA’s Ice, Cloud and land Elevation Satellite (ICESat)
- The joint NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE)
- ESA’s first and second European Remote Sensing satellites, Envisat and CryoSat-2
- The European Union’s Sentinel-1 and Sentinel-2 missions
- The Japan Aerospace Exploration Agency’s Advanced Land Observatory System
- The Canadian Space Agency’s RADARSAT-1 and RADARSAT-2 satellites
- The Italian Space Agency’s COSMO-SkyMed satellites, and
- The German Aerospace Center’s TerraSAR-X satellite.