WASHINGTON, June 13, 2018 /PRNewswire-USNewswire/ -- Ice
losses from Antarctica have
tripled since 2012, increasing global sea levels by 0.12 inch (3
millimeters) in 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. 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."
This latest IMBIE is the most complete assessment of Antarctic
ice mass changes to date, combining 24 satellite surveys of
Antarctica and involving 80
scientists from 42 international organizations.
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."
The satellite missions providing data for this study are 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.
Tom Wagner, cryosphere program
manager at NASA Headquarters, hopes to welcome a new era of
Antarctic science with the May 2018
launch of the Gravity Recovery and Climate Experiment Follow-on
(GRACE-FO) mission and the upcoming launch of NASA's Ice, Cloud and
land Elevation Satellite-2 (ICESat-2).
"Data from these missions will help scientists connect the
environmental drivers of change with the mechanisms of ice loss to
improve our projections of sea level rise in the coming decades,"
Wagner said.
To learn more about NASA's Earth science missions, visit:
https://nasa.gov/earth
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SOURCE NASA