A glacial ice shelf seen from the air.
Three years of observations, between 2010 and 2013, from the CryoSat-2 satellite show that the Antarctic ice sheet is now losing about 160 billion metric tons of ice each year –- twice as much as when it was last surveyed during the 2005 to 2010 period.
Recent land elevation changes via the CryoSat-2 satellite, showing the greatest amount of sinking land in West Antarctica.
The CryoSat-2 satellite, which is operated by the European Space Agency, uses high-tech altimeter instruments to detect changes in the height of the ice sheet, and see whether it is gaining or losing mass.
According to the study, the average elevation of the Antarctic ice sheet fell by 0.74 inches per year between 2010 and 2013. However, far more rapid rates of land elevation changes, which are a sign of a thinning ice sheet that is discharging more water into the ocean and thereby raising global sea levels, occurred in West Antarctica, the study found.
In the Amundsen Sea Embayment region of West Antarctica, where glaciers terminate in the ocean and extend over the waters via floating ice tongues, six major glaciers are experiencing rapid rates of retreat. These glaciers are being eaten away from underneath due to warm ocean waters that have been driven toward the continent by shifting wind patterns that have in turn been linked to manmade global warming, as well as natural climate variability. For example, the Smith Glacier has been sinking at nearly 30 feet per year, the Cryosat data showed.
“We find that ice losses continue to be most pronounced along the fast-flowing ice streams of the Amundsen Sea sector, with thinning rates of 4 to 8 meters per year near to the grounding lines –- where the ice streams lift up off the land and begin to float out over the ocean –- of the Pine Island, Thwaites and Smith Glaciers,” said lead author Malcolm McMillan of the University of Leeds in the U.K. in a press release.
Using observations of recent rates of ice loss and model-based projections of the future, two studies published in scientific journals last week found that a slow-motion "collapse" of parts of the West Antarctic Ice Sheet may be inevitable, due in large part to manmade climate change and other factors. This could raise average global sea level by up to 15 feet, inundating highly populated coastal areas around the world.
The new study does not explicitly address that conclusion, but it does underscore the rapid melting that is taking place in the West Antarctic Ice Sheet in particular. In West Antarctica, the satellite data shows a mass loss of about 134 billion metric tons of ice per year, which is 31% greater than over the 2005 to 2011 period.
"Our results are in broad agreement with these previous studies. We detect widespread thinning of this part of the West Antarctic Ice Sheet, which is what you would be expect to see from an ice sheet in a state of irreversible long-term collapse," said Malcolm McMillan, a research fellow at the University of Leeds, in an email to Mashable. "I should add that our study focuses on providing an up-to-date assessment of how the ice sheet has changed in the last 3 years, whereas one of the previous studies... uses models to investigate how the ice sheet may evolve in the future."
East Antarctica is losing a relatively small amount of 3 billion metric tons of ice per year, the study found, and McMillan described that part of Antarctica as "roughly in balance."
Projections of global mean sea level rise over the 21st century, based on different emissions scenarios.
Antarctic Ice Melt Rate Has Doubled Since 2010, Study Finds
ANDREW FREEDMAN May 19, 2014 mashable.com
A European Space Agency satellite has found that Antarctica has been shedding ice at an accelerated pace compared to when the continent was last surveyed, backing up other research that has detected similar trends. The study, accepted for publication in the journal Geophysical Research Letters, comes one week after other studies claimed that the "collapse" of some glaciers in the West Antarctic Ice Sheet may be inevitable, due to manmade global warming and other factors.
The new research, by a team of researchers in the U.K., used observations from the CryoSat-2 satellite to produce the first estimate of the volume and mass change of nearly the entire Antarctic ice sheet. The data used in the study included more than 455,000 independent estimates of changes in the land elevation of the vast ice sheets covering Antarctica, both in the western part of the continent, where ice is melting more rapidly, and in the east, where the ice is considered to be more stable, for the time being at least.
ANDREW FREEDMAN May 19, 2014 mashable.com
A European Space Agency satellite has found that Antarctica has been shedding ice at an accelerated pace compared to when the continent was last surveyed, backing up other research that has detected similar trends. The study, accepted for publication in the journal Geophysical Research Letters, comes one week after other studies claimed that the "collapse" of some glaciers in the West Antarctic Ice Sheet may be inevitable, due to manmade global warming and other factors.
The new research, by a team of researchers in the U.K., used observations from the CryoSat-2 satellite to produce the first estimate of the volume and mass change of nearly the entire Antarctic ice sheet. The data used in the study included more than 455,000 independent estimates of changes in the land elevation of the vast ice sheets covering Antarctica, both in the western part of the continent, where ice is melting more rapidly, and in the east, where the ice is considered to be more stable, for the time being at least.
Three years of observations, between 2010 and 2013, from the CryoSat-2 satellite show that the Antarctic ice sheet is now losing about 160 billion metric tons of ice each year –- twice as much as when it was last surveyed during the 2005 to 2010 period.
Recent land elevation changes via the CryoSat-2 satellite, showing the greatest amount of sinking land in West Antarctica.
The CryoSat-2 satellite, which is operated by the European Space Agency, uses high-tech altimeter instruments to detect changes in the height of the ice sheet, and see whether it is gaining or losing mass.
According to the study, the average elevation of the Antarctic ice sheet fell by 0.74 inches per year between 2010 and 2013. However, far more rapid rates of land elevation changes, which are a sign of a thinning ice sheet that is discharging more water into the ocean and thereby raising global sea levels, occurred in West Antarctica, the study found.
In the Amundsen Sea Embayment region of West Antarctica, where glaciers terminate in the ocean and extend over the waters via floating ice tongues, six major glaciers are experiencing rapid rates of retreat. These glaciers are being eaten away from underneath due to warm ocean waters that have been driven toward the continent by shifting wind patterns that have in turn been linked to manmade global warming, as well as natural climate variability. For example, the Smith Glacier has been sinking at nearly 30 feet per year, the Cryosat data showed.
“We find that ice losses continue to be most pronounced along the fast-flowing ice streams of the Amundsen Sea sector, with thinning rates of 4 to 8 meters per year near to the grounding lines –- where the ice streams lift up off the land and begin to float out over the ocean –- of the Pine Island, Thwaites and Smith Glaciers,” said lead author Malcolm McMillan of the University of Leeds in the U.K. in a press release.
Using observations of recent rates of ice loss and model-based projections of the future, two studies published in scientific journals last week found that a slow-motion "collapse" of parts of the West Antarctic Ice Sheet may be inevitable, due in large part to manmade climate change and other factors. This could raise average global sea level by up to 15 feet, inundating highly populated coastal areas around the world.
The new study does not explicitly address that conclusion, but it does underscore the rapid melting that is taking place in the West Antarctic Ice Sheet in particular. In West Antarctica, the satellite data shows a mass loss of about 134 billion metric tons of ice per year, which is 31% greater than over the 2005 to 2011 period.
"Our results are in broad agreement with these previous studies. We detect widespread thinning of this part of the West Antarctic Ice Sheet, which is what you would be expect to see from an ice sheet in a state of irreversible long-term collapse," said Malcolm McMillan, a research fellow at the University of Leeds, in an email to Mashable. "I should add that our study focuses on providing an up-to-date assessment of how the ice sheet has changed in the last 3 years, whereas one of the previous studies... uses models to investigate how the ice sheet may evolve in the future."
East Antarctica is losing a relatively small amount of 3 billion metric tons of ice per year, the study found, and McMillan described that part of Antarctica as "roughly in balance."
Projections of global mean sea level rise over the 21st century, based on different emissions scenarios.
Although the study did not find a significant change in the elevation of the interior East Antarctic Ice Sheet, it shows for the first time that the thinning of the Totten glacier in that region extends to the point where the ice meets the land surface below, known as the grounding line. Overall, the researchers found that West Antarctica, the Antarctic Peninsula and East Antarctica have all been losing mass, albeit at different rates.
The Antarctic Peninsula, which is the fastest-warming region on the continent, has been shedding about 23 billion metric tons of ice per year, the study found. Changes in snowfall amounts have helped balance out some of the ice losses there and especially in eastern Antarctica.
For Antarctica as a whole, the study found the current rate of ice sheet mass loss to be about 160 billion metric tons of ice per year. The extra water pouring into the sea is raising sea levels by about 0.1 inches per year, the study found.
That may seem small at first, but over time, especially when combined with other sources of sea level rise such as melting Greenland glaciers and the expansion of seawater as ocean temperatures increase, it adds up. In addition, there are no guarantees that the current rate will be maintained, since many studies have shown the likelihood of a higher rate of sea level rise as global warming continues.
"Antarctica is contributing more to sea level rise than previous measurements suggested. It is essential that we continue to monitor the ice sheet to understand how, and why, it is changing," McMillan said. While the study only includes data for the past three years, the observations extend a longer satellite record that dates back to the early 1990s, McMillan said. This data helps scientists make conclusions about how Antarctica's ice sheets are changing.
The most recent report from the U.N. Intergovernmental Panel on Climate Change projected a global average sea level rise of between about one to three feet, although that report did not take the new findings on Antarctic ice melt into account.
The Antarctic Peninsula, which is the fastest-warming region on the continent, has been shedding about 23 billion metric tons of ice per year, the study found. Changes in snowfall amounts have helped balance out some of the ice losses there and especially in eastern Antarctica.
For Antarctica as a whole, the study found the current rate of ice sheet mass loss to be about 160 billion metric tons of ice per year. The extra water pouring into the sea is raising sea levels by about 0.1 inches per year, the study found.
That may seem small at first, but over time, especially when combined with other sources of sea level rise such as melting Greenland glaciers and the expansion of seawater as ocean temperatures increase, it adds up. In addition, there are no guarantees that the current rate will be maintained, since many studies have shown the likelihood of a higher rate of sea level rise as global warming continues.
"Antarctica is contributing more to sea level rise than previous measurements suggested. It is essential that we continue to monitor the ice sheet to understand how, and why, it is changing," McMillan said. While the study only includes data for the past three years, the observations extend a longer satellite record that dates back to the early 1990s, McMillan said. This data helps scientists make conclusions about how Antarctica's ice sheets are changing.
The most recent report from the U.N. Intergovernmental Panel on Climate Change projected a global average sea level rise of between about one to three feet, although that report did not take the new findings on Antarctic ice melt into account.
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