Greenland and Antarctica are home to the two largest ice sheets in the world, and a new report released Wednesday says that they are contributing to sea level rise twice as much as they were just five years ago.
Using the European Space Agency's CryoSat 2 satellite, the Alfred Wegener Institute from Germany has found that western Antarctica and Greenland are losing massive amounts of ice.
"Combined, the two ice sheets are thinning at a rate of 500 cubic kilometres per year," said glaciologist Dr. Angelika Humbert, one of the authors of the AWI study, in a press release. "That is the highest speed observed since altimetry satellite records began about 20 years ago."
The report, published in the online magazine The Cryosphere, says the CryoSat 2 satellite measured over 200 million elevation data points in Antarctica and 14.3 million in Greenland to track the loss of ice mass over the last several years. "When we compare the current data with those from the ICESat satellite from the year 2009, the volume loss in Greenland has doubled since then," said Humbert. "The loss of the West Antarctic Ice Sheet has in the same time span increased by a factor of three."
Somewhat encouragingly, the East Antarctic Ice Sheet is gaining mass. However, those gains are very modest and don't make up for the loss of ice in West Antarctica and Greenland. Greenland is losing 350 cubic kilometers of ice annually, mostly from its southwestern coast, and accounts for almost 75 percent of the total volume lost each year. Together, the flows from Antarctica and Greenland could cover the entire Chicagoland area with 600 meters of ice each year.
The glacier melting the fastest among those measured was the Jakobshavn Glacier in Greenland and the Pine Island Glacier in West Antarctica. The Jakobshavn Glacier is descending into the ocean at a rate of 46 meters -- or half a football field -- each day. Last year, a chunk of ice twice the size of Detroit broke off the tip of the Pine Island Glacier.
Robert Bindschadler of NASA's Goddard Space Flight Center recently contributed to a similar study for the Potsdam Institute for Climate Impact Research. "Rising sea level is widely regarded as a current and ongoing result of climate change that directly affects hundreds of millions of coastal dwellers around the world and indirectly affects billions more that share its financial costs," he said in a press release. By 2100, ice melt from Antarctica alone could add up to 37 centimeters, or more than 14 inches, to global sea levels.
Another study published in the journal Science this month shows that in the last 20 years, human-caused climate change has become the primary driver of glacial melt.