More Bad News from Antarctica
December 3, 2014
The latest study of the West Antarctic Ice Sheet has provided more strong evidence of the devastating effect of global warming on this vulnerable region of Antarctica. The 21-year study found that the melting rate of the ice in the already-unstable Amundsen Sea region has tripled from 2003 to 2009. The findings, reported by scientists at the University of California, Irvine (UCI), and NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, are being described as the most authoritative estimate of ice loss in the region.
A number of studies have revealed that the West Antarctic Ice Sheet, which contains Antarctica’s fastest flowing ice, is warming much faster than scientists had estimated and that melting there has accelerated significantly since the early 1990′s. In May 2014, scientists from UCI and JPL reported that glaciers around the Amundsen Sea, the weakest of the continent’s ice sheets, appear to have begun a gradual but “unstoppable” slide into the sea. For the new study, the UCI and JPL scientists compared measurements of the “mass balance” of glaciers flowing into the sea using four different tools, including Earth-orbiting satellites, radars, and lasers. NASA defines mass balance as a measure of how much ice the glaciers gain and lose over time from accumulating or melting snow, discharges of ice as icebergs, and other causes. The scientists found that from 1992 to 2003, the melting rate increased by 6.7 billion tons (6 billion metric tons) of ice each year. From 2003 to 2009, however, the melting rate soared to 18 billion tons (16 billion metric tons) annually. The scientists calculated that the region has shed an amount of ice equal to Mount Everest, the highest mountain in the world, every two years for the past 21 years.
The glaciers in Amundsen Sea region of West Antarctica are losing ice faster than any other glaciers on the continent. (NASA/Michael Studinger)
The West Antarctic Ice Sheet is especially vulnerable to climate change, in part, because most of the ice sheet lies on terrain that is an average of 3,300 feet (1,000 meters) below sea level. As a result, the leading edges, or tongues, of the glaciers float on seawater. When a glacier melts, its grounding line–the point where a glacier attaches to underlying terrain and begins to float–also retreats. Nearly all the melting takes place on the underside of a glacier beyond the grounding line, where the ice comes into contact with warm seawater.
Additional World Book articles:
- Exploration (the Exploration of Antarctica)
- Global warming (2009) (a Back in Time article)
- The Great Meltdown (a special report)
- Science in Antarctica (a special report)
