For more than 120 years, the University of Zurich's World Glacier Monitoring Service has compiled worldwide data on glacier changes. The institute just published a new study in Journal of Glaciology. The study sets an alarm signal regarding the speed of climate changes, a warning that adds up to other studies published recently. According to the findings, world glaciers melt faster than ever.
Michael Zemp, lead author of the study and Director of the World Glacier Monitoring Service, explained that glaciers observed in the study currently lose between half a meter and one meter of their ice thickness every year, a rate two to three times more than the average of the 20th century.
Another study published earlier this year in journal Earth and Planetary Science by researchers from Princeton University has come to the same conclusion. The study has shown that, compared with the ice accumulated in the east, Antarctica's massive ice sheet lost twice the amount of ice in its western portion during the past decade. All these studies have come to a common overall conclusion: our southern continent's ice cap is melting faster than ever.
By using gravitational satellite data, researchers were able to measure Antarctica's ice sheet. They found that between the years 2003 and 2014, the ice sheet lost 92 billion tons of ice per year. That amount of ice, if stacked on the island of Manhattan, would be more than a mile high. That means more than five times the Empire State Building's height.
Most of that ice loss came from West Antarctica, the smaller of the continent's two main regions. Researchers found that since the year 2008 ice loss from unstable glaciers in West Antarctica doubled from 121 billion tons average annual ice loss to twice that by 2014. And what is even more worrisome is the fact that the ice loss is happening at rapidly accelerating rates.
Ice is melting from West Antarctica at a far greater rate than previously thought and compared to other regions of the Antarctica continent, the Western region is much more unstable, according to first author Christopher Harig, a Princeton postdoctoral research associate in geosciences.
Meanwhile, ice-loss rates from all of Antarctica increased overall each year by 6 billion tons per year during the 11-year period examined by the researchers. Heavy losses had been recorded along West Antarctica's Amundsen Sea, particularly Thwaites Glacier and Pine Island. In the year 2002, an iceberg with a size bigger than 2,000 square miles broke off from the Thwaites Glacier.
According to Harig, it's the ocean currents rather than air temperatures that melt the ice in Antarctica. The melted land ice contributes to higher sea levels. Floating ice shelves melt as the ocean warms. The accelerating ice-melt in West Antarctic region is alarming scientists because it has an increasing contribution to sea-level rise. If we continue losing mass in those areas, it has come to the point that the loss can generate a self-reinforcing feedback. That means we will be losing more and more ice, "raising sea levels by tens of feet."