The water melted from two Andean icefields over the past 12 years was enough to cover the United States in 3.3 centimeters (1.2 inches) of water, finds a new study. The rate of melting accelerated by about half during those dozen years compared to the previous 30.
In reality, only the shoreline of the U.S. and all other nations have to contend with this tremendous volume of water. The larger of the two regions, the Southern Patagonian Icefield, dribbled away approximately 20 billion tons of water per year into the ocean, which contributed about 2 percent of the global sea level rise since 1998.
A study by Cornell University and the Center for Scientific Studies in Valdivia, Chile studied the demise of the Northern and Southern Icefields in South America using two sets of satellite observations from the NASA’s Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Gravity Recovery and Climate Experiment (GRACE).
“Using ASTER, we think that we have a good idea of where things are changing. But with GRACE we get a good idea of when things are changing. So we have this powerful hybrid,” Michael Willis, lead author of the study and a research associate at Cornell University said in a press release.
The satellites revealed that the Southern Patagonian Icefield thinned by approximately 1.8 meters (5.9 feet) per year since 2000.
“We find some glaciers are stagnant and even that some have advanced slightly but on the whole, retreat and thinning is prevalent,” Willis said. “Interestingly, we see thinning occurring up to the highest elevations, where presumably it is coldest.”
The thinning of the Grey Glacier in Patagonia is visible by comparing the current glacier with the bottom of the vegetation line on the surrounding mountains — where the glacier reached until recently. (Credit: Rivera, from press release)