A recent study led by researchers at Cornell University reports that the Patagonian Ice Fields are thinning faster than expected. Over the past 12 years, these glaciers have released enough water to cover the entire United States with 3.3 cm (1.2 inches) of water.
Collaborating with the Center for Scientific Studies (CECs) in Chile, the study’s authors used over 150 satellite images taken since the year 2000 to map the Southern Patagonia Ice Field, which combined with the Northern Patagonian Ice Field, is smaller than only Antarctica in the southern hemisphere.
The team, which used data from NASA’s Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission, compared their findings with measurements from the twin satellites Gravity Recovery and Climate Experiment (GRACE). The results indicated that on average, the Southern Patagonian Ice Field has thinned by almost 1.8 metres (5.9 ft) per year since 2000.
In addition to observing the greatest thinning at the highest elevations, the scientists also found that warming air temperatures led to increased precipitation versus snowfall. This results in more water beneath the glacier, decreasing friction and allowing it to move faster, supplying even more glacial ice to the ocean. In addition, lakes that rise on the front end of glaciers may further accelerate melting of the glacial ice edges.
This melting results in a global sea level rise. From 1970 to 2000, melt from both Patagonian Ice Fields contributed an average rise in global sea level of 0.042 millimetres per year, which has since increased to 0.067 mm annually, representing an increase of two per cent in total sea level rise since 1998.
