Climate change may be leading to the melting of glaciers worldwide, and that melting is contributing to the rise of sea levels around the world. Data from two NASA satellites have been studied to determine the role glaciers play in this increase. Although it is well-established that glaciers are melting, the rate at which they are disappearing has been the subject of controversy. NASA's new findings, announced May 16, might definitively answer that question.
The study showed that over a six-year period, glaciers in Greenland and the Antarctic lost over 570 trillion pounds of mass. This equates to an ocean rise of 0.03 inches every year. This is about thirty percent of the total rise in sea level seen during that same time period. The glaciers measured, however, only contain one percent of all the world's land ice.
NASA used measurements from the Ice, Clouds and Land Elevation Satellite (ICESat) and the Gravity Recovery and Climate Experiment (GRACE) to determine how much ice was being lost from the glaciers. From those findings, researchers were able to calculate the total amount of ice mass lost from all glaciers worldwide. ICESat ceased functioning in 2009, and its successor, ICESat 2, is due to launch in 2016.
Alex Gardner, lead author of the study and Earth scientist at Clark University said, "For the first time, we have been able to very precisely constrain how much these glaciers as a whole are contributing to sea level rise. These smaller ice bodies are currently losing about as much mass as the ice sheets."
The study determined that ice was lost from glaciers worldwide over the course of the study, with the greatest damage occurring in Northern Canada and Alaska, along with Greenland, the Himalayas and the southern Andes Mountains.
Satellite data was needed for this study, since using information collected from the ground can be misleading.
Gardner said, "Ground observations often can only be collected for the more accessible glaciers, where it turns out thinning is occurring more rapidly than the regional averages. That means when those measurements are used to estimate the mass change of the entire region, you end up with regional losses that are too great."
The results of the study were released in the Journal Science, on May 16.