THE largest glacier in the French Alps, the Mer de Glace near Mont Blanc, is melting faster than at any time in its recent history. The discovery is the first to be made with a technique for monitoring changes in glacier thickness based on satellite data alone.
Etienne Berthier from LEGOS (the Laboratory for the Study of Geophysics and Oceanography from Space) in Toulouse and colleagues used stereoscopic pairs of satellite images dating back to 1979 to monitor changes in the height of the Mer de Glace. The images showed that below a height of 2100 metres the glacier has…
