Posted on: 2015-06-07 11:35:33 by davidof

Mont Blanc glacial retreat

Contrary to many newspaper reports climate change has not halted over the last decade, at least not in the Alps. The glaciers in the Mont Blanc range have lost 10 meters depth on average between 2003 and 2012. A much higher rate than during the period 1979 to 2003.

The loss of ice is principally due to the rise in temperatures during the summer which has accelerated melting because the quantity of snow fall over the last 40 years hald not really changed.

These are the main conclusions of a study carried out by a team of glacier specialists from Legos at Toulouse and the LGGE based in Grenoble. A study that was able to use the two observation satellites Pléiades from Airbus defence and space. These satellites have a resolution of 0.7cm enabling detailed digital terrain maps to be built with high resolution altitude readings by using multiple images of the same area. The precision altimeteric is 1 meter. A similar process was used with the previous study with the Spot 5 satellite.

The researchers, after checking results on the ground, were able to compare the images from 2003 taken with Spot-5 with those from 2012 taken with the Pléiades. A simple subtraction shows how the glacial altitude has evolved with a very good spatial resolution.

Further Information

The analysis shows that the glaciers are stable above 3800 meters but are strongly shrinking below. Some more than others such as the Brenva on the Italian side that is losing 12 meters depth per year or the famour Mer de Glace that is losing 4 to 5 meters per year.