Glacier shrinking before our very eyes

Glacier shrinking before our very eyes

by David Crookall, Https://, French Riviera, France

Massive retreat of the Mer de Glace, Chamonix-Mont-Blanc, France. Taken while the family was on holiday in the summer of 2016 (when we walked much of the Tour du Mont Blanc, and we were rope-guided across the top end of the Glacier du Géant, 3400m, accumulation zone for the Mer de Glace).

The level of the ice at certain recent dates is indicated by plaques. One gets a real feel for the accelerating melt. The valley walls smoothed by the passage of the glacier are visible.

A combination of warming and less precipitation mean that the glacier is retreating faster than ever. Between 1890 and 2016, the ice retreated vertically (thickness) by about 140 m and horizontally by about 2.4 km. Since 1939 the mean rate of melt has been about 0.3m/yr; recently it has accelerated to 4 m/yr. For discussions, see Berthier & Vincent, 10.3189/2012JoG11J083, and Vincent et al, 10.1002/2016GL072094.

The retreat has been so big that they constructed a cabin lift (not shown) to descend, and later they had to add on long stairs (shown), adding more steps each year. There is talk of building a new cabin lift further up the valley.

Half way down, a guide keeps watch over the tourists. I stopped and said with a tinge of wry humour “your job will soon disappear”; he replied “indeed it will”. It makes you want to weep.