Nowhere is global warming more keenly felt than in the mountain environment. Researchers from Grenoble have recently published a novel study that describes how this impacts upon climbers and mountaineers in the Mt Blanc massif.
Between the end of the 19th and the beginning of the 21st century the Western Alps has seen a temperature rise of 2 degrees C. This has resulted in a dramatic reduction in the surface area and thickness of glaciers - in recent decades the Argentiere glacier has lost 80m of it's ice depth and the Mer de Glace has receded at a rate of 40m per year.
Gaston Rebuffat's "The Mont Blanc Massif - The 100 Finest Routes". Not only has it been essential bed time reading for generations of aspiring alpinists but has now become a useful starting point for those investigating the effects of climate change.
But how has this affected climbers and mountaineers?
Jacques Mourey and his team analysed the effect of climate change upon 95 routes taken from Gaston Rebuffat's 1973 classic guide, "The Mont Blanc Massif - The 100 Finest Routes". A total of 31 experts, including guides, hut guardian's and guidebook editors were asked to identify specific climate-related changes to the approach, route and descent of each and determine whether these had an impact upon those seeking to climb it. The latter was determined by using a 5 point scale that ranged from no change (0) to complete change (4).
The results were striking. Only 2 of the routes were unchanged, whilst the remaining 93 had altered to some degree - 30 (slight - 1), 34 (moderate - 2), 26 (great - 3) and 3 (complete - 4). The leading reasons for these changes were the appearance of bedrock (85 routes), wider crevasses and bergschrunds (78 routes) and steeper glaciers (73 routes). In addition, warmer temperatures were also associated with weakening snow bridges, narrowing ridges and an increase in the risk of falling rock, snow and ice.
Collectively, the experts concluded that these changes meant that the routes had become harder and considerably more dangerous to climb.
The start of Rebuffat-Bacquet Route (red) on the south east spur of the Aiguille Du Midi can no longer be accessed from the glacier. Due to 25m of glacial recession the route now needs to be started via the harder Contamine Route (black) on the left. A short connecting pitch now links both routes (purple dots). A mean score of 2 was awarded to this route by the expert panel.
Historically, the Whymper Couloir on the south face of the Aiguille Verte was regarded as a classic early summer snow and ice climb (a - photo from late 1960's). However, climate change has meant that the bergschrund at the base of the route has receded and widened, whilst large sections of underlying rock are now often exposed (b - August 2017). Frequent rock falls are common (orange arrow). The orange star represents a massive rockfall that took place in 2015. A mean score of 3 was awarded to this route by the expert panel.
In 2005 an enormous rock fall stretching 700 vertical metres destroyed several lines, including the legendary Bonatti Pillar, on the Petit Dru. A mean score of 4 was awarded to this route by the expert panel.
Like much of our planet, mountainous regions are being affected by climate change. In future posts we'll take a look at the broader picture and discuss what is responsible for these changes and, perhaps more importantly, what we can do about it.
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The British Mountain Medicine Society (BMMS) are organising a Science Day in the Peak District on the 13th November 2019. Why not come along? Details can be found here.