Mountain Climbing More Dangerous due to Climate Change

Climate change increases the danger of falling rocks in the Alps and other mountain regions, adding to existing risks for mountain climbers.  This is the conclusion of a study by Arnaud Temme of Wageningen University using climbing guides written by mountaineers in the past.

Global warming causes thawing of permafrost and retreat of glaciers and snowfields.  More rocks get exposed to the air, reducing their stability and increasing the chance of rolling or falling.  After permafrost degrades, freezing and thawing in cracks and crevices start to alternate.  Every time water freezes, it expands and lets the cracks grow slowly until the rock breaks.  Higher temperatures lead to more [u]nstable rocks, increasing the risk of falling.

Old climbing guides
In his research Arnaud Temme of Wageningen University gathered information on safety of climbing routes from so called climbing guides.  These guides are written by very experienced mountaineers that describe the climbing routes in a certain area, in this case the Bernese Alps in Switzerland.

In addition to climbing routes, information about risks of falling rocks is mentioned in the guides. For all routes the type and orientation of the rock and an indication of all risks along the route are noted.

Until ...now there was little information available on the risks of falling rocks:  the available data was on large, rare rock avalanches or for small slopes.  However, in the climbing guides, multiple generations of climbers noted the climbing dangers for whole mountain ranges.

The oldest guide out of the dozens of guides used in the research was written 146 years ago. This allowed Temme to record the changes for a longer period and link these with climate change.

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