Tagged as the warmest and wettest year so far globally, 2015 closed with traditionally chilly regions of Siberia and the US Eastern seaboard sizzling right through Christmas. Then the weather see-sawed, with last weekend’s mega-blizzard crippling New York and nine other US states, while European ski resorts enjoyed generous sprinklings of snow.
Climate experts say people will still be able to ski for many more years to come although ideal winter conditions are predicted to become less common as the Earth warms. In a not-so-distant future the situation may start to become critical for some small ski resorts.
Skiing and mountain-climbing are high-adventure sports that attract many tourists to the cooler mountainous regions of our planet.
Yet the danger of falling rocks in the Alps and other mountain regions has seen an increase due to climate change, according to a study issued this month by the environmental science department of Wageningen University, the Netherlands.
Permafrost is a layer of soil or rock debris that has been permanently frozen wherever the ground temperature was below 0˚C for at least two years. As the Earth gets warmer this layer is slowly melting. The result is destabilisation and erosion of formerly frozen solid surfaces.
Referring to data from generations of climate guides, the Dutch study found that degraded permafrost exposes rocks so that they may roll or fall down.
Once exposed, rocks are more prone to the effects of continuous thaw/freeze cycles. Each time the water trapped in crevices is frozen there is expansion, which makes the crack grow until the rock breaks. Even small amounts of frozen water in fissures make rocks very susceptible to temperature changes.
The Alps are warming at the rate of 3.5°C every 100 years – faster than the European average. Natural variability of snow cover, with some winters seeing very little snow and other years having heavy snowfall, is a pattern set to continue. However, according to the Institute for Snow and Avalanche Research in Switzerland, a general long-term shift is expected toward winters with less snow.
Further warming could see some ski resorts closing down unless they can migrate to higher locations. While they may still have years when there is sufficient snowfall, the amount of snow cover is decreasing because with warmer winters the snow no longer stays on the ground for as long as previously.
Several small Swiss resorts have already become unprofitable and for others it is just a matter of time. Swiss public television has reported that there is now 30 per cent less snow than 35 years ago in smaller resorts in the lower-lying regions. Ski areas with the best chances of surviving into the foreseeable future will be those at the highest altitude in Switzerland and France.
Scientists have recorded the loss of half of Europe’s glacial ice since the 1850s, yet the melting of glaciers has been easier to measure than thawing permafrost, which is less directly visible in the landscape, until disaster strikes.
Warming and thawing of the frozen ground could cause problems for buildings as they tilt or collapse, as has already begun to happen
Arctic regions are warming at twice the global average rate as the warmth-reflecting properties of sea ice simply melt away. Two-thirds of Russia’s land mass lies in a permafrost zone on which entire cities are built.
Warming and thawing of the frozen ground could cause problems for buildings as they tilt or collapse, as has already begun to happen. Melting permafrost also poses a threat to infrastructure such as roads and pipelines in the far north. Even trees have been observed leaning drunkenly.
‘Drunken’ trees are now seen in lowland arboreal forests in Alaska, Canada and northern Eurasia. Birch trees and black spruce, with their shallow root systems, are species most likely to lean at a drunken angle as the solid ground beneath them melts into a shifting morass.
The effect of climate change on ski resorts has also come under the lens. The effect permafrost thaw may have on ski lift and cable car infrastructure has been the subject of a study by an Alpine monitoring network under the EU Permanet project.
Since infrastructure at many high-altitude ski resorts is located partially on permafrost this makes it potentially vulnerable to local ground movements that may affect the alignment of pylons supporting cables. Small movements of pylons on a moving permafrost body can be corrected by the adjusting of screws at the base. The study recognises that current problems with permafrost are have so far been quite moderate and are solved by frequent maintenance, although this has pushed up maintenance costs.
If the degree of movement is high, then total rebuilding or even abandonment of the damaged cable car infrastructure may be necessary. Although the present hazard factor is virtually nil, and no accident caused by permafrost creep has yet been reported, permafrost melt could “significantly increase damage” at ski resorts in the future, concludes the report.
Avalanche defence structures, built to retain snow in steep avalanche-starting zones, are located at high-altitude sites on unstable permafrost. Observations have helped to understand the particularly short service life of snow nets installed on an avalanche slope overlying the main road to Zermatt in Switzerland. Creep rates have caused displacement of the protective net infrastructure by up to 10cm.
After costly damage induced by permafrost melt and creep, leading to rock fall, the Swiss revised their guidelines for construction and maintenance of structures on permafrost.
Among case studies listed in the Permanet report, the Bouchet chairlift in Savoy, France, with four of its pylons on “deeply frost-shattered and creeping bedrock” is being closely monitored. This chairlift does not operate in summer when the ground is less stable, and before each winter season the cables have to be realigned.
A climbers’ refuge in the region of Brescia, Italy, is also under surveillance for its position on a steep slope of rock debris. The 1929-built hostel with capacity for 120 guests was rebuilt in 2005 as it had already become unstable due to retreating ice.
Technical recommendations for all other types of typical mountain infrastructure in existing permafrost terrain have been upgraded as engineering projects in permafrost become ever more challenging in this era of climate change.
As a final outcome of the transnational project it is hoped that an Alpine permafrost monitoring network will continue issuing periodic reports of the thermal state of permafrost in the Alps.
Increasingly, water in the Alps is used for snowmaking at precisely the time of year when reservoir levels are low. Beyond snow cannons, the future of the resorts may only be saved by providing a more varied range of tourist and sporting activities all year round.
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