In recent decades, France has seen some ski resorts close due to a lack of snow or a sustainable business model. However, the majority of resorts continue to cling to the hope of adapting to rising temperatures. But will reproducing the tried and tested recipes of the past be enough to meet the climate challenges ahead?

Published in Nature Climate Change, our study of 2,234 winter sports resorts in Europe sought to measure the impact of global warming on snowmaking in resorts and the possible room for maneuver available to adapt.

Winter sports resorts are unevenly distributed in 18 mountain massifs across Europe. Adapted from Francois et al., 2023, Fourni par l’auteur

This question is not just a concern for amateur or professional skiers. Skiing is also an economic issue, with a total turnover estimated at 30 billion euros in Europe. In France alone, 120,000 jobs depend directly and indirectly on the ski economy.

53% of ski resorts are at risk of running out of snow at +2degC

Climate change is a global phenomenon impacting resorts worldwide. Still, not all mountain areas are affected to the same degree or with the same speed, and the ability to limit the impact of these changes through snow production also varies greatly. We have measured the effects of climate change on winter sports resorts based on the level of global warming, using the graphical representation commonly used in IPCC reports of “burning embers”.

At 2degC of global warming above pre-industrial levels, 53% of European resorts are at very high risk of low snowfall. We assess the risk of low snowfall on the basis of the frequency of snow conditions considered to be the most unfavorable, those encountered on average one season in five between 1961 and 1990, the golden age of resort development.

However, the picture varies at a national level: in the French Alps, this proportion concerns a third of resorts, while in the Pyrenees and the Franco-Swiss mid-mountain massifs, 89% and 80% respectively, of resorts are affected by a very high level of risk of low snowfall.

At 4 degrees Celsius of global warming, 98% of European resorts are at very high risk of low snowfall. With this level of warming, the climate leaves winter sports resorts little margin for adaptation.

Changes in the use of snow production

One of the most popular solutions to adapt to scarcer snow is snowmaking, also known as “artificial snow.” Snow production involves projecting micro-droplets of water into the atmosphere so that they freeze before falling back to the ground. The resulting snow, made up of small balls of ice, is a suitable material for making an underlay.

In the past, snow was produced mainly to limit the impact of natural fluctuations in snow cover from one season to the next. Snow is now primarily produced in the pre-season, without any knowledge of the weather conditions for the coming winter, and then on a more ad hoc basis, if necessary, between the Christmas and winter holidays.

Snow production is also affected by rising temperatures.

Like natural snow, snow production is affected by rising temperatures, because snow production requires sufficiently cold weather conditions. This dual pressure is leading to increased investment to ensure that sufficient snow can be produced, thereby increasing the dependency of mountain resorts on snow tourism.

Not all ski resorts will equally be able to adapt to rising temperatures by producing snow. At +2degC global warming, snowmaking, if applied to 50% of the ski area, would reduce the proportion of resorts exposed to a very high risk of low snowfall in the Alps and Pyrenees to 7% and 9%, respectively, while in the mid-range mountain ranges the proportion would be 56%. These differences are even more marked at higher levels of warming.

However, it should be remembered that while the level of snow cover is critical to ensuring resorts’ long-term socio-economic viability, other criteria are just as fundamental, such as the state of the ski lift network, promotion/marketing methods, accommodation capacity, and attractiveness. It is, therefore, not possible to draw any direct conclusions from the figures for the risk of low snowfall as to the proportion or number of resorts likely to cease skiing.

The carbon footprint of snow production

What’s more, snow production is not carbon-neutral, so it’s important to bear this in mind before setting this technique up as the ultimate answer to reducing snow cover.

We have, therefore, also calculated the water requirements, production and energy demand involved, and the carbon footprint of the electricity used to produce snow. Over the reference period (1961-1990), the total quantity of snow made on the slopes covered by the installations represents 13% of the total precipitation that falls annually on these same slopes. Assuming that snowmaking facilities cover 50% of the slopes, the total volume should increase by between 8% and 25%, depending on the country, for a warming of +2degC and even more for a more marked warming.

This demand also tends to stagger over time, with lower production in November due to fewer cold spells favorable to output at the start of winter. It is, therefore, likely that the services provided by snow production will not be the same as in the past, which could make snow cover even more fragile over the high season.

In any case, the total volume of water that could be needed remains moderate, and a large part of this water is returned to the rivers as it melts. This is not to say complications can’t occur at a local scale further down the line, depending on how the water is drawn and of the makeup of affected ecosystems.