A new study led by Eurac Research in Italy has found that the number of snow cover days in the Alps could halve by the end of this century, if greenhouse gas emissions are not urgently curbed. This could have a major impact on water availability, local ecosystems, and ski resorts.
According to the experts, without emission cuts, snow loss would be particularly severe in the southern Alps (Italy, Slovenia, and parts of France), with the southwest Alps being particularly badly hit. However, with rapid climate mitigation efforts, up to 83 percent of current snow days could be saved.
“I expected reductions in snow cover, but our findings in this paper under a strong warming scenario of 4 to 5°C are very alarming. On the other hand, there is a large margin of potential savings, if warming is limited within the Paris Agreement – which certainly raises some hope,” said study lead author Michael Matiu, a senior researcher at Eurac.
The loss of snow cover could have a significant impact on areas downstream which rely on the yearly spring and summer snow melt for water. “Snow loss will lead to a temporal shift in water availability, with higher water flows in winter and less in summer. This is particularly challenging in areas which already fight for water usage,” explained Matiu. “In any case, the Alps or the countries sharing the Alps will need to find a way to manage water availability across regions and sectors, to have enough water for agriculture, energy production, domestic use, and tourism, at the right time and in the right location.”
According to Matiu and his colleagues, the number of snow days lost will vary with altitude. For instance, mountains at 2500 meters would lose 76 days worth of snow if emissions are high, while at 500 meters, only 14 days of snow cover would be lost. However, cutting emissions in line with the Paris Agreement and constraining global warming to 1.5-2°C above pre-industrial levels would save up to two months of snow cover per year at higher altitudes.
Since white snow reflects heat and cools the Earth, if this cover is lost for prolonged periods of time, exposed darker rocks and vegetation would absorb heat and further exacerbate warming. Higher temperatures in the mountains would threaten the Alps’ iconic biodiversity and fundamentally change Alpine ecosystems. Thus, as Matiu puts it, staying within the Paris Agreement targets is “most vital.”
The study is published in the journal Hydrology and Earth Sciences.