The Snow In The Alps Is Decreasing: What Is Happening And What Are The Causes And Consequences?

The duration of seasonal snow cover in the Alps is shorter today than it has been in the last 600 years. This phenomenon could have serious consequences on the environment and on human activities. We understand the trend and the causes thanks to an Italian study.

The Snow In The Alps Is Decreasing: What Is Happening And What Are The Causes And Consequences?

When we talk about the Alps we have in mind the mountain par excellence , the one with a capital M. Giants with glittering peaks, imposing glaciers with blue veins, silent valleys covered in immaculate snow… It's sad to say, but unfortunately it could be increasingly difficult to admire these landscapes.

A recent study carried out in collaboration between the University of Padua and the Institute of Atmospheric and Climate Sciences of the CNR (National Research Council) has in fact demonstrated that the duration of the snow cover in the Alps has considerably decreased in recent decades and , currently, the average annual duration is the shortest in the last 600 years: over a month less than the average duration analyzed over the long term. Let's see the causes and consequences of the phenomenon.

The snowpack of the Alps

In the mountains, at higher altitudes and during the cold season, precipitation occurs mainly in the form of snow and covers the ground and bare rock with a thick layer of snow capable of being preserved for several months, even when it is below the limit perennial snow (the altitude above which the accumulated snow never melts completely). In general, the duration of the snowpack depends on various geographical factors , such as the latitude, altitude and exposure to the sun of a territory, but also meteorological factors , such as the presence of the wind and a mostly cloudy or clear sky.

The study of the duration of the snow cover

To carry out an analysis of the Alpine snow cover that took into account long-term variations, the researchers from the University of Padua and the CNR based themselves on the study of the growth rings of the common juniper , a very long-lived shrub (it can live several centuries ) which grows parallel to the ground at high Alpine altitudes.

The growth rings are the concentric circles that we can see inside the woody stems of trees when we look at them cut by cross section and indicate the stages of seasonal growth of the plant. Variations in this growth, due to external factors, such as prolonged frosts or anticipated heat, therefore remain "imprinted" in the structure of the growth rings forever.

Since the juniper is a plant that at high altitudes does not rise from the ground for more than a few tens of centimeters, it is clear that the snow cover significantly affects its seasonal biological cycle . By cross-referencing data on local temperatures and precipitations with those on the variations in the structure of the juniper growth rings, the researchers were able to develop a model capable of analyzing the duration of the snowpack in the Alps, even in a past in which there was the collection of climate data.

Thanks to this methodology, the data already described were found: today the average annual duration of the snow cover in the Alps is the shortest in the last 600 years .

The causes of the decline in snow duration in the Alps

Although the researchers did not delve into the causes of the reduction in snow cover, other studies, carried out on the main mountain ranges of countries throughout the northern hemisphere, have highlighted numerous observable correlations between the increase in temperatures ( and therefore global warming) and the duration of the snow cover on the hills. In fact, higher temperatures determine a smaller amount of snowfall , which therefore occurs in the form of rain, and affect the storage and melting times of the snow and ice present on the ground.

This circumstance is made even more evident by the progressive retreat of the glaciers and the spread of vegetation at ever higher altitudes , in areas where the environmental conditions would not have allowed the growth of complex plant species until a few decades ago.

The consequences of the disappearance of snow

What could be the consequences of the progressive disappearance of snow in the Alps? To begin with, snow and ice are uncannily important in maintaining climate balances . Large surfaces covered with snow or ice, in fact, increase the albedo phenomenon , i.e. the reflecting capacity of the sun's rays by a surface. More reflected solar radiation means less solar radiation absorbed by the earth's surface, with the consequence of a lower temperature, compared, for example, to nearby areas where the albedo is lower and the solar radiation warms the ground more, with direct effects on landscapes and ecosystems.

However, the consequences of a shorter duration of the snow cover do not concern only the environmental and climatic balances, but can also affect a multitude of other sectors in the short and long term. Snow cover is in fact one of the main factors affecting the water cycle . Indeed, the glaciers and snow of the Alps are a gigantic reservoir of fresh water , essential for the biosphere , of course, but also for human activities . Less snow and less ice means less water in some of Europe's most important watersheds , such as the Po River , during the warm season.

In the Alpine regions (and also downstream), agriculture , breeding , industrial activities , hydroelectric energy production , construction and tourism are activities which, directly or indirectly, require large quantities of fresh water and snow. It is therefore extremely important to continue monitoring this phenomenon and to act promptly to safeguard not only the environmental balance, but also the most vulnerable economic sectors of the Alpine regions.

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