Avalanche. The shrinking of Italian glaciers
Iced cloud
A white cloud smashes against eleven people and kills them. It is composed by ice and snow: July 3rd the cloud swamped the walkers that were hiking near Marmolada glacier, in Trentino Alto Adige, a region in Italy’s North-East. The survivors can remember just a white noise, then the time to think a way out, not enough to move the first steps trough it. Memory snaps, until they woke up and saw the rescuers.
“The shrinking of glaciers is the most evident outcome of current climate change. Other consequences can be seen in some phenomena that affect our planet”, states the Italian glacier committee (IGC) in a note released after the separation of Marmolada. To say: other glaciers will fall down and there will be other separation, if the international community will fail to reverse the current trend.
In the public statement Aldino Bondesan, Roberto Francese, Massimo Giorgi and Stefano Picciotti explain that Marmolada “is the biggest glacier in Dolomite, which represents a thermometer of climate change thanks to its immediate reaction also to the smallest variation of rainfall and temperature”. The tragedy of the event itself hides an even more awful one: the separation of a part of Marmolada is the tip of the iceberg of a process started more than seventy years ago, that affects all Italian glaciers. Moreover, differently to the earthquakes and landslides, it is almost impossible to predict a glacier’s collapse. For this reason, experts suggest structural solutions to tackle the current issue of climate change.
Group photo
The oldest study on Italian glaciers dates back to 1925: it is the drafting of all glaciers, followed two years later by the first atlas. Between the Fifties and the Sixties, the Italian glacier committee edited three different editions, than in the Eighties the World Glacier Inventory was published.
However, the most detailed study was carried out in 2005, when the Research Geological Group of University of Milan – with IGC and Sanpellegrino – started mapping all Italian glaciers, analyzing a special kind of high-resolution photo, shot until 2011.
The evolution of glaciers is studied by IGC by the Fifties: all the studies show a clear reduction of glaciers’ surface in all the country. The picture highlights a surface of 368 km2, distributed in sever regions: Lombardy, Trentino Alto Adige, Aosta Velley, Piedmont, Veneto, Friuli Venezia Giulia and Abruzzo.
Studying the evolution of the 903 photographed glaciers, it is clear that a relevant surface reduction occurred in all regions.
The most important one can be seen in Aosta Valley, where the total surface was 174 km2 in 1962 and nowadays it states at 132 km2: a reduction of 24% of the total iced area of the region, that on the glaciers’ national surface impacts of 30%. In all region can be seen the same trend.
Adamello, the vastest glacier in Italy, hold out against this general reduction. It lays out between Lombardy and Trentino Alto Adige. Its surface measures 16 km2 and, with other two glaciers, overcome the extension of 10 km2. The other two are Ghiacciaio dei forni, in Lombardy, and Miage, in Aosta Valley. Glaciers are divided into three categories: valley glaciers, mountain ones and glacieret. Respectively, they represent 3%, 57% and 40% of the whole surface.
Navigate the map the see all glaciers in the Alps (data courtesy of Paul, Frank; Rastner, Philipp; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Fugazza, Davide; Le Bris, Raymond; Nemec, Johanna; Rabatel, Antoine; Ramusovic, Mélanie; Schwaizer, Gabriele; Smiraglia, Claudio (2019): Glacier inventory of the Alps from Sentinel-2, shape files. PANGAEA).
The extension of these three glaciers is an exception. In Italy, most of them has a quite small surface: 107 out of 368 km2 of iced crust measures between two and five square kilometers.
Generally, glaciers are grouped into seven size class, that are common in whole Europe. Starting from the glaciers with less than 0.1 km2 and ending up with the ones bigger than 10 km2. From 1957 until 2015, the correlation between size class is remained almost the same. In other words, the shrinking of iced surfaces affected all kind of glaciers, regardless their size.
Times up
Taking into account glaciers’ evolution in the last decades, it is evident an increase in terms of numbers. In 1950s were present 835 glaciers, today there are 903. However, this data must not be considered as a signal of increase in glaciers’ surface.
The trend shows, instead, a clear reduction. This increase occurred mostly because of the separations caused by higher temperatures: it usually happens during the phases of melting that a glaciers brakes down into small different parts, which start dissolving after a few times.
In order to understand the condition how health are Italian glaciers, it is important considering the total extension of iced surfaces, that is reduced by 30%. In figures, it means that a shrinking of 158 km2 occurred. The most relevant reductions, in percentage, took place in Piedmont and in Friuli Venezia Giulia: more than 40%.
A good way to keep under control the increase of temperatures, and the climate change, is studying the evolution of the melting level. This measure corresponds to the height where the temperature reaches zero degrees. Thanks to surveys made with radiometeorographs, a precise method to measure different atmospheric variables, it is evident that al least from 1980 the melting level is slowly, but constantly, increasing.
This happens most of all during summer months. An increasing melting level causes more glaciers’ shrinking and separations. Considering the average of melting level between 1980 and 2010, and comparing it with the same temperature in 2015, an increase of 300 meters can be seen, with an important peak in July, of 569 meters.
It is extremely difficult to predict what will happen with glaciers’ melting and what the next studies will show. However, the IGC states that “if the current trend will be confirmed also in the years to come, it is likely that Marmolada will disappear before 2040”. Until a few years ago, experts thought that the Marmolada wouldn’t disappear before one hundred or two hundred years.
Meanwhile attending to discover if this expectation will be matched, experts stress the need to act as fast as possible at an international level, involving states and organizations by forcing them to reduce greenhouse gasses, to mitigate global warming. The only way to handle this process is to build a structured multi-level governance, with middle and long-term goals that can be checked and revised periodically.
According the ICG, the reason why is very simple: “the progressive shrinking acceleration oblige a revision of the most optimistic scenarios about climate change that were prepared by scientists”.