Glaciers in Italy and elsewhere are now in a very vulnerable condition: their very existence is threatened by the effects of global warming
Glaciers in Italy and elsewhere are now in a very vulnerable condition: their very existence is threatened by the effects of global warming
Persistent abnormal, temperatures on Alpine glaciers are one of the most tangible effects of the climate crisis
anaries are very sensitive to the effects of methane and carbon monoxide; these birds were once used in coal mines to detect the presence of toxic gases and thus the need to evacuate the area. Under normal conditions these birds would sing most of the time; when the toxic gases were present, the birds would feel the effects and show signs of suffocation before the miners did, thus providing a clear signal to the workers. Similarly, we can track the progress of climate change by looking at the melting of glaciers; in this context, they play the same role as the canaries in the coal mines.
10%
The percentage of the earth's surface covered by glaciers
Climate change is exerting a huge impact on glaciers: with each passing year, we can see that during the summer months the glaciers lose more volume through melting than the amount of ice and snow they accumulate in winter: this phenomenon is on the rise and will produce serious and often unpredictable consequences. Also, Italian glaciers are under threat from global warming caused by man-made greenhouse gas emissions. According to Carlo Barbante, professor at the Ca' Foscari University of Venice and director of the Institute for the Dynamics of Environmental Processes (IDPA-CRN), gradually rising average global temperatures will lead to the disappearance of most Alpine glaciers below the 3,600-metre-threshold by the end of the century, with variations depending on altitude, position and conformation.
Worth knowing
Freezing level is calculated using weather balloons: as they ascend they measure air temperature and the data is sent to weather stations
In the last decade, the climate crisis has led to intense heat waves and increasingly long periods of drought, causing a rapid rise in the altitude at which glaciers melt. One of the most widely used indicators of this trend is “freezing level” i.e. the distance between the ground and the altitude where the air is at a temperature of zero degrees (this is the measurement is in metres and not degrees Celsius). When the temperature drops below zero degrees, the water around the glaciers begins to solidify. In the Alps, freezing level is between 3,200 and 3,700 metres, but rising temperatures are pushing it up towards 4,000 metres, with peaks even above 5,000.
Worth knowing
If temperatures like this continue at such high altitudes, they will threaten the long-term existence of glaciers
Between Sunday 20 and Monday 21 August 2023, the weather station in Payerne, Switzerland, recorded freezing level in the Alps at 5,298 metres – the highest altitude since measurement records began in 1954
900
The approximate number of glaciers in Italy
It is vital for mountains that glaciers are protected: their melting threatens the survival of entire high-altitude ecosystems and has a knock-on effect on systems downstream. Without the water reserves held by glaciers, the valley floor becomes increasingly prone to prolonged periods of drought. Glaciers in fact have a unique influence on river flows during periods when other water sources are scarce. Their melting will profoundly affect the natural environment, including many aspects of biodiversity.
900
The approximate number of glaciers in Italy
The biggest worry for glaciologists and meteorologists now is the frequency with which heat waves recur at high altitudes. Exceptionally high temperatures had indeed been recorded on Italian glaciers in the past, but much less frequently than in recent years. And it is this tendency that increasingly causes them to melt: 2022 had already been described as a “disastrous” year from this point of view. In the long term, global warming-linked heat waves could have effects even above 4,000 metres.
- 40%
The percentage of Italian glacier area that has retreated in the last 30 years
Another consequence of global warming on glaciers is the increased risk for people who live in or visit mountainous areas. Thawing at high altitudes can cause entire portions of glaciers to become detached, and this can lead to large-scale landslides and avalanches. Also, the formations known as snow bridges, which cover the crevasses on glaciers, can weaken and thus become more dangerous for people crossing them. However, such phenomena are not always easy to predict and monitor: a balance must therefore be found between mitigating risk and safeguarding the mountain-related economic activities that have developed in recent decades. ▲
ne of the most closely monitored and glaciologically studied Alpine glaciers is the Marmolada, the highest mountain group in the Dolomites, in Trentino-Alto Adige. Various studies have indicated that it will only last for another 15 years or so before being “downgraded” to glacieret status, i.e. an accumulation of ice and snow that, unlike a glacier, does not have downstream movement. The Calderone, on the Gran Sasso, is the southernmost glacier body in Europe and has recently been downgraded. Over the last century, the surface area of the Marmolada glacier has shrunk by an average of two and a half hectares per year. Since 2007, an average of nine hectares per year have been lost. The glacier currently has a total area of about 120 hectares.
- 30%
The amount by which the Marmolada glacier shrank between 2004 and 2014
In 2013, the glacier had a surface area of 1.9 square kilometres, but seven years later it had dropped to 1.5 square kilometres – about a quarter of what it was at the beginning of the 20th century. The Marmolada glacier has not only shrunk in terms of volume and surface area, but has also become fragmented. It can no longer be considered a single ice mass: it is now divided into several parts, partly due to the shape of the mountain. This exacerbates the melting during the summer months, as the mountain rock exposed to sunlight absorbs heat and further warms the surface of the glacier, causing it to disintegrate.
Mauro Varotto
Lecturer in Geography at the University of Padua and supervisor of annual measurements made on the Marmolada
The Marmolada is a precursor of what will happen to the vast majority of Alpine glaciers. By the end of the century, the only ones remaining will be found at higher altitudes, in the 4,000-metre zone
The gradual thawing and fragmentation of the Marmolada glacier led, in July 2022, to the collapse of about one third of its mass: a portion over 30 metres high and about one hundred metres long. The resulting avalanche of 64,000 tonnes of water, ice and debris killed eleven people and injured seven. The collapse, at an altitude of 3,212 metres in the highest part of the Marmolada’s northern slope, occurred in the wake of anomalous spring and summer temperatures.
At the time of the avalanche, temperatures had risen to above 10 degrees. The period between December 2021 and February 2022 was also one of the warmest and lowest, in terms of snowfall, since 1921. All these factors together caused a large portion of ice to break off and slide down the valley. The fact that there was a lot of water on the glacier indicates its stressed condition and its consequent extremely high melt rate. The Marmolada collapse also involved a small glacier that until a decade ago was actually part of the main glacier: the part that fell separated from the body of the glacier as a result the ongoing fragmentation.
+ 2°C
The higher temperature margin recorded in the two months before the avalanche, compared to the 2008-2021 average
Anselmo Cagnati
Glaciologist at the anti-avalanche centre of the Veneto Regional Agency for Environmental Protection (ARPAV)
The Marmolada collapse was a catastrophe in the making for some time, due to repeated and increasingly hot summers above the 3,500-metre level. Similar phenomena are likely to be more and more frequent in years to come
The Marmolada glacier was not one of the Alpine glaciers subject to monitoring because its structure rendered it liable to collapse in some places. Historical memory makes no mention of such a large portion of the Marmolada glacier breaking away. However, due to global warming, we cannot rule out the possibility of Marmolada-type collapses happening on glaciers that have been historically less affected by the phenomenon.
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After the tragedy, the local tourism sector found itself in serious difficulty when the widespread fear of avalanches on the Marmolada led to a sharp increase in cancellations
In that moment when the huge glacier block broke off and caused an avalanche, there were dozens of hikers, mountaineers and cyclists on the trails of the Marmolada and neighbouring mountains: the tragedy sparked a debate on the need for awareness among visitors to mountains and glaciers, especially in relation to the risks that climate change brings. ▲
ocated at the north end of Val Camonica, between Lombardy and Trentino-Alto Adige, is another of Italy's most closely monitored Alpine glaciers: the Adamello. This glacier lies at an altitude of between 2,500 and 3,500 metres and is the largest and thickest in the Italian Alps. Nevertheless, forecasts say it will disappear by the end of the century because the amount of ice that melts in the summer is much greater than the volume recuperated during the winter period. The Adamello glacier has already lost about half of its volume since 2000.
Between 2007 and 2022, its surface area shrunk by 2.6 square kilometres to about 13 square kilometres in total. In 2022, the low snowfall and particularly high temperatures significantly impacted on its mass: the ice sheet reduced by more than two metres – the most severe annual reduction in about thirty years.
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Although the glacial melt values recorded in 2022 were not reached, we can describe 2023 as one of the worst years for the Adamello in terms of melt since data collection began
As expected, in 2023, the thickness loss of the Adamello glacier was 2.6 meters. It is the second worst value in the historical series after 2022, a year marked by a serious drought and a very hot summer
On the main slope of the Adamello, the glacier front, i.e. the lowest and most visible part of the ice mass, retreated by 174 metres between 2020 and 2022. Like many other Alpine glaciers, the Adamello is fragmenting: it is no longer a single “glaciological unit”, but consists of several separate ice masses, a condition that could accelerate its rate of melting.
+ 50
The surface area in hectares – the equivalent to about 70 football fields – that the Adamello glacier has lost in the last 10 years
Last summer’s high temperatures have exposed the first rock outcrops in the frontal area of the Adamello glacier: this phenomenon both demonstrates the loss of thickness and accelerates the melting of the surrounding ice. The exposed rock absorbs increased levels of solar radiation during the day and this is released as heat during the night, thus furthering the melting process. ▲
