An ice giant under the spell of climate change: One of the best-studied Alpine glaciers has reached the day of the year when its ice mass balance begins to fall into the red earlier than ever before: Normally, this “Glacier Loss Day” of the Tyrolean Hintereisferner falls in August – but this year already on June 22nd. The summer will probably continue to gnaw at the ice giant. Glacier researchers fear that in 2022 it will probably suffer an unprecedented mass loss. If the trend continues, the Hintereisferner will lose half of its ice in the next 10 to 15 years.
Its tongue currently extends about 8.6 kilometers into the valley: the Hintereisferner in the Ötztal Alps has been closely observed for more than 100 years and is considered a particularly impressive witness to climate change. As early as 1952, scientists began to continuously record its mass balance development. “We measure how much mass the glacier gains in winter and loses in summer,” says Rainer Prinz from the University of Innsbruck. The glacier mass balance is always calculated from October 1st of the previous year to September 30th of the current year. “Similar to the deposits and withdrawals in a bank account, the annual balance is positive if the glacier gains mass during this period and negative if it loses mass,” explains Prinz.
Already in the red since June 22nd
Since 2016, the glacier researchers have been recording changes in the mass of the Hintereisferner on a daily basis: so-called terrestrial laser scanners scan the surface of the glacier in detail. This method enables precise statements about the mass balance and a precise determination of the day from which the glacier will only lose mass until the beginning of the colder season. The earlier in the year this day – Glacier Loss Day – is reached, the worse it is for the mass balance of the glacier, the researchers explain. “To stay with the bank account example, the ideal would be a balanced balance sheet, or even a positive one. We would have a balanced balance if the glacier lost as much mass as it gained after a year. However, the account of the Hintereisferner slipped into the red earlier and earlier,” says Annelies Voordendag from the University of Innsbruck.
And this year it is particularly bad, as the investigations show: Glacier Loss Day was reached on the Hintereisferner on June 22nd, earlier than ever since records began. “Due to the lack of snow in the winter and the warm spring, the Hintereisferner was already balanced by the summer solstice compared to the previous autumn. In the last two years, Glacier Loss Day was around the end of August. Even in the years with negative balance extremes – such as 2003 and 2018 – this day was not reached until the end of July,” says Prinz.
Enormous shrinkage feared
Overall, the glacier researcher therefore expects an extremely negative mass balance for the Hintereisferner. “Even if the summer of 2022 turns out to be a ‘normally warm’ summer, a lot of glacier ice will melt. More than half of the glacier is no longer covered with snow and is therefore at the mercy of the sun’s energy,” says Prinz. “This development is outside of previously known ranges of fluctuation – both the mass balance and the climate. These are clear climate change signals that can be traced back to man-made global warming. These are consequences of our greenhouse gas emissions, which are already hitting us hard today,” emphasizes the scientist.
The forecast is also bleak: “Warm springs and summers will continue to increase in the future. Effective and rapid climate protection measures can still have a decisive impact on many glaciers around the world, for example in high Asia. However, we already know that the Hintereisferner will lose an average of five percent of its current volume every year over the next few years. This means that by the middle of the century there will at best be very little glacier ice left,” says Fabien Maussion from the University of Innsbruck.
Source: University of Innsbruck