0.5 degrees Celcius: Small difference, large effect

For glaciers in the European Alps, it makes a large difference whether the earth’s atmosphere will warm by one, one and a half or two degrees Celsius by the end of the century. This is the finding of a new study from the Professorship of Glaciology at D-BAUG, which simulated the effects of the three climate scenarios on the nearly 4,000 glaciers in the European Alps.

Half a degree may not sound like much. But as glaciologists from D-BAUG demonstrate, every half-degree counts when it comes to global climate. For their study, the scientists combined different simulation models to calculate how the mass of Alpine glaciers would change over time – assuming one, one and a half, and two degrees global warming. According to their projections, today’s ice volume would decrease by 44% (+1.0°C), 68% (+1.5°C) and 81% (+ 2.0°C) until the year 2100. This means that glaciers such as the “Grosse Aletschgletscher” or the “Rhonegletscher” would lose about half of their todays volume even in the most moderate scenario (+1.0°C).

Furthermore, the study shows that these developments would also have a strong impact on the hydrological conditions in the Alps. Compared to the past 20 years, the annual average runoff from presently glacierized surfaces could decrease by about 25% (+1.0°C), 32% (+1.5°C) and 36% (+2.0°C) by the end of the century. In summer, glacier runoff could even decrease by up to 55% – with important implications for downstream water resources.

Illustration of modelled glacier evoluation
Modelled evolution of total glacier (a) volume, (b) area, (c) annual glacier runoff, and (d) monthly glacier runoff of the European Alps, assuming 1.0, 1.5, or 2.0 °C global warming by 2100. (Figure: Glaciology, D-BAUG/ETH Zurich)


Loris Compagno, Sarah Eggs, Matthias Huss, Harry Zekollari, and Daniel Farinotti, Brief communication: Do 1.0◦C, 1.5◦C, or 2.0◦C matter for the future evolution of Alpine glaciers? The Cryosphere (2021), doi: 10.5194/tc-15-2593-2021

Learn more about the Glaciology group of Prof. Dr. Daniel Farinotti

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