Glaciers, once a symbol of solidity and geological slowness, are also losing their last natural defense against global warming: their ability to cool their surroundings. This is revealed in research published in Nature Climate Change and coordinated by the Institute of Science and Technology Austria (Ista), with the collaboration of the Institute of Polar Sciences (CNR-Isp) and the Institute of Water Research (CNR-Irsa) of the National Research Council.
The team developed a mathematical model that can estimate how much longer glaciers can contribute to climate mitigation. The study is based on an impressive data archive: 350 weather stations installed on 62 glaciers around the world, with observations collected in 169 summer campaigns.
The result leaves no room for optimism: these ice masses will reach the maximum point of their self-cooling capacity within the next decade. After that limit, surface temperatures will rise rapidly and melting will accelerate exponentially.
When the ice stops defending itself
Making this “thermal resilience” possible is a phenomenon called decoupling-a kind of decoupling between the temperature of the ice and that of the surrounding air, which allows glaciers to maintain a cooler microclimate and slow melting. But, the authors warn, this balance is set to break down before mid-century.
“We can talk about the resilience of glaciers to melting, precisely because through cooling the surrounding air they protect themselves from climate change. But this effect will not last long,” explains Franco Salerno, a researcher at CNR-Isp.
When the decoupling ends, glaciers will lose their function as “natural conditioners” of Alpine valleys, triggering a vicious cycle that will amplify the water crisis and slope instability.
The urgency of data and the scarcity of observations.
The problem, the researchers warn, is that our knowledge is still partial. The paucity of observations in remote upland regions makes it difficult to identify critical thresholds of change. “We have an urgent need to expand measurement networks, especially in underrepresented areas, to understand how crucial water resources such as glaciers will evolve,” stresses Nicolas Guyennon of CNR-Irsa.
In other words, science is racing against time to measure the fever of glaciers before they stop breathing cold. A countdown that affects not only the alpine landscape, but also the water and climate security of millions of people.
