Rome, December 4th. (Adnkronos) – New study on climate and its effects on glaciers. A surprising phenomenon discovered on the glaciers of the Himalayas. An international research team led by the Institute of Polar Sciences and the Water Research Institute of the Cnr has actually found that the increase in global temperatures has caused the Himalayan glaciers to increasingly cool the air in contact with the frozen surface, thus causing the Temperatures moderate locally. The study, conducted in collaboration with the Institute of Science and Technology Austria, has just been published in Nature Geoscience and explains how this cooling, found throughout the Himalayan range, could preserve permafrost and high-altitude ecosystems. The research team recalls that it is known that the world’s glaciers are at risk of completely melting and disappearing over time due to global warming. Therefore, it is surprising to know that the glaciers of the Himalayan chain are developing against the trend: the measured average air temperatures, instead of increasing as expected, have remained stable and summer temperatures are decreasing, shows the study coordinated by the Institute Science Polar (Cnr -Isp) and by the Water Research Institute (Cnr-Irsa) of the National Research Council, carried out in collaboration with the Institute of Science and Technology Austria (Ista). “We know that the effects of warming depend on altitude: the mountain peaks are more affected by the effects of global warming and are warming faster,” explains Franco Salerno, co-author of the study and Cnr-Isp researcher, “We “discovered that a high-altitude climate station at the foot of Mount Everest in Nepal showed an unexpected phenomenon: the measured air temperature averages remained suspiciously stable instead of increasing.” To explain the observed phenomenon, the research team had to carefully examine the meteorological data provided by the climate station International Pyramid Laboratory-Observatory Ev-K2-Minoprio, located 5,050 meters above sea level on the southern slopes of Mount Everest, recorded three decades, the world’s longest high-altitude climate series. A series that represents the only evidence of how the climate in the mountains of the Third Pole has changed. “Glaciers respond to global warming by increasing temperature exchange with the surface. Global warming is actually leading to an increase in the temperature difference between the warmer ambient air above the glacier and the air mass in direct contact with the glacier surface.” highlights Francesca Pellicciotti, ISTA researcher and co-author of the paper. And “this – he adds – leads to increased heat exchange at the surface of the glacier and greater cooling of the surface air mass. The fresh and dry air masses at the surface become denser and sink along the slopes towards valleys, cooling the lower parts of the glaciers and the surrounding ecosystems , which are thus dependent on the health of the glacier itself.” “Essentially, we believe that climate warming is triggering an increase in these cold air masses – called katabatic winds – descending from the slopes of glaciers, and that this phenomenon contributes to the preservation of permafrost and the surrounding vegetation,” says Nicolas Guyennon, co-author of the study and researcher at Cnr-Irsa. To delve deeper, the team turned to the latest scientific advances in climate models: the global climate reanalysis called “ERA5-Land,” which combines model data with observations from around the world. By interpreting this data, the researchers were able to prove that the observed phenomenon occurred not only on Mount Everest, but throughout the entire Himalayan chain. “The next step will be to find out which key properties of glaciers promote this response. We need to understand which glaciers can respond to global warming in this way and for how long,” adds Salerno. Guyennon emphasizes: “While other glaciers, for example our Alpine glaciers, are experiencing dramatic changes, the high mountain glaciers at the Third Pole in Asia are much larger, contain more ice and therefore have longer reaction times.” Of course, warns the researcher Guyennon, “this phenomenon should concern us “The perceived cool temperatures descending from the glaciers are more of an emergency response to global warming and not an indicator of the long-term stability of climate change.” Future study prospects are interesting for scientists: the team will investigate whether the glaciers of the Pamirs and Karakoram, which are “stable” or “growing” unlike the rest of the world, are actually responding to global warming by getting colder and colder winds along their slopes. “The slopes of the Pamir and Karakoram glaciers are generally flatter than those of the Himalayas, so we assume that the cold winds cool the glaciers themselves more than they reach the surrounding areas further down,” but all that, notes the scientist, “we will find out in the next few years.
