“A new example of the effects of global warming“, “a threat exacerbated by global warming“… The day after the collapse of the Marmolada glacier, which killed at least six people and injured eight, the press is unanimous. this dramatic accident is further evidence that climate change can have catastrophic effects. Italian Prime Minister Mario Draghi also noted.climatic situationas the main culprit of this spectacular collapse.
This conclusion seems to be the easiest. Marmolada, the largest glacier in the Dolomite massif in northern Italy, suddenly collapsed without any warning signs, even though this region of La Bot had just experienced a severe heat wave. A popular route for hikers, it seemed safe. Specifically, the glacier broke off at the level of one of the peaks of the massif, called Punta Roca, which is 3,309 meters above sea level. So who else is to blame if not the endemic heat?
Accumulation of melt water?
However, the culprit is perhaps a little too quickly condemned. “We still know very little about the causes of the collapse“, moderates Figaro with Christian Vincent, a specialist in the effects of global warming on glaciers at the Institute of Environmental Geosciences. His transalpine colleagues have provided some preliminary data, but it is too early to judge. For now, “The origin of the fall of this serum is probably related to the melt water coming from the surface, which penetrated the glacier and accumulated in the bottom.says Christian Vincent. As the melting progressed, the water pressure increased and reached the breaking point“.
Like his Italian colleagues, the researcher still does not understand how this water could have been trapped in the glacier. “In general, water inside a glacier is preserved due to its thermal regime; if the ice is at a negative temperature, it is impermeable to water and forms an impermeable barrier.“, our interlocutor explains. In the case of marmolada, “we can reasonably assume that its temperature was temperate, that is, not negative, and therefore that the ice was not impermeable.“. But then why was the water held back and not circulated? This is what scientists are trying to find out.
Serak waterfallare not related to temperature»
If this hypothesis, which is related to glacial hydrology, is accepted, then it was indeed environmental warming in July that caused the surface ice to melt. “But global warming didn’t necessarily cause the glacier to retreat“, thinks Christian Vincent. “This region of Italy has been experiencing a heat wave for two weeks, which has certainly led to increased melting. But this heat is not unique in recent years. To link this rupture directly to global warming would therefore be a bit of an insult.“, he develops. In summary, making a direct connection between this particular collapse and several years of warming climate may seem like a shortcut.
Especially since the Serak waterfall is part of the normal operation of a high altitude glacier. “By definition, a glacier flows, and when it hits a slope crack, it breaks off.– recalls Christian Vincent. In this particular case, “the fracture occurred on a very steep slope“, he adds. In addition, serac fallsare not related to temperatureclaims the researcher. They can happen at any time of the day or year“.
Source: Le Figaro
