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All the newsGlaciers are melting more quickly
This summer, melting glaciers again attracted the attention of researchers. From Arctic to Alpine glaciers, the impact of climate change on frozen regions, clearly apparent in summer, is being closely monitored
The ice sheet: the point of no return?
A study published at the beginning of August in the review Nature warned of the potentially irreversible melting of the Greenland ice sheet. This study is based on the analysis of thirty years of satellite images and shows that the loss of ice has accelerated by 10% a year since the 2000s in comparison to the 1980s and 1990s. In addition, since the 2000s, the ice has been melting faster than it can be replaced by snowfall. Although the period of analysis is too short and scientific knowledge too uncertain to assert that the point of no return has been reached, the researchers nonetheless warn of the need to considerably slow down greenhouse gas emissions, the cause of climate change.
The main consequence of ice sheet melting is that it could cause the sea level to rise by 7 metres in the worst-case scenarios, initially affecting coastal areas and islands.
What is Polar amplification?
The phenomenon of Polar Amplification leads to doubling the speed of warming in Siberia and the Arctic than in the rest of the world. This phenomenon is due to the difference in the rate of reflection of solar radiation between ice (85 %) and the ocean (10 %). When the sea ice melts and changes into water, it absorbs much more solar radiation than when frozen. The absorption of solar radiation means the absorption of heat, which in turn accelerates melting. Thus, the larger the ocean surface – and thus less ice – the larger the surface that absorbs heat, and the more the surface absorbs heat, the more the temperature increases, thus melting more ice, which in turn increases the surface area of the ocean.
It’s a vicious circle with impacts in both the regions concerned and in the rest of the world, since the Arctic participates in maintaining the global temperature.
Furthermore, another less visible but equally worrying phenomenon is the thawing of the permafrost. This is a layer of permanently frozen earth and rock whose temperature is lower than or equal to 0°C for at least two years running. This permafrost covers a fifth of the Earth’s surface area. It is situated in Canada, Greenland, Siberia and Alaska. Permafrost thawing is dangerous because it releases greenhouse gases – CO2 and especially methane – captured in the earth, further speeding up global warming.
Ice is also melting in Europe
The Arctic is not the only region affected by ice melt. In Europe, climatologists are monitoring alpine glaciers very closely. As with the case of Greenland, higher temperatures disturb the balance between the seasons. The summer melt now exceeds the accumulation of ice and snow during winter, the result of which is the “loss of about one metre a year over a period of thirty years”, according to the Director of Research at the Institute of Geosciences and the Environment of Grenoble, Gaël Durand, when questioned by Le Monde. When the base of a glacier warms to a temperature above 0°C, it becomes unstable and collapses. The risk of subsequent rockslides is worrying for the villages located nearby.
The glacier of Planpincieux on the Italian side of the Mont-Blanc massif hit the headlines this summer, as it threatened the village and led to the evacuation of its inhabitants and tourists. The situation returned to normal at the beginning of August, but this incident showed the importance of more intensive monitoring given the likelihood of the frequent recurrence of such events.