Mont Blanc, the summit of Western Europe in the Alps, was measured in September 2026 at 4,807.47 m, or 1.88 meters higher than the previous measurement communicated in 2023, French surveyors announced on Wednesday October 14. This increase does not necessarily represent good news for the fight against global warming in high mountains according to glaciologist and geomorphologist Jean-Bapstise Bosson.
franceinfo: Do these variations of a few centimeters or a few meters serve to give an indicator of the state of Mont Blanc or is this not something that you, glaciologists, particularly scrutinize?
Jean-Baptiste Bosson: No, it is not fundamental since it is the summit of Mont Blanc which varies. What glaciologists measure is mainly the thickness of the ice and the height of the ice in the downstream parts, where there is either accumulation or melting. Unfortunately this year we have astronomical melting rates.
So the fact that Mont Blanc has gained two meters almost in three years, doesn't that mean that it's doing better and that it's suffering less from climate change?
Very locally, this means that the summit of Mont Blanc is not suffering for the moment, and so much the better. On the other hand, from the summit of Mont Blanc, via the Glacier des Bossons, which is one of the largest Alpine glaciers, melts at dizzying speed. So obviously, at 4,800 meters where it is very cold and wet all year round, we have snow and ice that forms and which varies little. And so much the better that it’s in the right direction. The entire rest of the glacial system is deeply impacted by climate change and is melting far too quickly.
And is that worrying?
It's more than worrying, we no longer know how to raise alarm about the situation of the Alpine glaciers. Since the Little Ice Age, since the last natural cool period, around 1850, therefore the beginning of the industrial era, Alpine glaciers have lost 70% of their surface area. We have already lost more than two thirds. This year we have melting records in the Mont Blanc massif or elsewhere, close to the melting records for 2022. This is an enormous speed.
“We just experienced the hottest summer on record in the Western West in over 150 years. And so the consequence for the glaciers is that they are melting much too quickly, and that is extraordinarily worrying.”
Jean-Bapstise Bosson, glaciologist and geomorphologist
Remind us of the consequences of this melting ice. Does this increase the dangers in the mountains, notably with more rock falls?
Yes, there is that, but at the same time, there are new ecosystems that are emerging and which have great ecological value. There is a real change in ecosystems in the high mountains. We lose the white of the glaciers and then we gain others. Sometimes there are more natural hazards, but not all the time and not everywhere. Far from it. I think we shouldn't make broad generalizations.
What do these new ecosystems look like?
In the absence of these poor glaciers which are in the process of disappearing, at the very beginning of history we have very mineral surfaces, stones which accumulate, and then very quickly vegetation arrives. We are particularly studying primary forests which are being born from glacial retreat in the Alps. And then there are lakes, new wetlands, new rivers, so it’s also the water of the future. We are losing the extraordinary water tower that is the glacier at the top of the mountains, but failing that, we will have wetlands and healthy soils. If we preserve them, we can support the habitability of the territory a little.
You have already seen the change in these ecosystems. But you are already alerting us to the fact that we will have to preserve what is being created, right?
Look, Donald Trump wants to take over part of Greenland for mining and oil extraction. We are losing glaciers, which is catastrophic for the functioning of the planet and the habitability of the planet. We will have rising sea levels, a much warmer climate and a planet that will be difficult for humans to inhabit. And besides that, people are arriving in the territories abandoned by the glaciers and saying that we are going to have extractivist hypercapitalism instead with mines and ski areas. We are really in this race against time.
Is this also the case in France?
Today, the French state is committed to protecting all of these glaciers and post-glacial ecosystems. But there are still issues in Europe, in France, in the Alps, on dams, on ski areas that are trying to develop, which sometimes destroy ecosystems, on tourist practices that are not sustainable. For the moment, we don't have any mines, but it could happen.
For example in Austria, we have installations of solar parks or wind farms in these areas which are not good for nature protection. These are the wildest ecosystems in Europe, this high glacial and post-glacial mountain. So it's not at all trivial to take care of it and really let this nature evolve and give us solutions to the water crisis, to the climate crisis and to the habitability of future territories.
