Let's take a step back in time! You're probably familiar with the famous Würm Ice Age, which affected the planet between 115,000 BC and 10,000 BC, and during which the area around Lake Geneva underwent major transformations! It was during this last glaciation that the Rhône Glacier and its siblings were born, forming a thick frozen mantle that could reach a height of 1,000m in places... One arm of the glacier reached as far as Solothurn, while the other extended as far east as Lyon. This gives us a good idea of the surface area it covered and the amount of ice present in our regions at that time.
After this intensely cold period, temperatures eased around 15,000 BC and the ice gradually melted, creating the landforms and lakes we know today. Lake Geneva is obviously one of them! A remnant of the mastodon that the glacier once was, the Rhône now flows quietly down its valley, generating most of the water in Lake Geneva. But what remains of this thousand-year-old ice?
All the glaciers we can see today come from this period of glaciation. The Rhône glacier, however, is in no way comparable to what it was in the past, as are all the glaciers in Switzerland and more widely on the planet. Climate change is inflicting heavy penalties on glaciers.
For example: a well-known tourist attraction, the famous grotto of the Rhône glacier is even reworked every year due to the rapid retreat of the glacier tongue. Every year, the glacier retreats by 8.5 metres, losing an average of 25cm in thickness. All Alpine glaciers are subject to this massive melting. According to a 2018 international study entitled "Global-scale hydrological response to future glacier mass loss", the total summer flow of the Rhône could fall by 15% by 2100.
Photo : Pegasus2 / WWF
