France's Mont Blanc shrinks by a further two metres

France's tallest mountain, Mont Blan,c has shrunk by more than two metres over the past two years, researchers say. While its height naturally fluctuates according to the winds and snowfall at its summit, ithe mountain's decline over the last 10 years is a likely indicator of global warming.

Mont Blanc, the tallest mountain in the Alps, has shrunk by 2.2 metres since 2021 to its lowest height in recent memory. © AFP/Philippe Desmazes

The 2.22-metre decline could be down to lower precipitation during summer, said Jean des Garets, chief geometer in the Haute-Savoie department of southeastern France.

"Mont Blanc could well be much taller in two years" when it is next measured, he added.

The mountain's rocky peak measures 4,792 metres above sea level, but it's thick covering of ice and snow varies in height from year to year depending on wind and weather.

Researchers have been measuring it every two years since 2001, hoping to collect information about the impact of climate change on the Alps.

"We're gathering the data for future generations, we're not here to interpret them, we leave that up to the scientists," des Garets said.

Around 20 people scaled the mountain in mid-September to carry out measurements over several days, divided into eight parties equipped with high-tech tools and for the first time a drone.

"We've learned a lot from these measurement campaigns: we know that the summit is constantly changing in altitude and position, with changes of up to five metres," des Garets said.

Evolution of Mont Blanc elevation over the last decade ⛰️
Obviously the trend is negative (~ 5 m loss) likely as a result of increasing number of heatwaves with isotherms 0°C above 5000 m in recent years 🔥

Sept. 2023: 4805.59 m (lowest value) pic.twitter.com/Dd9sZh8RcD

— Melaine Le Roy (@subfossilguy) October 5, 2023

Vanishing glaciers

"Mont Blanc's height has been fluctuating since time immemorial, the geometers say.

Within the year, strong winter winds usually scour away more snow than in summer, meaning the peak is higher as autumn begins than in early spring.

"We've learned a lot from these measurement campaigns. We know that the summit is constantly changing in altitude and position, with changes of up to five metres," des Garets said.

Faster melting has been observed in Alpine glaciers as a result of climate change.

European glaciers – many at lower altitude than elsewhere on the globe – are especially vulnerable to global warming.

They lost around one-third of their volume between 2000 and 2020, according to scientific data.

In 2022 alone, glaciologists believe up to seven percent of the remaining mass of the glaciers may have vanished.

But one of the Mont Blanc team members, Denis Borel, urged people to "stay humble" about climate's impact on the mountain.

People shouldn't "draw hasty conclusions about measurements that have only been made precisely since 2001", he added.

(with AFP)