France's tallest mountain Mont Blanc has shrunk by more than two metres in two years

France's tallest mountain Mont Blanc has shrunk by over two meters in height over the past two years, researchers said Thursday, measuring the Alpine peak at 4,805.59 meters (15,766.4 feet).

The 2.22-meter (7.28 feet) 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 meters above sea level, but its 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 garner information about the impact of climate change on the Alps.

But "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.

People shouldn't use the height measurement "to say any old thing", he urged.

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 meters," des Garets said.

(AFP)