The tallest mountain in France has shrunk over the last two years, according to researchers.

Mont Blanc's peak has been measured at 4,805.59m (15,766ft 4 in), which is 2.22m shorter than in 2021.

Chief geometer Jean des Garets said the shrinking could have been caused by less rain this summer.

The mountain in south east France is measured every two years, to try and track the impact of climate change on the Alps.

Mr des Garets said that his team have learned a lot about Mont Blanc since measurements began in 2001. "The summit is constantly changing in altitude and position, with changes of up to five metres," he said, "Mont Blanc could well be much taller in two years."

But if previous measurements are anything to go by, this may not be the case. After the 2021 measurement experts said that, on average, the mountain was losing around 13cm of height a year.

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

But he also urged caution, saying people shouldn't use the height measurement to "say any old thing".

Mont Blanc's rocky peak sits at 4,792m above sea level, but the variation in height comes from snow and ice at the summit. The amount there depends on the wind and weather, and the researchers said that the shrink could have been caused by "lower precipitation" - or less rain - this year.

A higher peak would have been recorded if there had been stronger precipitation and lower winds.

And there is not just concern at Mont Blanc. Last week it was revealed that glaciers in Switzerland had suffered their second biggest annual loss - which scientists called a clear symptom of global warming.

Last month a team of 20 people climbed Mont Blanc to carry out the measurement, which took several days. Dividing themselves into eight groups, this was the first time they had used a drone to determine how high the summit was.

The height is determined by planting small receivers in the snow to model the ice cap that sits at the top. The receivers emit a GPS signal which is then used to obtain a measurement to the nearest centimetre.

Mont Blanc is nicknamed "the roof of Europe", and it's estimated between 20,000 and 30,000 people each year attempt to climb it. The most popular route up the mountain is limited to 214 climbers a day to avoid overcrowding.

In 2013, a climber found a box of buried treasure which included emeralds, rubies and sapphires on the mountain. He was given half of the box's contents in 2021 which were worth about £128,000.

The highest recorded height of the mountain was 4,810.90m (15,783ft 79in) in 2007.

Heatwaves have become more frequent, more intense, and last longer because of human-induced climate change.

The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.