仏最高峰モンブランの標高、２年で２メートル超低下

【シャモニーＡＦＰ＝時事】フランス最高峰モンブランの標高が、２年で２．２２メートル低くなり、４８０５．５９メートルになったと、測量班が５日、発表した。（写真は仏最高峰モンブラン〈資料写真〉）
　測量班は、気候変動がアルプス山脈に与える影響に関する情報の蓄積を目的に、２００１年から２年に１度、測量に当たっている。今年は９月中旬に行われた。
　モンブランの山体（岩盤）は標高４７９２メートルだが、頂上は厚い氷と雪に覆われており、その厚みは風や天候の状態によって毎年増減する。
　測量責任者は今回の結果について、夏季の降水量の減少に起因している可能性があると説明し、次の測量が行われる２年後には「モンブランがまたずっと高くなっていることもあり得る」と述べた。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2023/10/06-15:41）

France's highest mountain, Mont Blanc, has shrunk by over two metres in height over the past two years, researchers said on Thursday, measuring the Alpine peak at 4,805.59 metres (15,766.4 feet).
The 2.22-metre (7.28-foot) 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, saying this was not the first time such a large change had been seen.
The mountain's rocky peak measures 4,792 metres 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.
We're gathering the data for future generations. We're not here to interpret them, des Garets said.
People shouldn't use the height measurement to say any old thing, he urged.
Instead, it's now up to the climatologists, glaciologists and other scientists to make use of all the data we've collected and come up with theories to explain the shrinkage.
Mont Blanc's highest recorded summit was in 2007, at 4,810.90 metres.
A one-metre fall was measured in 2021 compared to 2017 -- after 2019's unusually low result was kept secret as experts judged it not representative.
- 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.
Around 20 people scaled the mountain in mid-September to carry out the measurements over several days, divided into eight parties equipped with high-tech tools and -- for the first time -- a drone.