「気候変動の物差し」 融解が止まらないチリ最南端の氷河

【ＡＦＰ＝時事】チリ最南端のサンラファエル湖に浮かぶ、１０階建てのビルほどの氷塊──湖に流れ込むサンラファエル氷河に大きなひびが入り、砕け落ちてできた。地球温暖化の影響をまざまざと見せつける光景だ。（写真はチリ南部アイセン地方のサンラファエル湖に浮かぶ、氷河から崩れた氷塊）
　今日、サンラファエル湖には、氷河から崩れ落ちた約１００の氷塊が浮かぶ。５０年前には氷河が湖面の３分の２に広がっていたが、今や氷の覆いはない。
　面積３５００平方キロの北パタゴニア氷原には、サンラファエル氷河を含む３９の氷河がある。アイセン地方にある１万１０００平方キロの南パタゴニア氷原が合わさり、世界最大級の氷原を形成している。
　欧州宇宙機関（ＥＳＡ）の衛星画像によって明らかになったのは、サンラファエル氷河が世界で最も崩壊が激しい氷河の一つであり、またパタゴニアで最も速く移動している氷河の一つだということだ。移動速度は１年で約７．６キロ。ＥＳＡは「地球温暖化の影響で劇的な後退が起きている」と指摘した。
　サンラファエルの東、アルゼンチンとチリにまたがるヘネラルカレーラ湖の湖畔でヒツジとウシの小規模な酪農を営むサントス・カタランさんは、気候変動の最前線で暮らしている。
　過去１５～２０年で氷が解け、降雪が減ったために、一面真っ白だった景観が一変してしまった。「様変わりしてしまいました」とカタランさん。「暑すぎるのです」と付け加えた。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2022/03/31-09:43）

A crack widens in the San Rafael glacier in Chile's extreme south, and a ten-storey iceberg crashes into the lake by the same name -- a dramatic reminder of the impacts of global warming.
In the lake San Rafael, about 100 icebergs float today, pieces broken off from the glacier that 150 years ago stretched out over two-thirds of the body of water now free of ice cover.
The San Rafael glacier is one of 39 in the Northern Patagonian Ice Field (3,500 square kilometers or 1,350 square miles), which with the Southern Patagonian Ice Field (11,000 km2) in Chile's Aysen region forms one of the world's biggest ice masses.
According to the European Space Agency satellite images show San Rafael to be one of the world's most actively calving glaciers and the fastest-moving in Patagonia, flowing at a speed of about 7.6 kilometers (4.7 miles) per year -- receding dramatically under the influence of global warming.
Glaciers are bodies of slowly-moving ice on land that can be several hundred or several thousand years old.
Seasonal glacier melt is a natural phenomenon that with global warming has accelerated significantly, Jorge O'Kuinghttons, a regional head of glaciology at Chile's water directorate, told AFP.
- 'Excellent indicator' -
At the moment, Patagonia's glaciers are retreating faster than anywhere else in the world.
Glaciers are an excellent indicator of climate change, said Alexis Segovia, another government glaciologist who works in the remote region of southern Chile.
All but two of Chile's 26,000 glaciers are shrinking, he said, due to rising temperatures caused by manmade greenhouse gas emissions.
It is a vicious cycle.
Ice-covered surfaces of Earth reflect excess heat back into space, and if these are reduced through melting, temperatures rise even more.
Melting glaciers also add to sea level rise, which increases coastal erosion and elevated storm surges.
And water dammed by glaciers can be released by a sudden collapse.
Areas are being flooded these days that were never flooded before, said O'Kuinghttons.
To learn more about what to expect in the future, glaciologists study the evolution of Chile's glaciers, which contain a frozen record of how the climate has changed over time.
According to the WWF, more than a third of the world's remaining glaciers will melt before 2100 even if mankind manages to curb emissions from the burning of fossil fuels.
- The heat is 'strong' -
East of San Rafael, on the lake General Carrera that is shared by Chile and Argentina, small-scale sheep and cattle farmer Santos Catalan has been living on the forefront of the change.
To augment his income, he criss-crosses the lake in a wooden boat with glacier-watching tourists.
Over the last 15 to 20 years, he told AFP, the landscape has become a lot less white as the ice has melted and snow dwindled.
Things have changed a lot, he said. The heat is very strong.