北極圏の温暖化、地球平均の３倍の速さで進行　報告書

【オスロＡＦＰ＝時事】北極圏の温暖化は地球平均の３倍の速さで進行しており、そのペースはこれまで考えられていたよりも速いとする報告書が２０日、発表された。（写真はホッキョクグマ。北極海のノバヤゼムリャ島沖で。ロシア北極圏国立公園提供）
　この報告書は北極圏監視評価プログラム作業部会（ＡＭＡＰ）によるもので、アイスランドのレイキャビクで今週行われた、北極圏の国が集まる北極評議会（ＡＣ）の閣僚会合に合わせて発表された。
　１９７１～２０１９年の半世紀に満たない間に、北極圏の年平均気温は３．１度上昇。一方、地球全体では１度上昇した。
　これは、従来の推定を上回る速さだ。国連の「気候変動に関する政府間パネル（ＩＰＣＣ）」が２０１９年に発表した雪氷圏（地球の凍結部分）に関する報告書では、北極圏の地表気温の上昇は「地球平均の２倍以上」と推定していた。
　ＡＭＡＰの報告書によると、転換期は２００４年。この年、北極圏の気温が大幅に上昇したが、その理由はほぼ説明がつかないという。以降、温暖化はそれ以前の数十年間と比べて、３割増しのスピードで進行し続けている。
　温暖化が今後すぐに止まることはない。報告書は、北極圏の平均気温は今世紀末までに、１９８５～２０１４年の平均を３．３～１０度上回ると予想している。
　最終的な値は、人類がどれだけ迅速に温室効果ガス排出量を削減するかにかかっている。
　温暖化は北極圏の生態系に直接的な影響をもたらす。それには、ホッキョクグマをはじめとする動物の生息地や食性、また動物間の関係性などにおけるさまざまな変化が含まれる。一部の種の移動もある。

■世界への影響
　北極地域に暮らす４００万人、とりわけ先住民も多大な影響を受ける。
　気候評価と政策に関するアラスカ・センターのサラ・トレイナー代表は、「グリーンランド北西部の猟師らは、氷海を犬ぞりで移動できる期間が５か月から３か月に減ったと報告している」と語る。
　カナダやロシアの先住民の猟師や漁師の報告によると、アザラシがやせ、野生動物の健康が悪化し、魚や海洋哺乳類に寄生虫がまん延していると同代表は指摘している。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2021/05/26-13:29）

The Arctic has warmed three times more quickly than the planet as a whole, and faster than previously thought, a report warned on Thursday.
Arctic sea ice looks set to be an early victims of rising temperatures, with each fraction of a degree making a big difference: the chance of it disappearing entirely in summer is 10 times greater if Earth warms by 2 degrees Celsius above pre-industrial levels compared to 1.5C, the goal set by the 2015 Paris Accord.
The alarming finding comes from the Arctic Monitoring and Assessment Programme (AMAP) in a report timed to coincide with a ministerial meeting this week of the Arctic Council in Reykjavik, which gathers countries bordering the region.
The Arctic is a real hotspot for climate warming, said Jason Box, a glaciologist at the Geological Survey of Denmark and Greenland.
In less than half a century, from 1971 to 2019, the Arctic's average annual temperature rose by 3.1C, compared to 1C for the planet as a whole.
That?s more than previously suspected. In a 2019 report on Earth?s frozen spaces, the UN?s Intergovernmental Panel on Climate Change (IPCC) concluded that Arctic surface air temperature has likely increased by more than double the global average.
- Forest fires -
According to researchers, a turning point came in 2004 when the temperature in the Arctic surged for largely unexplained reason.
Since then, warming has continued at a rate 30 percent higher than in previous decades.
The region is now experiencing more and longer lasting winter warm events, Box told AFP.
During the summer months from June to September, there is added heat from the ocean, which is increasingly free of ice and the insulation it provides.
And the warming is not coming to an end any time soon.
According to forecasts in the report, by the end of the century average temperatures in the Arctic are expected to rise 3.3 to 10 degrees above the average for the period 1985-2014.
The final figure depends on how rapidly humanity draws down greenhouse gas emissions.
Warming has immediate consequences for the Arctic ecosystem, including changes in habitat, food habits and interactions between animals -- including the iconic polar bear -- and the migration of some species.
From Siberia to Alaska, forest fires have also become a problem.
This is what 3C looks like, it's not just numbers, it's forests on fire, said Box.
The impacts of wild land fires are not limited to public safety concerns, such as protecting life and property, said US researcher Michael Young, Arctic Council Wildland Fire Projects Coordinator.
The smoke they produce also contains carbon dioxide and black carbon, which both contribute to climate change.
- Global impact -
The consequences are also dramatic for the four million people who live in the region, especially indigenous peoples.
Hunters in northwestern Greenland report that the period when travel by dog sleds on sea ice is possible has decreased from five to three months, said Sarah Trainor, director of the Alaska Center for Climate Assessment and Policy.
Indigenous hunters and fishermen in Canada and Russia have reported thinner seals, decreased health of wildlife and a greater prevalence of worms in fish and sea mammals, she added.
A warmer Arctic is also more humid, with rain replacing snow.
Reindeer herders in Fennoscandia (Finland and Scandinavia) and Russia have experienced major losses in their herds due to extreme snowfall and rain-on-snow events, added Trainor, as layers of frozen rain prevent reindeer from reaching the lichen they eat.
No one on Earth is immune to Arctic warming, the AMAP report said, noting its effects were felt far and wide.
The melting of hundreds of billions of tonnes of ice each year in Greenland leads to rising sea levels, which endanger the lives of people living thousands of kilometres away.
The receding ice has opened up economic opportunities -- often to the dismay of environmental activists -- including new fishing zones, new commercial shipping routes, and easier access to potential mineral and oil and gas resources.
However, notes Trainor, the potential for expansion of these industries is tempered by efforts to limit greenhouse gas emissions and achieve goals established under the Paris Agreement.