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南極大陸の氷溶解 数カ国が国全体が水没の危機に直面
タグ: 記事一覧, 国際, 社会・歴史, アジア・オセアニア
27.04.2012, 10:15
© Flickr.com/Rita Willaert
南極大陸を覆う氷の層は急速な勢いで薄くなっている。その原因は水と接触している下層の氷の溶解速度が急速化したことにある。こうした米国航空宇宙局（ＮＡＳＡ）の最新の調査報告をＢＢＣが伝えた。
人工衛星が行った４５０万枚にもおよぶ計測結果では、南極の表層の氷の厚さは年間７メートルも減少している。しかも主な氷の減少は下層で進行しており、その原因となっているのが南極海の水温の上昇だった。
水の上にある氷の層が急速に溶解していることで、南極大陸からは同時に氷が離れていく減少が起きている。ＮＡＳＡの専門家らは、南極大陸から氷が溶け出せば、世界海洋の水位の上昇が起きてくると警告する。
海洋の水位上昇は年を追うごとに拡大している。これによって海抜の低い沿岸部が浸水する国や、国そのものが完全に水没する恐れがあるケースも予測されている。
ロシアのマスコミ各社の報道による。
http://japanese.ruvr.ru/2012_04_27/kaiyou-suii-agaru/
World's glaciers 'out of balance'
By Jonathan Amos
Science correspondent, BBC News, Vienna
The retreat of McCall Glacier in North Alaska. The left panel is 1958; the right panel is 2003
Continue reading the main story
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Asian glaciers 'putting on mass'
Taking the pulse of Ngozumpa
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Earth's glaciers are seriously out of balance with the global climate and are already on their way to losing almost 40% of their volume.
That is the assessment of scientists after studying a representative group of 144 small and large glaciers around the world.
Their figure assumes no further warming of the climate.
However, if temperatures continue to rise as models predict, the wastage will be even higher, the team says.
"When we look at the data, we can see that the glaciers are out of balance, meaning the climate has actually changed faster than the changes we've seen in ice area and volume," explained Sebastian Mernild from Los Alamos National Laboratory, New Mexico, US.
"Our data suggests the glaciers will commit about 30% of their area and about 38% of their volume to global sea level rise."
Dr Mernild's group calculates this figure to be on the order of 22cm.
"This will happen in the next decades to centuries," he told BBC News.
Dr Mernild, from the Climate, Ocean, and Sea Ice Modeling (COSIM) Group at Los Alamos, was describing his team's work here at the European Geosciences Union (EGU) meeting in Vienna, Austria.
A glacier is in balance when the snow at higher, colder elevations equals the volume of snow and ice lost through melting at lower, warmer elevations.
If precipitation is greater, the glacier will increase its mass; if melting dominates, the glacier will thin and retreat until it reaches a state of equilibrium again.
Dr Mernild's team says its assessment of the glacier sample indicates climate conditions have changed so fast that many ice bodies have not yet had time to fully adjust to their new equilibrium position.
Alpine glaciers are said to be more out of balance than the global average
This means a certain amount of mass loss is already locked into the system even if there is no further warming.
"Glaciers will move up in the terrain, they will become smaller and thinner and they will adjust to the climate conditions.
"On the other hand, we expect the climate will warm continuously in the future, meaning that the glaciers will become even more out of balance, and that means the glaciers will commit even more volume to sea level rise."
If the models are correct and further warming is seen during the next several decades and longer, the study projects that the Earth's glaciers could ultimately lose more than half their mass.
The picture is described as regional, with some areas said to be more out of balance than others.
Dr Mernild cites the Alps as one glacier group that is farther from balance than the global average.
He says alpine glaciers are likely to lose most of their mass by 2100.
"But if you take into account the volume of ice in the glaciers here in the Alps, it won't have the same impact on the global sea level rise compared to if we see the same out of balance conditions in other places on the globe where we know there is more ice located.
"So, the contribution to sea level rise will not be that big from the Alps region."
The COSIM assumption is that there is a sea level equivalent of 60cm locked away in all the world's glaciers (the number excludes the ice sheets of Antarctica and Greenland).
That figure has been debated here at EGU. Dr Matthias Huss, from the University of Fribourg, Switzerland, presented new data suggesting there was only 48cm of sea level tied up in all the world's glaciers (and the larger glaciers referred to as ice caps).
"Our number is 192,000 cu km. This is about 25% less than some previous estimates. It is a total potential sea-level rise of 0.48m," Dr Huss told BBC News.
"We're using a physically based approach. Until now, people have relied on simple statistical methods."
The Fribourg researcher said his team's work captured much better the range of thicknesses in the world's glaciers, of which there are estimated to be about 160,000.
Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter
More on This Story
Related Stories
Asian glaciers 'putting on mass' 15 APRIL 2012, SCIENCE & ENVIRONMENT
Taking the pulse of Ngozumpa 26 DECEMBER 2011, SCIENCE & ENVIRONMENT
French Alpine glaciers in retreat 07 DECEMBER 2011, SCIENCE & ENVIRONMENT
Glacier melt 'fastest for years' 03 APRIL 2011, WALES
Chile glacier record retreat footage 08 DECEMBER 2011, LATIN AMERICA & CARIBBEAN
Swiss glaciers 'in full retreat' 19 DECEMBER 2008, SCI/TECH
Related Internet links
EGU2012 Los Alamos - Climate, Ocean and Sea Ice Modeling (COSIM)
CICE
The BBC is not responsible for the content of external Internet sites
http://www.bbc.co.uk/news/science-environment-17843648
モスクワ上空に異常な緑色の雲が出現
http://www.youtube.com/watch?v=G4tIJJ14bK8&feature=player_embedded
27.04.2012, 11:35
Photo: SXC.hu
２６日モスクワ市民の間では突如出現した異常な黄緑色の雲に反応した書き込みがブログやソーシャルネットで飛び交った。
鮮やかな緑色の雲を見たという者、自動車や窓がまちが緑色に染まってしまったという声、黄色と緑の混合物がヘリコプターによってモスクワ上空にまかれているというものまで様々だったが、このヘリコプターからの散布説に関してはロシア非常事態省から事実無根だという声明が表されている。また、モスクワ郊外のポドリスク市の企業で起きた火事によって黄緑色の雲が出たという説も飛び交ったが、こちらのほうは市の政府サイドで事実ではないことが発表されている。
この不思議な現象について専門家らは、ちょうどこの時期に開花を迎える白樺の花粉が度を越して空中に放出されたためではないかと考察している。白樺の花粉はアレルギーを呼ぶやっかいもので、この時期は平均で１平方メートルあたり１万９６５４個が浮遊しているが、２４日はこの値を２０倍も上回る量が飛散していた。
モスクワ市政府の自然利用・環境保護課はこの現象について、突如として気温が上昇したことと関連づけた見方を表している。
http://japanese.ruvr.ru/2012_04_27/roshia-mosukuwa-midoriiro-kumo/
この記事を読んだ人はこんな記事も読んでいます（表示まで20秒程度時間がかかります。）
- Warm Ocean Currents Cause Majority of Ice Loss from Antarcti MR 2012/4/27 21:14:58
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