南極氷床の下で進む融解、海面上昇は予想以上に加速か 英研究所

The melting under the Antarctic ice sheet, the rise in the sea level is more accelerated than expected or the British Research Institute

The melting under the Antarctic ice sheet, the rise in the sea level is more accelerated than expected or the British Research Institute
南極大陸で氷床の融解が進むなか、氷床の下に暖かい海水が少しずつ流れ込んでいる現象が新たに見つかり、海面が予想以上の速さで上昇する可能性が指摘されている

As the melting of the ice sheet progresses in Antarctica, it has been pointed out that a new phenomenon in which warm seawater is flowing under the ice sheet has been flowing little by little, and it has been pointed out that the sea surface may rise at a speed higher than expected.

As the melting of the ice sheet progresses in Antarctica, it has been pointed out that a new phenomenon in which warm seawater is flowing under the ice sheet has been flowing little by little, and it has been pointed out that the sea surface may rise at a speed higher than expected.
英南極研究所(BAS)のチームが、25日発行の地球科学の専門誌「ネイチャー・ジオサイエンス」に報告した

The team of the British Research Institute (BAS) reported to the global journal Nature Geoscience published on the 25th.

The team of the British Research Institute (BAS) reported to the global journal Nature Geoscience published on the 25th.
チームによると、氷床が海へ押し出されて棚氷となる境界の「接地線」から、比較的暖かい海水が氷床の下に向かって入り込んでいる

According to the team, a relatively warm seawater is entering under the ice sheet from the grounding line at the boundary of the ice sheet that is pushed into the sea and becomes a shelf.

According to the team, a relatively warm seawater is entering under the ice sheet from the grounding line at the boundary of the ice sheet that is pushed into the sea and becomes a shelf.
これによって氷に空洞ができ、より多くの海水が流れ込み、さらに空洞が大きくなるというサイクルが続いている

This continues to have a cavity on the ice, a more seawater flows, and the cavity is larger.

This continues to have a cavity on the ice, a more seawater flows, and the cavity is larger.
海水温がわずかに上がるだけでも、解ける氷の量は大きく影響されるという

Even if the seawater temperature rises slightly, the amount of ice that can be solved is greatly influenced.

Even if the seawater temperature rises slightly, the amount of ice that can be solved is greatly influenced.
BASの研究者によると、このサイクルに歯止めがかからず、融解量が突然変化して後戻りできなくなる「転換点」に至る事態も想定される

According to BAS researchers, this cycle is not stopped, and it is also assumed that the transmission rate changes suddenly and cannot be returned.

According to BAS researchers, this cycle is not stopped, and it is also assumed that the transmission rate changes suddenly and cannot be returned.
転換点を越えると大陸の氷が海へ流れ出す速度が急に上がる

After crossing the turning point, the rate of ice on the continent flows into the sea suddenly increases.

After crossing the turning point, the rate of ice on the continent flows into the sea suddenly increases.
海面上昇を予測する現行のモデルにはこの要因が含まれていないため、実際の上昇は大きく速まる可能性がある

The current model that predicts the rise of the sea level does not include this factor, so the actual rise may be significantly increased.

The current model that predicts the rise of the sea level does not include this factor, so the actual rise may be significantly increased.
チームによれば、海面上昇への影響はすぐには実感できないが、10年、100年単位で世界の海岸線に脅威を及ぼすことが予想される

According to the team, the impact on the rise of the sea level cannot be realized immediately, but it is expected to threaten the world coastline in 10 or 100 years.

According to the team, the impact on the rise of the sea level cannot be realized immediately, but it is expected to threaten the world coastline in 10 or 100 years.
研究チームは転換点の時期や、予想される海面の上昇幅を示していない
ただし、南極大陸の氷床ではすでに毎年平均1500億トンの氷が融解していて、すべて解ければ世界の海面は約58メートル上昇する計算だ
南極大陸ではこれまで、「終末の氷河」とも呼ばれるスウェイツ氷河など、主に西部での融解が研究されてきた
だがチームによると、今回の研究では大陸東部にある氷河の一部も危機にさらされていることが明らかになったという