永久凍土 は 北極 の 川 岸 の 侵食 を 遅らせ て いる
Emily C Geyman1, Madison M Douglas2,3, Jean-Philippe Avouac2
1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. egeyman@caltech.edu.
Nature
|October 9, 2024
まとめ
永久凍土は北極の川岸の侵食を 47%減速させています 永久凍土が溶けると 北極の河川の流れは 30~100%増加し インフラや炭素の流れに影響を及ぼします
科学分野:
- 地球と環境科学
- 地形学
- 気候科学
背景:
- 川の移動は北極のインフラやコミュニティ そして地球化学のサイクルに 影響を及ぼします
- 北極の河川の移動を予測するのは,永久凍土の役割 (減速 vs 加速) が矛盾しているため,困難です.
研究 の 目的:
- 高周波の河岸浸食検出のための新しい計算方法を開発する.
- 永久凍土が川の移動速度に及ぼす影響を定量化する.
- 永久凍土の融解のシナリオで 将来の北極川の移動をモデル化するためです
主な方法:
- 川岸の浸食を検出するためのサブピクセル解像度の計算方法を開発した.
- 熱的 (永久凍土の融解) と機械的な (河川の流れ) 侵食要因を区別するために高周波観測データを利用した.
- アラスカのコユクク川のデータを用いて数値モデルを カリブレーションし 検証しました
主要な成果:
- 永久凍土の存在は 川岸の侵食率を47%低下させることが判明しました
- 侵食は主に堆積物と輸送能力によって制限され,永久凍土の熱状態に影響されます.
- 開発されたモデルは,観察された侵食パターンを正確にシミュレートします.
結論:
- 永久凍土の融解は 北極の川の移動を加速させる 重要な要因です
- 北極の川の移動率は 永久凍土の完全解凍で 30~100%増加すると予測されています
- 発見は北極のインフラストラクチャと生態系の変化の安定性を予測するのに不可欠です.
関連する概念動画
Threats to Biodiversity
22.2K
There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species that adapted to the new conditions. In the current geological epoch, the Holocene, there is a sixth extinction event in progress. This mass extinction has been attributed to human activities and is thus provisionally called the Anthropocene. In 2019 the human population reached 7.7 billion people and is projected to comprise 10 billion by...
22.2K
Adaptations that Reduce Water Loss
25.1K
Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.
25.1K
Global Climate Change
24.2K
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
24.2K
Habitat Fragmentation
17.4K
Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land conversion, as well as slower geological processes leading to changes in the physical environment, are the two leading causes of habitat fragmentation. The fragmentation process typically follows the same steps: perforation, dissection, fragmentation, shrinkage, and attrition.
17.4K
Responses to Drought and Flooding
10.6K
Water plays a significant role in the life cycle of plants. However, insufficient or excess of water can be detrimental and pose a serious threat to plants.
10.6K
Responses to Heat and Cold Stress
13.4K
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
13.4K


