過去の極端な温暖化現象は,永久凍土の解凍による大量の炭素の放出と関連しています
Robert M DeConto1, Simone Galeotti, Mark Pagani
1Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01002, USA. deconto@geo.umass.edu
Nature
|April 7, 2012
まとめ
パレオセノ・エオセノ熱最大値 (PETM) を含む地球の古代の超熱は,永久凍土の炭素の放出を引き起こす軌道サイクルによって引き起こされました. これは,これらの極端な地球温暖化イベントのタイミングと規模を説明します.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 地質化学 地質化学
- 気候モデリング
背景:
- 地球は5550万年前から5200万年前にかけて,極端な地球温暖化現象 (超熱現象) を経験しました.
- パレオセーヌ・エオセーヌ熱極限 (PETM) は,大量の炭素の放出,海洋酸性化,そして5°Cの気温上昇を伴う.
- 現存するモデルでは,これらの超熱波の炭素源,規模,タイミングを説明するのに苦労しています.
研究 の 目的:
- PETMを含む初期エオセンのハイパーサーマルの背後にあるドライバーを調査する.
- これらの温暖化イベントの間に炭素の放出のための統一モデルを開発する.
主な方法:
- イタリアからの新しい天文学的に校正されたサイクロストラティグラフィック記録を利用した.
- 温室効果ガスと軌道強制を組み込んだ気候・生態系・土壌シミュレーションを実施した.
主要な成果:
- 初期のエオセンの超熱は,特定の地球軌道構成 (高離心率と傾き) と一致しました.
- シミュレーションは,永久凍土の土壌の有機炭素の軌道で引き起こされた分解がPETMとその後の超熱現象を説明することを示しています.
- 何千ペタグラムもの炭素が永久凍土から放出され,PETM以前の温暖化値によって増幅された.
結論:
- 地球の軌道特性は,永久凍土から大量に炭素が放出されるのを誘発する重要な要因です.
- 永久凍土は,繊細な炭素貯蔵庫として機能し,超熱波の規模と頻度に影響を与えました.
- 永久凍土の範囲が減少し,背景温度が上昇すると,その後の超熱流は小さくなりました.
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