過去8回の氷河期における地球生物圏の一次生産性の変化
Ji-Woong Yang1, Margaux Brandon1,2, Amaëlle Landais1
1Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre-Simon Laplace, Université Paris Saclay/CEA/CNRS/UVSQ, Gif-sur-Yvette, France.
Science (New York, N.Y.)
|March 10, 2022
まとめ
過去の氷河期には,最大の二酸化炭素 (CO2) 吸収量である地球生物圏の生産性が低かった. 二酸化炭素のレベルが上昇すると この生産性が向上し 気候変動のフィードバックループが 形成されていることを示唆しています
科学分野:
- 古代気候学
- 生地化学
- 地球システム科学
背景:
- 世界生物圏の生産性は,大気中の二酸化炭素 (CO2) の循環の重要な要因です.
- 過去の世界的な生物圏の生産性を正確に推定することは,炭素循環のダイナミクスを理解するために不可欠です.
- 生物圏の歴史的生産性を推定する現在の方法には限界があります.
研究 の 目的:
- 生物圏の生産性を再構築する
- 過去の生物圏の生産性と大気中のCO2レベルとの関係を調査する.
- 氷河期間の気候サイクルにおける生物圏の生産性の役割を理解する.
主な方法:
- 極地の氷の核に閉じ込められた大気中の酸素の三重同位体比の分析
- 過去80万年の大気組成の再構築
- バイオスフィアの生産性指標とCO2と気候データとの相関関係
主要な成果:
- この研究は,氷の核の酸素同位体から導かれた 世界生物圏の生産性の 最初の800,000年の記録を提示しています.
- 過去の8つの氷河期間の地球生物圏の生産性は 工業化以前のレベルより低かった.
- 生物圏の生産性の上昇は 脱氷に数千年先行し CO2の変化と一致しました
結論:
- 大気中のCO2は地球生物圏の生産性の主要な原動力である.
- 生物圏の生産性は 氷河のような気候条件下で 負のフィードバックメカニズムを示しています
- 過去の生産性の変動を理解することで 気候変動に対する 将来の炭素サイクル反応の予測が向上します
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