最後の氷河期最大期以来の二重モードの炭素循環
H J Smith1, H Fischer, M Wahlen
1Scripps Institution of Oceanography, University of California San Diego, La Jolla 92093-0220, USA. hjsmith@aaas.org
Nature
|September 7, 2001
まとめ
極地氷の記録は,大気中の二酸化炭素 (CO2) の大幅な増加に関連した急速な温暖化現象を明らかにしています. この研究では,世界の炭素循環を理解するために炭素同位体を分析しています.
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
- 気候科学 気候科学
- 地質化学 地質化学
背景:
- 北極の氷芯は,過去の気候と大気組成の詳細な記録を提供します.
- 急激な温暖化現象は,氷河期から氷河間期への移行を特徴づける.
- 過去の急速な温暖化で大気中のCO2濃度が80〜100ppm増加したが,原因は不明である.
研究 の 目的:
- 過去の急速な温暖化現象で大気中のCO2が増加した原因を調査する.
- 南極の氷核からのCO2の安定した炭素同位体組成 (デルタ13CO2) を分析するために.
- 異なる気候モードの間,地球規模の炭素循環の振る舞いを理解する.
主な方法:
- 南極の氷に閉じ込められた空気からCO2を抽出する (テイラードーム).
- 安定した炭素同位体組成 (デルタ13CO2) の分析.
- 最後の氷河期最大期からホロセーン期までの,地球規模の炭素循環のモードの再構築.
主要な成果:
- 世界的な炭素循環は,千年間の時間尺度で2つの異なるモードで動作しました:一つは,ゆっくりとした気候変動,もう一つは,急速な温暖化です.
- 各モードは,大気,陸地,海洋間のCO2交換のための特徴的な平均的な安定した炭素同位体組成を示した.
- delta 13のCO2は,5°Cの海面温度上昇により,海洋CO2流出によって予測されたよりも多く増加し,他の要因が関与していることを示唆しています.
結論:
- 過去の急速な気候温暖化には,地球規模の炭素循環の同位体シグネチャーの明確なシフトが含まれていました.
- これらの温暖化イベントの間にCO2の増加の正確なドライバーは,さらなる調査を必要とします.
- 安定した炭素同位体データは,地球の気候システム内の複雑な相互作用に関する重要な洞察を提供します.
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