将来の大気中のCO2に対する地球温暖化と海洋炭素循環のフィードバック
1Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.
まとめ
地球温暖化シミュレーションでは,北大西洋の循環が弱まり,高レベルの二酸化炭素下では崩壊していることが示されています. 海洋の炭素循環の変化は,大気中のCO2にわずかな影響を及ぼし,海面温度が上昇すると,海洋の炭素吸収が減少する.
科学分野:
- 気候科学 気候科学
- 海洋学 海洋学とは
- バイオジオケミストリー バイオジオケミストリー
背景:
- 気候変動に関する政府間パネル (IPCC) は,将来の気候予測のためのシナリオを提供しています.
- 気候,海洋循環,炭素循環の相互作用を理解することは,将来の大気中のCO2レベルを予測するために重要です.
- 北大西洋の熱ハリン循環は,世界の気候規制において重要な役割を果たしています.
研究 の 目的:
- 将来の大気中の二酸化炭素と地球温暖化を物理的・生地化学的気候モデルを使用して予測する.
- 気候変動シナリオが北大西洋の熱ハリン循環に与える影響を調査する.
- 大気中のCO2濃度に対する海洋炭素循環の影響を評価する.
主な方法:
- 低次元の物理・生地化学気候モデルを利用した.
- IPCCによって開発された様々な地球温暖化シナリオをシミュレートした.
- 大気中の二酸化炭素,地球温暖化,海洋の炭素循環の動態の変化を分析した.
主要な成果:
- 北大西洋の熱ハリン循環は,すべての地球温暖化シミュレーションで弱まり,高濃度のCO2で崩壊する.
- 海洋の炭素循環における予測される変化は,大気中のCO2にわずかな影響を及ぼします.
- 大気中のCO2は,対照シミュレーションと比較して2100年に4%,2500年に20%増加した.これは主に,海洋表面の温暖化により,海洋の炭素吸収が減少したためです.
結論:
- 海面の温暖化は,海洋の炭素吸収の減少の主な要因である.
- 海洋生物の循環は,熱ハリン循環の崩壊時を除いて,炭素混合の減少を補うことができる.
- 北大西洋の熱ハリン循環の崩壊は,海洋の炭素循環と大気中のCO2レベルに大きな影響を及ぼします.
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