土地利用の変化による新たな排出は,CO2の空気中の割合が減少していることを示している
Margreet J E van Marle1,2, Dave van Wees1, Richard A Houghton3
1Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
Nature
|March 17, 2022
まとめ
大気中の二酸化炭素 (CO2) の排出量は減少しており,陸地と海洋の炭素吸収量が増加していることを示しています. この発見は,土地利用の変化による安定した排出量と大気中のCO2レベルへの影響に関する以前の仮定に異議を唱えます.
科学分野:
- 地球と環境科学
- 気候科学
- 大気化学
背景:
- 人為的な二酸化炭素 (CO2) 排出量の約50%は,陸上と海洋の吸収所によって吸収されます.
- 海洋温暖化や永久凍土の融解などの要因による 沈殿効率の低下は 気候変動を加速させる可能性があります
- 炭素吸収源の効率の変化の見積もりは,空気中の部分の動向の分析に基づいていますが,特に土地利用と土地の覆面の変化 (LULCC) に関する不確実性が残っています.
研究 の 目的:
- LULCCの長期にわたる一貫したデータセットを構築する.
- 大気中の二酸化炭素の割合のトレンドを再評価する.
- 人為的な排出量に対応する陸と海の炭素吸収容量を評価する.
主な方法:
- 森林破壊地域からの可視性データを用いてLULCCの排出量データセットを開発しました.
- LULCCに関連する排出量を長期間にわたって推論するために,可視性観測を用いた.
- 新しく構築されたLULCC排出量データセットを使用して,空気中のCO2分数の動向を分析した.
主要な成果:
- 熱帯森林伐採による排出量は1958年以来大幅に増加しています.
- LULCCの排出量は以前から考えられていた 安定した排出量とは対照的に 大きく増加した.
- 空気中のCO2の分子は1959年以来,0.014±0.010 decade−1で減少した.
結論:
- 陸と海の二酸化炭素吸収源は 人為的な排出量と共に 増加する能力を示しています
- LULCCの排出量の増加傾向は,炭素吸収の増加によって効果的に相殺されています.
- この研究は,以前に推定されたより強い炭素吸収システムを示唆し,気候変動予測に影響を与えています.
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