過去50年間,陸地と海洋による二酸化炭素の純吸収の増加
A P Ballantyne1, C B Alden, J B Miller
1Department of Geology, University of Colorado, Boulder, Colorado 80309, USA. apballantyne@gmail.com
Nature
|August 4, 2012
まとめ
陸地と海洋による世界の炭素吸収は,以前の気候モデルの予測に反して,過去50年間で倍増しました. この発見は,炭素吸収と気候変動のフィードバックループに関する仮定に異議を唱える.
科学分野:
- 気候科学 気候科学
- 地球システム科学 地球システム科学
- 炭素循環に関する研究
背景:
- 将来の気候予測は,地球規模の炭素循環が気候変動に与える影響により,不確実性に直面しています.
- 海と陸の炭素貯蔵庫は現在,人類による二酸化炭素 (CO2) 排出量の約半分を吸収しています.
- モデルは,炭素吸収の将来の減少を予測し,炭素-気候のポジティブなフィードバックを示唆しています.
研究 の 目的:
- 過去50年にわたる世界の二酸化炭素 (CO2) 源と沈殿地の変化を分析する.
- 大気中のCO2の測定と排出量在庫を用いて,世界の炭素吸収の動向を評価する.
- 炭素吸収量の減少を予測する既存のモデルに異議を唱える.
主な方法:
- 世界規模の大気中のCO2測定を用いた.
- 組み込まれたCO2排出量インベントリーとその不確実性.
- 世界的なCO2源と吸収槽の変化を計算するために質量バランス分析を行った.
主要な成果:
- 世界的な炭素吸収量は,年間約0.05億トンの炭素で大幅に増加しています.
- 世界的な炭素吸収量は1960年から2010年の間に,年間2.4 ± 0.8から5 ± 0.9億トンに倍増した.
- 陸地と海の二酸化炭素吸収が,地球規模で減少したとは,あまり思えません.
結論:
- 観測された世界の炭素吸収の増加は,炭素吸収の減少に関する予測と矛盾しています.
- 1959年以来排出された3500億トンの炭素の約55%が陸と海によって吸収されています.
- 炭素吸収の増加を促すメカニズムを特定することは,世界の炭素予算を精錬し,将来の気候の相互作用を予測するために不可欠です.
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