全世界の窒素酸化物源と吸収源の包括的な定量化
Hanqin Tian1, Rongting Xu2, Josep G Canadell3
1International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA. tianhan@auburn.edu.
Nature
|October 8, 2020
まとめ
窒素酸化物 (N2O) の排出量は,特に農業における人間の活動により増加しています. この増加は 気候変動とオゾン層の破壊を促し 緊急の緩和措置を講じています
科学分野:
- 環境科学
- 大気化学
- 気候科学
背景:
- 酸化窒素 (N2O) は強力な温室効果ガスであり,オゾン層の枯渇と気候変動に貢献しています.
- 現在のN2Oの在庫は不完全で,天然の源と正確な人為的帰属が欠けている.
- 大気中のN2O濃度は10年ごとに約2%増加しています.
研究 の 目的:
- 自然と人為的な源を含む包括的なグローバルなN2O在庫を提示する.
- 1980年から2016年までのN2O源とシンクを数値化するために,複数の方法論を使用します.
- N2O排出量の増加の要因を分析し,新たな傾向を特定する.
主な方法:
- 集積されたボトムアップアプローチ:在庫,流量測定,陸/海洋モデリング.
- トップダウンアプローチ:大気逆転モデリング
- N2Oの排出量と吸収量の21の自然と人間のセクターの分析
主要な成果:
- 2007年から2016年にかけての世界のN2O排出量は17.0TgNyr (bottom-up) と16.9TgNyr (top-down) と見積もられている.
- 人類によるN2O排出量は,主に耕作地から40年間で30%増加し,7.3TgNyrに達しました.
- 新興国 (ブラジル,中国,インド) で顕著なN2O排出量増加が観測された.
結論:
- N2Oの排出量の増加は主に人間の活動,特に農業による窒素添加によって引き起こされています.
- 窒素添加と気候変動によって引き起こされる新興のN2O気候フィードバックループが特定されています.
- N2O排出量の急速な増加は予測を上回り,緩和戦略の必要性を強調しています.
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