アメリカ合衆国 (US) の 炭素予算:土地利用の変化による貢献
1Woods Hole Research Center, Post Office Box 296, Woods Hole, MA 02543, USA.
まとめ
米国における土地利用の変化は,1945年より前には炭素を大量に放出したが,その後は森林の再生により炭素を吸収した. 土地管理の慣行は,米国の炭素排出に影響を与え,化石燃料の生産を相殺しました.
科学分野:
- 環境科学 環境科学
- エコロジー エコロジー エコロジー
- 気候科学 気候科学
背景:
- 伐採,放棄,木材の採集を含む歴史的土地利用は,陸上の炭素貯蔵に重大な影響を及ぼしています.
- これらの歴史的土地利用の動態を理解することは,正確な炭素循環モデリングに不可欠です.
研究 の 目的:
- 1700年から1990年までのアメリカの土地利用の歴史的変化を再構築する.
- これらの土地利用の変化の結果として,陸上の生態系への,そしてそこから排出される純炭素の流れを定量化するために.
主な方法:
- 既存のデータを用いて,歴史的土地利用率 (清掃,放棄,収穫,燃焼) を再構築する.
- エコシステムの炭素貯蔵の年間変化をシミュレートするために,陸上の炭素モデルを適用する.
主要な成果:
- 土地利用の変化は,1945年以前に大気中に推定27+/- 6ペタグラムの炭素 (PgC) を放出した.
- 1945年以降,陸上の生態系は2 +/- 2 PgCを蓄積し,これは主に火災撲滅と放棄された農地の植林によるものです.
- 1980年代,土地管理による炭素の流れは,米国の化石燃料の炭素排出量の10~30%を相殺した.
結論:
- 歴史的な土地利用は,過去3世紀にわたって大気中の炭素の主要な原動力となっています.
- 近代的な土地管理,特に火災撲滅と森林再生は,米国の陸上生態系を純炭素源から吸収源に変えた.
- 土地管理は,国の炭素予算と気候変動緩和の取り組みを調整する上で重要な役割を果たしています.
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