過去の永久凍土の炭素の大幅な損失が現在の土壌に蓄積される
Amelie Lindgren1,2, Gustaf Hugelius3,4, Peter Kuhry3,4
1Department of Physical Geography, Stockholm University, Stockholm, Sweden. amelie.lindgren@natgeo.su.se.
Nature
|August 3, 2018
まとめ
最後の氷河期 (Last Glacial Maximum,LGM) の間,永久凍土の炭素貯蔵量は今日よりも小さかった. 永久凍土は大気中の炭素の増加に寄与していないことを示唆している.
科学分野:
- 古代気候学
- 生地化学
- 永久凍土科学
背景:
- 大気中のCO2は,最後の氷河期 (Last Glacial Maximum,LGM) から工業化以前の時代まで増加した.
- 永久凍土の解凍と分解は,氷河期から氷河期間のCO2とメタンの移行に影響を与えた可能性があります.
- 脱氷中の不規則な大気同位体信号は,LGMの陸上の炭素蓄積と関連している可能性があります.
研究 の 目的:
- 永久凍土の炭素貯蔵量を 経験的に推定する.
- LGMバイオームの範囲と炭素含有量を再構築する.
- LGM以降,大気への永久凍土炭素の純貢献を評価する.
主な方法:
- LGMバイオームの範囲を再構成する.
- LGMの永久凍土,泥炭地,沈殿地における炭素含有量の推定
- 北部の永久凍土地域におけるLGMと現在の土壌の炭素貯蔵量の比較
主要な成果:
- LGM 北部の永久凍土地帯の土壌の炭素貯蔵量は現在の貯蔵量より小さかった.
- 永久凍土面積の減少に伴い,土壌全体の炭素が400ペタグラム増加しました.
- 永久凍土に閉じ込められた炭素の 潜在的減少 1,000ペタグラム
結論:
- 永久凍土の炭素は LGM以降,大気中の炭素に 純で貢献していない可能性が高い.
- 炭素の貯蔵は,LGMの永久凍土の鉱物土壌から,今日より均等な分布に移りました.
- この結果は,氷河期後の永久凍土の炭素貯蔵量に関する以前の研究を裏付けている.
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