プリオセンの温暖化,極域の増幅,そしてプレイストセンの段階的な冷却が,北北極ロシア北北東部で記録されています
Julie Brigham-Grette1, Martin Melles, Pavel Minyuk
1Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, USA. juliebg@geo.umass.edu
まとめ
北極の夏は,低二酸化炭素のレベルが低いにもかかわらず,プレオセーン時代に著しく暖かかった. この研究は,北極の気候に関する重要なデータを提供し,最初の氷河期に至る段階的な冷却傾向を明らかにしています.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 北極の気候の動態 北極の気候の動態
- 地質時間のスケール 地質時間のスケール
背景:
- 連続した,高解像度の北極のタイムシリーズの欠如は,過去の気候進化の理解を制限しています.
- 暖かいプレオセーンから初期の氷河周期への移行は,ほとんど理解されていません.
研究 の 目的:
- 北極圏の気候の進化を,平世中期からプレイストセンの初期まで再構築する.
- 過去の気候変動を理解するために,高解像度の北極のタイムシリーズを提供すること.
主な方法:
- ロシア北極東部のエルギギトギン湖のマルチプロキシ証拠を利用した.
- パレオ気候の再構築のための堆積物核を分析した.
主要な成果:
- 中期プレオセーン (3.6~3.4万年前) 北極の夏は今日より約8°C暖かく,約400ppmのCO2であった.
- 証拠は,プレオセンの中期に極度の温暖化と極極増幅があったことを示唆している.
- 突然の冷却イベントは,プレオセーン-プレイストセーン移行期に発生しました.
- 北極の夏は北半球の氷河期が始まってから,約2.2万年前まで,現在のより暖かいままでした.
結論:
- 北極の冷却は,プレイストセンの初期まで,大きな氷床を支えるには不十分でした.
- この発見は,海平面記録やその他のプロキシデータと一致しています.
- この研究は,北極の気候の感受性や氷河の形成に関する理解を深めるものです.
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