2023 Fiscal Year Final Research Report
Reconstruction of atmospheric carbon dioxide concentration during the last 6 million years and the study of the interaction between atmospheric carbon dioxide and climate
| Project/Area Number |
19H05595
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Review Section |
Broad Section B
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
吉森 正和 東京大学, 大気海洋研究所, 准教授 (20466874)
阿部 彩子 東京大学, 大気海洋研究所, 教授 (30272537)
関 宰 北海道大学, 低温科学研究所, 准教授 (30374648)
入野 智久 北海道大学, 地球環境科学研究院, 准教授 (70332476)
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| Project Period (FY) |
2019-06-26 – 2024-03-31
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| Keywords | 二酸化炭素 / 温室効果 / C4植物 / 氷期間氷期変動 / 気候変動 / 海底コア / 長鎖脂肪酸 / 同位体 |
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| Outline of Final Research Achievements |
Using an original method based on carbon isotope ratios of long-chain fatty acids, we found that the highest atmospheric CO2 concentration over the past 6 million years was only around 300 ppm. The results also revealed that the CO2 concentration decreased from 3.5 million to 2.5 million years ago, and that the period of change modulated from 400,000 to 40,000 years at the time when the CO2 concentration dropped first to around 190 ppm. The long-term decrease in CO2 concentration was synchronized with the oxidation in the deep Pacific Ocean, presumably resulting from a decrease in the total amount of carbon in the atmosphere-ocean system.
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| Free Research Field |
古気候学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で得られた過去600万年間の大気中CO2濃度記録は，従来の過去80万年間のアイスコア気泡のCO2濃度記録
をはるかに超えており，過去の環境変動・気候変動の原因を考察するうえで不可欠なデータである．IPCCでの地
球環境予測評価等，地球環境研究において広範囲に活用されることが予想される．
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