19,000年前の海面の急速な上昇とその世界的な影響
Peter U Clark1, A Marshall McCabe, Alan C Mix
1Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA. clarkp@geo.oregonstate.edu
Science (New York, N.Y.)
|May 25, 2004
まとめ
19,000年前,北半球の氷床から発生した海面上昇または融水パルスが顕著でした. この現象により北大西洋は冷却され,熱帯と南半球は温暖化しました.
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
- 海洋学 海洋学とは
- 氷河学 氷河学とは
背景:
- 脱氷期における海面の変化と気候の動態は,地球の気候システムを理解する上で極めて重要です.
- 北半球の氷床が突然の気候変化に果たす役割については,さらなる調査が必要である.
研究 の 目的:
- 現在より約1万9000年前の急激な海面上昇のタイミングと発生源を調査する (B.P. ) を実施する.
- この融水パルスに対する世界的な気候反応を駆動するメカニズムを解明する.
主な方法:
- アイルランド海流域からの証拠の分析.
- 北大西洋の深水形成と海洋温度を含む気候記録の調査.
主要な成果:
- 証拠は,海面の急激な上昇 (融水パルス) が19,000 B.P.年に起こったことを支持しています. アイルランド海流域に存在する.
- 北大西洋の深水形成の減少と北大西洋の冷却は,融水パルスと一致しました.
- 熱帯の大西洋,太平洋,南半球で同時に温暖化が発生した.
結論:
- 融水パルスは北半球の氷床から発生した可能性が高い.
- この研究は,氷河解凍の気候シグナルを世界的に拡散するメカニズムを特定し,北半球の冷却と南半球の温暖化を説明する.
関連する概念動画
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
02:22The Colonization of Land
Changes in the environment of the early Earth drove the evolution of organisms. As prokaryotic organisms in the oceans began to photosynthesize, they produced oxygen. Eventually, oxygen saturated the oceans and entered the air, resulting in an increase in atmospheric oxygen concentration, known as the oxygen revolution approximately 2.3 billion years ago. Therefore, organisms that could use oxygen for cellular respiration had an advantage. More than 1.5 years ago, eukaryotic cells and...
02:35What is Evolutionary History?
Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and provides evidence for evolution. However, both fossil and living organisms offer evidence that outlines Earth’s evolutionary history.Phylogenetic trees illustrate the evolutionary relationships among these organisms. Scientists infer organisms’ common ancestry by evaluating shared morphological and genetic characteristics. Together, the fossil...
01:06Tidal Forces
The origin of Earth's ocean tides has been a subject of continuous investigation for over 2000 years. However, the work of Newton is considered to be the beginning of the proper understanding of the phenomenon. Ocean tides are the result of gravitational tidal forces. These same tidal forces are present in any astronomical body; they are responsible for the internal heat that creates the volcanic activity on Io, one of Jupiter's moons, and the breakup of stars that get too close to black holes.
01:26Influence of Earth's Curvature and Atmospheric Refraction on Leveling
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
01:26Origin of Photosynthesis
Photosynthesis represents a fundamental biological process that transformed Earth's atmosphere and paved the way for complex life. Emerging roughly 3.4–3.8 billion years ago, the earliest photosynthetic organisms harnessed light energy to produce organic compounds. These anoxygenic phototrophs used electron donors like hydrogen sulfide (H₂S) or ferrous iron (Fe²⁺), rather than water, and did not release molecular oxygen (O₂) as a byproduct. Various groups, including green sulfur and purple...