北半球の氷河化が強まったことで,千年来からの気候の変動が始まりました
David A Hodell1, Fátima Abrantes2,3, Carlos A Alvarez Zarikian4
1Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, UK.
まとめ
北半球の氷床が約270万年前に膨張したことで,氷河期にミレニアム気候変動 (MCV) が発生した. この気候の変動は,四季期の氷河気候の恒常的な特徴となった.
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
- 四季地質学 四季地質学
- 気候変動のダイナミクス
背景:
- クォーターナー期 (過去258万年) は北半球の氷床の大幅な変動を特徴とした.
- この期間の気候変動の発生と影響を理解することは,古気候の再構築にとって極めて重要です.
研究 の 目的:
- 四年生期におけるミレニアム気候変動 (MCV) の出現を調査する.
- 北半球の氷床の膨張と気候の変動の関係を見極めるため.
主な方法:
- イベリア・マージンからの堆積物配列の分析.
- 地質学的な出来事と気候の振動の年代付け.
- 北大西洋の氷河川の破片記録と相関する.
主要な成果:
- 北半球の氷床が2億7000万年ほど前に膨張したのは,MCVの発生と一致した.
- 先駆的なイベントは,約2.5万年前から始まった,数千年にわたる複数の気候振動が続いた.
- これらの振動は,氷のラフトからの破片と相関しており,海洋を終わらせる氷床の関与を示しています.
結論:
- ミレニアム気候変動 (MCV) は,約270万年前に北半球氷河期とともに発生した.
- MCVは四季期の氷河気候の不可欠な特徴となった.
- 北半球の氷河化は,さまざまな時間スケールにおける気候の変動に大きく影響した.
関連する概念動画
The Carbon Cycle
32.8K
Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle.
32.8K
What is Climate?
17.5K
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
17.5K
Global Climate Change
24.4K
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.
24.4K
Isothermal Processes
3.8K
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
3.8K
Precipitation Processes
5.0K
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
5.0K
Microbes and Climate Change
91
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...
91


