在地球早期大气中的-温室变暖
Robin Wordsworth1, Raymond Pierrehumbert
1Department of Geological Sciences, University of Chicago, Chicago, IL 60637, USA. rwordsworth@uchicago.edu
Science (New York, N.Y.)
|January 5, 2013
概括
早期地球可能由于- (H2−N2−) 相互作用而保持温暖,而不仅仅是二氧化碳. 这种大气变暖允许液态水尽管较低的太阳亮度,与早期微生物的潜在冷却效应.
科学领域:
- 行星科学 行星科学
- 气候科学 气候科学
- 地质科学是地球科学.
背景情况:
- 地球的早期历史呈现出一个悖论:较低的太阳亮度,但持续的表面液态水.
- 了解维持宜居温度的机制对于行星进化研究至关重要.
研究的目的:
- 调查- (H(2) -N(2)) 碰撞引起的吸收在早期地球变暖中的作用.
- 为了确定H2−N2的变暖与CO2水平相结合,是否可以在减少的太阳流下保持液态水.
主要方法:
- 大气模型包括H(2) -N(2) 碰撞诱导的吸收.
- 模拟了早期地球的气候条件,其中有不同的大气组成和太阳流量.
主要成果:
- 碰撞引起的吸收显著地使早期地球变暖,与最近的大气约束相一致.
- 在2~3倍N2质量和0.1H2混合比率的情况下,发生了足够的变暖,以保持在75%的太阳流下温度高于0°C的温度.
- 这种变暖只能在二氧化碳的水平是当前值的2-25倍的情况下实现.
结论:
- -相互作用为早期地球的持续液态水提供了一个可行的机制.
- 早期的甲基生物可能通过将H2和CO2转化为甲 (CH4) 来影响气候,可能会留下地质证据.
相关概念视频
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
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.
03:25Free Energy Changes for Nonstandard States
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
01:20Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
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01:26Origin of Photosynthesis
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