Journal ArticleDOI
Enhanced CO2 greenhouse to compensate for reduced solar luminosity on early Earth
TLDR
In this article, it was shown that CO2-H2O in a weakly reducing atmosphere could have caused a change in the early Earth's temperature by the so-called greenhouse effect.Abstract:
CURRENT models for the evolution of the Sun require an increase in solar luminosity by 25% since the formation of the Solar System1. Such an increase in the solar constant should have profound effects on the terrestrial climate, but there is no evidence from the fossil record of a corresponding change in the Earth's global mean temperature2. This apparent conflict cannot be explained by the apparent inability of solar models to account for the low observed neutrino flux3. Even models that are forced to fit the neutrino data require a similar increase in the solar luminosity. As Newman and Rood1 state: “a faint young Sun is one of the most unavoidable consequences of stellar structure considerations”. We discuss here whether CO2–H2O in a weakly reducing atmosphere could have caused this change in the early Earth's temperature by the so-called greenhouse effect.read more
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A negative feedback mechanism for the long‐term stabilization of Earth's surface temperature
TL;DR: In this article, it is suggested that the partial pressure of carbon dioxide in the atmosphere is buffered, over geological time scales, by a negative feedback mechanism, in which the rate of weathering of silicate minerals (followed by deposition of carbonate minerals) depends on surface temperature, which in turn depends on the carbon dioxide partial pressure through the greenhouse effect.
Journal ArticleDOI
Earth's early atmosphere
TL;DR: A better understanding of past atmospheric evolution is important to understanding the evolution of life and to predicting whether Earth-like planets might exist elsewhere in the galaxy.
Journal ArticleDOI
Greenhouse warming by CH4 in the atmosphere of early Earth
TL;DR: It is found that a CH4 mixing ratio of 10(-4) (100 ppmv) or more in Earth's early atmosphere would provide agreement with the paleosol data from 2.3-2.4 Ga, which could have triggered the Earth's first widespread glaciation.
Journal ArticleDOI
Carbon dioxide cycling and implications for climate on ancient Earth
Norman H. Sleep,Kevin Zahnle +1 more
TL;DR: In the early Earth, processes involving tectonics were more vigorous than at present, and the dynamic mantle buffer dominated over the crustal one as discussed by the authors, and the mantle cycle would have maintained atmospheric and oceanic CO2 reservoirs at levels where the climate was cold in the Archean unless another greenhouse gas was important.
Book
Energy Balance Climate Models
TL;DR: In this article, an introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. But the model parameterizations are examined critically in light of many current uncertainties.
References
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Journal ArticleDOI
Earth and Mars: evolution of atmospheres and surface temperatures.
Carl Sagan,George Mullen +1 more
TL;DR: Solar evolution implies, for contemporary albedos and atmospheric composition, global mean temperatures below the freezing point of seawater less than 2.3 aeons ago, contrary to geologic and paleontological evidence, but ammonia mixing ratios of the order of a few parts per million in the middle Precambrian atmosphere resolve this and other problems.
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Atmospheric homeostasis by and for the biosphere: the gaia hypothesis
James E. Lovelock,Lynn Margulis +1 more
TL;DR: In this paper, the authors present an alternative explanation that early after life began it acquired control of the planetary environment and that this homeostasis by and for the biosphere has persisted ever since.
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Hydrogen and oxygen isotope ratios in nodular and bedded cherts
L. Paul Knauth,Samuel Epstein +1 more
TL;DR: In this paper, a suite of samples from the central and western United States were used to determine the hydrogen and oxygen isotopic compositions of the cherts and showed that the change with time of the isotopic composition of cherts can be satisfactorily explained in terms of past climatic temperature fluctuations.