Results 1 -
7 of
7
Faint young Sun problem more severe due to ice-albedo feedback and higher rotation rate of the early Earth
- Geophysical Research Letters
"... was up to 25 % less luminous than today, yet there is strong evidence that the Earth’s ocean surface was not completely frozen. The most obvious solutions to this ‘faint young Sun problem ’ demand high concentrations of greenhouse gases such as carbon dioxide. Here we present the first comprehensive ..."
Abstract
-
Cited by 5 (0 self)
- Add to MetaCart
(Show Context)
was up to 25 % less luminous than today, yet there is strong evidence that the Earth’s ocean surface was not completely frozen. The most obvious solutions to this ‘faint young Sun problem ’ demand high concentrations of greenhouse gases such as carbon dioxide. Here we present the first comprehensive 3-dimensional simulations of the Archean climate that include processes as the sea-ice albedo feedback and the higher rotation rate of the Earth. These effects lead to CO2 partial pressures required to prevent the Earth from freezing that are significantly higher than previously thought. For the early Archean, we find a critical CO2 partial pressure of 0.4 bar in contrast to 0.06 bar estimated in previous studies with 1-dimensional radiative-convective models. Our results suggest that currently favored greenhouse solutions could be in conflict with constraints emerging for the middle and late
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM
- J. Geophys. Res. (Atmos
, 2013
"... Different solutions have been proposed to solve the ’faint young Sun problem’, defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1D radiative convective mod-els and did not account well for the clouds ..."
Abstract
-
Cited by 3 (0 self)
- Add to MetaCart
Different solutions have been proposed to solve the ’faint young Sun problem’, defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1D radiative convective mod-els and did not account well for the clouds and ice-albedo feedback or the atmospheric and oceanic transport of energy. We apply a Global Climate Model (GCM) to test the different solutions to the faint young Sun problem. We explore the effect of greenhouse gases (CO2 and CH4), atmospheric pressure, cloud droplet size, land distribution and Earth’s rotation rate. We show that, neglecting organic haze, 100 mbars of CO2 with 2 mbars of CH4 at 3.8 Ga and 10 mbars of CO2 with 2 mbars of CH4 at 2.5 Ga allow a temperate climate (mean surface temperature between 10◦C and 20◦C). Such amounts of greenhouse gases remain consistent with the geological data. Removing continents pro-duces a warming lower than +4◦C. The effect of rotation rate is even more limited. Larger droplets (radii of 17 µm versus 12 µm) and a doubling of the atmospheric pressure pro-duce a similar warming of around +7◦C. In our model, ice-free waterbelts can be main-tained up to 25 ◦ N/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem. 1. Introduction and
A Closer Earth and the Faint Young Sun Paradox: Modification of the Laws of Gravitation, or Sun/Earth Mass Losses?
, 1306
"... life ..."
(Show Context)
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM
"... [1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clo ..."
Abstract
- Add to MetaCart
(Show Context)
[1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clouds and ice-albedo feedback or the atmospheric and oceanic transport of energy. We apply a global climate model (GCM) to test the different solutions to the faint young Sun problem. We explore the effect of greenhouse gases (CO2 and CH4), atmospheric pressure, cloud droplet size, land distribution, and Earth’s rotation rate. We show that neglecting organic haze, 100 mbar of CO2 with 2 mbar of CH4 at 3.8 Ga and 10 mbar of CO2 with 2 mbar of CH4 at 2.5 Ga allow a temperate climate (mean surface temperature between 10ıC and 20ıC). Such amounts of greenhouse gases remain consistent with the geological data. Removing continents produces a warming lower than +4ıC. The effect of rotation rate is even more limited. Larger droplets (radii of 17 m versus 12 m) and a doubling of the atmospheric pressure produce a similar warming of around +7ıC. In our model, ice-free water belts can be maintained up to 25ıN/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem.
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM
, 2013
"... [1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clo ..."
Abstract
- Add to MetaCart
(Show Context)
[1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clouds and ice-albedo feedback or the atmospheric and oceanic transport of energy. We apply a global climate model (GCM) to test the different solutions to the faint young Sun problem. We explore the effect of greenhouse gases (CO2 and CH4), atmospheric pressure, cloud droplet size, land distribution, and Earth’s rotation rate. We show that neglecting organic haze, 100 mbar of CO2 with 2 mbar of CH4 at 3.8 Ga and 10 mbar of CO2 with 2 mbar of CH4 at 2.5 Ga allow a temperate climate (mean surface temperature between 10ıC and 20ıC). Such amounts of greenhouse gases remain consistent with the geological data. Removing continents produces a warming lower than +4ıC. The effect of rotation rate is even more limited. Larger droplets (radii of 17 m versus 12 m) and a doubling of the atmospheric pressure produce a similar warming of around +7ıC. In our model, ice-free water belts can be maintained up to 25ıN/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem.
Article A Closer Earth and the Faint Young Sun Paradox: Modification of the Laws of Gravitation or Sun/Earth Mass Losses?
, 2013
"... galaxies ..."
(Show Context)
unknown title
, 2015
"... www.clim-past.net/11/559/2015/ doi:10.5194/cp-11-559-2015 © Author(s) 2015. CC Attribution 3.0 License. Diminished greenhouse warming from Archean methane due to solar absorption lines ..."
Abstract
- Add to MetaCart
www.clim-past.net/11/559/2015/ doi:10.5194/cp-11-559-2015 © Author(s) 2015. CC Attribution 3.0 License. Diminished greenhouse warming from Archean methane due to solar absorption lines
