Snow_Miser Posted December 3, 2012 Share Posted December 3, 2012 A few hundred million years ago, there was significantly lower solar output than today, but yet the Earth's Temperature was quite a bit warmer than today's. Why is this? Some researchers have proposed that because there were much higher levels of Greenhouse Gases than there are today, that this was sufficient to keep Earth very warm compared to today. Other scientific researchers disagree, saying that there was no evidence for such high levels of Greenhouse Gases when the sun was faint, pointing to less CCNs than today, and a lower albedo overall than today. Discuss. Link to comment Share on other sites More sharing options...
skierinvermont Posted December 3, 2012 Share Posted December 3, 2012 A few hundred million years ago, there was significantly lower solar output than today, but yet the Earth's Temperature was quite a bit warmer than today's. Why is this? Some researchers have proposed that because there were much higher levels of Greenhouse Gases than there are today, that this was sufficient to keep Earth very warm compared to today. Other scientific researchers disagree, saying that there was no evidence for such high levels of Greenhouse Gases when the sun was faint, pointing to less CCNs than today, and a lower albedo overall than today. Discuss. I think all the hot air from these fake 'scientific researchers' you've been reading traveled back in time to cause this warm period. Also to Venus. Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 3, 2012 Author Share Posted December 3, 2012 I think all the hot air from these fake 'scientific researchers' you've been reading traveled back in time to cause this warm period. Also to Venus. Thank you for this absolutely meaningless post. Link to comment Share on other sites More sharing options...
Vergent Posted December 3, 2012 Share Posted December 3, 2012 A few hundred million years ago, there was significantly lower solar output than today, but yet the Earth's Temperature was quite a bit warmer than today's. Why is this? Some researchers have proposed that because there were much higher levels of Greenhouse Gases than there are today, that this was sufficient to keep Earth very warm compared to today. Other scientific researchers disagree, saying that there was no evidence for such high levels of Greenhouse Gases when the sun was faint, pointing to less CCNs than today, and a lower albedo overall than today. Discuss. I would be glad to discuss if you supply peer reviewed reference links for the bolded. Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 3, 2012 Author Share Posted December 3, 2012 I would be glad to discuss if you supply peer reviewed reference links for the bolded. Yes. Rosing et al. 2010 Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions1, 2, 3, as well as increases in the Sun’s luminosity of about 25 to 30 per cent over the Earth’s history4. It has been inferred that the greenhouse effect of atmospheric CO2 and/or CH4 compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere5, 6, 7, 8. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II–III) oxides (magnetite) in banded iron formations9 is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations10, 11, 12, 13, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei14, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox. Link to comment Share on other sites More sharing options...
Vergent Posted December 3, 2012 Share Posted December 3, 2012 Yes. Rosing et al. 2010 Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions1,2,3, as well as increases in the Sun’s luminosity of about 25 to 30 per cent over the Earth’s history4. It has been inferred that the greenhouse effect of atmospheric CO2 and/or CH4 compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere5,6,7,8. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II–III) oxides (magnetite) in banded iron formations9 is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations10,11,12,13, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei14, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox. Full text behind a paywall. Could you look and see if they took into account that back then; back then the Earth day was significantly shorter. The Earth was orbiting closer to the sun The moon was orbiting closer to the Earth(brighter moonshine). All of these are due to tidal acceleration, the first and third due to the earth accelerating the moon losing rotational energy, the second the sun accelerating the earth. http://en.wikipedia....al_acceleration Editorial standard are lax for letters. Do you have peer reviewed? This letter received three strongly worded negative replies, and received no positive replies. That, in my view is equivalent to failing peer review. http://www.nature.co...ature09959.html http://www.nature.co...ature09960.html http://www.nature.co...ature09961.html Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 3, 2012 Author Share Posted December 3, 2012 Full text behind a paywall. Could you look and see if they took into account that back then; back then the Earth day was significantly shorter. The Earth was orbiting closer to the sun The moon was orbiting closer to the Earth(brighter moonshine). All of these are due to tidal acceleration, the first and third due to the earth accelerating the moon losing rotational energy, the second the sun accelerating the earth. http://en.wikipedia....al_acceleration Editorial standard are lax for letters. Do you have peer reviewed? This letter received three strongly worded negative replies, and received no positive replies. That, in my view is equivalent to failing peer review. http://www.nature.co...ature09959.html http://www.nature.co...ature09960.html http://www.nature.co...ature09961.html Criticism of the study means that the study was not peer reviewed? What's that supposed to mean? The full text is available here: http://gondwanaresearch.com/hp/fys.pdf Their rebuttal to the criticism is available here: http://www.nature.com/nature/journal/v474/n7349/abs/nature09962.html Link to comment Share on other sites More sharing options...
aslkahuna Posted December 4, 2012 Share Posted December 4, 2012 Planetary perturbations in Earth's orbit and Solar mass loss through the Solar wind would be more effective in enlarging our orbit than tidal interactions from the Sun. Steve Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.