Old Rocks
Diamond Member
- Thread starter
- #21
Wrong!Those not ignorant of the basics know the last snowball earth phase happened over 500 million years ago, when the sun was over 5% dimmer. Very dishonest to leave that out.
However, a fact that the confused AGW scammer always seem to forget is a time when CO2 levels were ten times what they are now the earth was a snowball
Also, the thing that broke the earth out of the snowball earth phase was ... increasing CO2. Again, it's not possible to explain paeloclimate without including the effects of CO2.
Why do you all think CO2 no longer has the effect that it had over all of earth's past? That makes you all sound some combination of stupid, delusional and dishonest.
If CO2 is such a greenhouse gas that you idiot Moon Bat scammers claim it is with levels ten times what it is now we should have turned into a hothouse like Venus did. Instead we were a snowball.
Another AWG scam busted!
The initiation of modern soft and hard Snowball Earth climates in CCSM4
J. Yang*,1, W. R. Peltier2, and Y. Hu1- 1Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
- 2Department of Physics, University of Toronto, Toronto, Ontario, Canada
- *formerly at: Department of Physics, University of Toronto, Toronto, Ontario, Canada
Abstract. Geochemical and geological evidence has suggested that several global-scale glaciation events occurred during the Neoproterozoic Era in the interval from 750–580 million years ago. The initiation of these glaciations is thought to have been a consequence of the combined influence of a low level of atmospheric carbon dioxide concentration and an approximately 6% weakening of solar luminosity. The latest version of the Community Climate System Model (CCSM4) is employed herein to explore the detailed combination of forcings required to trigger such extreme glaciation conditions under present-day circumstances of geography and topography. It is found that runaway glaciation occurs in the model under the following conditions: (1) an 8–9% reduction in solar radiation with 286 ppmv CO2 or (2) a 6% reduction in solar radiation with 70–100 ppmv CO2. These thresholds are moderately different from those found to be characteristic of the previously employd CCSM3 model reported recently in Yang et al. (2012a,b), for which the respective critical points corresponded to a 10–10.5% reduction in solar radiation with 286 ppmv CO2 or a 6% reduction in solar radiation with 17.5–20 ppmv CO2. The most important reason for these differences is that the sea ice/snow albedo parameterization employed in CCSM4 is believed to be more realistic than that in CCSM3. Differences in cloud radiative forcings and ocean and atmosphere heat transports also influence the bifurcation points. These results are potentially very important, as they are to serve as control on further calculations which will be devoted to an investigation of the impact of continental configuration.
We demonstrate that there exist ''soft Snowball'' Earth states, in which the fractional sea ice coverage reaches approximately 60–65%, land masses in low latitudes are covered by perennial snow, and runaway glaciation does not develop. This is consistent with our previous results based upon CCSM3. Although our results cannot exclude the possibility of a ''hard Snowball'' solution, it is suggested that a ''soft Snowball'' solution for the Neoproterozoic remains entirely plausible.