Tuesday, March 18, 2008

The Minor "Greenhouse Gases" CO2 and CH4 Not The Cause Of Global Warming

This study clearly shows that the "greenhouse gases" carbon dioxide (CO2) and methane (CH4) do not cause significant global warming or climate change. They did not do so in the past and can not reasonably be considered to be doing so now.

Preprint in press for Physical Geography (July 4, 2007)
Quantitative implications of the secondary role of carbon dioxide climate forcing in the past glacial-interglacial cycles for the likely future climatic impacts of anthropogenic greenhouse-gas forcings
Willie Soon
Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
A review of the recent refereed literature fails to confirm quantitatively that
carbon dioxide (CO2) radiative forcing was the prime mover in the changes in
temperature, ice-sheet volume, and related climatic variables in the glacial and
interglacial periods of the past 650,000 years, even under the “fast response” framework
where the convenient if artificial distinction between forcing and feedback is assumed.
Atmospheric CO2 variations generally follow changes in temperature and other climatic
variables rather than preceding them. Likewise, there is no confirmation of the often posited
significant supporting role of methane (CH4) forcing, which – despite its faster
atmospheric response time – is simply too small, amounting to less than 0.2 W/m2 from a
change of 400 ppb. We cannot quantitatively validate the numerous qualitative
suggestions that the CO2 and CH4 forcings that occurred in response to the Milankovich
orbital cycles accounted for more than half of the amplitude of the changes in the
glacial/interglacial cycles of global temperature, sea level, and ice volume.

Consequently, we infer that natural climatic variability – notably the persistence of insolation forcing at key seasons and geographical locations, taken with closely-related thermal, hydrological, and cryospheric changes (such as the water vapor, cloud, and ice-albedo feedbacks) –suffices in se to explain the proxy-derived, global and regional, climatic and
environmental phase-transitions in the paleoclimate. If so, it may be appropriate to place
anthropogenic greenhouse-gas emissions in context by separating their medium-term
climatic impacts from those of a host of natural forcings and feedbacks that may, as in
paleoclimatological times, prove just as significant.

1. A rare but incomplete consensus on the relationship between CO2 concentration, temperature, and ice-sheet volume
One of the most notable, but somewhat surprising, consensus conclusions from ice-core
drilling projects and researches at both poles (see e.g., Fischer et al. 2006; Masson-
Delmotte et al. 2006) is the fact that the deduced isotopic temperatures lead other climatic responses, including especially the atmospheric levels of minor greenhouse gases like CO2 and CH4. Fischer et al. (1999) first reported that atmospheric CO2 concentrations increased by 80 to 100 ppm 600± 400 years after the warming of the last three deglaciations (or glacial terminations) in Antarctica and that relatively high CO2 levels
can be sustained for thousand of years during glacial inception scenarios when the
Antarctic temperature has dropped significantly. Later, Monnin et al. (2001) and Caillon
et al. (2003) offered clear evidence that temperature change drove atmospheric CO2
responses during more-accurately dated periods near glacial terminations I (at about 18
kyr before present, BP) and III (at about 240 kyr BP), respectively.

(Continued here:)

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