The primary greenhouse gas is carbon dioxide. Human annual production of carbon dioxide is about two orders of magnitude greater than average annual emissions of carbon dioxide by volcanoes. (Please see the USGS page Volcanic Gases and Their Effects for details; look down the page for the comparison.) But regardless of the amount of CO2 produced by volcanoes, the simple fact is that the CO2 in the atmosphere has gone steadily upwards by about 2 parts per million per year, for the fifty some years it's been measured. It has gone up from 270 ppm before the 20th century to the present 382 ppm.
The primary greenhouse gas is carbon dioxide.
Actually water vapor is by far the primary and most prevalent as well as one of the strongest greenhouse gases.
Anthropogenic (man-made) Contribution to the "Greenhouse
Effect," expressed as % of Total (water vapor INCLUDED)
Based on concentrations (ppb) adjusted for heat retention characteristics % of All Greenhouse Gases % Natural
% Man-made
Water vapor 95.000% 94.999%
0.001% Carbon Dioxide (CO2) 3.618% 3.502%
0.117% Methane (CH4) 0.360% 0.294%
0.066% Nitrous Oxide (N2O) 0.950% 0.903%
0.047% Misc. gases ( CFC's, etc.) 0.072% 0.025%
0.047% Total 100.00% 99.72
0.28%
The variation of water vapor in the formation and destruction of clouds is by far the greatest factor on climate and climate variation. In fact the UN/IPCC climate models fail to even begin accounting for this factor.
That is why Solar Activity and its effect on the magneticsphere deflection cosmic ray flux from the atmosphere is of such interest as regards any climate change. The latest research in this area suggests that the dominant factor in climate change currently is indeed the effects of solar activity in modulation of the Earth's lower cloud levels.
Refer: http://spacecenter.dk/xpdf/influence-of-cosmic-rays-on-the-earth.pdf
the simple fact is that the CO2 in the atmosphere has gone steadily upwards by about 2 parts per million per year, for the fifty some years it's been measured. It has gone up from 270 ppm before the 20th century to the present 382 ppm.
The simpler fact is that the direct radiative effects of CO2 have only marginal effect on climate change. The models erroneously relying on feedback factors that are not demonstated to actually exist in nature in the magnitude or even sign required in global warming models of the UN/IPCC.
Of even interest is that the radiative heating effects of CO2 actually decline in efficacy as concentration increases in a logrithmic relationship providing only a linear increase with an exponential increase in CO2 such that it only adds ~0.2oK for each doubling of CO2 concentration in the atmosphere.
"the direct radiative effects of doubled CO2 can cause a maximum surface warming [at the equator] of about 0.2 K, and hence roughly 90% of the 2.0-2.5 K surface warming obtained by the GCM is caused by atmospheric feedback processes described above."
--- "Increased Atmospheric CO2: Zonal and Seasonal Estimates of the Effect on the Radiation Energy Balance and Surface Temperature" (V. Ramanathan and M. S. Lian), J. Geophys. Res., Vol. 84, p. 4949, 1979.
And what is the primary 'greenhouse' gas found in a typical actual Greenhouse ? Is it Nitrogen ? Is it Oxygen ? I always thought the 'green' in the typical Greenhouse consumed CO2 and produced O.