Millet, before you leave this, could you provide a link to the IPCC page that you said shows human activities only contribute 0.12% of the CO2
This IPCC link:
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch02.pdf
does not seem to support that.
Since it is pdf format I can't copy and paste it, but to quote a part of it: "The global mean CO2 in 2005 was 379 ppm, leading to an RF of +1.66[+/- 0.17] Wm-2. Past emissions of fossil fuels and cement production have
likely contributed about three-quarters of the current RF"