> Unfortunately there is no magic fingerprint to distinguish between tectonic, volcanic and antropogenic carbon. Wrong again. Fossil fuels come from plants an

> Unfortunately there is no magic fingerprint to distinguish between tectonic, volcanic and antropogenic carbon. Wrong again. Fossil fuels come from plants and animals, and they all ultimately come from photosynthesis, which prefers C12 over slightly heavier C13 atoms.[1] As a result, CO2 emitted by burning fossil fuels have a lower concentration of C13. "Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes fossil fuels, the C13/C12 should be falling. Indeed this is what is occuring (Ghosh 2003) and the trend correlates with the trend in global emissions."[2] As for "humanity is smaller", I'll refer to the excellent xkcd[3]. I believe no further elaboration is necessary. [1] https://en.wikipedia.org/wiki/Isotopic_signature#Carbon_isotopes https://en.wikipedia.org/wiki/Isotopic_signature#Carbon_isot... [2] http://www.skepticalscience.com/print.php?r=109 http://www.skepticalscience.com/print.php?r=109 [3] http://xkcd.com/1338/ http://xkcd.com/1338/