I say BS for Co2, page-20

"As for your numbers I dont follow them"

You might want to try it sometime... and your slur is noted.

I meant both 14-C and 13-C. 14-C is produced by cosmic radiation colliding with atmospheric nitrogen and is radioactive, so any carbon more than about 40k years old will have no 14-C. Plant biology meanwhile is selective for 12-C over 13-C - materials of biological origin have a 13-C:12-C ratio lower than the atmosphere or inorganic materials. And, funnily enough, the relative levels of these three isotopes in the atmosphere are changing in exactly the way you'd expect if the extra carbon was indeed of fossil biological origin.