In message
,
Weatherlawyer writes
I don't have the literature to hand, but supposedly carbon isotope ratios
demonstrate the anthropogenic source of the additional atmospheric
carbon dioxide.

You mean it is less radio-active?

No. Apart from the problem of C-14 from atomic weapons testing, the
dilution of the level of C-14 would seem to be independent of the source
of the additional atmospheric CO2. It's C-13/C-12 ratios which are
relevant here, not C-14/C-12 ratios.

Similarly equipped without armour for my opinion, I can only offer:
radio-active carbon is less likely to be accepted by vegetables than
the real thing. Which would indicate a build up of radioactive carbon
dioxide in the atmosphere.

--
Stewart Robert Hinsley