In message
,
Dick Lovett writes
On Jan 28, 1:070 wrote:
In message , Ron Button
writes

I don't have the literature to hand, but supposedly carbon isotope
ratios demonstrate the anthropogenic source of the additional
atmospheric carbon dioxide.
--
Stewart Robert Hinsley

As far as I am aware - source Hadley Centre - it has not been possible
to measure the isotopic signal of anthropgenic CO2
since 1945 due to atomic bomb contamination of the atmospheric.

Dick Lovett
Charlbury

Even if true, that would still leave 100 years of signal. (I know that
atomic weapons testing has messed up the atmospheric C-14 equilibrium,
which makes radiocarbon dating of recent material problematical. However
it is C-13 concentrations which are the smoking gun for anthropogenic
emissions, and it is not obvious why atomic weapons testing would affect
this.)

http://www.realclimate.org/index.php?p=87

--
Stewart Robert Hinsley