The message
from The Natural Philosopher contains these words:

Yes, but they don't put out CO2 that hasn't already been taken out of
the air..recently.

Oh, I'm not knocking that bit, but there's a good deal of
misunderstanding about how clean they are. Some modern stoves are very
good at burning the flue gases but older/simpler stoves pour out
hydrocarbons and things like...
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

The stoves which are best at reducing this are those with the tightest
control over airflow etc - so no more doors open while burning and the
like. The content of the flue gas varies enormously with what the
stove's doing. Burning fiercly will produce very different outputs to
smouldering overnight, for example.

--
Skipweasel
Pay no attention to that man behind the curtain.