On 18 Jan, 23:38, Fred the Red Shirt wrote:
On Jan 18, 2:44*am, delboy wrote:

... Maybe the 'natural'
concentration of CO2 already gives the maximum greenhouse effect and
increasing it causes little or no difference.
...

Clearly no.

Consider Venus.

Venus is much closer to the Sun, so much hotter for that reason. Its
atmosphere is 97% Carbon Dioxide with smaller concentrations of
sulphuric acid, and chlorine and fluorine compounds. The concentration
of CO2 in the Earth's atmosphere is currently only 387 ppm (parts per
million), even with carbon emissions. The atmosphere of the Earth may
have had much higher levels of CO2 in its early history, but the
evolution of plant life tied most of the Carbon up in biomass, and
converted CO2 to Oxygen in the atmosphere, fortunately for us oxygen
breathing animals. Even with these higher CO2 levels, the Earth most
have been cool enough to allow Carbon and water based life to form.

Just a worrying thought. We humans breathe in the oxygen in the air
and breathe out CO2. We also give out methane (CH4) which is also a
potent greenhouse gas. Will Governments want to close us down as well
as the fossil fuel power stations? Or will we be taxed on our entire
carbon footprint? Frightening!

Derek Copeland