Tim the Plumber wrote: The basic idea of AGW is that; 1 Human
activity produces CO2 (absolutley) You need to go further than
that the evidence is clear that human activity has increased the
the level of CO2 in the atmosphere by 40% since the late 1700
and we are responsible for CO2 in the atmosphere continuing to
rise by about 2 PPM per year. 2 CO2 increases greenhouse warming
of the atmosphere (Beyond me, let's assume so). The important
question here is to what degree (sensitivity). The reason co2
increases temperature at the surface is simple co2 is opaque to
the heat waves that the earth gives off when it tries to cool
especially at night. From experiments we know that any doubling
of the amount of CO2 in the atmosphere will directly increase
the temperature by about 1 deg C + or - 0.2 deg C. We also know
that any warming of the atmosphere will lead to knock on effects
particularly an increase in the amount of water vapour in the
air which is even more opaque to heat trying to escape from the
surface. The