SaveGreenEarth.com Blog

Actually it's pretty frustrating with fragmented doctrines all accepting the output of climate models as gospel. The above is a prime example because they are either unaware of or blithely ignore the inherent contradiction in the above claim.

The effect of doubling carbon dioxide in the absence of confounding feedbacks is moderately well understood -- all other things being equal increasing Earth's atmospheric concentration of carbon dioxide from 280 - 560 ppmv delivers a theoretical +1.2 K warming of global mean temperature (1.2 °C or ~2.2 °F), approximately half of which has already occurred since ~1750.

To derive a slightly scary +3 °C warming from 2 x CO2 an amplification factor of 2.5 is applied (2.5 x 1.2 = 3) -- which regular readers know we call the marvelous magical multiplier -- and the rationale is that warming due to increased CO2 increases evaporation and adds to the stock of the primary greenhouse gas -- yes, water vapor -- which increases greenhouse effect...

Inevitably, adding more water vapor to the atmosphere leads to more precipitation (what goes up must come down unless it reaches escape velocity). So, to get the temperature increases used as inputs to guesstimate drying and reduced runoff (as the above modelers do) actually requires a significant wetting of the atmosphere and consequent increase in precipitation and runoff (as gorebull warming modelers do).

All of which leaves us with the truly wonderful situation where a hypothetical wetting of the atmosphere causes a hypothetical drying of the atmosphere. At the same time we have recent publication of studies suggesting observed increases in runoff (in Europe, as I recall) are due to increased water efficiency of plants in the slightly less CO2-depleted atmosphere with reduced transpiration loss causing higher retained soil moisture levels between precipitation events (which, if memory serves, is supposed to increase the risk of damaging floods).

What a thoroughly stupid game this is.

(Note: The above was pasted from http://junkscience.com)