"Some iterations of the models showed the climate cooling after an
injection
of CO2, but these were discarded after close examination because the
temperature fall resulted from an unrealistic physical mechanism, says
Stainforth. In these scenarios, cold water welling up in the tropics
could
not be carried away by ocean currents because these were missing from the
models.

There are no obvious problems with the high temperature models, he says.
The
climateprediction.net team were left with a range of 1.9?C to 11.5?C.
"The
uncertainty at the upper end has exploded," says team-member Myles
Allen."

Discarded only the cooling models? Sounds like fudging to me...

If you know good reasons why the model is broken in some scenarios, it
makes
sense to discard them.

Pffft. Well that is not science. Ever heard of The Michelson-Morley
Experiment? The problem most people had with it was that it *seemed* wrong.
The strength that Einstein had over others was that he took the experimental
result at face value. There were many others as smart or smarter than
Einstein, but Einstein was not entrenched in preconceived notions. Others
wasted time trying to see how the experiment must be flawed. It was not
flawed.