There's a chart in the article from the IPCC report showing observed vs simulated global average temperature changes. How are the scientists making these models guarding against overfitting?
I am not a climate change skeptic - I am simply asking an honest question that I don't know the answer to (which will be useful for dispelling the common argument that I hear some of my friends make). I also shouldn't have to place this kind of disclaimer in my post in the first place.
In principle, these models can be run a la 'ab initio' (from first principles) so no fitting is required. Of course, there are subtleties and unknowns, so some fitting is needed, but overfitting can be checked in the usual ways.
I am not a climate change skeptic - I am simply asking an honest question that I don't know the answer to (which will be useful for dispelling the common argument that I hear some of my friends make). I also shouldn't have to place this kind of disclaimer in my post in the first place.