It's actually very easy to overfit climate models. They are fit to observed data with statistical inverse problem techniques (the same as I imagine they do with astronomical data). Climate change models are just directly discretized physical equations. Just like astronomy, the decisions are made on what physics are represented in the model and what are parameterized.
> Climate change models are just directly discretized physical equations.
I'm no expert, but it's my understanding that they're hugely more complicated than that implies. Sure, there's lots of physics there. But also chemistry and biology. The best ones are general circulation models,[0] and the outcomes will never fit some pretty theoretical structure.
