Nuclear burning models were driven by relatively straight forward formulae based directly on known laws of physics. The program calculations were tested against observation because good scientists know that any man made (we make computers and write their programs) calculation is subject to error. In contrast, by necessity climatology models are not simply direct physics equations but contain many empirical formulae with arbitrary constants based on the best science we know at the present. We also are limited to modeling aspects of the environment that we understand well enough to write some kind of equations for. Other aspects are left out. However, the real world leaves out nothing. Climatology is much more complicated than the relatively simple and straightforward pure physics of nuclear reactions.

I see it as hubris to accept such models on faith. Although most every model that I know of predicts a temperature increase, the amount of predicted increase varies wildly. The wildest predictions are those that make it into the popular press and Hollywood polemics.