They have a real issue of choosing physical constants which aren't really constants, some models get it more right, others get it wrong and some are just unread

They have a real issue of choosing physical constants which aren't really constants, some models get it more right, others get it wrong and some are just unreadable so I couldn't get a conclusion. There are also other issues, some code is clearly untestable, the whole thing is written in incoherent merged up pieces so you might be using different constants / calculations for the same grid location from different modules. NASA GISS code looks even worse, but I couldn't link to GitHub it's only available as tar gz download. They have even worst stuff there. And remember the entire calculation is meant to measure the effect of changing CO2 which is only 0.0042% of the atmosphere. You need very high accuracy in everything in the first place to get the real effect rather than the model drifting into an alternative climate of imaginary world with different constants. And then remember that the real system is chaotic and the only signal that they claim to get is the average over many different simulations all drifting in average temperatures, over decades. The way the code is written there's just no way it's suitable for these kinds of predictions. And actually in most cases these models weren't built to predict climate over decades.