[the8472]

> The theory is not falsifiable.

That is fundamentally wrong. At the worst you would have to run an experiment with many earth-replicas and individual changed variables. Quite impractical but not relevant for determining falsifiability of a theory.

But more importantly models don't just have to fit data of the past, they also make predictions of the future which will automatically be tested as time advances. And pretty much all climate models do not make a singular prediction they map some input domain to an output domain. Decrease factor A by x% and the global averages of effect M will stay within some confidence interval with the mean y% lower etc.

Of course it is complex, but complexity is no excuse to throw up your arms and claim we can't possibly know anything when it's inconvenient.