Show me a computer model, being used to build policy, that lacks validation.
Name the specific model, who is applying it to policy, and what important validation it lacks.
Name more than one, if you can. There should be dozens to choose from, if what you are saying is true.
They are the sole deciding factor for determining the human contribution to climate change.
What important policy-setting body is only using computer models as the
sole deciding factor for determining human contribution to climate change?
(We already saw that the IPCC is
not an example.)
I should mention that it is the
model that gets adjusted. Not the data.
It's those model adjustments that help us understand new factors that affect climate (and wheather) better. Computer models can help us do that much more effectively than non-computer models.
Non-computer models, including theories devised solely through empirical means are
ALSO adjusted, when their future predictions deviate from the actual data.
So, your case is hardly rested, if you are making one against computer simulations. Non-computer ones have these issues.