This is ironic -- Congressional Republicans do not, of course, believe in climate change. In part, that means they don't believe in climate models.
The GOP recently voted to also start analyzing legislation by their economic effects -- so-called "dynamic scoring." Basically, you need to project out the legislation's impact on the economy over so many years.
Here's the rub -- the models used for dynamic scoring use aren't stable. They need to equivalent of "flux corrections" -- factors inserted to keep the model stable, instead of its variables running away to infinity. From Bloomberg Businessweek:
Flux corrections were a significant issue in the early days of climate modelling -- ad hoc, hand-inserted functions to keep the model from heading off to infinity -- think Manabe and Wetherald plus 20-25 years.
But flux corrections are no longer needed in most models: climate models are stable as time goes on (which is a different issue than parametrizations, which are simplifed functional representations of difficult-to-calculate-from-first-principles factors like clouds)
Models for thee, but not for me. And the Republicans stumble blindly forward....