You cite a lot of uncertainty about Solar activity!

Sure, you can use models to make predictions for a date in the future. Then, you wait to see if you reach that date and the predictions come true. Then you can make qualitative assertions about the accuracy of the model, its shortcomings, and whatnot. Do we have evidence of past climate models making accurate future predictions? (I really don’t know, now you have me curious.)

Surely we have historical data to validate models with?! I'm no expert, but this all sounds very plausible to me. Some parts are even basic physics, like reflection and black-body radiation, which I'm pretty sure we have nailed down exactly by now. Other parts are uncertain: simplifications of topology, chaotic processes, methane content of melting grounds, etc.

The model allows to answer "what-if" questions, and the uncertainty of the answer also depends on the question. Would the temperature rise if earth's atmosphere suddenly had the composition on Venus? Hell yes, we can predict that with high confidence, without ever trying it for real. Can we predict the gusts of wind caused by this, the global heat distribution, the exact timing? Probably not, at least it's not plausible to me that we could model every effect that matters for such a detailed prediction.

But does it sound so unbelievable that we have a model accurate enough to predict the rough effect of additional CO2 on global temperature? Or would you argue that it is more plausible that most scientists are corrupt and follow someone's agenda, and have discarded the idea of doing honest science which they must have had when starting?

> does it sound so unbelievable that we have a model accurate enough to predict the rough effect of additional CO2 on global temperature?

Yes, it does sound unbelievable because CO2 is a tiny fraction of the atmosphere, and water vapor is approximately 2.5% of the atmosphere while also being the strong greenhouse gas.

It's a giant fraud used a political tool for the brainwashed masses.

You can make hypotheses and test them with models, that is science and it can shed light on how processes work. But these models have input variables that have some randomness and some which are currently unknown to us.

It's putting the cart before the horse to consider these models to be simulations, which is how we treat them politically. The only appropriate reaction to how we frame the climate in politics is skepticism.

There is clearly a push to amp the climate rhetoric up to crisis levels right now. It's easier every day to be a skeptic.