That's not entirely true. You can test by comparing the models against what actually happens over time. So far none of the models have proven accurate.
My theory is that when it comes to future predictions of something as complex as climate and weather, the likelihood the predictions will be accurate won't be good in my lifetime. They're good enough that I can probably avoid flying into a thunderstorm and dying and maybe ice. Better than Orville and Wilbur had, so I'm cool with it. (No pun intended.)
There's always the possibility of a major breakthrough, another interesting area of history. Scientists love to think they're Einstein, but we tend to only get one of those people where all the circumstances and genetics align to make the person who can nail down something big, every generation. Otherwise we wouldn't know their names.
Just like pilots love to think they're Hoover. Only going to be one Hoover a generation, too.
I'm sure the Eclipse will cool the earth sufficiently to prevent warming. I have a model that predicts it. It's going to be published in the Journal of the Flat Earth Society.
Cheers
All the fossil fuels burnt to go see it, will kill that. LOL LOL LOL.

I'm amazed the group of climate AGs hasn't announced that they're going to arrest people driving cars to see it. Hahahaha. Asses.
We humans do a pretty good job of making fun of any particular group that thinks they've got it all figured out. Sometimes they do, more often they don't. It's just normal.
The whole planet thought the flat-earth scientists were right for an awfully long time. It was the "settled science" of the day. Now we know better.
How we will know better on climate will be the day we wake up and realize the models work so well the meteorologists and climate researchers lost all their jobs. Probably by then it'll just be a quick check of the brain implant for the day's weather. Haha.
(Even funnier -- even by then there will be some idiot who drives into a thunderstorm and dies because they didn't check. The entropy of being human is never ending.)
I particularly like reading about those who thought the arctic would be warm and have palm trees, so they sent a boat and a crew who were locked in the ice for years and most of them died. Of course the crew knew what they might be in for and took the risks willingly, while the scientist who convinced a newspaper owner to pay for it all, sat home in relative comfort.
Well, technically the scientist died and the newspaper guy didn't make any money on the story until the survivors got back.
(Book recommendation: In The Kingdom of Ice, if you like the above summary.)