Maybe the models they create give the results their bosses want/need and therefore looking for other causes of global temp variances have not a very high priority for them AND they were ignorant to solar activity cycles.
The fact is that over the last 500 years, temperatures have swung from hot ( hotter than today ) to cold ( much colder than today ) back to hot again etc etc without any help from CO2 x man.
There is a very strong corelation from historically recorded solar activity and temperature data, that these temperature swings line up with solar activity intensity or lack there of. e.g. that solar activity caused temperature variances.
So no models needed here, its all based on historical facts supplied and verified by many Solar Physists (eg scientists). It is not proven, just likely. The proof will be what happen in the next 11 to 50+ years IMO. If the northen hemisphere starts experiencing record cold winters & snow falls, shorter summers, cereal crop failures…these are all indicators we are entering a Grand Solar Minimum ( the Eddy Solar Minimum ) and ■■■■ is gunna happen.