So far they have virtually NO empirical data and their entire theory is based on computer derived fiction.
Shall we do this again?
The temperature record indicating warming unprecedented in magnitude or rate in over 10,000 years is empirical data. It is not "computer derived fiction". The CO2 record, indicating levels unprecedented in magnitude or rate for several million years is empirical data. It is not "computer derived fiction" The PIOMAS record of shrinking ice mass in the Arctic, Greenland, the West Antarctic Ice Sheet and the records showing that a very high majority of the world's glaciers and snow fields are shrinking is empirical data. It is not "computer derived fiction". The satellite data showing a continuing and growing radiative imbalance at the ToA is empirical data. It is not "computer derived fiction". The spectra showing that CO2 and all the other greenhouse gases, absorb EM falling on the Earth from the sun and reradiate it in the infrared band is empirical data. It is not "computer derived fiction". Evans 2006 (W.M.F. Evans) direct measurement of the IR radiation of greenhouse gases from the atmosphere to the surface of the Earth is empirical data. It is not "computer derived fiction".
So, Mr Westwall, take this claim of yours and shove it where the sun don't shine because that's where it came from and that's where it really ought to stay.