It really hasn't. A lifted air parcel allowed to expand adiabatically is just as isentropic (and follows the same temperature and pressure relationship) today as it was over a century ago. Similarly, the derivation of an atmosphere's temperature profile from the lapse rate hasn't changed.
We can measure accurately out to parts per million and accordingly to climate "Scientists" an increase of just 200PPM will raise temperature a few degrees. That's what Climatologists are now alleging.
Show me that in a lab.
Unfortunately a single laboratory experiment can't mimic the numerous real-world feedbacks that determine climate sensitivity. That's why climate sensitivity has to be determined empirically from the real world with its real clouds and ice and lapse rate, etc. We know how the variables work together--that's the theoretical physical bit and that can be verified piece by piece in some lab jar. But inserting the real-world values of the variables to make quantitative predictions can't be done in a lab. That's the stage climate dynamics is on today.
Unfortunately for some the "debate" doesn't seem to have moved beyond the basic physics yet. Infrared opacity determines the radiating pressure level of the atmosphere. Increase that and you'll bump up that pressure level a bit higher, making the surface warmer. None of this is in doubt. Now the empirical contours of the climate system are being mapped out and attempts to model their future evolution are being made. Yes, that's hard. No, that doesn't make your opinions any more interesting.