In a nonpolitical world, this Testimony by this prominent of an expert would be viewed by anyone who understands science as Checkmate, game-set-match, QED to the Climate Alarmist view of CO2 as a Climate Control Knob.
The GHG Theory and the Positive Feedback theory both manifest themselves ( in Climate Models) first as an increased temperature in the mid Troposphere which is the main layer measured by the balloon and satellite data sets.
None of the 4 balloon or 3 satellite data sets are measuring anything close to the predicted increases so the predicted “Climate Sensitivity ” to changes in CO2 is over estimated by several times. Carbon Dioxide has continued to rise and over a third of the total man made CO2 has been produced in the last 20 years and yet reality is that Temperatures have not risen as predicted. The empirical measurements say the theory is busted.
The surface temperature data sets show more warming but are also way below predictions despite the “hottest year ever” claims. The surface set is subject to UHI error , adjustments, estimates for large areas like the arctic and questionable handling of ocean data (70% of the area!).
It is also worthwhile to read the appendix as he shows how many of the claims about adverse effects of climate change are not happening. There is no increase in droughts, wildfires, crop losses and he could have included actual decreases in tornados and hurricanes and hurricane strength.
This has become such a stupid political football and is being used to justify expensive and damaging policies such as denying cheap fossil fuel energy to the third world which will continue to cost many lives.