Read here, here, here, and here. If one reads the previous linked articles, one will find that multiple scientists are taking serious issue (on multiple levels) with the most recent NASA study done by its climate modeling scientists.
This NASA publication quotes the lead "scientist" as stating that "CO2 acts as a thermostat in regulating the temperature of Earth," and the NASA web page headline "Carbon Dioxide Controls Earth's Temperature" suggests the same. The use of the term "thermostat," in regards to the trace gas CO2, implies a specific, fine tuning capability, a CO2 tweaking mechanism so-to-speak that can be used to "control" the ups and downs of global temperatures. If this were true, the CO2 thermostat (changes in CO2 levels) would have an obvious correlation with global temperature changes. In fact, as the below chart reveals, there is almost a zero relationship between CO2 changes and temperature changes.
As the chart depicts, since the mid-1940's, every single year has the atmospheric CO2 level increasing. In contrast, the annual global temperature change has varied in a narrow band, usually between a -0.20 and 0.20 degree Celsius. (Note the red line, which is the 20-year average of annual temperature changes - it's basically flat.) When viewing the data in this manner, it becomes obvious that the NASA proclamation of CO2 being a "thermostat" is empirically absurd, if not fraudulent.
The scientists at NASA know this, yet they use the blatantly false analogy of a thermostat that "controls" Earth's temperature. Knowing that NASA climate scientists have previously been exposed misrepresenting climate science and temperatures (more here), is it fair to start asking the obvious question?: Have NASA climate scientists become pathological liars? Based on the scrutiny their work now receives, it would seem a lot of scientists are taking no chances with NASA's research.
Archived NASA web page. (click on images to enlarge)
If the above chart represents the short-term period of "thermostat" capabilities, does a longer-term perspective provide better support for NASA's "CO2 thermostat" is a Earth temperature "control" statement? Nope. Per the study of ice cores, the high resolution evidence found that CO2 changes lagged temperature changes by approximately 800 years, just the opposite of what NASA scientists are claiming. The ice core chart below is another indication of the NASA "thermostat" bogosity.