Many years ago, I worked for the Program Analysis Office of the U.S. Bureau of the Budget (yes, this was before the M was added to OMB; it was just BoB).
One of the things we learned was the extreme difficulty of analyzing government programs. The variables are too many and too uncertain, and one quickly winds up following chains of abstract conjecture that have little relation to reality. So we learned to look for Dominant Information -- facts determinative of outcomes under wide varieties of assumptions -- call it DI.
For climate change, such DI is now available, and it is not good for Al Gore.
CO2 is indeed a Greenhouse Gas (GHG). It absorbs outgoing radiation on particular wave lengths, with a resultant warming effect. On this, there is no scientific dispute. The question is whether this effect matters. Looking at CO2 alone, it does not. The effect would be quite small. To get to the predictions of doom, and thus to justify the destruction of industrial civilization, requires computer models based on the assumption that the small initial effect of CO2 is somehow amplified by positive feedback mechanisms.
Some 20 climate change models exist, and every one of them assumes that such positive feedback exists, and thus that a minor uptick in CO2-induced warming will cause a major upward movement in temperature. Note the "assumes"; there is no empirical evidence of this. If the assumption is wrong, if there is no positive feedback, then the problem becomes negligible.
(Why does every model make the same positive feedback assumption, you might ask? Probably because any model that assumes anything else would not show a problem, and that is no way to get the government to renew the builder's grant for next year.)
Recent empirical work indicates that this assumption of positive feedback is in fact wrong, that the actual feedback mechanisms are negative. See Lindzen (p.4); Carlin (pp.13-27). This means that the models of disaster not only have no empirical support, but that they are contradicted by the only empirical evidence that has been found.
This, my old BoB bosses would have said, is DI, in a pretty pure form.
As Lindzen says:
In a normal field, these results would pretty much wrap things up, but global warming/climate change has developed so much momentum that it has a life of its own – quite removed from science. One can reasonably expect that opportunism of the weak will lead to efforts to alter the data (though the results presented here have survived several alterations of the data already). Perhaps most important, these results will of necessity ‘offend the sensibilities of the of the educated classes and the entire East and West Coasts,’ and who would want to do that.
The tech world should be interested in this, because it is incredibly energy dependent. Tech as we know it cannot survive an energy drought.
For more on the implications, see more Alan Carlin comments.