What was done
In a wide-ranging survey of the peer-reviewed scientific literature, the authors review a number of "common deficiencies in general circulation model (GCM) calculations of atmospheric temperature, surface temperature, precipitation and their spatial and temporal variability," along with a host of other items related to the climate modeling enterprise.

What was learned
In light of their amassed findings about important technical details generally not communicated to the public (although openly discussed by climate model specialists in their scientific papers), the authors conclude that "at the current level of understanding, global environmental change resulting from increasing atmospheric CO2 is not quantifiable," further noting that "given the host of uncertainties and unknowns in the difficult but important task of climate modeling, the unique attribution of observed current climate change to increased atmospheric CO2 concentration, including the relatively well-observed latest 20 years, is not possible."

What it means
Although acknowledging their review of the pertinent scientific literature "does not disprove a significant anthropogenic influence on global climate," the authors but declare the obvious in saying it "has shown that GCMs are not sufficiently robust to provide an understanding of the potential effects of CO2 on climate necessary for public discussion."  Their translation: "we are not ready to tell what the future climate of the Earth will look like."  Our translation: proponents of the Kyoto Protocol have gotten the political cart so far before the scientific horse there is no longer a rational linkage between the two, as raw emotion prevails over reason in driving the cart ever onward.  President Bush was clearly right to decline passage on the errant vehicle.