Patrick J. Michaels sticks it to the global warming theories and the U. S. National Assessment of the Potential Consequences of Climate Variability and Change, which he says "can't pass the simplest of scientific tests."

I didn't know there was such a thing as a Federal Data Quality Act (which must be one of the more oxymoronic law names. "Federal" and "Data Quality" in the same phrase?).

Michaels is particularly on point with his comment on the use of computer models to predict climate changes, especially 100 years into the future. He writes:

A climate model is nothing but a statement of scientific
hypothesis: What we "think" should happen based upon
currently fashionable theory. When a hypothesis doesn't
work (i.e., performs worse than a bunch of darts thrown at
the Dow Jones), the ethic of science requires that it be
thrown out. In this case, it means that the USNA should
have used better models, or, absent a defensible model, it
should have used none. If a computer simulation of climate
can't beat a table of random numbers over the United States,
it borders on scientific malpractice to continue to apply it.

This is the key to understanding global warming claims. They are all based on computer models, which are nothing more than the embodiment of a particular hypothesis which has not been tested.

When it comes to long range predictions, we have to understand the concept of trans-science, the inability of science to resolve some problems due to their extreme complexity. This is similar to chaos theory, and the old saw about a butterfly flapping its wings in Brazil causing a tornado in the U.S. What it means is that, the further out you try to predict, the less likely you are to be successful. The earth is such a complex system and so poorly understood, that computer models of it cannot claim any degree of validity sufficient to base public policy on them.

Should we try to limit pollution? Yes, but not because it will destroy the earth. It's sufficient that it causes smog and is ugly. Is CO2 a pollutant? Given that all plant life needs it, I'd say probably not, but anybody who claims to know the long term effect of adding CO2 to the atmosphere is definitely blowing smoke.