RICHARD EPSTEIN: Forget the Paris Accords.

The defenders of the Paris Accords are as dogmatic on the science as they are on the economics. To them, it is an axiomatic truth that carbon dioxide emissions pose a grave threat to the environment, even though the putative causal chain is filled with missing links. The current practice is to assume that every adverse climate event is somehow the result of the rather smallish increases in carbon dioxide levels over the past 65 years. In order to reach that result, however, it is necessary to exclude other explanations for the adverse events. An observed rise in sea level in Florida, for example, is more likely attributable to the draining of local aquifers than to increases in global temperature. Indeed, sea level rises have, if anything, slowed down in recent years, notwithstanding increases in carbon dioxide levels. In a similar vein, the rapid melting of ice on the western part of the Antarctic is more likely attributable to underground volcanic activity, particularly given that the overall ice levels in the Antarctic are up and not down. And highly variable adverse events are probably more closely associated with changes in water vapor patterns, the recent El Niño, active sunspots, aerosol levels, and a host of other factors, some of which are well known and others of which are only dimly understood.

The situation is even more complex if one looks to the long run. Climate variability has been a constant long before human beings inhabited this earth. Of course, carbon dioxide is a greenhouse gas that can trap energy. But so is water vapor, and its levels are far harder to track because its amount and distribution are not constant across the earth’s surface. Most crucially, observed cyclical patterns of temperature change do not correlate with slow but steady increases in carbon dioxide. Recent work by climate scientists Richard Lindzen and others shows that during the so-called Holocene period (roughly covering the last 11,000 years), there was a negative correlation between temperatures and carbon dioxide concentrations—strongly suggesting that carbon dioxide levels cannot be the main driver of temperature changes. It should, therefore, come as no surprise that recent climate models that have predicted sharp temperature increases have consistently run “hot,” so much so that observed increases are less than 50 percent of those predicted. As climate scientist Judith Curry points out, the uncertainties involved are large and the role of natural forces in driving temperature change are systematically underestimated.

The Paris Accord is statism masquerading as religion gussied up as science.