The Heritage Foundation - Leadership for America

Of all the overblown predictions of a future global warming apocalypse in the Environmental Protection Agency’s “Analyses of the Effects of Global Change on Human Health and Welfare and Human Systems,” the one the agency should be most ashamed of is its claim that warming will exacerbate ozone, otherwise known as smog. The others, like increased hurricane and flood damage, are also at odds with the actual trends and scientific evidence. But smog is within the agency’s expertise, and it knows full well its assertions are misleading.

The claim that global warming worsens smog is based on the fact that, all other things being equal, hotter temperatures create more smog. This is why smog is a summertime problem. Thus, EPA argues that continued warming will lead to “ozone levels more likely to increase than decrease.” The agency then projects more smog related health problems like cardiovascular and pulmonary illnesses.

However, as EPA knows, all other things are not equal. The agency’s own data shows that emissions of the pollutants that form smog are declining, and regulations already in place ensure that this decline will continue. Thus, even if future temperatures are higher, we will almost certainly see continued reductions in smog levels.