False Claim That Global Warming Will Increase Smog Levels

Deceptive studies harm science's credibility

Heat Advisory,” a new report from the Natural Resources Defense Council (NRDC), argues that global warming will cause increases in future ozone smog levels, because warmer temperatures favor ozone formation. NRDC claims that the number of exceedances of the 8-hour ozone standard will increase 60% as a result of global warming.

As Tech Central Station readers well know, there are reasons to be skeptical of claims of substantial human-caused warming. But even taking NRDC’s warming estimates at face value, NRDC’s smog claim is bogus. As the report itself states:

“Note that this work investigated the effect of changes in climate and not changes in anthropogenic emissions—This research was not intended to provide realistic estimates of future ozone concentrations, but rather the increase in ozone in direct response to changes in climate, holding anthropogenic emissions constant.” (p. 7; emphasis added)

NRDC used smog-forming emissions levels from the mid 1990s to predict smog levels in the 2050s and 2080s. But volatile organic compounds (VOC) and nitrogen oxides (NOx), the two smog-forming emissions, have dropped, respectively, at least 50% and 25% just in the last 10 years. So NRDC’s modeling estimates don’t even apply now, much less 50 or 80 years from now.

Actually, the situation is even worse than that (or better if you’re not an environmental activist), because we’ve already taken actions that will eliminate most remaining smog-forming pollution over the next 20 years or so.

For example, starting in May 2004, EPA’s “NOx SIP Call” regulation required a 60% reduction in NOx emissions from coal-fired power plants and industrial boilers during the May-September “ozone season,” when compared with previous levels. Data from on-road measurements and vehicle inspection programs show automobile emissions are dropping about 10% per year as the fleet turns over to ever-cleaner models. A fleet meeting EPA standards implemented in the 2004 model year–that is, the fleet that will be on the road in 15 to 20 years–will be 90% cleaner than the current average vehicle. EPA’s diesel truck regulation requires a 90% reduction in NOx and soot from diesel beginning in the 2007 model-year, a requirement that will eliminate almost all remaining diesel truck emissions by the 2020s. A similar requirement for off-road diesel equipment comes into effect in 2010. (See details on emissions requirements and their future effects here and here.)

Despite NRDC’s admission that the report’s smog estimates are not and are not intended to be realistic, the report’s Executive Summary is a bit less circumspect:

“Researchers project under a climate change scenario that by mid-century people living in 15 cities in the eastern United States would see a 60 percent increase–from 12 to almost 20 days per summer–in the average number of days exceeding the health-based 8-hour ozone standard.”

The press release on the study includes similar claims. NRDC presumably realizes that most journalists will only report this headline, and won’t ever get to NRDC’s self-refutation buried on page 7. But putting the qualification somewhere in the report gives NRDC plausible deniability when more diligent readers claim the report is deceptive.

Given the actual emissions reductions already achieved, along with future reductions that are already in the pipeline, whatever climate change does occur will make virtually no difference for air quality, because smog-forming emissions will be essentially eliminated long before any significant warming occurs.

Indeed, global warming or not, no claim by environmental activists is more ridiculous than the claim that air pollution will increase in the future. Since 1975, a period during which climate alarmists argue the climate has already significantly warmed, the national-average number of exceedances of the 1-hour ozone standard declined 95% (from 10 to 0.5 days per year), while the number of 8-hour ozone exceedances declined about 60% (from 14 to 6 per year). In other words, if the climate has warmed over the last 30 years, that warming hasn’t prevented extraordinary improvements in air quality. (See details on pollution trends here.)

NRDC and the report’s authors claim to be motivated by concerns over human health and welfare, but then go on to manufacture fake health risks from smog that won’t exist in the future, while ignoring the health and welfare risks of the costs and restrictions they wish to impose on energy production and use. In NRDC’s selective view of human welfare, these costs and tradeoffs simply don’t exist.

NRDC also cherry picks its climate change impacts. For example, climate change models predict most warming to occur in winter and in northern latitudes, rather than in summer or southern latitudes. Since winter cold has a larger effect on mortality than summer heat, warming would be expected to reduce mortality, but NRDC simply ignores this aspect of health and climate change.

The omissions and fakery of NRDC’s report would be bad enough if the report had been produced merely by NRDC’s activists. But the report was written by university scientists and medical doctors, including researchers from the Johns Hopkins Bloomberg School of Public Health and Columbia’s Mailman School of Public Health, as well as government scientists from NASA’s Goddard Institute for Space Studies and the U.S. Department of Agriculture.

Scientists’ credibility is rightly diminished when they produce deceptive studies for political activists under the color of their scientific credentials.

Joel Schwartz is an adjunct fellow at Reason Foundation and visiting scholar at American Enterprise Institute.