Planet Gore

How Environmentalists and Scientists Mislead Americans about Air Pollution and Climate Change

The Natural Resources Defense Council has just published a report titled Heat Advisory: How Global Warming Causes More Bad Air Days. NRDC claims ozone will rise in the future due to climate warming. In reality, ozone and all other air pollution will fall in the future, regardless of climate change. Here’s how NRDC faked its future air pollution increases: they used air pollutant emissions during 1996 to “predict” ozone levels in the 2050s and 2080s. Actual emissions of ozone-forming pollutants are already more than 25% lower than they were in 1996 and will drop another 70%-80% in just the next 20 years, based on already-adopted and implemented federal requirements.


NRDC certainly knows its report is based on fake emissions numbers, because NRDC has been putting out press releases marking the adoption and implementation of the federal regulations that will eliminate most remaing air pollution during the next two decades (I provide links to some of these in an appendix below).


In reality, all NRDC did was estimate what ozone levels might have been back in 1996, had the temperature been a few degrees warmer—a counterfactual scenario that’s irrelevant for predicting future ozone levels. NRDC’s claim of future ozone increases has nothing to do with climate change. Its report generated increasing ozone levels by assuming unrealistically high future ozone-forming emissions—at  least four or five times higher than they’ll actually be, and more than 30% higher than they are right now.


Most egregious of all, the NRDC report was authored by prominent university and government climate and public health scientists. Under the color of their scientific credentials and government and university affiliations, these scientists are helping NRDC activists mislead Americans with false information about air pollution and climate change.


If you want a more realistic picture of future air pollution levels in a warming climate, look at this article from the Journal of Geophysical Research by researchers from NESCAUM, a coalition of northeastern air regulators, along with scientists from Georgia Tech. They used a more realistic estimate of future pollutant emissions—one that attempts to account for the required declines in total pollutant emissions during the next few decades. Low and behold, they predict substantial future reductions in both ozone and particulates, despite a warmer climate.

Here are their headline results on the change in air pollution levels between 2000 and 2050: “The combined effect of climate change and emission reductions lead to a 20% decrease (regionally varying from −11% to −28%) in the mean summer maximum daily 8-hour ozone levels over the United States. Mean annual PM2.5 concentrations are estimated to be 23% lower (varies from −9% to −32%).”  Their results are actually conservative, as pollutant emissions and ambient levels are dropping much faster than they assume in their study (a fact which I show here).  

The NESCAUM/Georgia Tech study is one of the few that even attempts realistic estimates of future air pollution levels under a warming climate. Other studies in the scientific literature, including one by the scientists who wrote NRDC’s report, assume steady or increasing ozone-forming emissions in the future. I discuss these unrealistic studies here and here.

There’s an interesting irony here. Climate alarmists act as if their model projections represent relatively certain predictions of future climate parameters, and they vigorously defend the purported realism of their results. Yet when it comes to future air pollutant emissions, this ostensible quest for realism suddenly disappears, in favor of scenarios that are patently at odds with reality. If anything, the proposition that air pollutant emissions will sharply decline in the future is far more certain than any predictions of how and why the Earth’s climate will change due to greenhouse gas emissions. Yet the ostensible guardians of scientific propriety and the public interest continue to mislead the public about future air pollution levels in a warming climate. 
For those who want more details, here is additional backup information to support the discussion above: 

  1. Some of NRDC’s press releases and other documents lauding the large reductions in air pollutants for new motor vehicles, power plants, and other sources that have been adopted and implemented during the last few years. I’ve also included one or two items from other environmental groups discussing large future emission reductions from existing regulations. These documents from NRDC and other environmental groups show they are well aware that existing regulations will eliminate most remaining air pollution during the next two decades: 

Link (See “EPA touts new, cleaner cars” congratulating the Bush administration on implementing the Tier 2 regulation adopted by the Clinton EPA, requiring automobiles which are “are 77 percent to 95 percent cleaner than current models.”)


Link (comments on EPA’s proposed heavy-duty diesel rule “By the end of the decade, tailpipe emissions of smog-forming nitrogen oxides would be cut by 95 percent” on new heavy-duty diesel trucks. That regulation was adopted and starts phasing in this year.)


Link (2003 press release supporting proposed rule to impose similar NOx reductions on off-road diesel engines. That regulation has since been adopted and comes into effect in 2010). 


Link (2006 press release lauding roll-out of low-sulfur diesel fuel in preparation for the roll-out of super-clean new diesel-truck engines later in the year.)


Link (Lauding EPA’s adoption of non-road diesel emissions standards. “These standards, which will reduce particulate soot and nitrogen oxide emissions by 90-95 percent in most cases, will be phased in from 2008 to 2015. As part of today’s announcement, EPA also committed itself to promulgating new emission standards for locomotive and marine diesel engines that could be implemented as early as 2011.)


Link (Environmental Defense report lauding how EPA regulations will reduce smog-forming emissions from diesels by more than 90%.)


Link (Clean Air Task Force press release on how NRDC and other environmental groups are intervening to protect EPA’s Clean Air Interstate Rule from legal challenges by the power industry. According to the press release, “CAIR is aimed at bringing down smog and soot emissions from power plants east of the Mississippi River by about 50% by 2015.”) 


Link (Environmental Defense 2005 fact sheet discussing how EPA’s new Clean Air Interstate Rule will reduce power plant NOx by 50% and sulfur dioxide by 73%.


2.      National trends in monitored pollution levels: Click on individual pollutant links to see national trends. Note the large continuing declines in air pollution levels.


3.      Estimated trends in air pollutant emissions from 1970-2006: Scroll to the bottom for a table with emissions of each pollutant from 1970-2006. Note that since 1996 emissions of nitrogen oxides (NOx), volatile organic compounds (VOC), and carbon monoxide (CO) have already dropped, respectively, 26%, 29%, and 24% (I linearly interpolated between 1995 and 2000 to estimate 1996 emissions). In other words, NRDC “predicted” ozone in the 2050s and 2080s using a level of ozone-forming emissions that is already more than 30% higher than current emissions.


4.      Here’s a list of the authors of the NRDC report and their affiliations.

Jonathan A. Patz

Nelson Institute for Environmental Studies and the Department of Population Health Sciences, University of Wisconsin-Madison, and Johns Hopkins University, Bloomberg School of Public Health 
Patrick L. Kinney

Columbia University, Mailman School of Public Health 
Michelle L. Bell

Yale University, School of Forestry and Environmental Studies 
Hugh Ellis

Johns Hopkins University, Whiting School of Engineering 
Richard Goldberg

NASA Goddard Institute for Space Studies 
Christian Hogrefe

Atmospheric Sciences Research Center, University at Albany, State University of New York 
Samar Khoury

Johns Hopkins University, Bloomberg School of Public Health 
Kim Knowlton

Columbia University, Mailman School of Public Health 
Joyce Rosenthal

Columbia University, Mailman School of Public Health 
Cynthia Rosenzweig

NASA Goddard Institute for Space Studies 
Lewis Ziska

U.S. Department of Agriculture, Agricultural Research Service 

Joel Schwartz is a visiting fellow at the American Enterprise Institute, where he studies air pollution, climate change, and other environmental health, energy, and transportation issues. He is the author ...


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