How
Environmentalists and Scientists Mislead Americans about Air Pollution and
Climate Change
An Exchange between Joel Schwartz
and the Natural Resources Defense Council
On September 13, 2007, NRDC published an update of
its 2004 report Heat Advisory: How Global Warming Causes More Bad Air Days.
Below is my critique of Heat Advisory, followed by a response from NRDC’s Dan Lashof, and my
response to Lashof. These comments originally
appeared on National Review Online’s Planet Gore blog. – JS
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SCHWARTZ’S ORIGINAL CRITIQUE OF HEAT ADVISORY
How Environmentalists and Scientists Mislead
Americans about Air Pollution and Climate Change [Joel Schwartz]
September 14, 2007
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 remaining
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
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
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: http://www.epa.gov/airtrends/.
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: http://www.epa.gov/airtrends/econ-emissions.html.
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
Richard
Goldberg
NASA Goddard Institute for Space Studies
Christian Hogrefe
Atmospheric
Cynthia Rosenzweig
NASA Goddard Institute for Space Studies
Lewis Ziska
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NRDC’S DAN LASHOF RESPONDS TO SCHWARTZ’S CRITIQUE
OF HEAT ADVISORY
September 21, 2007
Here is our response to Joel Schwartz's attack.
Please feel free to forward it to anyone who has received Schwartz's email.-Dan
******
Our report is based on a peer-reviewed paper by
The Bell et al. (2007) research is based on the
New York Climate and Health Project, one of the largest-scale ozone modeling
efforts conducted in the
The analysis of climate impacts on ozone kept
anthropogenic ozone precursor emission levels constant as a way of evaluating
the climate change effect on ozone concentrations. Because of its complex
formation chemistry, ozone concentrations don't necessarily change in direct
proportion to precursor changes. In spite of some recent reductions in
precursor emissions, nationwide ozone levels have decreased only slightly (9%)
since 1990. (Source:
NRDC has applauded some recent regulations to
reduce precursor emissions and has sued EPA over other proposed regulatory
changes that would increase emissions. While we would expect significant
reductions in precursor emissions over the next decade there are no reliable
estimates of precursor emissions extending to the mid 21st century. Thus
different research projects use different sets of assumptions to project future
precursor emissions. The project on which Heat Advisory is based kept
anthropogenic ozone precursor emission levels constant as a way of evaluating
the effect that climate change alone could have on ozone concentrations. Other
researchers may choose alternative assumptions about how anthropogenic ozone
precursors could change in the future, and will arrive at different projected
ozone concentrations.
Projections of how global warming would affect
ozone levels are not predictions of what will happen. Our goal and our hope is
that both global warming pollution and ozone precursor pollution will be
reduced fast enough and far enough to avoid the risks we describe.
Daniel A. Lashof, Ph.D.
Science Director,
Natural Resources Defense Council
1200 New York Ave., N.W.
Suite 400
Washington, DC 20005
Phone: 202 289-6868
Fax: 202 789-0859
Email: [email protected]
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SCHWARTZ’S RESPONSE TO NRDC
How NRDC Continues to Mislead Americans about
Future Air Pollution Levels
[Joel
Schwartz]
September 26, 2007
A couple of weeks ago I
showed how the Natural Resources Defense Council (NRDC) worked with a group
of university and government scientists to mislead Americans into thinking that
ozone smog levels will rise in the future. The report, Heat
Advisory: How Global Warming Causes More Bad Air Days, is an update of
a report NRDC first released in 2004. Dan Lashof, the
Science Director of NRDC’s
The central point of my
original critique is that NRDC and its team of outside climate and health
scientists misled reporters and the public by claiming that ozone levels will
be higher in the 2050s than they are today and that climate change will be the
cause of this increase in ozone. I showed that in reality NRDC generated an
appearance of increasing ozone by assuming higher emissions of ozone-forming
pollutants in the future. Climate change is a minor factor compared to
assumptions about ozone-forming emissions, but NRDC and its scientists obscured
this fact. Dan Lashof doesn’t dispute this central
conclusion, but he does continue NRDC’s history of
evasive and misleading claims about Heat Advisory’s assumptions and
about future ozone-forming emissions.
Rather than acknowledge
that NRDC vastly exaggerated future ozone-forming emissions, Lashof equivocates: “While we would expect significant
reductions in precursor emissions over the next decade there are no reliable
estimates of precursor emissions extending to the mid 21st century. Thus
different research projects use different sets of assumptions to project future
precursor emissions. The project on which Heat Advisory is based kept
anthropogenic ozone precursor emission levels constant as a way of evaluating
the effect that climate change alone could have on ozone concentrations.”
Let me unpack the false
and misleading claims and insinuations here.
First, Lashof says NRDC “kept anthropogenic ozone precursor
emission levels constant.” His phrasing could lead readers to the mistaken
impression that NRDC held future ozone-forming emissions constant at current
levels. In fact, NRDC held emissions constant at the 1996 level, which, as
already noted, is more than 30% higher than current emissions and at
least four or five times greater than emissions will be in the 2050s under
current regulatory requirements (see below for more on future ozone-forming
emissions).
Second, Lashof says “While we would expect significant reductions
in precursor emissions over the next decade there are no reliable estimates of
precursor emissions extending to the mid 21st century.” In other words, NRDC
realizes that ozone-forming emissions will decline. But since they don’t know
how large the declines will be, they’ll just assume emissions will increase
by more than 30%.
Lashof’s special pleading here is particularly ironic.
Climate activists have no problem trying to force the people of the world to
spend trillions of dollars for CO2 reductions based on the
presumption that climate models are accurate. But when it comes to ozone, NRDC
pleads uncertainty and then chooses increases in future ozone-forming emissions
that are grossly at odds with any plausible future scenario. If anything, the
statement that “there are no reliable estimates….extending to the mid 21st
Century” is far more applicable to greenhouse gas emissions and climate models’
predictive skill than it is for ozone-forming emissions.
Third, Lashof says “The project on which Heat Advisory is
based kept anthropogenic ozone precursor emission levels constant as a way of
evaluating the effect that climate change alone could have on ozone
concentrations.” Just imagine if climate skeptics used 1996 greenhouse gas
emissions levels to project future climate change. NRDC would be all over them
like a cheap suit, and rightly so. Lashof seems
unaware that using 1996 ozone-forming emissions to predict future ozone levels
is equally ridiculous. Just as annual CO2 emissions will continue to
rise, ozone-forming emissions will continue to fall.
NRDC got its analysis
backwards. They should have started with an estimate of likely ozone-forming
emissions in the 2050s, and then estimated future ozone levels with and without
warming. That would answer the policy-relevant question. The answer: ozone
declines a lot either way, but it declines slightly less in some areas if the
climate warms. You can see this by looking at Tagaris et al. (2007), which came closer to using
realistic future levels of ozone-forming emissions (though even they
overestimate future emissions, as I show here).
One might conclude that NRDC and its allied scientists didn’t do the study that
way because it wouldn’t have served their political goal of creating an
impression that air pollution will increase in the future. Headlines like
“Ozone exceedance days will decline 90% instead of
95% if climate warms” don’t generate the kind of fear and outrage NRDC thrives
on.
Fourth, just as important
as what NRDC did do in its study is what it did not do. Notice
that Heat Advisory focuses on ozone levels in the northeastern and
southeastern
What about future
ozone-forming emissions? In my original critique, I cited a number of NRDC
press releases in which NRDC highlighted the proposal, adoption or
implementation, of EPA regulations that will eliminate most remaining
ozone-forming during the next couple of decades. Here is Lashof’s
response: “NRDC has applauded some recent regulations to reduce precursor
emissions and has sued EPA over other proposed regulatory changes that would
increase emissions. While we would expect significant reductions in precursor
emissions over the next decade there are no reliable estimates of precursor
emissions extending to the mid 21st century.”
Lashof could have strengthened his case by providing
some specifics about these “proposed regulatory changes that would increase
emissions.” He would also need to show that these supposed emissions increases
would be sufficient not only to offset the emissions-reducing regulations, but
to also cause more than a 30% increase in ozone-forming emissions above current
levels. I submit that the reason Lashof does not give
specifics is that if he did he would have to admit that ozone-forming emissions
are guaranteed to drop in the future, even if we interpret EPA regulations in
way that’s as favorable as possible to NRDC’s
desires. But if he made that admission, he’d also have to concede that NRDC’s study is based on fraudulent premises. Instead, Lashof chose evasive, equivocal statements that make it
appear as if it is difficult to discern the net effect of EPA requirements on
future ozone-forming emissions. Actually, it’s quite easy.
Most ozone-forming
emissions come from motor vehicles and power plants. As I showed in my original
critique, NRDC has put out press releases highlighting EPA regulations that
require at least a 90% reduction in per-mile emissions of NOx
and soot from on- and off-road diesel vehicles; a 77%-95% reduction in NOx and VOC emissions from automobiles (including SUVs and
pickups, and even Hummers, with the larger percentage reductions applying to
the larger vehicles); and a 50% reduction in NOx from
coal-fired power plants (actually EPA claims the reduction is more than 60%
below 2003 levels).
But there’s more. Under
Title III of the Clean Air Act EPA has imposed dozens of
Maximum Achievable Control Technology (MACT) requirements for dozens of
industrial sources. The MACT requirements eliminate most emissions from
dozens of different categories of industrial sources, such as refineries and
organic chemical manufacturers. And there are still more rules for various and sundry
other sources of air pollution, such as reductions in emissions from paints and
coatings and consumer products, various types of specials engines and vehicles,
locomotives, commercial establishments, and on and on. Furthermore, many
states, including
We also have tons of
direct evidence that emissions are steadily dropping. For example, under EPA’s NOx SIP Call regulation, coal-fired power plants reduced May-September
NOx emissions (that’s the time of year NOx matters for ozone formation) by 57% between 1998 and
2006. On-road measurements from the mid-1990s through 2004 show that VOC
emissions of the average automobile have been dropping about 12% per year, CO
by about 10%/year, and NOx by about 6%/year (I show
the evidence through 2001 here;
I can provide more recent evidence on request). And that’s before the 2004
implementation of the “Tier 2” automobile emissions standards which, by NRDC’s own admission, will reduce emissions of
2004-and-newer automobiles by 77-95% below the emissions of previous models. A
new study from scientists at UC Berkeley (in press in the journal Atmospheric
Environment, but not yet posted online) finds that diesel truck NOx emissions per mile declined about 30% between 1997 and
2004. These improvements will speed up as the 2007 emissions standards come
into force.
We can also see
real-world reductions in ozone-forming emissions by looking at ambient air
measurements, which show that NOx, CO, total VOC, and
specific VOCs like benzene and 1,3-butadiene
continue to decline by a few percent to several percent per year around the
nation.
Since existing federal
regulations already require the elimination of most remaining ozone-forming
emissions, where are these “proposed regulatory changes that would increase
emissions” that Dan Lashof refers to but about which
he provides no specifics? The only thing he could mean is changes to New Source
Review (NSR)? Environmentalists have spent the last several years in a
successful campaign to convince reporters and the public that reforming NSR
would increase industrial emissions. But this claim was and is false, because
caps on total emissions from power plants and industry under Title IV and Title
III of the Clean Air Act, as well as the new, even tougher caps under the NOx SIP Call and the Clean Air Interstate Rule, remain in
effect regardless of any changes to NSR. If there are any policies that would
actually increase emissions, I would ask Dan Lashof
and NRDC to please reveal specifically what they are, and also to explain how
any such policies would offset even a tiny fraction of emissions reductions
that are coming down the pike from existing regulations.
Overall, suffice it to
say that existing regulations and requirements will eliminate at least 70% to
80% of remaining ozone-forming emissions during the next two decades or so. Yet
NRDC assumed more than a 30% increase in ozone-forming emissions between
now and the 2050s. Once again, NRDC predicts higher ozone in the future, not
because of climate warming, but by assuming ozone-forming emissions will be at
least four or five times higher than they actually will be.
In defending the
assumptions NRDC chose, Lashof says “Other
researchers may choose alternative assumptions about how anthropogenic ozone
precursors could change in the future, and will arrive at different projected
ozone concentrations.” Yes, indeed, you can make any assumptions you want about
future ozone-precursor emissions. But Lashof omits
the fact that NRDC chose assumptions that are patently at odds with reality. If
realistic assumptions would have generated increases in future ozone, NRDC and
its allied scientists would probably have done a realistic study. But the study
wasn’t done as an inquiry into likely future ozone levels. Rather, the
outcome—higher future ozone—was chosen up front. Then the assumptions were
chosen so as to generate the desired outcome.
Despite the media blitz surrounding the release of
Heat Advisory, Lashof now claims that NRDC
wasn’t making any predictions at all about future ozone levels. He says “Projections of how global warming would
affect ozone levels are not predictions of what will happen.” That would be
news to anyone who read NRDC’s press release announcing Heat Advisory.
Here’s how it begins:
New Study: Smog
Poses Greater Health Risk Because of Global Warming
More Bad Air
Days for Southern, Eastern
WASHINGTON, DC (September 13, 2007) —
People living in ten mid-sized metropolitan areas are expected to experience
significantly more 'red alert' air pollution days in coming years due to
increasing lung-damaging smog caused by higher temperatures from global
warming.
No predictions there.
How about these lines
from later in the press release:
Researchers project that, unless action
is taken to curb global warming, by mid-century people living in a total of 50
cities in the eastern
·
A doubling of the number of unhealthy
‘red alert’ days
·
A 68 percent (5.5 day) increase in the
average number of days exceeding the current 8-hour ozone standard established
by the U.S. Environmental Protection Agency (EPA)
·
A 15 percent drop in the number of
summer days with “good” air quality based on U.S. Environmental Protection
Agency (EPA) criteria because of global warming
I guess those aren’t
predictions either. Oh, right, they’re “projections,” not “predictions.” Now
there’s a distinction without a difference. Either way, NRDC has misled people
into the mistaken belief that ozone will increase in the future. Yet now that
the damage is done and Americans have been snookered, Lashof
is trying to weasel out of taking responsibility for NRDC’s
unfounded scare-mongering.
Heat Advisory is a case study in how scientists can generate a
pre-determined result—in this case, the false appearance of rising ozone
levels—by careful management of assumptions and analytical boundaries, by
crafting statements that are true on their own but that lead readers to draw
false conclusions, and by shrewd choices about what information to omit from a
paper.
Here are a few ways that
these efforts played out in Heat Advisory:
While all of the above
examples are illuminating, the most profound flaw in Heat Advisory is
that its misleading results were built in right from the outset in the very
question NRDC chose to ask, namely: Given “current” ozone-precursor emissions
(really 1996 emissions), how will climate warming affect ozone levels in the
2050s? In effect, this really amounts to asking how much higher ozone would
have been back in 1996 if the temperature had been a few degrees warmer—a
counterfactual scenario of no relevance for climate or air pollution policy.
The beauty of NRDC’s sleight of hand is that Heat
Advisory appears to be asking a question about future ozone levels when in
fact it is asking a question about past ozone levels.
The real policy-relevant
question is this: Give likely ozone-precursor emissions in the 2050s, how will
climate warming affect ozone levels in the 2050s? A question neither asked nor
answered by NRDC.
NRDC and other
environmental groups style themselves as arbiters of scientific probity in
environmental debates. Examples such as Heat Advisory show that these
groups and their university and government allies can be as crassly political
in their use of scientific authority as they imagine their opponents to be. (Here is
an example of similar behavior by the Union of Concerned Scientists.)
Heat Advisory is a cynical exercise in manipulation and
fear-mongering masquerading as science. Perhaps we shouldn’t be surprised that
NRDC manufactures bogus increases in ozone in order to scare people (and then
dissembles further when someone like me calls them on it). After all,
environmentalists derive their power from public fear and outrage. Where there
is no legitimate reason for fear and outrage, environmental groups and some
scientists have shown themselves to be only too willing to manufacture it.
APPENDIX: Additional
ways in which Heat Advisory misleads Americans
I haven’t yet discussed NRDC’s health effects claims in my Heat Advisory
critique. Of course, the purpose of Heat Advisory is not merely to
create the misimpression that ozone will rise in the
future—the ultimate goal is to foment greater fear of harm from air pollution
and to link that fear to climate change. But just as NRDC exaggerates ozone
levels, it also exaggerates the harm from any given level of ozone. I give
details, with citations to the literature, here, here, and here.
I also haven’t yet
discussed the predictions of climate warming on which Heat Advisory’s ozone
predictions are based. In fact, NRDC used a greenhouse gas emissions scenario
that likely exaggerates future warming. This is true even if we assume that
climate models do a good job at predicting future climate. The researchers who
wrote NRDC’s report and the companion journal article
in Climatic Change used the IPCC’s
A2 scenario of future greenhouse gas emissions to predict future climate
change. A2 is the second warmest of the IPCC’s six
scenario groups, but it is also one of the least plausible. Here’s why: A2
assumes that world population continues to rise steadily, reaching 15 billion
by 2100. But the International Institute for Applied Systems Analysis (IIASA) projects, based on world
fertility and life expectancy trends, that world population will peak just
above 9 billion around 2070 and decline thereafter. In fact, the A2 scenario’s
population assumption for 2007 already overestimates actual world population by
about 275 million people, or more than 4 percent. The discrepancy only grows
larger with time as the A2 scenario continues to add greenhouse gas emissions
from those non-existent 275 million people and the children and grandchildren
those non-existent people will never have.
The A2 scenario includes
other assumptions that exaggerate future greenhouse gas levels. For example, A2
assumes atmospheric methane levels steadily rise after 2000 and nearly double
by 2100. But actual atmospheric methane concentrations have been
steady since 1999. The A2 scenario’s assumption for 2006 is already nearly
6% higher than the measured level. A recent
study of methane emissions concluded “Seeing that the total source has
remained constant for at least the last two decades, it is questionable whether
human activities can cause methane concentrations to increase greatly in the
future.”
After carbon dioxide and
methane, tropospheric ozone is the next most
important human-caused greenhouse gas. But methane helps form ozone, so
overstating methane levels also causes an overestimate of ozone. Likewise, NRDC’s assumption of rising ozone-forming emissions
exaggerates future ozone levels, thereby overstating greenhouse warming.