The Clean Air Act requires the EPA Commissioner to
regulate pollutants "which in his judgment cause, or contribute to,
air pollution which may reasonably be anticipated to endanger public
health or welfare."
A number of States and environmental organizations
petitioned EPA to begin regulating CO2 and other greenhouse
gases because climate change (aka global warming) was problem likely to
endanger the public health.
In response, EPA found that they lacked the authority to
regulate greenhouse gasses because they were not pollutants (at least not
in the traditional sense).
EPA seriously suggested that CO2 doesn't make
people sick, and makes plants grow, so it was a good thing, not a
EPA further argued that even if they did have the
authority to regulate greenhouse gasses, it was within EPA's discretion
to choose which pollutants to regulate, and they chose not to.
EPA felt that other laws designed to improve fuel
economy were good enough.
The States (led by Massachusetts) sued the EPA to force
them to begin regulating greenhouse gases.
Specifically, Massachusetts argued that:
EPA does have authority over global warming and
greenhouse gases because of the broad wording of the Statute.
EPA's decision not to regulate greenhouse gases exceeded
the scope of its discretion under the law.
EPA violated the Clean Air Act by not giving it
EPA argued that the petitioners did not have standing to
sue EPA because they could not show that they had been harmed by
(Because in the Republican EPA Commissioner's view,
global warming was a just a myth propagated to destroy capitalism.)
The Appellate Court affirmed EPA's decision to not
regulate greenhouse gas emissions.† Massachusetts appealed.
The US Supreme Court reversed and found that EPA must
regulate greenhouse gas emissions.
The US Supreme Court found that the petitioners did have
standing to sue EPA.
Massachusetts argued that global warming would cause sea
levels to rise and the State would lose valuable beachfront property.
But in order to have standing an injury has to be
'imminent'.† Was sea level rise really an imminent threat?† Also, can
Massachusetts show that their sea level rise is directly caused
by the emissions that they are asking EPA to regulate?
The majority found that Massachusetts had standing
because, as a sovereign they had a special duty to protect their
The Court found that the Clean Air Act does indeed
give the EPA the authority to regulate greenhouse gases.
"Greenhouse gases fit well within the Clean Air Actís
capacious definition of air pollutant."
The Court also found that EPA's rationale for not
regulating greenhouse gases was inadequate.† If they did a scientific
study and found a scientific basis for not regulating, then that would be
ok, but they can't decide not to regulate solely on the opinion of the
The Court remanded the case back to EPA to make a
scientific study and make a factual determination.
Despite the fact that the regulation says, "In the
In a dissent, it was argued that the alleged injury that
Massachusetts suffered was far too speculative to give them standing to
sue.† In addition, since CO2 emissions are a worldwide
problem.† EPA did not have the ability to significantly affect global CO2
levels, therefore it was pointless to bother to regulate it.† Also, CO2
isn't a 'pollutant' in the same way that toxic heavy metals are (you can't
get sick from breathing it in), so it isn't really covered under the
purpose of the Clean Air Act.