What a difference a decade makes!  (or not)

Ten years ago — and again this past month — I was honored to join a group of climate scientists, a roster of both new and distinguished colleagues who to my mind are some of our climate science heroes (see the list here), to speak to the role of climate science in public policy.  Ten years ago, we addressed the U.S. Supreme Court (more about which below). This past month, we addressed Donald Trump’s Environmental Protection Agency (EPA) Administrator Scott Pruitt.  Our letter responded to Mr. Pruitt’s widely reported comments on CNBC that “there is tremendous disagreement about the degree of impact” humans have had on climate, “so, no, I would not agree that [CO2] is a primary contributor to the global warming we see.”

Coming from the head of the EPA, these statements are insidious.  Some have said that Pruitt is “absolutely correct.” However, to the extent he is correct (and his first statement, about disagreement, is certainly correct in a sense — of course there is disagreement among climate scientists, as among scientists in any active field), they are irrelevant to EPA’s mission.  To the extent that they are relevant to EPA’s mission, which includes an accurate assessment of what the science says about the legal standard for action on climate, they are false.

EPA’s mission, under the Clean Air Act, is not concerned with whether there is some disagreement about aspects of climate science, or whether greenhouse gases pose a risk beyond all doubt. It’s mission, first, is to ask: does the scientific evidence on climate change, including its appropriately weighed uncertainties, meet the legal standard for protective action – that is, does it support a judgment that greenhouse emissions “may reasonably be anticipated to endanger public health or welfare”?  The law does not require a scientific conclusion that greenhouse gases will endanger welfare, only that it is reasonable to anticipate that they may. And, as we wrote in our letter to Pruitt,

“focusing on disagreements over details, or among a few individuals on the margins of consensus, or on the uncertainties that are part of any accurate statement of scientific knowledge, misses the big picture: human beings are changing the Earth’s climate.  This key conclusion follows from the basic laws of physics. Just as there is no escaping gravity when one steps off a cliff, there is no escaping the warming that follows when we add extra carbon dioxide and other greenhouse gases to the atmosphere.”

Science by itself contains no moral imperative and prescribes no particular policy, and scientists who suggest that it does do their discipline a disservice. Science by itself does not care about the fate of the Earth — but science can help humans who do care answer the question:  is a given standard for action that humans have set for themselves through law met by the evidence at hand?

According to the standards of law applied to the science of climate change, we think that the science has long since passed the point where the law’s precautionary standard for action is met.   And wouldn’t you know it —  EPA agrees!  Back in 2009, EPA issued what is known as an “endangerment finding” that the scientific evidence shows that CO2 and other greenhouse gases (which will likely raise sea levels, cause terrible heat waves, damage crops and food production) in fact meet the “reasonable anticipation of endangerment” standard.  The endangerment finding triggers a legal obligation on the EPA administrator to act to reduce the danger.  And, as Brad Plumer very clearly explains on Vox, it would be extraordinarily difficult, absent a change in the Clean Air Act itself, for Pruitt or Trump to overturn the endangerment finding.

It was exactly 10 years ago (on April 2, 2007) that the basis for this endangerment finding was laid by the U.S. Supreme Court, when it issued its decision in the case of Massachusetts v EPA, recognizing the strength of the science behind global warming. This was the first case on climate change to reach the high Court, and it arose because the Bush era EPA had declined to make an endangerment finding on climate change, arguing that CO2 and other greenhouse gases were not “pollutants” within the meaning of the Clean Air Act, and that even if they were pollutants, the science was too uncertain to regulate them (citing for its scientific authority a 2001 National Academy of Sciences report).  Massachusetts, 11 other states, and environmental groups sued, arguing that these gases needed to be regulated to reduce the risk of global warming.

Leading up to the case, I helped organize a group of 18 climate scientists to put together an Amicus Curiae (friend-of-the-court) brief to the Court (disclosure:  my wife, Kirsten Engel, who helped start the climate change lawsuit against EPA when she was working at the Massachusetts Attorney General’s Office in the early 2000’s, was one of our lawyers and is the one who got us started). The core of this scientist group of authors is also the core of the group that sent the letter today, minus the now departed and much missed Sherry Rowland, the Nobel chemist who (together with Amicus brief co-author Mario Molina) predicted the environmental problem of stratospheric ozone depletion.

Notably, the scientist group included a majority of the panel of authors of the above-mentioned 2001 Academy report on which EPA had relied in deciding not to regulate.  Like Scott Pruitt today, EPA then was distorting climate science for political ends by making the uncertainties appear greater than they were.  Indeed, it was the very distortion of their work by the EPA that really angered and motivated many of the members of the Academy panel to join the brief. I remember in particular that Mike Wallace, the distinguished atmospheric scientist from University of Washington who was a co-author of the academy report, said “I just wanted to set the record straight.”

I think it is fair to say our Amicus brief helped convince the court then (it was the only Amicus brief, of hundreds submitted, that was cited from the bench during oral argument, by John Paul Stevens, while Justice Scalia, perhaps confusing global warming with stratospheric ozone depletion, mixed up the troposphere and stratosphere), and we won! (Science magazine: A Clean Victory).  Perhaps the most memorable line to me during oral argument (which several of us were able to attend in person), was Justice Breyer’s response to the concern that limiting CO2 emissions from cars and trucks was simply too insignificant to address the concerns of Massachusetts and the other states:

Suppose others cooperate? Suppose, for example, they regulate this and before you know it, they start to sequester carbon with the power plants, and before you know it, they decide ethanol might be a good idea, and before you know it, they decide any one of 15 things, each of which has an impact, and lo and behold, Cape Cod is saved.”

Massachusetts v EPA became the foundation for EPA’s 2009 endangerment finding, and hence for everything that followed, from tailpipe emissions for cars and trucks to the clean power plan for electric utilities.  As the U.S. signed the Paris agreement in 2015, I felt that although it was only a beginning, we were finally starting to make real progress on climate change.

Yet here we are again, a decade after victory at the Supreme Court, and with the science becoming more compelling almost by the week, writing almost the same words, about the same agency, about the same issues in climate science.  It is disheartening to see that we now have an EPA Chief who is willing to throw science overboard in order to sweep away all the progress that has been made.  He will certainly be able to stall, and we should make no mistake:  stalling is dangerous at this late date for those who want to mitigate the awful risks of climate change.  But it is at least a little encouraging to know that the science is strong, and that given the strength of the scientific evidence supporting the endangerment finding (see again Brad Plumer at Vox), Mr. Pruitt will likely find it very difficult to do anything more than stall.