Last week, newly appointed EPA head Scott Pruitt made some comments about climate change that were clearly at odds with a basic scientific understanding of the climate. Since then, various groups of scientists have pointed out just how wrong he was and have offered to help out if he decides to come to grips with reality.
First, a reminder of what Pruitt said during a CNBC interview:
I think that measuring with precision human activity on the climate is something very challenging to do, and there's tremendous disagreement about the degree of impact. So no, I would not agree that it's a primary contributor to the global warming that we see. But we don't know that yet. We need to continue the debate and continue the review and the analysis.
That statement is wrong on a number of levels, and various groups have not been shy in pointing out its flaws. The day following, the head of the American Geophysical Union, Eric Davidson, penned a short response. "In contrast with [Pruitt's] statement," he wrote, "an impressive array of scientific societies and many academies of science, national governments, and other organizations worldwide have agreed on the scientific basis of climate change and the conclusion that human actions are a primary driver." He referred Pruitt to the AGU's position statement on climate change, which calls for urgent action on humanity's role in climate change.
Davidson also noted that the statement was developed by scientific experts, and the entire AGU membership was given the chance to provide input. He also suggested that Pruitt check in with the EPA's sister agency, NASA, which details the scientific consensus behind human-driven climate change.
Keith Seitter, the executive director of the American Meteorological Society, also checked in, bluntly telling Pruitt, "In reality, the world’s seven billion people are causing climate to change and our emissions of carbon dioxide and other greenhouse gases are the primary cause." And it's not just the AMS saying it; that finding "is based on multiple independent lines of evidence that have been affirmed by thousands of independent scientists and numerous scientific institutions around the world."
If Pruitt isn't clear on any of this, the AMS also has a position statement on climate change that covers the ground in more detail. Seitter also clearly delineates the difference between scientific and policy issues while making it clear that policy differences aren't an excuse for distorting the science:
We understand and accept that individuals and institutions both public and private can reach differing conclusions on the decisions and actions to be taken in the face of this reality. That’s the nature of the political process in a democratic society. But mischaracterizing the science is not the best starting point for a constructive dialogue.
But the most detailed response has come from a group of 30 individual scientists, 28 of whom are active in climate research. They're about as blunt as AMS' Seitter, saying that climate change is a matter of basic 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."
The letter also notes that the science is nowhere near as questionable as Pruitt suggested it is: "[Your] statement is incorrect. In fact, we know with an exceptionally high degree of confidence that most of the climate warming over at least the last six decades has been caused by rising levels of carbon dioxide and other greenhouse gases in the atmosphere due to the burning of fossil fuels and other human activities."
While it's normal for scientists to have disagreements about specific details (and climate science is no exception there), these shouldn't be a sign that the overall picture is in doubt.
In the end, the letter argues, our understanding of what's happening is simply a reflection of what the natural world is telling us. The letter notes that glaciers and Arctic sea ice are shrinking, sea levels are rising, growing seasons are shifting, and plants and animals are shifting their habitats. Those changes are being driven by the climate, and the only viable scientific explanation for climate change involves humanity.
In sum, the letters argue that Pruitt's statement was wrong on multiple levels. We can measure the impact of humanity on the climate, and there's not much reasonable scientific controversy over that or the results, which clearly show humanity's impact. Continuing the analysis is obviously critical, but there's not much point in continuing debates that, by any reasonable standard of evidence, should have ended years ago.
The two organizations that sent letters have both offered to help Pruitt understand the state of the science in this field. As head of the EPA, it would be appropriate for him to take them up on this offer....