By Faye Flam
LAST week, the day after President Trump signed an executive order to undo his predecessor’s efforts to fight climate change, the House Committee on Science, Space and Technology held a hearing that encapsulated everything that’s wrong with the way US lawmakers handle science.
Global warming is a time-sensitive threat; greenhouse gases are accumulating in the atmosphere, threatening a sharp increase in heat waves, droughts, and floods by mid-century (and eventually, the melting and collapse of the ice sheets at the Earth’s poles). But last week’s hearing, titled “Climate Science: Assumptions, Policy Implications, and the Scientific Method” and chaired by Texas Republican Lamar Smith, meandered from one tangent after another. A good chunk of time was spent questioning whether Penn State University climatologist Michael Mann called a colleague who disagreed with him “a carnival barker” and “a denier pundit.” Some evidence was presented that he had. But does this diminish the evidence that carbon dioxide emissions pose a threat?
The Republicans dwelled on distractions that have bogged down policy for years, like a mangled historical factoid about scientists previously predicting an ice age, and an unrealistically optimistic interpretation of a temporary flattening in the global temperature curve. The latter, sometimes called “the pause,” was hailed as a sign that global warming was over. It isn’t.
But few lawmakers seemed interested in exploring the subtleties of the scientific method as it applies to climate research. The Democrats directed nearly all their questions toward Mann, who, of the four scientists called as expert witnesses, was the only one to clearly express mainstream views about the connection between human-generated greenhouse gases and climate change. The Republicans gave most of their attention to the other three, and expressed mostly innuendo, suggesting that Mann and his fellow climatologists were untrustworthy.
It wasn’t until the tail end of the nearly three-hour hearing that the one physicist in Congress, Bill Foster of Illinois, spoke up: “Does everyone on this panel agree,” he began, “that the temperature of the earth is set in general terms by radiative balance, and that the infrared absorption spectra of carbon dioxide is a very relevant driving term, and that the uncertainty really is in the other positive and negative feedback terms that may or may not be present, changes in the convection…?”
Foster rambled on about albedo and Siberian swamps, and most people in the room appeared to have no idea what he was asking about. But his was the only pointed question any Democrat had aimed at the three contrarians. In essence, Foster was asking if they agreed that well-established physics underlies the mechanism by which carbon dioxide causes global warming, and that the only remaining uncertainties are due to feedbacks that can damp down or amplify warming.
Even the contrarians agreed he was right. They also agreed that cutting climate research was a mistake. This rendered most of the previous squabbling irrelevant.
Anyone following the mainstream science journals would see that while politicians debate whether carbon dioxide really causes climate change, most scientists have moved on to the details—charting Arctic sea ice, examining the repercussions of warming oceans, and investigating the influence of climate change on human health.
I noticed a similar divide a few years ago when I wrote a series of columns about evolution. While certain members of the public and politicians were arguing that Darwin’s theory wasn’t well-established enough to teach in school, the mainstream science community had moved on to figuring out how fish evolved proto-limbs and crawled onto the land, how and why some dinosaurs sprouted feathers, and where in Africa non-human primates first evolved into us. Those trying to keep evolution out of school would often misrepresent these detail debates as threats to the whole scientific paradigm.
Some of the congressmen at the hearing similarly misrepresented a disagreement over whether surface temperatures had flattened out for a few years in the early 21st century. In 2015, a group led by Tom Karl, director of the National Centers for Environmental Information in Asheville, North Carolina, published a paper in the journal Science saying temperatures during the so-called “pause” weren’t as flat as people thought. The next year, a team led by Canadian climate scientist John Fyfe offered new evidence that the pause was real. But in a phone conversation, Fyfe said the pause is easily explained as a temporary effect of El Niño and La Niña. With three years of record-setting warmth behind us, the pause is over—but some lawmakers won’t let it go.
Republicans also harped on the notion that scientists in the 1970s forecast a coming ice age. A few did worry about global cooling because they’d discovered that some of the constituents of smog block sunlight. And a few did use the term “ice age.” As Mann explained at the hearing, scientists also knew about greenhouse warming, but weren’t yet sure what would have the biggest impact—smog or carbon dioxide.
What we know now is that smog eventually dissipates and gets rained out. Carbon dioxide stays in the atmosphere for centuries. Some scientists compare the situation to a bathtub with a badly clogged drain. You might turn down the spigot, but the tub will keep getting fuller.
Current models say doubling atmospheric carbon dioxide will cause global temperatures to rise between 1.5 and 4.5 degrees Celsius above pre-industrial levels. But even if we reduce emissions, the total will keep rising. No one at the hearing suggested a better, more scientific way to make this kind of forecast.
The hearing went on for more than two and a half hours, and despite the promise of a discussion of the scientific method, the representatives never got around to asking about it. That’s too bad. In an interview after it was all over, climate researcher Richard Alley of Penn State University said that in the broadest sense, the scientific method is this: “the human attempt to learn, done by people who have agreed to follow a rule set that makes it hard for those people to fool themselves.” There’s something in that even Congress could use.
