The National Center for Atmospheric Research (NCAR) is the world’s premier research institution for understanding everything from weather to climate. Founded in 1960 it’s the envy of the world scientific community.

Now it’s being dismantled.

I start with this piece of current events to demonstrate the very real threat American science is facing at the hands of organized, and now empowered, science denial. Two weeks ago I wrote a post titled Is It Time For Scientists To Stop Being Polite? The reaction was strong and positive. Today I want to follow up on the theme of pushing back against willful, purposeful ignorance. This time let’s highlight the clearest way to understand the state of a scientific field, i.e. consensus.

Back in the early 2010’s I was writing the 13.7 Cosmos and Culture blog for NPR. I’d often do pieces on climate change. After a while I’d noticed a change. Any climate change post I did would quickly fill up with hostile comments (this was back when there was a comments section). In response I’d do my best to explain how the vast majority of scientists studying Earth’s climate now understood it was changing because human activity. After decades of research, I said, the community of climate researchers had reached a consensus about the state of their field.

This line of argument did not work because, as I discussed in the previous post, most of the commenters were not interested in the science. Still, when I talked about consensus, they’d retort that science isn’t consensus. What matters, they’d say, where the facts (turns out hey weren’t much interested in facts either).

At a much deeper level they are right about the facts (some scientists on twitter make this point too). Science is a special kind of dialogue with Nature. If you ask the right questions, in the right kind of way, then nature will return the favor by giving you back public knowledge. This means knowledge that’s demonstrably true for everyone.

But that deeper level about scientific methodology (and even philosophy) is not the point. Instead, the question is much simpler. How are people not trained in science supposed to know what scientists - as a community - think about their science?

The answer is simple: consensus.

The conspiratorial science-denial folks talk about consensus like it’s just a vote taken at latest meeting of the American Association for the Advancement of Science. In their heads they see a bunch of PhD’s getting together with a list of questions and a show of hands.

Vaccines. Yes. Check.

Climate Change. Yes. Check.

UFOs are Aliens. No. Check.

This view is so profoundly uninformed it makes my head explode. What consensus really means is a community-wide understanding about the state of a particular field made by the scientists in that community. Scientists know the consensus because they live it. They read hundreds of papers. They attend hundreds of meetings. They talk with hundreds of colleagues. Consensus is not a a vote. It’s the fruit of thousands of people spending thousands of hours working together to understand a problem.

So, yes, consensus itself isn’t science. It’s the result of science.

And here is the important thing. Sometimes there isn’t consensus. Is coffee good or bad for you? Those endlessly flip-flopping studies covered by the media (Coffee will Kill You! Coffee will make you live to 120!) tell you there’s no consensus on this question. And of course, over time, a well-worn consensus can change. It can be over-turned. That’s how science works. But on big questions this does not happen often. In fact, the longer a consensus has been around and the more it’s based on basic physics and chemistry (living things are complicated) the less likely it will get flipped.

But the folks tearing down NCAR, or getting pushed into weird corners of non-reality by their anti-science politics, don’t want to hear this. They don’t want to know what consensus means in science because it would force their hand. So they purposely get the arguments wrong or live in edge cases.

For the rest of us the task is simple. Getting clear on how to know what scientists think they know is the first step in defending American (and all) science.

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PS If you have specific questions or issues you want me to address leave a comment on the website or email me at [email protected]

— Adam Frank 🚀