The Climate Consensus Is a Political Achievement, Not a Scientific One

That Famous Number 

TJ Thorne 

 

 

You’ve heard it. I’ve heard it. Everyone’s heard it. Ninety-seven per cent of scientists agree that climate change is real and caused by humans. Ninety-seven per cent. It’s one of those numbers that gets dropped into conversations, newspaper articles, television debates, and the moment it lands, the conversation is supposed to be over. Who are you to argue with ninety-seven per cent?

Well, I’m not a scientist. I’ll say that straight away. But I am someone who’s spent a lifetime in industry, dealing with facts, figures, and processes where getting things wrong has actual consequences. And when someone tells me that ninety-seven per cent of anything all agree on a complex question, my first thought isn’t “well, that settles it.” My first thought is “that’s a suspiciously tidy number.” Ninety-seven per cent. Not ninety-three. Not eighty-eight. Ninety-seven. Just high enough to sound overwhelming, just short of a hundred to sound believable.

So I thought I’d have a look at where this number actually comes from. Not to shout about it. Just to look. That’s all. Let’s just look.

Where the number comes from

The most widely cited source is a 2013 study by a researcher called John Cook and his colleagues. What they did apparently, was examine nearly twelve thousand scientific papers on climate change published over a twenty-year period. They read the abstracts, the summaries at the top, and sorted them into categories based on whether the abstract expressed a position on human-caused global warming.

Now here’s where it gets interesting.

Of those twelve thousand or so papers, about two thirds expressed no position at all. They didn’t say humans were causing climate change. They didn’t say they weren’t. They just didn’t address the question. They were papers about climate-related topics, rainfall patterns or ice measurements or whatever it might be, and they simply got on with the science without making a declaration either way.

So straight away, the study isn’t telling us that ninety-seven per cent of scientists agree. It’s telling us that of the roughly one third of papers that expressed any opinion at all, ninety-seven per cent of those fell on the “yes” side. That’s a different thing entirely. You’ve quietly set aside the majority who didn’t take a position, and then claimed near-unanimity from those who remained.

I suppose it’s a bit like surveying everyone in a room, ignoring the ones who shrugged, and then announcing that “almost everyone agreed.” Well, yes. Almost everyone who had an opinion had an opinion. There we go.

The question behind the question

There’s another layer to this, and it matters.

What does “agree” actually mean in these studies? When they say ninety-seven per cent agree on climate change, what exactly are they agreeing on? Because climate science, like any science, isn’t one single question. It’s a whole web of questions. Does the climate change? Has it always changed? Are human activities contributing to it? How much are they contributing? Is carbon dioxide the main driver? How sensitive is the climate to carbon dioxide? What will happen in fifty years? A hundred years? What should we do about it?

These are all different questions, and a scientist might answer “yes” to the first few and “I’m really not sure” to the rest. In actual fact, most of the papers classified as “endorsing” the consensus were simply acknowledging that humans have some effect on the climate. Well, that’s a fairly modest claim. Burning things produces gases, gases go into the atmosphere, the atmosphere does something with them. Very few serious people dispute that.

But that’s not how the number gets used, is it? It doesn’t get used to mean “most scientists accept that humans have some influence on the climate.” It gets used to mean “the science is settled, the catastrophe is coming, and anyone who questions any part of this is a denier.” The modest, reasonable finding gets inflated into a grand, unchallengeable verdict. And the ninety-seven per cent becomes the stamp on the envelope.

It wasn’t the only study, either

Cook’s wasn’t the only one. There was a 2009 study by Doran and Zimmerman that surveyed earth scientists. They sent questionnaires to over ten thousand scientists. About three thousand responded. But the famous result, the one that produced another “ninety-seven per cent agree” figure, was based on a subset of just seventy-seven scientists. Seventy-seven. Selected because they were actively publishing in the field of climate science.

Seventy-seven people. I don’t mean to be rude, but I’ve had more people than that at a family barbecue. And the question they were asked was carefully worded: do you think human activity is a significant contributing factor to changing mean global temperatures? Again, that’s a fairly gentle question. “Significant contributing factor” covers a lot of ground. You could think humans contribute twenty per cent of the warming and still answer yes.

So when someone says “ninety-seven per cent of scientists,” what they might more honestly say is “seventy-seven carefully selected scientists answered a carefully worded question, and most of them said yes to something most people would say yes to.” Doesn’t quite have the same ring, does it? No, I don’t suppose it does.

Who picked the number up and ran with it

This is the part that interests me most, I think.

The ninety-seven per cent figure didn’t just sit in an academic journal gathering dust. It was picked up, polished, and deployed. Politicians used it. Campaigners used it. It appeared in Barack Obama’s tweets. It was repeated by the BBC, by newspapers, by pressure groups, by anyone who wanted to close down a debate rather than have one.

And that’s the thing. That number was never really about informing people. It was about ending conversations. Once you say “ninety-seven per cent of scientists agree,” what’s left to discuss? You’ve positioned anyone who asks a question as part of a lunatic three per cent fringe. You’ve made curiosity look like crankiness. You’ve turned a complex, evolving, genuinely difficult scientific question into a slogan.

I’ve seen this in other areas, shall we say. In politics, in business, wherever someone wants to shut down discussion, the move is always the same: find a number, make it sound overwhelming, and use it to make the other person feel foolish for asking. It works, too. That’s the trouble. It works very well.

Science isn’t supposed to work like this

Here’s what bothers me, and I feel strongly about this.

Science, real science, is built on disagreement. It always has been. That’s the whole point of the thing. Someone proposes an idea. Someone else tries to knock it down. If it survives, it gets stronger. If it doesn’t, we learn something. That’s how we got from bloodletting to antibiotics. That’s how we got to the moon. Not by everyone agreeing, but by people arguing, testing, failing, and trying again.

The greatest scientists in history were people who said “I don’t think that’s right” when everyone around them said it was. That’s not denial. That’s science doing what science is supposed to do.

When you tell scientists they must agree, when you make funding dependent on reaching the right conclusions, when you call people “deniers” for asking awkward questions, you haven’t strengthened science. You’ve weakened it. You’ve turned it into something else. Something more like politics.

And I think most people can feel that, even if they can’t quite put their finger on it. When someone says “the science is settled,” something doesn’t sit right. Because science is never settled. That’s the whole point. If it were settled, we wouldn’t need scientists anymore. We’d just need a filing cabinet.

The pattern is bigger than climate

Once you see this pattern, you start noticing it everywhere. A complex question gets reduced to a simple number. The number gets repeated until it becomes a fact. Anyone who questions it gets labelled. And the original complexity, the genuine uncertainty, the honest “we’re not entirely sure” that real experts actually feel, gets swept under the carpet because it’s inconvenient.

I’m not saying there’s nothing to worry about with the climate. I’m not saying humans have no effect on the environment. I’m saying that when someone uses a number to stop you thinking rather than to help you think, you should probably look at the number a bit more carefully. That’s all. Just look.

I’m eighty-one going on eighty-two. I’ve been around long enough to see a few certainties come and go. Things that everyone agreed on, that were absolutely beyond question, that turned out to be wrong, or at least a good deal more complicated than we were told. I don’t get angry about it anymore. I just notice it. And I think it’s worth saying, every now and then, that asking a question isn’t the same as denying the answer. It’s just asking a question.

There we go. That’s that one.