In popular discussion, uncertainty serves as a wedge—a point of weakness with which you can destroy an idea you don’t like. So it isn’t that surprising that the selfish and self-serving use scientific uncertainty as a wedge as well; it doesn’t work in the scientific literature, but it does work in the minds of the public. We hear “uncertainty around climate change” and, for many of us, it means “we don’t know.”
The simplicity is appealing—after all, we know something or we don’t. Can you really half-know? Well… yes. Even that simple question shows us the difference between our gut feeling about knowing, and how it actually works. There is a great range of nuance in the idea of uncertainty, and when scientists say that something has uncertainty, they mean something much more specific than what most people think of as uncertain.
The language of science requires us to embrace uncertainty in order to understand it. Science is all about shrinking uncertainty, not to zero, but to the smallest reasonable range that evidence and method can support. The whole endeavor of science is to presume we don’t know, and then eliminate things we can be sure are wrong. Not to be certain about what is true, but to arrive at an approximation we can work with.
That means in order for us to have a discussion about so nuanced and evidence-heavy a topic as climate change, we need to go out of our way to understand uncertainty. The good news? We already do—we just need to think about it in different terms.
Let’s start with a little bit of a thought experiment: what are you doing one year from today?
For most of us, that’s far enough away that our first answer to the question is “I have no idea!” And for most people, that makes perfect sense—a year is a long time, and a lot can change between now and then. There is a lot of uncertainty in the answer, and in this case there is so much uncertainty that you probably don’t know the answer.
For comparison, let’s also ask one other question: is it going to rain tomorrow?
Again, as a baseline, you probably don’t know. But for most of us, answering that second question is a lot easier than answering to the first. You don’t know, but you know something about it. If you live in Nevada, you know the chances are pretty slim. If it’s winter in Alaska, you know rain is much less likely than snow. If it’s August in New England, you know there might be a good chance of thunderstorms.
So you have an idea to start from, and you also know how to find out more. You can check the weather channel, or a weather app, or look it up online. You’ll probably even be able to find some percentages—maybe there is a 90% chance of rain in your area tomorrow. That doesn’t mean it will definitely rain, but, for my part, when I see a 90% chance of rain, I assume it will rain during the day sometime and plan accordingly.
I can’t be certain—but I can shrink my uncertainty to the point where it’s useful to act on it.
Now what about a year from now? What am I doing? What are you doing? I don’t know any more than you do, and it’s much harder for us to find out. Maybe one of us has specific plans that cover that time frame, which will make it easier. Maybe it’s an important day, which will narrow it a little more. And yet, the uncertainty in what I will do a year from now is much, much larger than the uncertainty in whether it will rain tomorrow.
You can also imagine any number of questions in between. What will you have for dinner tomorrow? What will be the top news story next Tuesday? When will the next major hurricane hit the east coast of the United States? Uncertainty isn’t a yes-or-no answer to the question “do we know?” Instead, uncertainty is a nuanced answer to the question “how much do we know?”
And of course, we already know that. We translate uncertainty into action every day of our lives. We don’t know when the mail will come, or to the minute how long our commute to work will be, or which stocks we should invest in, or if it will rain tomorrow. But we know something about how likely those things are, and we make important decisions based on how small our uncertainties are.
Which is exactly how climate science works, and exactly why uncertainty in the science isn’t about questioning the whole endeavor. There are people out there who want to say “we don’t know exactly, so we don’t know at all.” They want to say that because they don’t want to have to make any decisions about it, and just like you can reasonably cry off making decisions about what you will be doing one year from today, they want an excuse not to make any decisions about climate change.
But climate science isn’t uncertain the way what you’re doing in a year is uncertain. Climate science is uncertain the same way 75 degrees and a 90% chance of rain tomorrow is uncertain. We would roll our eyes at people who said “Oh, it’s only a 90% chance. Let’s not bring rain jackets.” People who say “Maybe climate change won’t be bad for people, and maybe it won’t even happen!” are the next level up. They’re saying “Well, you don’t know for sure it will be 75 degrees and raining, so I can’t decide what to do because maybe it will be 10 degrees and snowing instead!”
It’s time we stop letting those people make plans for us. Because you know, some of them are just falling prey to misunderstanding uncertainty, and that’s a thing we can all learn to be better at. But some of them understand it perfectly well, and they just don’t want to admit it because it will cost them some time or money. They don’t care that it will cost the rest of us more time and more money, so they’re not the people we should have making decisions about climate change in the first place.
I don’t know about you, but if it’s likely to rain, I don’t waste my time pretending maybe it won’t. I make sure I’ve got my raincoat, and I put the umbrella in the car. For most of us, that’s what makes sense. So why don’t we start making sense together?
Image Credit: My own