Scientists around the world are celebrating the discovery of the Higgs boson. Last December, researchers announced that they might have glimpsed the elusive particle, but refrained from declaring victory, since there was a one percent chance that their result was a fluke. Now they’re confident: the odds of error in the new calculations are less than one in three million.
Keep those numbers in mind when you hear smart scientists say that we’re uncertain about whether humans cause climate change and whether the consequences will be tolerable. Scientists can have immensely high thresholds for what counts as solid knowledge. Even if we knew with ninety percent certainty that climate change was poised to cause the sorts of wildfires that are raging across the American West, many physicists would stand up and attack anyone who made the connection. If we knew with similar confidence that the planet would heat by ten degrees this century absent efforts to curb greenhouse gas emissions, some scientists would still insist that the case wasn’t closed. Those sorts of odds aren’t usually good enough for physicists, and certainly weren’t adequate for the Higgs. Why should climate scientists be allowed to get away with less?
Here’s why: We’re talking about two totally different sorts of scientific knowledge. Particle physicists are after the absolute truth. They’re building fundamental theories of nature where firmly distinguishing between right and wrong is the ultimate goal in itself. When that’s the aim, ninety nine percent confidence isn’t enough. Demanding perfection turns out to be reasonable.
The most important goal of climate science, though, isn’t to build a perfect model of the planet. It’s to help societies and leaders manage risk. (To be a bit more precise: It’s about clarifying risks so that societies and leaders are better informed in their efforts to manage them.) Knowing that there’s a nine in ten chance that we’re cooking ourselves is a lot more important that knowing that there’s a one in ten chance that we aren’t. That’s because it lets us take action to slash risks by cutting our emissions. Waiting for Higgs-like confidence in climate predictions before waiting to act misses the point.
It would be wonderful if our knowledge of climate change was as solid as what we now know about the Higgs. But it never will be. Society acts on far weaker odds and much murkier knowledge all the time, whether it’s investing in national defense or developing new medicines. Waiting for perfect knowledge is great when we’re trying to understand the origins of the universe. It’s downright dangerous when it comes to protecting ourselves from dangers at hand.