You may remember a 2009 earthquake in L’Aquila, Italy, that killed 308 people and wound up causing seven members of Italy’s National Commission for the Forecast and Prevention of Major Risks to be convicted of manslaughter for their failure to predict the quake. I had forgotten all about it until I found a piece on Medium called “The Aftershocks,” by David Wolman. It’s a great case study in the inability of scientists and lay people to communicate with each other when it comes to issues of risk and probability, which has echoes in how we talk about climate change:
Conventional wisdom tells us that people are terrible with numbers. But as Kent realized back in the 1950s, we are even worse with words. In one study that Fischhoff co-authored, people had trouble understanding a 30-percent chance of rain. It wasn’t the probability that tripped them up, but the word: rain. Are we talking drizzle or downpour? All day or just part of the day? And over what area, exactly? (Communicating forecasts in Italian is extra challenging. In English, we can use forecast instead of prediction to convey uncertainty. In Italian, there is only previsione, which has a strong deterministic connotation.)
The divine cruelty of what happened in L’Aquila is that when Boschi said that a major earthquake was “improbable,” he was — and remains — correct. But where a career scientist hears the word improbable and knows that rare events do occur, a non-scientist hears improbable as shorthand for ain’t gonna happen.
Science is about study and exploration, not about knowing everything to a certainty, but for some reason a lot of non-scientists don’t seem to get that. This is why, when it turns out that the ocean-climate relationship is more complex than previously thought, too many people hear “scientists wrong, planet not warming” when what it really means is that we’re learning more about how the planet works, and the forecast still isn’t good.