Read the full story at FiveThirtyEight.
Whenever we talk about the consequences of climate change, we’re talking about probability. Scientists present a rainbow of possible outcomes for our little experiment in fossil fuel consumption, some more likely than others. We’re used to thinking of that uncertainty as being driven by the physics of the natural world. The more we learn about heat absorption, fluid dynamics and the behavior of clouds, the better our understanding of climate as a system becomes. The more we know, the less uncertainty.
But the release of Volume II of the federal National Climate Assessment late last week got me thinking about uncertainty in a different way. As I read through the report, I saw example after example of uncertainty driven not by physics — but by human society. It’s one thing to say that we can expect a global temperature increase of somewhere between 0.3 and 4.8 degrees Celsius, depending on emissions rates and natural processes we don’t fully understand. It’s another thing entirely to guess what happens when those global temperature changes meet human society. It could turn out to be harder to predict how humans will react to the climate crisis we’ve caused than it is to predict the details of the crisis itself.