Contrary to popular perception, most research yields very few conclusions with 100 percent certainty. That's why you'll often hear economists state their conclusions with "95 percent certainty." It means they're pretty sure, but there's still a small margin for error. The science of climate change is no different, and, according to a Washington Post blog post, scientists are currently struggling with how to explain that uncertainty to the public. "What do you do when there’s a small but real chance that global warming could lead to a catastrophe?" asks Brad Plumer. "How do you talk about that in a way that’s useful to policymakers?"