In his controversial first op-ed for the New York Times last week, neoconservative writer Bret Stephens argued that there’s great uncertainty about the threat of climate change, and thus, environmentally minded scientists, activists, and politicians ought not be so confident about what they claim as fact. “We live in a world in which data convey authority,” he wrote. “But authority has a way of descending to certitude, and certitude begets hubris.”

Stephens, conveniently, cited almost no data in his column, instead employing bromides and anecdotes about the pitfalls of certainty. He quoted the work of Polish poet Czeslaw Milosz in his epigraph: “Whoever says he’s 100 percent right is a fanatic, a thug, and the worst kind of rascal.” Then he cited the widespread certainty that Hillary Clinton would defeat Donald Trump in last year’s election as reason enough to be skeptical of “overweening scientism.” Aside from the 1.5 degrees Fahrenheit warming of the planet since 1880, he wrote, “much else that passes as accepted fact is really a matter of probabilities.”

Stephens was widely criticized for mischaracterizing the nature of scientific uncertainty. In an open letter to the Times, 35 climate scientists noted that they never claim “total certainty regarding the rate of warming”—indeed, they rarely claim to be completely certain about anything. Their research, however, has reduced uncertainty significantly, and they now know that there are a range of scenarios regarding how quickly the world will warm, and what exactly will happen to the world when it does. Those scenarios depend on how much carbon we emit, and how much the planet is impacted by those emissions.

In other words, yes, climate science is uncertain—just not in the way Stephens characterizes it. When he says the majority of climate science is “a matter of probabilities,” he is implying that scientists don’t actually know what, if anything, will happen. But scientists say there’s almost zero chance that nothing will happen; their uncertainty lies in just how severe global warming and its impacts will be. “Stephens suggests that risk management should only be guided by the possibility that warming and its impacts could be less than the best estimate, and not the possibility that it could be more,” the scientists wrote. “This cherry picking presents only one side of the range of uncertainties. But uncertainty cuts both ways, and reasonable risk management demands looking at both.”

But Stephens didn’t even cherry-pick; he simply ignored the data. With that in mind, here are the actual uncertainties within climate science that Stephens should have written about.

