A probably reasonable reaction

I stand by my argument that calling Bret Stephens a “denier” is asinine.

I had never heard of Bret Stephens before reading the Slate piece at issue in that post. I am not defending Bret Stephens’ record in general. But the reaction to this particular column, very little of which invokes his prior record, continues to seem ridiculous. I can’t read anyone’s mind, so I don’t know why so many people seem to have so badly misread Stephens’ column, but I continue to be kind of astonished by the whole hullabaloo.

Let’s recap what I would have (naïvely) taken to be the obvious points of Stephens’ essay, as written by Stephens (note that this first quote has been changed, since he originally wrote that the temperature change was only in the northern hemisphere – see the correction at the end of the column):

  • “…while the modest (0.85 degrees Celsius, or about 1.5 degrees Fahrenheit) warming of the earth since 1880 is indisputable, as is the human influence on that warming, much else that passes as accepted fact is really a matter of probabilities. That’s especially true of the sophisticated but fallible models and simulations by which scientists attempt to peer into the climate future.”
  • Claiming total certainty about the science traduces the spirit of science and creates openings for doubt whenever a climate claim proves wrong.”

To recap the recap, with respect to the science, I read Stephens as saying that anthropogenic climate change is true without a doubt, but that the magnitude and exact nature of the changes we should expect to see is less certain. I don’t see how you could read him as saying anything else.

With respect to the advocacy, I read Stephens as saying that too much certainty about the science can provide a handy excuse for skeptics to cast doubt on even the parts of climate science that we are most certain about. This seems to be a pretty unobjectionable point to me.

Gizmodo has a post summarizing the situation. It doesn’t help me see the response to Stephens as more reasonable (emphasis in original):

As several scientists contacted by Gizmodo explained, it is reasonable to be skeptical about the exact magnitude, timing and breadth of the impacts of climate change, and the appropriate societal response. In fact, few in the scientific community would claim certitude about the impacts, as Stephens suggests.

But the existential threat itself? That’s undeniable.

I don’t understand this at all (put aside the dog-whistley invocation of denial). The first bit seems entirely consistent with Stephens’ claim about the effects of climate change being probabilistic rather than utterly certain. But if it is reasonable to be uncertain about “the exact magnitude, timing, and breadth” of the effects of climate change, how is it undeniable that climate change is an “existential threat”?

I ask this question with total sincerity. These two statements are not consistent with one another. It cannot be simultaneously reasonable to be skeptical about how bad the effects of climate change will be and unreasonable to argue that the threat might be less than existential.

Here’s another bit from the Gizmodo post:

Richard Alley, a climate scientist at Penn State University, pointed out that in his area of research, glaciology and Antarctic ice sheet dynamics, the uncertainty boils down to whether the world will have to prepare for three feet of sea level rise over the coming century, or more than ten.

“The impacts of warming may be slightly better or worse than we expect. Or much worse,” he told Gizmodo. “Averaging over all possible futures, more uncertainty makes the costs much higher than if we were certain we would get the most-likely IPCC projections.”

Again, this is completely consistent with a claim that the effects of climate change are probabilistic, not certain. In fact, the quote that begins the second paragraph just is a claim that the effects of climate change are probabilistic, not certain. (Tangentially, as bad as 3-10 feet of sea rise will be, especially for the large number of often very poor people who live in coastal regions around the world, it’s not an existential threat to the planet or humanity as a whole.)

One more quote from the Gizmodo piece, if only to be clear that I’m not just trying to cherry pick bits that support my argument:

“Reasonable people can disagree about the best way to avoid the dangers,” Oreskes told Gizmodo. “We can also disagree about exactly how bad things are going to get. But there is no substantive, reasonable, evidence-based argument that climate change is not a substantial danger. To suggest otherwise is to misrepresent the current state of knowledge.”

This is also clearly consistent with claims about probabilistic effects, and I would emphasize the difference between claiming that the effects of climate change represent a “substantial danger” is different from claiming (with total certainty) that it represents an “existential threat.” Multiple feet of sea level rise is indeed a substantial danger, particularly to people who live near to ocean, and particularly if these people are poor.

But once again already one more time, the claim is manifestly, plainly not that climate change isn’t real, nor that it won’t have any negative effects. The claim is, again obviously if you read Stephens’ column, that there is uncertainty about the effects of climate change.

 

As I mentioned in my last post, I’m far from an expert in climate science. So, while I’m glad that Gizmodo reached out to some actual climate scientists to ask what they thought, I figured it would also be worth checking more direct sources of the science. As far as I can tell, these are also entirely consistent with the argument that the effects are probabilistic.

Here are explicitly probabilistic temperature projections. Here are explicitly probabilistic precipitation projections. Here are explicitly probabilistic projections about droughts. Look in my last post for links to explicitly probabilistic claims about hurricanes and climate change.

Granted, these aren’t links to the primary scientific literature on climate change. But I’m skeptical (additional dog-whistling unintentional) that if I had the time and energy to really dig into this, I would find non-probabilistic predictions about the effects of climate change.

This whole thing leaves me kind of despondent about the state of scientific and political discourse, even putting aside the civil discourse garbage disposal that is Twitter (link from the Gizmodo piece, since I try to just avoid Twitter anymore). It doesn’t help that it’s consistent with a much broader, rather long-term change in how people deal with political disagreements.

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