Pinker too optimistic on climate change

In "Enlightenment Now" (my main review of it is <here>, Pinker freely admits that climate change is a big problem and potentially very disruptive.

He notes that it is a serious free rider problem -- we suffer collectively from the emissions of everyone in the world, but any cost we pay to reduce our emissions is borne by us alone. He feels that radical de-industrialization is totally unrealistic. He feels that some people inappropriately measure their contribution by how much they sacrifice rather than how much good it actually does. I can't help have this reaction to exhortations to save paper by not printing out emails. So I agree with him about all that.

He thinks there are many promising technologies that could help reduce emissions a great deal, and his overall assessment is that it's not cause to panic or conclude that "humanity is screwed". I've made posts suggesting we are heading for <profound disaster> from climate change. So I started with separate assumptions, and I hoped he could convince me that we're better off than I think.

Among the good ideas he mentions are carbon taxes and much-expanded nuclear energy (from a few standardized well-tested designs). I was arrested protesting nuclear power at Seabrook in 1977, but have come to feel that in the era of serious climate change it can be well worth the risks. Pinker speaks of carbon capture and mentions a number of technologies, but with no convincing evidence that they are actually practical.

Having considered all the methods for controlling emissions of greenhouse gases, he gives this sobering quote: "the effort needed to prevent climate change is immense, and we have no guarantee that the necessary transformations in technology and politics will be in place soon enough to slow down global warming before it causes extensive harm."

"No guarantee" seems to me punting on a probability estimate right when one is needed most. I put it at around 90%. I expect most climate scientists would agree with me. Of the other 10%, 9% is uncertainty is around whether high CO2 levels will cause extensive harm, leaving only 1% for the chances we humans will change our behavior enough to make a difference. Despite the melting of the arctic ice and the hottest years on record, there is nothing resembling a political consensus developing around such proven measures as carbon pricing or nuclear power.

But following this quote, he brings us to the "last-ditch protective measure", climate engineering to reduce how much sunlight hits the earth. He mentions dispensing sulfates, calcite, nanoparticles, or seawater into the atmosphere. He quotes only one scientist on this, the physicist David Keith. There is no consensus that any of those things would work without causing unacceptable side effects. I would also prefer an engineer rather than a physicist to declare this would work. How many tons of this stuff do we need to dispense, how much of what comes out of the planes will be effectively deployed, and on what timetable do we have to repeat it? (In its favor, this solution does get around the free rider problem -- any one rich country could do this on their own without needing the cooperation of others). His previous quote about "no guarantee" should come after this discussion of last-ditch protective measures rather than before it, as this leaves the erroneous impression we have a proven solution if all else fails.

So where does this all leave us? It seems to me that there are many generalizations with conflicting implications.

One is that technology has over and over again allowed us to improve the human condition in ways that people did not foresee.

Another is that doomsayers have said doom a great many times before and so far none of them has been right.

Another is that it only takes one kind of doom to doom us -- as Pinker recognizes when discussing "entropy" early in the book.

Another is that if we look at the subjective probabilities of various dire possibilities, they all seem to be very low -- with the one exception of global warming. Others might not accept my 90% estimate, but I can't see justifying an estimate below 40%.

While a realistic appraisal of our fate is important in its own right, the more practical question is what we should do right now. He argues that suggesting unrealistic changes such as de-industrialization or simply saying we're doomed don't lead to productive action. He says our best bet is to go right on getting richer and using a portion of our riches to find technological solutions. I don't have any clearly superior course to suggest.

The climate goal for a long time now has been to limit the rise in world temperatures to 2 degrees Celsius. Pinker does not get into what the consequences would be if the temperature rises by 4 or 6 or 8 degrees. We know they would be bad. <This article> suggests a sea level rise of between 3 and 9 feet by the year 2100 -- within the lifetime of today's young children. A great many people will have to move. Hotter temperatures inland may limit suitable places to move to and disrupt water supplies. Food production is likely to be reduced.

Naturally people who predict more dire consequences will get more press coverage than those who say things won't be so bad. With that in mind, the fact that the Trump administration <expects a 7-degree rise by 2100> is rather alarming.

I had been alarmed by the realistic prospect that seas will rise by 200 feet, but am comforted to learn that it would take thousands of years, which is ample time to adjust gradually.

One thing Pinker does leave me with is more optimism that as the exact environmental consequences become clear, we would develop clever technological solutions to mitigate some of their effects.

In my own <latest post> on the subject, I suggested we go right on extending human achievements, which Pinker would surely agree with. I also suggested we be prepared for true civilization-ending catastrophe, and if it becomes warranted, take for inspiration the Roman Empire and do such things as inscribing human achievements in rock for the benefit of those who emerge from dark ages hundreds or thousands of years in the future. We're not to that point yet, but we should get ourselves used to the idea of catastrophic disruption to civilization and think about what we should do then.

Pinker is on a roll of optimism, listing all the things that have gotten better and the low probabilities of anything getting substantially worse. He didn't ignore global warming, but he didn't make a probability estimate for bad outcomes. I think it is very high, and the question is just how bad it will be and how good our mitigation strategies will be.