Freeman Dyson on Climate

The futurist and physicist Freeman Dyson wrote a piece for the New York Review of Books on Climate Change. He’s a very (very) bright guy, but I think he is wrong. Actually, I think that the whole framing of the climate issue in the media, in the government, and possibly in many scientific circles, is wrong.

The policy debate, and the loudest voices in the science debate, are arguing over knowledge, but I think the best argument for dramatically curbing our greenhouse emissions actually comes from our ignorance. Given that:

1. The climate system is complex and highly non-linear.
2. The current anthropogenic change in atmospheric composition constitutes a significant perturbation to the climate system.
3. Industrial and agricultural civilization depends on the climate system utterly.

We really should stop emitting CO₂ as quickly as possible. Debating how bad climate change will be, and the cost of mitigation vs. adaptation presupposes that we actually understand the consequences, climatically and economically. We don’t. We have no idea what our economy will look like in 50 years. Or 100 years. Or 200 years. Running economic models that far into the future is sheer nonsense. We also don’t know what the climatic effects of changing the atmosphere’s composition will be, but we do know that smaller perturbations in the past have resulted in abrupt climate changes of a scale that would be devastating to modern civilization. Trying to make policy based on the predicted interactions between these two very complex systems is insane.

Our spectacular ignorance, and the magnitude of the plausible negative outcomes of climate change are certainly terrifying enough to justify immediate, drastic efforts to re-organize industrial society around returning the atmosphere to its pre-industrial composition.

If you disagree, I highly recommend you read:

1. Either Fooled by Randomness or The Black Swan by Nassim Taleb, and
2. The Two Mile Time Machine by Richard B. Alley.

We, as scientists especially, should have the courage to admit what we don’t understand, and to make clear that not knowing is a good enough reason to change humanity’s carbon emissions, because there are very bad plausible outcomes, whose probabilities we are unable to ascertain. If after admitting this to ourselves, and conveying this fact to the politicians in private, we decide it’s necessary to tell the public a specific scary story about the future to get them on board, I’m fine with that. But when I see this kind of commentary from someone like Freeman Dyson, it becomes clear to me that we are unfortunately still unwilling to admit both our ignorance, and the gravity of the situation.