Sunday, August 02, 2009

Nuclear power and bias

When I started this blog as a 17-year-old with too much time on his hands, I promised that I would regularly review my past posts and note when I'd been wrong. Since I haven't made many explicit predictions here (with a few successful exceptions), it's not clear how to decide whether I'm objectively "wrong," but I can still look back and see where I strayed.

I feel a particular tinge of embarrassment when I read some of my past writing on nuclear power, because I realize that I had an unusually crude case of confirmation bias. Essentially, I interpreted every fact about nuclear power in the least favorable way possible, and I interpreted every fact about renewable power in the most favorable way possible. It's true, for instance, that nuclear power plants have frequently gone over budget, and that official protections of cost ignore the reality that capital outlays are often much higher than first estimated. This is still no excuse for handpicking the most speculatively high cost estimates for nuclear power and placing them alongside the most optimistic estimates for renewable electricity. It also elides the main issue: why is nuclear power going over budget anyway? If it's something that we could cure with streamlined regulatory processes or simple economies of scale, it may be just as amenable to cost improvements as the most promising renewables.

So that's cognitive bias number one: interpreting every new piece of evidence in a way predestined to support a single position. But I think there's more to this story. Why wasn't I more interested in a favorable evaluation of nuclear power, since it holds the promise to provide carbon-free electricity at a massive scale? Partly I was put off by legitimate drawbacks of nuclear power: the risk of accidents, the problem of waste, and the specter of proliferation. Yet I also suffered from simple overcertainty. I was convinced that an ambitious program of social thermal power, improved efficiency, and possibly cheap photovoltaics could achieve the necessary reduction in coal-fired electricity.

A moment's reflection should reveal that this is a highly speculative hope, rife with assumptions about technology, scalability, infrastructure, and cost. Perhaps it is no less reasonable than its mirror image, the assumption that nuclear power can swoop in and solve all our energy needs the instant we muster the political will, but it is still fundamentally misplaced. Indeed, part of the reason why global warming is such a threat is that our limited models of the climate can't account for all its potentially devastating complications and feedbacks, and we're left with a dangerous uncertainty. In this light, it's positively crass to exclude possible solutions to climate change based on a simple mental model that tells us they'll be unnecessary. We can't be sure what will work: that's why we need to try every good option.

Confirmation bias and overcertainty are everywhere, and though I'm sorry I was such a pathetic victim, I'm glad that this issue provides such a nice example of common flaws in our reasoning. With any luck, my future punditry will be better.


Darf Ferrara said...

I hate to bring it up, since it's been but 24 hours since your last confession, but opinions on global warming seem to follow similar confirmation biases. The fact that climate models are so poor is hardly a reason to panic and proceed foolishly (although I agree with you that nuclear power isn't necessarily foolish). Indeed, many in third world countries would suffer greatly attempting to scale back energy use. If you want to do a serious cost/benefit analysis, the costs to current generations have to be balanced against the benefits to future generations. I would really like to see a climate study that made these numbers explicit, because I've never seen these issues seriously addressed.

By the way, for a great book on energy I highly recommend Sustainable Energy - without the hot air by David McKay, available as a free download. said...

Michael - I hope that you get the recognition you deserve for your honest introspection. We cannot claim credentials in critical thinking unless we are constantly vigilant for our own confirmation biases.

And I support Darf Ferrara's recommendation of David McKay's new book. It is worth noting that Dr. MacKay has been appointed Chief Scientific Advisor to the UK Department of Energy and Climate Change. Dr. MacKay is a Cambridge physicist who approaches the climate change/energy policy issues with the same critical-thinking, level-headed approach that we have applauded in the work of University of Adelaide prof. Barry Brook.