Thursday, February 17, 2011

Modding what Gavin Schmidt said about the science-policy interface, slightly (UPDATED)

Eli's post refers to the non-scientific controversies over climate change. Gavin Schmidt (no relation) doesn't want to participate in a "science" discussion with denialists that ignores the politics that the denialists are using. Gavin says:

The fundamental conflict is of what (if anything) we should do about greenhouse gas emissions (and other assorted pollutants), not what the weather was like 1000 years ago. Your proposed restriction against policy discussion removes the whole point. None of the seemingly important ‘conflicts’ that are *perceived* in the science are ‘conflicts’ in any real sense within the scientific community, rather they are proxy arguments for political positions. No ‘conflict resolution’ is possible between the science community who are focussed on increasing understanding, and people who are picking through the scientific evidence for cherries they can pick to support a pre-defined policy position.

I agree with all of that except the bolded section. Leaving the denialists behind us, there are important real-world scientific disagreements with policy implications. For example, in my position at the Santa Clara Valley Water District, we build flood control projects and levees that are supposed to last for 50 years, built to contain San Francisco Bay and many low elevation, potentially-flooding creeks. The height of what I'd guess to be over 100 miles of rebuilt levees should be designed to be sufficient to compensate for sea level rise for the next 50 years. It would sure help if we knew what that rise would be under realistic emission scenarios, and might even save us money by not having to overbuild. With budget cuts, we're also thinking of postponing these rebuilds - we need to know how long we can postpone. Getting the science nailed down on this is important.

Getting regional and smaller levels of climate change predictions would also help on policy. That's not exactly a scientific disagreement - the science is barely touching on this level yet - but it's a crucial component for planning water supply and flood control. It's not enough to know that there will be less water when we need it, more water when we want it to not flood, and more water demand created by a warmer climate. We need quantitative predictions where the science will ultimately help us a lot in determining policy, so the sooner we can get those scientific results, the better.

UPDATE: to rephrase a little, the denialist perception of a conflict in the science over whether sea levels are rising is not a real conflict in the scientific community, and I agree with Gavin there. The conflict over how much sea levels will rise in 50 years is a truly open question, and one with immediate policy ramifications.


  1. I don't see how your example leaves you disagreeing with Gavin. I agree entirely with the text you've bolded.

  2. Hope my update helps: whether sea level is rising isn't a question, but how much it rises is an important science question and policy question.

  3. I agree that we don't know the exact answer. But I think that "truly open question" is too vague still, and gives to much to the denialists (I know: you didn't write that to be quote-mining proof, and you shouldn't). We're pretty sure that it will be greater than the 2-3 mm/yr we're currently seeing. And I've yet to see a sane estimate of more than 2 m in 100 years, which switfly narrows it down quite a lot. And you only want to know out to 50 years, which makes things easier. We could probably get it down to a factor of two for that period, which is massively less than the economic uncertainties.

  4. A factor of two might not sound like a lot, but every extra foot we have to build means a wider and bigger levee, and ultimately over 100 miles of levees (just a guess on length for our county, tho). And that's just one county. This translates into serious money.


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