Last June, the Washington Post reported on a conflict over flood maps in North Carolina. These are not your standard, everyday flood maps. They do not limit themselves to definite-but-boring historical evidence of flooding. They go a step beyond, to include computer models of how future flooding may change as the climate changes. As was the case with Armstrong’s hop off the ladder, that is one small step for a flood mapper, but a giant leap for the law and politics of flood mapping. Too giant a leap, as we shall see.
The story starts with a state agency project to estimate how much the sea would rise by the year 2100, under the influence of a warming climate. The agency projected a 39-inch rise by century’s end and made maps showing precisely which parts of the North Carolina coast would be under water under that assumption. The agency was in the process of making a public website to share those maps, when the legislature intervened. The project is now limited to using historical trends extrapolated to a 30-year forecast. Modelers are projecting an 8-inch rise with those assumptions.
The Post story linked to Steven Colbert’s satirical take on the conflict. He joked that the legislature had “addressed the crisis predicted by these climate models, by outlawing the climate models” (minute 2:40). “If your science gives you a result you don’t like, pass a law saying the result is illegal” (minute 4:04).
Of course the legislature did not outlaw a result, it prohibited a state agency from using a particular model. But the puzzle is still there. Isn’t it odd to legislate against a model?
Colbert and others saw the legislature’s action as evidence that legislators are anti-science. They may be, but I think the restriction comes from a different social conflict, one that will challenge climate adaptation far more than scientific debates will. Namely, should the state be able to make authoritative statements about the distant future without considering the present-day effects of those statements?
The legislature was acting on behalf of people whose property is in the areas that were projected to be under water by 2100. The owners were objecting to that specific fact: that the state asserted that their property would be under water by 2100.
The assertion is specific as to place — the maps were at a fine resolution. It is also specific as to time — by 2100. Those two things are necessary to mobilize landowners as an interest group. Without them, no individual’s interest is sufficiently threatened by the map.
But why is it the map that is seen as the threat instead of sea level rise itself? Answer: the sea threatens future landowners, who may not yet be born. The map threatens today’s landowners.
The threat comes from the first italicized word above: “asserted”. The maps were an assertion, a claim, an allegation. Statements like that, once launched into the public debate, can be used, reinterpreted, and modified by anyone. Their original creators no longer control them.
The threat to the landowners was that the state’s maps would be used by others in a way that hurts the landowner’s property values. Specifically: that potential buyers would not pay as much for the property, due to a misunderstanding of the map’s significance or some other reason.
If the maps were known to be 100% true projections of the year 2100, the landowners would still have a reason to object to the presentation of the maps today. But the objection is strengthened by the uncertainty of the maps.
The uncertainty of the models is technical, hard to understand, and hard to find in the underlying analysis. Anyone who wanted to disagree on the merits would have to do a comparable level of work. And unlike the form of science heralded by Colbert, projections of the distant future are non-disprovable. There is no way to test them.
Of course there are many reasons to used modeled projections anyway. They can help people consider long-term risks to present-day investment decisions. This reason is especially salient for municipalities who are investing in very long-term infrastructure. Climate projections can also be seen as a public good, under-provided by firms acting independently. Maybe there are scale economies of production or learning-by-doing that support state work on projections. Perhaps they play a signaling role, like a bargaining position or a pre-commitment device by the state.
Those reasons may be sufficient from the state’s point of view. They may even be sufficient from a social welfare point of view. But they do not negate the landowners’ objections.
Should the state be able to make authoritative statements about the distant future without considering the present-day effects of those statements? Those harmed by the statements will say “no”. Before we judge them too harshly, let’s remember that, at some point, we may also be the ones harmed by a state action.