Geologists have for a long, long time been telling people not to build things in certain places. Barrier islands? They move and evolve, which means property comes and goes. Not good. Floodplains? They, um, get flooded. Landslides? Only if you want a mobile home with a mobile yard. Sometimes we get heard, but usually we don’t. And the more subtle stuff, like recognizing how paving large areas can make floods worse? Lots of luck there. Doesn’t matter if the communities are rich or poor, building in bad places seems a national habit.
Maybe that is changing.
Even as the national media seems to just be noting that flood insurance is encouraging building in vulnerable spots, Politico has a big story on Louisiana’s program to consider how some communities will be forced to move and how to prepare to absorb that exodus as it occurs. For the Grumpy Geophysicist, this is a moment of actual hope, a ray of sunshine in the currently clouded over world of using science to guide public policy. [If you want more darkness, consider that politicians are rewarded for disaster relief and not disaster preparedness.]
The basic point is that people don’t like getting hammered by really bad weather (you know, like floods). And so they leave–and this isn’t typically a slow migration but instead a real wave of refugees from hurricanes or floods or other such unpleasantries. They don’t often go really far away, so neighboring communities suddenly are flooded with people. There are two main forks to preparing for this: one is to try and get the vulnerable communities to start to think about how they will evolve in the face of the next storm, and the other is for those neighboring communities to prepare for the eventual migration of their neighbors. The state is actively trying to do this kind of work.
While there are uncertainties in our future, there are a few things that will happen. There will be sea level rise. There will be bigger rainfall events. These are both so clearly tied to the basic physics of increasing CO2 in the atmosphere that there really is no avoiding them; the best we can do now on that side of the ledger is to try and keep the magnitudes lower than they might otherwise be (and some areas also see land subsidence, which is unrelated to global warming but also causes problems). So we need to prepare, which means surrendering land we cannot defend and defending land we dare not surrender.
That Louisiana is starting to consider this landscape triage may just mean we’ve moved off the “we will rebuild it” mantra of the past century. As the article makes clear, this won’t be easy–but it should be much better than letting the chaos of the next disaster drive change.