Stationarity, ecology and law: which decisions are final?

There is a very interesting post over at Law 2050 on stationarity and climate adaptation in law. And it makes reference to a new 2013 paper in the Duke Law Journal.

The idea of stationarity is well-known in hydrology as the assumption that natural variability fluctuates within an overall envelope of stability. So we might have more or less precipitation or water availability in a given year but outer limits of variability exist such that, year over year, things are relatively stable. This is what allows planners to build for 50- or 100-year floods. But as many people will notice, we seem to have 50- or 100- year floods more often than fifty or one hundred years. And this has led to a sustained questioning of the assumed stability of things and to a 2008 by a paper in Science claiming that stationarity is dead. The argument is that human forcing on climate and hydrological systems has taken natural variation out of the envelope – there are now no clear limits to variability.

I used the rejection of stationarity in a recent paper to show how we need to rethink policy concepts in the Anthropocene. For instance, the idea of “renewable water” is common in policy discourse, but it relies on the idea that there are annual stocks and seasonal flows of water and this assumes that water variability is relatively stable over time. Take away that assumption of stability and the idea that water is “renewable” is not so straightforward (if it remains workable at all).

If we consider the idea of stationarity as it pertains to law, it raises anew a question asked in the early 1990s by legal scholar Dan Tarlock in his essay “The nonequilibrium paradigm in ecology and the partial unraveling of environmental law.” In that paper, Tarlock argues that the idea of a stable, natural world is what links science to law in a relevant way. This is because in a stable world the outer limits of things are more or less fixed. This is helpful in law because we need to be able to bind a case somehow in order to reach a final judgment – binding a case in certain ways is what allows certain things to be evidence and other things not to be. Similarly, the idea of outer limits in early ecosystem science suggested that what we need to do is develop environmental laws that would keep us from pushing things off balance. Think of early ideas of a “maximum sustainable yield” in forestry. There the idea was that we can keep taking a certain harvest because the forest as a whole was stable over time – things were in equilibrium.

It is now common, however, to think of complex systems as being at a distance from equilibrium. Think of your body. It hums along at 37 degrees C and works hard to keep it that way regardless of the temperature in your room, building or the environment. So your body is at a distance from equilibrium. If it was not, you would be ill; possibly dead. Similarly, the nonequilibrium paradigm in ecology suggests that broader systems, even the earth itself, work not by seeking stability or equilibrium, but by not doing so. So too in the forestry example. It is not the case that we can develop maximum sustainable yield models that assume the forest itself is always oriented towards stability. Forests are changing and adapting, as Nancy Langston’s classic book on the topic makes clear (Forest Dreams, Forest Nightmares).

The idea of nonequilibrium systems troubles the fit of ecological science and the law. In brief, the law will need to catch up to what we are learning about complex systems and to formulate other ways of reaching decisions that do not presume that things will remain relatively stable over time. The paper out in the Duke Law Review is really a nice contribution on how we might begin to think of the fit between environmental law and complex systems without the assumption of stationarity and, in addition, how we might use what we have learned from non-stationary systems to adapt to surprises both in ecological systems and in social systems, like the law itself.


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