I've just begun preparation for my PhD qualifying exam. In my department, this is the biggest pinch point of the entire doctoral program, and it entails mapping out the nature of my dissertation and providing supporting evidence that I have everything for it all to happen. I'm interested in many things (can you tell?) but ultimately my dissertation will be about salt marshes.
Marshes are high priority for attention under climate change and environmental collapse because of the myriad "ecosystem services" they provide (sometimes also called "environmental services"). These include: providing crucial habitat for various species which support broad food webs, filtering out toxins as water moves through them, sequestering carbon, and ameliorating flood risk to local areas. Ecosystem Services is a bit of an anthropocentric term in how it positions the environment as subservient to humans, valued only for the typical kinds of civilizational activities the ecosystem can support (ala infrastructure services), but seemingly a necessary designation in order for capitalism to value these places.
Does a marsh support the GDP? If this wiki page is any indication, it's been an ongoing challenge to assess ecosystem services the way we might assess a new outlet mall—as an investment by its developers and with some kind of revenue per square foot. I believe that a lot of this is due to the intelligibility of benefits by engineered versus natural features on the landscape. A new shopping mall is a planned, designed space with particular measurable physical and economic metrics in mind: a spatial and intellectual parameter space that is articulated in advance by engineers and planners on top of a razed ("empty") lot. At the core of engineering is the drawing of a system boundary around the system, and relative neglect of that which falls outside the system. This approach means that in any system, we essentially only measure that which we anticipate, that which we know how to measure, and that which we follow after the system boundaries have been drawn. All the rest are externalities. As far as metrics go, monetary values of goods and real estate are concrete numbers which are closely monitored and comparatively "easy" to reckon with (sorry, economists). When we want to pin monetary values to environmental metrics and their effects, a lot more complicated work (or a broad set of assumptions) is required to quantify the metrics and their repercussions, given that most ecological processes do not obey firm boundaries in space or time.
What I mean to draw attention to is that it is really quite hard to measure and causally relate all of the things that any given land cover does to the world around it, because hydrologic and ecologic processes are patchy and happen across complicated micro-, meso-, and macro-scales. They defy the typical ways that civil engineering projects are measured as successful or not—as within the bounds of a designed system. It's difficult to say what processes in the world need to be included or not in the accounting. (I am a proponent of afforestation efforts in general, but as I wade into the literature a little bit more, I have learned that the devil is truly in the details when it comes to net carbon budget effects.)
This difficulty comes to a head in carbon markets as well as what I will broadly call "green infrastructure." By the EPA's definition, green infrastructure only means when grey (i.e. concrete) flood control infrastructure—storm sewers and flood control channels—can be replaced with more green space. Soils and plants are, generally, good at absorbing water and playing this role, but they may not function within a narrow parameter space that is preferable to engineers. I think the denomination "green infrastructure" deserves to be at least a bit more expansive: there is solid evidence that green coastal margins (beaches, marshes, mangroves) provide more effective, resilient, and dynamic flood protection than concrete seawalls. In the near future, as technocratic carbon sequestration projects will grow to a scale similar to our water and energy infrastructure (optimistically???), I hope that natural carbon sequestration will also be considered a part of "green infrastructure."
For us to position the lifecycle of a marsh as if it were a grey infrastructure project requires improved quantifying of its infrastructural roles, which requires a lot more research! (I hope that my dissertation can contribute to this.) We still have a lot of big questions around how a marsh even "works." How does water flow through a marsh? hard question, incredibly. How fast does it sequester carbon? Uhh, this we can actually measure with some careful assumptions and cores, but it may come with wide error bars. How many species does the marsh support? Good luck counting butterflies.
But we also don't really grasp all the impacts of paving over a marsh to build on top. Maybe the local flood risk will skyrocket, maybe the dandelions will love it. A wonderful conversation with AWS this past weekend also pointed to how the greening of grey spaces will often come with interest in "redevelopment" or up-zoning, and various good and bad and complicated repercussions will follow. The eco-utopian in me wants to believe that efforts towards replanting and ecosystem restoration (or, more generally, degrowth with its landesque repercussions) will come plush with unanticipated benefits that may be good for environmental health, and that we can ease through this awkward instrumentalization of ecological processes to justify their care. But some systems are complex to the point where we don't know what is good or bad for them a priori. And, through some logic of ecosystem services, good or bad for humanity.
Producing revenue,
Lukas