Firth, L. B., Airoldi, L., Bulleri, F., Challinor, S., Chee, S. Y., Evans, A. J., … & Hawkins, S. J. (2020). Greening of grey infrastructure should not be used as a Trojan horse to facilitate coastal development. Journal of Applied Ecology.
The fig leaf can be used to cover a multitude of sins – or so medieval art censors would have you believe. When nudity in art became passé, it was a common practice to cover the genitals of sculptures with a small, curly fig leaf. In the book of Genesis, when Adam and Eve discover they are naked, they cover themselves in leaves, leading Saint Bede the Venerable to declare the fig leaf as a symbol of the tendency to sin. Now a group of marine scientists have pointed out the most recent iteration of the fig leaf, but this time it represents a tendency to sin against the environment. They warn that the practice of “greening” new coastal developments, or changing new projects so they look more environmentally friendly, is nothing but a fig leaf if it is simply used as a fast pass to continue exploiting the environment. Just as a fig leaf doesn’t really stop Michelangelo’s David from looking naked, greening gray infrastructure may do little to actually stop environmental harm.
How can infrastructure be green?
As the human population continues to grow, so do our impacts on the environment. We build more and more, especially along coveted coastlines that are valuable for business, leisure, and beauty. However the structures we build in and around the water are understandably a hard surface (think seawalls). While these may be essential for continued development and protection of our buildings, these hard surfaces are usually a poor replacement for the roles played by natural coastal ecosystems.
To try to lessen the environmental impact of coastal developments, some have tried integrated greening of gray infrastructure, or IGGI for short. The principle behind it is that if a green solution, or one that is more environmentally friendly, cannot be found, then the harm of the development is minimized by building in such a way that the development should still help promote biodiversity. A common example is an artificial reef, where hard surfaces underwater offer a place for coral to grow. The idea has quickly gained momentum, but the study of greening gray infrastructure is still a very young science, and we still have a lot to learn.
The tragedy of the mitigation hierarchy
The phrase “reduce, reuse, recycle” is unavoidable in a world struggling with the polluting effects of plastic. This is a form of mitigation hierarchy, in which steps are outlined in terms of effectiveness. Reducing plastic use is best, reusing our materials is good, and if all else fails, recycle. Still, guess which one of those steps gained the most traction in American culture.
Sustainable development has its own hierarchy: avoid, minimize, restore/rehab, and compensate. However just as recycling plastic has become infinitely more popular than reducing plastic use, compensating for development, or greening gray infrastructure, is gaining momentum and could quickly surpass the first three more effective steps in the hierarchy.
While making infrastructure greener is a good thing, the ecological benefit often falls short of the goal. Furthermore, we still don’t know how these new structures might spread pathogens or invasive species. For example, some scientists have hypothesized that large blooms of jellyfish are worsened by increased human development since part of the jellyfish life cycle relies on hard substrate. More seawalls and artificial surfaces may mean more places for baby jellyfish which will lead to more stinging creatures in the water.
Fig, laurel, or Trojan horse
The scientists proposed three potential categories of green infrastructure. The first is a laurel wreath, or a win-win situation. When used right, greening infrastructure can retrospectively improve buildings and seawalls that have already been constructed, making them more ecologically valuable while also maintaining the same level of benefits we’ve had for years. For example, the Billion Oyster Project is using hard structures as a place to grow oysters in New York.
The second category is the fig leaf, in which a greening proposal for a new development is used to cover over the ecological damage that is about to be done. For example, breakwaters serve as a home to a wide variety of species, but they are not the same plants and animals that would live in soft sediment, for example. While a breakwater can support its own kind of ecosystem, it would behave very differently than the habitat that it replaced.
The third category is the most nefarious. The scientists noted a number of times where developers would weakly “green” their proposals as a deliberate method to “expedite, facilitate, and reduce costs of regulatory processes.” In their words, a number of constructed artificial reefs are “merely disguised ocean dumping grounds” (see the picture of the treadmill underwater). The intent behind this kind of decision is not to protect the sea but to avoid regulations, and is thus a “Trojan horse.”
In the future, we need to be on the lookout for these Trojan horses and fig leaves. In the past, scientists have studied the success of greening infrastructure by measuring biodiversity, but Firth and her colleagues challenged scientists to come up with more accurate ways to compare two different ecosystems, like an artificial reef and a sea grass bed. They also warned that we need to pay more attention to failure. Scientists like to talk about what worked, but journals also prefer to publish successful studies. This can leave us unaware when we do something that is useless or even potentially harmful. If we fail to recognize fig leaves in our coastal development, years later we will see them as we now see fig leaves on sculptures – an ugly, symbolic gesture that ultimately did nothing.
I am a PhD student studying Biological Oceanography at the University of Rhode Island Graduate School of Oceanography. My interests are in food webs, ecology, and the interaction of humans and the ocean, whether that is in the form of fishing, pollution, climate change, or simply how we view the ocean. I am currently researching the decline of cancer crabs and lobsters in the Narragansett Bay.