by Rafe Sagarin
But the slow pace of natural water management often jibes with the speed expected out of commerce and economic growth. Nowhere was this desire to optimize commerce, nor the consequences of ignoring natural security systems, better demonstrated than in New Orleans. There, the Army Corps of Engineers (the same outfit that cemented the Los Angeles River) were brought in to create the Mississippi River Gulf Outlet (MRGO), affectionately known by its acronym as “Mister GO.” The lazy, meandering course of waterways from the Mississippi River delta to the open waters of the Gulf of Mexico were apparently far too burdensome for commerce. What’s more, an enormous wetland system was smack in the middle of the most direct route from the river to the gulf. Already, much of the natural wetland systems surrounding New Orleans had been filled in, built upon by engineers who replaced the wetlands’ storm-buffering abilities with levee walls. The Army Corps, using its most linear, most hyper-efficient mindset, simply drew a straight line across the remaining wetlands and started mixing the concrete. When the dredges finished cutting Mister Go in 1963, New Orleans had a fabulous new aquatic highway, perfect for the fast and direct passage of freight barges, oil tankers, fishing boats, and recreational watercraft, as well as salt water from the oceans (which killed the most-stabilizing wetland plants), and . . . hurricanes.
As Hurricane Katrina bore down on the southeastern United States, its strength varied between a tropical storm and a full-force Category 5 hurricane. Within the last forty-eight hours before it struck, forecasts became very clear that it would hit New Orleans. As if in preparation, Mister GO rolled out the red carpet for Katrina. With no complex topography or wetland vegetation to slow her winds or the waves of tidal and storm surge she brought with her, Katrina—although only a Category 3 storm at landfall—was able to march right into New Orleans, nearly as grand and powerful as ever.
Of course, New Orleans has always been concerned about getting flooded, being as it was constructed below sea level at the confluence of the Gulf of Mexico and the Mississippi River, the biggest drainage system in the United States. Accordingly, it has become a city behind walls, protected by a series of drainage pumps and over 350 miles of levee walls to hold back the floodwaters.16 One of the problems with walls as a means of slowing water from its natural course is that they’re not very adaptable. Floodwalls can be made to be resistant to the “100-year flood,” a figure based on past performance of nature. But nature, especially now in the era of rapid human-caused climate change, isn’t contingent on history. Climate, and the tropical storms fueled by a warming climate, is changing in unprecedented ways. A 100-year flood threshold calculated based on the intensity of storms in the past two decades would look much different than the same threshold calculated when New Orleans’s levees were built, but the levees can’t be changed so easily. Katrina wasn’t the biggest hurricane to hit New Orleans in the previous 100 years, but its storm surges, up to 10 meters (33 feet), were definitely the largest.17 The current system was designed to withstand a Mississippi River flood the size of the Flood of 1927 and a hurricane with wind conditions similar to a very strong Category 2 hurricane.18 Sure enough, although the levees had protected New Orleans for hundreds of years, they didn’t do the job during Hurricane Katrina.
The other problem with the particular levees in New Orleans is that they essentially eliminated the natural process of sediment accumulation in the Mississippi delta that provided the base layer for wetlands. This natural process had resulted in wetlands growing larger in the delta for thousands of years, a trend that was radically reversed in the twentieth century due to human activities.19 So, on the one hand you had walls, which are not adaptable to the changes in nature, and that hand was taking away from the other hand, which was holding the best natural buffer against nature’s extreme forces: the coastal wetlands.
There is a growing body of evidence, arising after disaster strikes, supporting the claim that natural, intact ecosystems are effective buffers against storm surges, flooding, and tsunamis. Typically, this is hard to study, precisely because of the variability and unpredictability of these events. Where and when to deploy experimental sensors is a tricky question, and once such sensors are deployed, scientists find themselves sitting on the ethically flimsy fence of wishing for an intense natural disaster to get some data so that maybe we’ll learn more about how to protect people from the next disaster.
So it was something of a silver lining to otherwise grim events that Elise Granek and Ben Ruttenberg, two friends of mine conducting field ecology research in Belize unrelated to storm protection, lost a whole bunch of their experimental equipment to Tropical Storms Wilma and Gemma. Field ecologists studying interactions between organisms typically deploy a range of homemade apparatus to study different variables of interest. These might be PVC and chicken-wire cages laid over plants to keep herbivores away, or barriers bolted to rocks on the shoreline to see how well mussel beds grow in the absence of voracious starfish predators. Ecologists will typically set up several replicate plots of these cages and barriers and put them in different contrasting environments as well. Especially in coastal areas, they have to be designed to be “bomb proof ”—anchored by thick galvanized hardware bolted directly into rocks—just to deal with the continual force of coastal waves.
Elise and Ben had set up a large number of these treatments in sites with natural intact mangroves and in places where coastal mangroves had been cleared. They had wanted to see how the ecology of the mangrove and the cleared coastline differed. Their experiments were going well until the storms hit and destroyed a lot of their equipment. They wouldn’t end up getting much useful ecological data, but it wasn’t a complete loss. Specifically, they were able to quantify which equipment was lost, and they found a difference between how many of their solidly bolted pieces of equipment were ripped away by the storms, with significantly more equipment surviving in the intact mangrove shore versus on the transformed shoreline where the mangroves had been removed. 20 It was an accidental experiment, but one that demonstrated just how much intact ecosystems buffer the forces of natural disasters.
Unfortunately, most of our tests of the protective capacity of mangroves and other natural systems destroy a lot more than experimental equipment. The 2004 Boxing Day Tsunami, which killed 600,000 people, provided a sobering overview of the power of intact coastal forests to protect from storm surges. As researchers and aid workers examined satellite imagery and the on-the-ground destruction of the tsunami, they saw a consistent pattern. Those villages behind intact mangrove forests and tree plantations survived with much less damage than those that had no coastal buffer or had converted their mangroves into large flat pools for raising aquacultured shrimp. While the largest and most intense parts of the tsunami could easily overcome even dense coastal mangroves, slightly less forceful tsunamis, which could still destroy an unprotected village, can be reduced by as much as 90 percent by coastal forests.21
The value of these protective services is enormous both in lives and economic infrastructure. A team of economists and ecologists estimated the value of wetlands for storm protection in the United States alone at over $23 billion per year. Yet, even as the evidence for the protective value of wetlands and mangroves accumulated, it took some time for anyone with any power to listen. Oddly enough, the 2006 Townsend “After Action” about “lessons learned” from the federal response to Hurricane Katrina doesn’t contain the word wetlands and doesn’t discuss the benefits of natural storm buffers,22 even though much of these lands were under federal jurisdiction or had been altered by federal agencies like the Army Corps. A report by several colleagues of mine on the value of wetlands for flood control, although contracted by the government, was suppressed for well over a year. But as evidence accumulated from around the world, the voices speaking for wetlands protection were eventually heard, and they even came to dominate the discussion of post-Katrina New Orleans. Perhaps the biggest turnaround is symbolized by the Army Corps response to a congressional call for an e
nd to “deep draft” navigation in the MRGO. In 2006 the Army Corps responded more strongly by recommending closing the MRGO to all traffic and restoring the surrounding wetlands, a remarkable change for an agency that for most of its existence thrived on replacing natural protective barriers with concrete.
Unfortunately, after disaster strikes we often retreat to the apparent security of technological security. After Hurricane Ike, a massively destructive storm that hit the Texas coast in September 2008, one of the first responses was to call for an “Ike Dike,” essentially a huge 60-mile-long concrete wall to protect against annual hurricane season storm surges. The lack of an adaptable mindset marked both the attitudes of the Ike Dike planners and the news coverage of the dike. A former Texas mayor on the commission to study the dike’s feasibility proudly proclaimed, “The elegance and the appeal of something like the Ike Dike is, with one swath, all the problems are solved.” The Wall Street Journal article in which the mayor was quoted noted that Houston area leaders were “hoping to end the annual storm threat once and for all.”23
THE PROBLEM WITH WALLS
The idea that walls will save us from any dynamic and changing security threat, be it storms or humans or viruses, has been proven wrong time and again. The border wall between the United States and Mexico, which cost between $1 million and $10 million per mile, slows down illegal immigrants by an estimated twenty minutes, even in its most fortified areas.24 As former Arizona governor Janet Napolitano said in criticism of the border wall, “You show me a 50-foot wall and I’ll show you a 51-foot ladder at the border. That’s the way the border works.”25 What the wall has done is provide limitless cover for anti-immigration advocates who have used it as a type of political blackmail, saying they won’t support immigration reform policies until the border is “secure.”
From the physical world to the digital world to the biological world, hardened security systems like walls often lead to more damage inside their defenses than outside. Much of the damage in New Orleans occurred inside the levee walls, once the water got through. Likewise, for forty years cybersecurity experts have attempted to make “perfect” systems, but even as they continue to fail this probably impossible task (there are estimated to be 1 million bugs in Microsoft’s Office Suite26) they put up firewalls as a signal that the system is perfectly secure.27 The wall illusion quickly crumbles in the face of determined hackers who can cause considerably more damage once safely ensconced inside a walled cyber city than if there was no firewall at all.
Organisms in nature aren’t immune to such breaches of their defenses. A certain jumping spider turns out to be a deadly hacker of ant “firewalls.” This spider breaks into the ant nest by mimicking the unique olfactory signal of the ant colony—essentially stealing their password. Then, in a second act of deception, it gently taps ants carrying larvae, just as a fellow ant would do with its antennae. This causes the ant to drop the larvae, as if passing off the burden to another worker ant, and the spider has earned a meal.28
The spider’s “hack” of the ant colony is mirrored in a simple and effective cyberattack that has been successful in both deliberate simulations and actual attacks. This hack involves physically scattering virus-infected USB drives in a parking lot and letting employees with security clearance inadvertently introduce the virus behind the firewall when they insert the drives into their workstations.29
We’ve mostly been talking about the two poles of nature-based natural security—either leaving nature to do its thing or making completely artificial barriers. What if, instead of making walls and diorama-like security systems that physically cannot adapt to changing conditions, we made truly living security systems? We can start by using nature itself. The storm-buffering benefits of the natural curvature of rivers can be restored. The wave- and wind-dampening effects of natural wetlands can be put back into place by creating “living shorelines” rather than hard sea walls (which actually increase coastal erosion). Sometimes the barriers to implementing these improved systems are just bureaucratic. For example, in North Carolina, a state blessed with abundant wetlands but cursed with being incredibly vulnerable to sea-level rise, living shorelines in front of wetland properties are not as popular as putting up hard cement walls (which make up 79 percent of the constructed barriers to flooding) mostly because building a concrete sea wall requires only a relatively simple “general permit” from the state, whereas constructing a living shoreline requires an odious and costly “major permit.”30
The benefits of these living systems are not trivial but accrue at many different levels, a hallmark of natural security systems. Consider that production of cement used to build sea walls creates a huge amount of greenhouse gases, while wetlands serve as a sink for greenhouse gases. Wetlands are also effective water filters. My own research on a tiny remnant wetland being restored in Los Angeles shows that even small wetlands help remove human pathogens,31 and wetlands also serve as a nursery for important fish species that attract a huge diversity of bird species. In turn, as I discussed earlier, a high diversity of bird species has recently been shown to be a key factor in reducing transmission of some diseases such as avian flu. That means we can create security systems that protect us from intensifying storms but also reduce our climate impact, protect our water supplies, increase biodiversity, improve coastal fisheries, and lessen the impact of infectious diseases. Can a cement wall do all that?
Indeed, essentially the whole living Earth is built on these synergistic cooperative arrangements and through them becomes a self-regulating system. This system isn’t static—I’ve argued throughout this book that biological systems are changing at every level all the time—but it is constrained within boundaries that have supported some kind of life for billions of years and life that is fairly like our own for at least several hundred million years.
This kind of dynamic stability requires balance—a temperature neither too hot nor too cold, abundant oxygen for metabolism but not so much that everything instantly catches on fire, enough available nutrients for primary productivity (the algae and other photosynthetic organisms at the base of most food webs) but not so much to overpopulate an area to the point of eutrophication (the drawdown of oxygen due to the decomposition of too many primary producers in a given area). This is the basis of James Lovelock’s “Gaia hypotheses”—that the Earth as a whole is a self-regulating system that supports life and evolution. Some have overextended the Gaia idea—giving the Earth mystical powers to control Her own development, or suggesting that the purpose of green plants is to support the herbivores that eat them or the animals that breathe the oxygen they produce—but there is evidence to support the basic idea that interactions at small scales can build into an essentially self-regulating complex system.32
Although these complex self-regulating systems don’t have any goals, they do tend to protect components of the system, especially those, like humans, that are adapted to a range of conditions. This is the element of “resilience” or “robustness” that people who study complex systems are always looking for. Resilient natural systems protect us—not just from instant planetary conflagration through unchecked oxygen production but from a range of other security threats; from individual infections to epidemics and from a house flooding to a city drowning.
These are the “nature’s services”33 or “ecosystem services” that refer to the many things, essential to society, that nature provides to us. These include the pollination services of insects, birds, and bats, as well as the nursery habitat for economically valuable fish stocks provided by wetlands and mangroves.34 The list goes on: blockage of damaging UV radiation by ozone in the upper atmosphere. Conversion of dead organisms into organic fertilizer. Chemical-free control of pests like mosquitoes. Key ingredients for medicinal products. Recreational opportunities afforded by intact ecosystems. The aesthetic value of a pristine wilderness.
So, how much are all these services worth to us? A lot. There has been some controversy over exactly what “a
lot” means. You can imagine how difficult it would be to put a price on some things—for example, add up the total sold value of all the paintings, novels, photographs, and poems inspired by nature, then develop and add in some kind of “happiness” quantity related to human appreciation of nature (to capture the value to the many nonartists and nonwriters, and to the many artists and writers who never sell a thing) and for good measure add in the reduced cost of medical care for the reduced stress and improved breathing that comes through interactions with intact nature. That crazy exercise (which economists try to do, I guess because economists never really have to get anywhere close to a real number for things) might give us a ballpark estimate of just the aesthetic value of ecosystem services. Probably the most accurate statement of the value of ecosystem services is that we don’t know how much they are worth, but we know they are worth a lot more than nothing, which is how we currently value most of them.
The same could be said of “natural security” in general. With countless individual organisms and billions of years of evolutionary history to look at, we have only made the very beginnings of a much deeper journey back into the natural world. But just as not having a precise value for the Earth’s ecosystem services is no reason to ignore them altogether, not having all the answers from nature at our disposal is no reason not to begin transforming our society into a more adaptable organism. In the concluding chapter, I will outline the first steps. If taken correctly, they will generate their own momentum and lead us down a path toward ever greater adaptability.