Defensive Maps

Maps orient us to familiar and unfamiliar places, and trace our journeys.   They represent the nature of terrain and the presence of water, plus the manmade world: building and open space, public and private, circulation, access, roads and transport, land use, and density.  Even further, maps establish the territories of the political world: nation, religion, ethnicity, poverty, voting precinct, education, commerce, disease, taxation, and post code, often invisible to passersby.

Maps are one of the first visual languages that we learn.  In the classroom, we translate the globe and wall map into directories of our own relationship with place.  Maps do not command the universe, but they do place the viewer face-to-face with the known world.  We conceive the shapes and icons, the colors and lines into natural phenomena, built form, and areas of political control so that we may understand and act with this knowledge.  The world from the ground is much less legible than the world from the air, and maps eliminate the irrelevant details.
Maps present a group of arguments, a set of posits about what stands here or there.  Maps can only reveal the limit of knowledge at the time of their creation, with guesses about what lay beyond, or reports unconfirmed by reliable eyewitnesses.  Along the water’s edge lie the most fiercely contested, most carefully explored, detailed, and drawn features of our planet.  In the days when sailors drew the maps, coastlines and a very short range of inland features were all there was to a map.  Winds and water were of the greatest importance to the explorers who went by sea; they feature in detail and color and scale more vividly than the mountains and lands, which rapidly disintegrated into Terra Incognita.  The angry and cherubic faces of the winds were often drawn around the perimeter of maps, to appease these shifting currents. 
The most ancient maps appropriately show what is closest to us, the city and neighborhood in which people once lived.  And the very oldest one of all, drawn in 6200 BCE on a wall near Ankara, Turkey, shows the town plan of Catal Hyuk under an ancient and active volcano.  The plan of the city shows about 80 buildings in an orderly grid, with very little variation of hierarchy of scale or geometry.  The figure-ground drawing indicates rows of houses with central courtyard voids, and above the neatly scribed town looms a volcano in elevation, the forested slope of its sides leading to a pinnacle spraying lava.  In this remarkable drawing, the artist captured the critical moment when the most important things in his world were threatened.
By selecting details to include or discard, maps have the ability to persuade viewers to see subjects within a defined context.  We expect human-made images to (in some way) decrease the information given, to reduce the truth about what is real.  Maps are, after all, art and not life.   But the experience of being immersed in an environment can be overwhelming.  Maps focus on one set of variables, and restrict the number of distractions.  This leads to new insights about relationships between structures which were previously masked by obstacles; alerting us to the presence of hidden landscapes beneath our feet; or presenting all manner of fragments of the past that coexist within the brand-new city.
If maps can inspire action, what is the most critical threat that they can address?  What dangers are currently facing cities that maps can solve?  What insights can maps impart that will make our cities safer and more durable against future threats?
Now, as ever, populations prefer coastlines.  A majority of the people on earth are concentrated in coastal areas, on just 10% of the earth’s land surface. As of 1998, about 3.2 billion people lived and worked within 200 kilometers (120 miles) of the sea, while a full two-thirds, or 4 billion, are found within 400 kilometers of a coast.  The most densely populated coastal area is the mega-region stretching from Sao Paulo to Rio de Janeiro, Brazil, with 40 million inhabitants, but 17 of the 20 largest global mega-cities lie along coastlines.

Mapping the defense of a coastline used to mean showing safe harbors and rocky promontories, gun emplacements and unexploded ordinance.  Today maps indicate a greater threat, one that does not discriminate between political boundaries.  This is the sequence of maps that show predictions of change over time to sea levels worldwide.  A single map alone won’t show the extent of the possible if sea levels rise 3’, 6’, or 8’ in the next generation.  The realization comes with seeing the difference between what was then, is now, and will be; the historic sequence reveals that this change has already been underway for many years. 
Maps that prompt action present a new viewpoint for consideration, show changes over time, outline the extent of a threat, or introduce something so beautiful, so sublime that we will fight for it.  The maps have to engage us in our own backyards: the cities where we work, have family homes, and the beaches where we play.  Maps of the Greenland Ice Shelf, as scary as each summer’s loss of ice pack may seem, won’t work.  We have to know the places that are going underwater for the maps to become real, the losses to become tangible.
The Flood Insurance Rate Maps (FIRM) chart land across the United States exposed to coastal and inland flooding, and define Zones indicating high hazard and low hazard areas.  These are used by cities and counties to determine minimum elevations for building, by state Community Rating Bureaus to define floodplain compliance, and by insurance companies to establish rates.  Generally, there are three categories: Velocity (V) zones where building is severely curtailed, AE zones within the 100-year recurrence interval, and X zones, outside of the dangerous boundary.  The 100-year flood zone seems like a reasonable gamble, “a convenient, credibly long time frame for humans who seldom live past their nineties and prefer round numbers.”[i]  FIRM maps chart the 100-year recurrence, but that doesn’t mean if it flooded last year, your property is safe for the next 99 – instead, your home has a 1% chance of flooding every year.  It sure sounds a lot worse, put that way. 
The FIRM maps are a purely social construction.  They are based on map voodoo – not created solely from past data, and sometimes not even with a prediction for the future.  When FIRM maps were rushed out after Hurricane Katrina with new (and more restrictive) Advisory Base Flood Elevations, people were relieved to see that they didn’t condemn every place that received water for that gigantic storm, until they realized the financial impact on their communities: defying historic downtowns from rebuilding unless retail areas were raised 10 feet or more, eliminating funding to put public buildings back at former locations, and requiring demolition of many buildings with damages greater than 50%.  (The financial impact of the insurance hikes came much later, when property owners learned that FIRM maps also provide the rationale for charging higher rates in riskier places.)
Several cities fought against significant changes to their business as usual policy, and quietly won.  If this map can be influenced by activism, it is clearly a social construction, albeit a valuable planning tool.  The flood lines do not follow either strict topographic contours or the historic extent of flooding; they gain utility by setting a community-wide datum for the lowest floor elevation of inhabited space.  Although not perfect, the maps protect homeowners against devastating losses by getting them out of the danger zone.
Coastal maps showing land use are a pretty good indicator of the places where there will be vigorous resistance to sea level rise, accompanied by demands for public investment in artificial shoreline protection.  Retreat is more likely where property values are low and untaxed, in areas where there are farms or conservation easements.  But in beach communities where tourism has resulted in high-rise condominiums and outlet malls, in industrial waterfronts and shipping docks, in wealthy enclaves of housing with a water’s edge view, there will be strong, well-funded, and organized unwillingness to let nature take its course.  Instead, the business-as-usual response will be to elevate structures, defend the infrastructure with revetments, beach renourishment, and seawalls.  They will let the shoreline retreat somewhere else.
“Somewhere else” is the place without power, the locus of the vulnerable.  These may be the low and shattered lands, carved by generations of abuse and neglect, or the much-beloved places of childhood, overcome by more successful economic development down the road.  When these assets are not highly valued, the lives of the people are considered with less favor, and the investment may take the form of buy-outs and resettlement, rather than protection.  After Katrina, offers from the government to buy out repetitive loss properties were received with great suspicion by their owners, and only the elderly and destitute participated.  But these were exactly the people that needed to be relocated out of the danger zones; they were the people who would have required assistance in the storms to come.
The loss has to hit our own pockets to inspire action.  In wealthy nations, where we can afford warnings and evacuations, coastal armoring is mostly about protecting assets, and not people.  This is when we fight – not for the loss of uninhabited islands, not for subsiding wetlands, not for the receding glaciers far from home, but for our own homes.  If you knew that Miami would have $3,513 billion in assets exposed to coastal flooding in 2070, plus a limping flood insurance program funded by the federal government, would you invest in a building with a lifespan of over 50 years?

People can argue the cause of sea level rise – whether manmade or natural. They can even argue the science of prediction, and the uncertainties of the future. But they may find it harder to argue against a real and accurate map that shows the history underway, and which points to a very clear future trend. We place our faith in maps and in the potential for a map to show the truth. Maps may accomplish what rhetoric cannot, explaining the danger to coastlines without exaggeration… and without blame. Facts with inescapable consequences. And a limited time for response. This is our call to action.