Draining swamps and wetlands has, over the course of human civilization, been seen as a way to grasp land from the greedy waters that cover most of the Earth’s surface.
Add to this that much of the drained, reclaimed land is then conveniently located on prime river or coastal property, and the terrestrial inclination to dry out wetlands makes even more sense. There’s gold in them there swamps.
A MODIS image from NASA’s OceanColor Web shows floodwaters and sediment emptying into the Gulf.
Conservationists usually look at the loss of ecosystems, plant and animal life, habitat degradation and so on. But the real price of the gold rush mentality is slowly revealing itself.
The impact of river levees on flooding has become well known over the past couple of decades. Heavily developed rivers areas around the world experiencing regular and expensive inundations when water flow in flooded rivers is blocked from flowing into tributaries, marshes or swamps.
I found a report from 2005 that shows the impact of land drainage on Florida – not in terms of habitat loss, but in terms of local and regional climate change.
Human influence has transformed southern Florida. The transformation occurred not only on land converted to cropland or cities, but even in protected and undeveloped areas like the Everglades. Changes in water flows transformed deep-water sloughs into drier sawgrass marshes, and mangrove forests have shrunk dramatically. Source: NASA
A multi-disciplinary team examined historical land cover and climate evidence from pre-development Florida (i.e. 19th-century), and found that in comparison to a drier, drained modern Florida, local climates were cooler and wetter in summer, and warmer in winter. The lack of local water cover changed local climate patterns.
This begins to get at the argument made by Sandra Postel, Director of the Global Water Policy Project, in a recent piece in National Geographic, namely, that wetlands in their watery form are worth more than the land we take from them.
She cites a new study in the journal Global Environmental Change, which shows that “the global area of freshwater wetlands and floodplains shrank by nearly two-thirds between 1997 and 2011, from an estimated 165 million hectares (408 million acres) to 60 million hectares (148 million acres).”
We’ve never been very good at weighing intangibles against objects of immediate human value, like land. But Postel makes the argument for putting wetland and watershed services in a language we understand: Money.
Landsat images clearly show different types of landcover in southern Florida.
Source: NASA/Robert Simmon
Citing the role of wetlands, like those that have been drained in Florida, as well as coral reefs, marshes and tropical forests, in mitigating flood and drought, the research team put together a list of water ‘services’ provided. These include recharging groundwater and filtering water in lakes and rivers, maintaining water levels that facilitate shipping, and several other long-term uses.
The total value of global ecosystem services to humans was evaluated at $120 trillion/year (for 2011). This is compared to a global GDP of $75.2 trillion/year for the same year.
Now, the question is this:
If we look at everything through the lens of cost effectiveness, do we really believe humans can provide all the same services at a better price, even assuming we could develop the technology to do so?
Is a new condo development, mall, golf course or business center really the most cost efficient way to make use of the golden value of the world’s wetlands?