There is mounting evidence that numerous coastal cities face the very real threat of sea-level rise. Unsurprisingly, the response is not to consider investments to relocate people, infrastructures and economies, but rather to optimistically assume that sea levels will not rise as much as the experts predict and therefore the easiest solution to contemplate will be to build dykes.
Whether we are talking about the Thames River or the Mekong Delta, planning is already underway to design and fund dykes. But what if the experts are correct, or even conservative? Not only will expenditures escalate as sea levels rise higher than expected, they will subtract from the funding required for other more constructive purposes. Furthermore, what will be the ecological consequences of effectively slicing what are currently integrated eco-systems into two as the walls go up?
For example, the Vietnamese Government is considering dykes to protect the Mekong Delta from sea level rise. But this will mean cutting off the Delta from tidal inflows and the outflows of wastes from increasingly polluted rivers. The eco-systems of the Delta will die thus threatening the livelihoods of millions of people who live off the fish harvests and agriculture that are sustained by the Delta.
If we extrapolate into the future, we can imagine collapsing cities and eco-systems walled in by increasingly ineffective towering dykes. Is building dykes the ultimate folly? Will dykes become the modern day equivalents of the Moai Statues that the Easter Islanders built over 500 years ago as they got closer to their own extinction?