Although it would appear that the unfathomable damage wrought by hurricane Katrina is due to an extraordinary act of nature, this limited perspective misses important lessons we had better learn this time: Distinguishing a natural disaster from a human-induced one is getting more difficult. And we need to enlist nature's help, not assign it blame.
Storms, floods, earthquakes, and tidal waves are natural events, to be sure, but the degree to which they produce disaster is now often strongly influenced by human actions. By necessity or choice, more people are living along coastlines, in floodplains, and on fragile hillsides - zones that place them in harm's way. At the same time, the clearing of trees, filling of wetlands, engineering of rivers, and destruction of coral reefs and mangroves has frayed the natural safety nets that healthy ecosystems provide. Consequently, when a natural disaster strikes, the risks of catastrophic losses are higher.
Data collected by Munich Re, one of the world's largest reinsurance companies, show the loss of life and property due to natural disasters has been climbing for two decades. Worldwide economic losses from natural catastrophes during the past 10 years have totaled $566.8 billion, exceeding the combined losses from 1950 through 1989. More than four times as many "great" natural catastrophes occurred during the 1990s as during the 1950s.
In the case of Katrina, the failure to adequately maintain and upgrade artificial levees to keep floodwaters out of New Orleans has emerged as an obvious human cause of the suffering. But so were decisions to allow coastal wetlands to be drained and filled for commercial development and to allow more than two dozen dams and thousands of miles of levees on the Mississippi River to sequester sediment that would otherwise replenish delta lands.
Coastal wetlands and barrier islands reduce the power of hurricanes and storm surges, a vital natural service largely missing when Katrina struck. Louisiana alone has lost more than 1.2 million acres of coastal lands since the 1930s. Whether blind to or dismissive of the risks, the Bush administration in 2003 effectively gutted the "no net loss" of wetlands policy initiated during the administration of the elder Bush.
Along with Katrina, other recent disasters suggest the value of nature's protective ecological infrastructure. …