New Orleans: only the beginning? Rest in peace; We need the delta more.

• Author: Woodwell, George M.

Katrina thundered into New Orleans on energy accumulated from a superheated Gulf of Mexico. The superheating was no surprise. It has been building for the last century as we have accelerated the accumulation of heat-trapping gases in the atmosphere and steadily watched and measured the consequences. The process continues as we compete to burn the last of the easily accessible oil in the world, struggle to find the least obnoxious ways of burning massive quantities of coal, and transform the last of the primary forest into agricultural land or to other purposes, releasing at each step more heat-trapping carbon dioxide into the atmosphere.

Meanwhile, the polar regions have warmed differentially, glaciers have melted and contributed to a rise in sea level, and storms have grown in size and strength as energy has accumulated in the atmosphere. As though conspiring to flood New Orleans, we have pumped water and oil out from under the Mississippi Delta, and New Orleans has sunk. To protect New Orleans and other lowlands along the Mississippi River, we have built extensive dikes to keep the water that drains from half a continent in ever-narrower channels. The dikes confine the flow, and the level of the river rises further above the city in times of flood. Safety requires still higher dikes. The once-extensive marshes of the Delta that served as a buffer against storm surges and floodwater have been cut again and again for access to oil, and have eroded away. These and other changes have made the city more vulnerable year by year to storms, tidal surges, and floods.

The disaster was predicted. The dikes were widely recognized as inadequate against a major storm. Safety in this case depended on a regulatory function of government, the very purpose of government. The failure was inexcusable, but it existed at multiple levels: Congress failed to produce the necessary funds and the U.S. Army Corps of Engineers tolerated the inadequacy of its dikes. Local governments and the public also ignored the inadequacy and took no action. Oil and water were pumped from the sediments and the city sank.

The disaster was also a product, albeit less predictable, of climatic disruption. Storms are getting larger as energy builds in the atmosphere, so the hazards of wind and flood and erosion are rising. Coastal cities are vulnerable, and one already below sea level is especially vulnerable. As the climatic disruption continues--and storms strengthen, sea level...