weather terror error—or not

new orleans' first line hurricane defense is the marshland of the mississippi delta between the city and the gulf of mexico.

at least that was the case before much of the wetland turned into open water.

see, storms absorb heat from open water and so gain energy and wind speed. when wind beats against land, the ground (including wetlands) sucks energy out of the high-speed air and slows it down.

the delta got built up over countless eons from silt deposited by the mississippi every time it overflowed its banks in spring. rain continually washes soil from the delta into the gulf, but it got replenished by river floods.

when the french settled there 300 years ago, they soon had a flood. knowing what happens once can happen again, they built a little wall. it kept them dry a few years, then the river changed course and went around the levee, so they extended it. that cycle continued till the levee reached its present length.

it got so long it prevents most flooding in the delta. the river carries more silt into the gulf, where it fouls water and makes it harder for fish and other marine species to live and reproduce, which also makes life harder for birds that live on fish, such as louisiana's state bird, the brown pelican.

since its eroded soil no longer gets replenished by floods, the wetland is shrinking. it now loses an area the size of manhattan EVERY YEAR.

open water area has also grown from canals drillers dug to get to oil and natural gas, bring in equipment, and so forth. oil companies have also buried thousands of miles of underground pipelines that crisscross the wetlands. soil loss is exposing them to seawater. they were designed to be under the delta, not in the gulf of mexico. oil spills have already killed a lot of pelicans and other creatures. a lot more will suffer and die every time a pipe bursts.

so, as hurricanes gain in strength and frequency from warmer waters, new orleans grows more exposed, and as the ecology gets more vulnerable, potential for disaster grows.

ain't civilization wonderful?