


louisiana_wetlands.JPGSea level rise is contributing to the loss of Louisiana wetlands.

Geologists at the university said the sea level along the Gulf Coast accelerated greatly in the last century. Co-author Torbjörn Törnqvist, chairman of the Department of Earth and Environmental Sciences, said the Gulf's sea level rose 8 inches in modern times, five times the rate of sea level rise in the 1,000 years that preceded the country's industrialization.

Mr. Törnqvist said the current sustained rate of sea level rise has not occurred in this region for more than 7,000 years -- the period in which a relatively slow increase in sea levels allowed the Mississippi River sediment to accumulate and build the current delta that includes South Louisiana. Researchers attributed the faster sea level rise to the warming of ocean temperatures and melting of polar ice caps accelerated by climate change.

The finding on the Gulf's level highlights one of the factors contributing to the loss of Louisiana's coast. As Mr. Törnqvist said, public discussions on Louisiana's coast often include factors such as levees blocking river sediment from wetlands, canals that allowed saltwater intrusion and sinking ground caused by the extraction of underground oil and gas, among other factors.

But the one thing seldom mentioned is the faster rate of rising sea levels. "Well, it has accelerated," said Mr. Törnqvist, "and made things worse."

Not all the study's findings were bad news. Researchers said the rate of subsidence deep below Louisiana's coastline is much slower than previously thought. Still, the combination of sinking soil and rising seas at the Mississippi Delta is averaging 10 millimeters a year, or 3.3 per 100 years.

That would represent a serious challenge for our region even with a healthy coast -- which is why speeding efforts to restore the coast is crucial.