This article was published in the Louisiana Weekly in the May 2, 2011 edition.
Before the BP spill, a number of Louisiana towns were underwater, local marshes were ailing and non-native plants and animals dominated habitats. But with the recent spotlight on oil, dispersants and seafood safety, memories are blurred about decades-old factors that imperil the coast.
Dr. Virginia Burkett, senior science advisor for Climate and Land Use Change at the U.S. Geological Survey, said the spill contributed to Louisiana's wetlands loss, which was already well underway because of multiple stressors. And, she said, a year after BP's rig explosion, cumulative effects of climate change and the spill are still poorly understood. Climate change itself, however, has been well studied.
Based in Many, LA, Burkett spoke at a President's Forum on the Gulf, held at Loyola University New Orleans on April 27.
She said the Mississippi Delta Plain began to form 7,500 years ago, creating most of the land in Louisiana's coastal parishes. Fast forward to the last century, when coastal erosion became a concern. The Mississippi Delta has now lost over one million acres of wetlands since the 1930s as a result of natural and manmade menaces.
Louisiana is in the grip of global, environmental change. "Temperatures and ocean waters are rising because of increased greenhouse or heat-trapping gases, like carbon monoxide, in the atmosphere," Burkett said. "Glacial mass and annual snowcover are declining more rapidly than many scientists had predicted." Ocean temperatures and acidity are increasing, and rainfall volume has grown. But spacing between rain events has expanded so droughts are more frequent in some regions of the world, she said. And in several ocean basins around the globe, hurricanes have become more intense.
"In the Gulf of Mexico, the sea level is rising faster than the global average," Burkett said. The ice melt in the European nation of Greenland threatens the low-lying Gulf Coast. The sea rises because of thermal expansion and the melting of ice sheets, and those factors contribute to Louisiana's contracting coastline.
Looking ahead, Burkett said, "In the next twenty years, we can expect fewer frost days, longer growing seasons -- good for farmers in the northern U.S. and Canada -- and increased precipitation, but greater spacing between rainfall events. The intensity and frequency of heat waves is projected to increase substantially." Louisiana residents can expect more days above 90 degrees Fahrenheit.
"The intensity of hurricanes generated off the West African coast and reaching the Gulf is likely to increase," Burkett said. "Serious wildfires that burn forests and marshes could increase in the southern and western U.S." Fires will torch root masses in addition to trees, with lasting consequences.
"Events that cause the browning or dying of Louisiana marshes could become more common," she predicted. Drought, salinity, heat and low sediment discharges from rivers have killed cordgrass in Louisiana and caused marshes to brown.
"Cypress tree, ghost forests exist where salinity has risen in south Louisiana," Burkett said. "Unless fresh water and sediment reach marshes through rainfall or from flow from the Mississippi and Atchafalaya Rivers, marshes and cypress trees will continue to die."
Burkett said that because of increased salinity, oyster spats or spawns will shift from their current locations further inland. "For instance, the spat has already moved northward up into the Barataria Basin."
She continued, saying, "Non-native plant and animal species like nutria, which destroys young, bald Cypress trees, will able to live in more northerly climates as the temperature rises." Originally from South America, nutria are large rodents that were introduced to Louisiana's fur farms more than seventy years ago.
"Non-native, exotic plants will continue to expand in the wetlands, crowding out native species," Burkett said. "Chinese Tallow, an exotic species from Asia that cannot tolerate harsh winters, has taken over coastal forests and roadsides and become one of the most common trees in Louisiana, though it has little value to wildlife or the timber industry."
So as the climate changes, what should state agencies and communities be doing? "Barrier islands and wetlands can be restored for hurricane protection," Burkett said. "River sediment can be used to build marsh, instead of letting sediment wash out to sea." Preparations can be made for more intense drought and wildfires.
"Home owners and communities can elevate houses, and cities can adapt infrastructure to the rising sea. In some areas, however, retreat may be the most effective option." Her parents, for example, moved inland when they lost their home in Biloxi, MS to Hurricane Katrina.
Cynthia Sarthou, executive director of the Gulf Restoration Network in New Orleans, also spoke at the Loyola University panel, and said, "Over 10,000 miles of oil and gas canals built in Louisiana since the 1940s have allowed salt water intrusion, killing off marshes. Soil dug for the canals and left on banks prevented sediment from moving into wetlands." Nonetheless, canals are still being built every year in south Louisiana, she said.
Sarthou said, "The oil and gas industry needs to backfill their canals and pay their share of wetlands restoration costs."
Under a public participation provision in the law, GRN looks at hundreds of wetland permit requests a year among a larger number submitted to the U.S. Army Corps of Engineers. "There are way too many wetlands permit requests for us to review" them all, Sarthou said.
The Army Corps grants permits to dredge or fill U.S. waters, including wetlands, under section 404 of the Clean Water Act. A permit is needed to construct a road or building or to alter the wetlands in other ways. And since the process requires public involvement, GRN comments on permit requests for projects that pose the greatest threat to wetlands.
Meanwhile, the Bureau of Ocean Energy Management, Regulation and Enforcement or BOEMRE last month provided over $25 million to Louisiana to build a protective land bridge to combat erosion and preserve marsh along Lake Borgne, east of New Orleans. The state will partner with Orleans Parish to construct the bridge with funds provided under the Coastal Impact Assistance Program, created by the Energy Policy Act of 2005.
Burkett said events that hastened coastal erosion in recent decades won't be the last."When I was a child, Hurricane Camille was the big benchmark event, then it was Katrina." And in the current decade, the Gulf oil spill is the gorilla.
She noted that "Louisiana Highway 1 used to be protected by vast wetlands on either side, but because it became so floodprone, the highway department is now elevating it." The Port Fourchon oil and gas industry makes Highway 1 economically valuable, she noted.
Burkett was awarded the 2011 National Wildlife Federation's Connie Award for Science on Apr. 13 for furthering environmental knowledge. Sarthou received the Peter Benchley Hero of the Seas award last July and a Tom's of Maine and River Network Heroes Award last June.