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Louisiana Wetlands Suffer Sea-Level Rise 4 Times the Global Average
The study by researchers in Tulane’s Department of Earth and Environmental Sciences and published in the open-access journal Nature Communications shows that the rate of sea-level rise in the region over the past six to 10 years amounts to half an inch per year on average.
“In the Mississippi Delta, about 65 percent of study sites are probably still keeping pace, but in the westernmost part of coastal Louisiana, more than 60 percent of sites are on track to drown,” said Tulane geology professor Torbjörn E. Törnqvist, a co-author of the study.
A swamp-to-marsh transition near Houma, Louisiana shows dead trees that are most likely the result of saltwater intrusion.
Törnqvist conducted the research with lead author and PhD candidate Krista L. Jankowski and co-author Anjali M. Fernandes, a former postdoc in Törnqvist’s group who is now at the University of Connecticut.
The researchers used an unconventional method to measure sea-level change that integrated information from different data sources. They analyzed measurements of shallow subsidence rates at 274 sites across the coast and combined these with published GPS-measurements of deeper subsidence rates. Adding published satellite observations of the rise of the sea surface in the Gulf of Mexico, they were able to calculate how rapidly sea level is rising with respect to the coastal wetland surface.
“The bottom line is that in order to assess how dire the situation is in Louisiana, this new dataset is a huge step forward compared to anything we’ve done before,” Törnqvist said.
Justin Lawrence of the National Science Foundation, which provided funding for the study, agreed.
“These researchers have developed a new method of evaluating whether coastal marshes in Louisiana will be submerged by rising sea levels,” Lawrence said. “The findings suggest that a large portion of coastal marshes in Louisiana are vulnerable to present-day sea-level rise. This work may provide an early indication of what is to occur in coastal regions around the world later this century.”
A link to the research article can be found here.
Contacts and sources:
Barri Bronston
Tulane University
Source: http://www.ineffableisland.com/2017/03/louisiana-wetlands-suffer-sea-level.html
Sea levels do rise and fall. This is not the first time the wet lands have experienced this and it won’t be the last. We will probably lose a good portion of the wetlands to the salt incursions but over a period of many years this too shall pass. Problem is, is this a 100 year cycle we are looking at or 500 or 1000 or 10,000 or 25,000. This we are not so sure of.
“Not all the wetlands are receding; in fact some wetlands are stable, and others are growing.”
“USGS and other studies indicate that major shifts in the course of the Mississippi River have contributed significantly to the demise of the wetlands.”
“Moreover, forced drainage of the wetlands to accommodate development and agriculture also contribute to wetlands deterioration and loss.”
Source: https://pubs.usgs.gov/fs/la-wetlands/
Let’s also not forget the damage that hurricanes inflict on barrier islands and wetlands.