MAY 28, 2020 10:38 AM PDT

Are marshes on the Mississippi Delta at a point of no-return?

A study published recently in the journal Science Advances warns that marshes in the Mississippi Delta are likely to be submerged by sea-level rise within the current context of climate change. The study uses sediment data from the last thirty years to monitor sea-level rise over the past 8,500 years, documenting the longest-known marsh record in the Delta.

"Previous investigations have suggested that marshes can keep up with rates of sea-level rise as high as half an inch per year (10 mm/yr), but those studies were based on observations over very short time windows, typically a few decades or less," said lead author Torbjörn Törnqvist, who is the Vokes Geology Professor in the Tulane Department of Earth and Environmental Sciences.

"We have taken a much longer view by examining marsh response more than 7,000 years ago when global rates of sea-level rise were very rapid but within the range of what is expected later this century."

This long-view showed the researchers that, contrary to previous estimates, once the rate of sea-level rise exceeds about one-tenth of an inch per year (3 mm/yr), marshes in the Mississippi delta “drown” in a few hundred years. But when that rate increases to a quarter of an inch per year (7.5 mm/yr), marshes drown in about fifty years. Törnqvist refers to this phenomenon as a tipping point for coastal marshes. 

"The scary thing is that the present-day rate of global sea-level rise, due to climate change, has already exceeded the initial tipping point for marsh drowning," Törnqvist said. "And as things stand right now, the rate of sea-level rise will continue to accelerate and put us on track for marshes to disappear even faster in the future."

Photo: Pixabay

The findings from the study estimate that the remaining 15,000 square kilometers of marshland in coastal Louisiana will “inevitably drown,” although pinpointing when exactly is challenging because of varying topography in the delta. Over the past century, 5,000 square kilometers of wetlands in coastal Louisiana have already been lost. 

Despite this grim news, Törnqvist says curbing greenhouse gases and implementing major river diversions could be meaningful actions in order to prevent the worst possible outcomes. Though to be effective, both require fast action.

Sources: Science Advances, Science Daily

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
AUG 03, 2021
Plants & Animals
Teeth Record Life's Stressful Events in Primates
AUG 03, 2021
Teeth Record Life's Stressful Events in Primates
New research suggests stressful physical and social events leave permenant lines on your teeth.
AUG 05, 2021
Space & Astronomy
Einstein Was Right, Again: X-rays Observed Behind a Black Hole for the First Time
AUG 05, 2021
Einstein Was Right, Again: X-rays Observed Behind a Black Hole for the First Time
  In an astrophysics first, a team of researchers have directly observed light coming from the backside o ...
SEP 07, 2021
Earth & The Environment
The Future of Flooding
SEP 07, 2021
The Future of Flooding
In the wake of recent flooding on the east coast as a result of Hurricane Ida, many people are wondering what the future ...
SEP 29, 2021
Cardiology
New Evidence on the Association between Nitrogen Dioxide Emissions and Cardiovascular Disease
SEP 29, 2021
New Evidence on the Association between Nitrogen Dioxide Emissions and Cardiovascular Disease
Human activities such as burning fossil fuels have been the primary driver of climate change over the past two centuries ...
OCT 06, 2021
Chemistry & Physics
Chemistry and Magic: Identifying the Oldest Records of Merlin the Magician
OCT 06, 2021
Chemistry and Magic: Identifying the Oldest Records of Merlin the Magician
Historians may have found the earliest manuscripts that tell the story of Merlin the Magician. Merlin is a character fro ...
OCT 18, 2021
Plants & Animals
How Have the Fukushima & Deepwater Horizon Disasters Impacted Wildlife?
OCT 18, 2021
How Have the Fukushima & Deepwater Horizon Disasters Impacted Wildlife?
Two new, unrelated studies have examined how very different environmental disasters affected wildlife in the areas where ...
Loading Comments...