Most U.S. coastal wetlands are slowly disappearing underwater, with a new national study revealing that 84 percent are gradually inundating. This puts many of these vital ecosystems on a path to become open water if current trends continue. The Gulf Coast faces the most severe threat, experiencing rapid submergence fueled by rising sea levels and human activities.[ecomagazine+3]
Wetlands Losing Ground to Rising Waters
Scientists tracking nearly 450 wetlands across the Atlantic, Gulf, and Pacific coasts for up to 20 years found a sobering reality. While 89 percent of these wetlands are still gaining some elevation from sediment buildup, only 16 percent are doing so fast enough to outpace rising sea levels. The rest are falling behind, sinking lower against the tide each year.[ecomagazine+3]
This submergence does not look dramatic at first. It appears as longer periods of flooding and thinning vegetation. Eventually, it leads to bare mud and open water. Glenn Guntenspergen, a coastal wetland ecologist with the U.S. Geological Survey, explained that all coastal plants have optimal ranges. If they get flooded too much, the system shuts down, plants decrease production, and eventually die.Global sea level rise averaged 1.7 millimeters per year during the 20th century. This rate accelerated to 3.8 millimeters per year from 2006 to 2018.[courthousenews+4]
Human Activity and Extreme Weather Accelerate Decline
The loss of U.S. coastal wetlands is not a new problem, but it is speeding up. A recent study covering 1985 to 2023 indicates a net loss of 1,640 square kilometers of tidal wetlands, representing 7.6 percent of the area present in 1985. The rate of loss is accelerating, driven largely by climate change and extreme weather events.[pmc]
While direct human damage, such as filling and draining marshes, now accounts for only a small fraction of total wetland loss, other human activities still play a significant role. Urban and rural development, agriculture, and silviculture lead to losses, particularly in freshwater wetlands.Development and infrastructure alter hydrology, increasing runoff and water withdrawals. This indirectly impacts nearby wetlands.[epa+3]
More recently, extreme weather events like hurricanes, droughts, and hard freezes are increasingly contributing to the acceleration of wetland decline.These acute shocks are now dominating the acceleration of loss at 1.4 times the rate of chronic stressors like sea level rise.[facebook+2]
Gulf Coast Bears the Brunt
Wetlands along the Gulf Coast are generally faring the worst.Louisiana, which holds one-third of the coastal wetlands in the contiguous U.S., is particularly vulnerable.Experts predict that approximately 800,000 acres of Louisiana wetlands could disappear in the lifetime of a child born today. This would push the coastline inland by as much as 33 miles in some areas.[ecomagazine+5]
The Mississippi River Delta Plain specifically shows the heaviest deficit in wetland area.Here, human pressures like shipping canals have altered waterways, reducing the flow of river sediments that naturally sustain wetlands. Oil and gas extraction also contributes to land subsidence.Reduced flooding from stream control prevents the deposition of sediments vital for land-surface growth. It also allows saltwater to intrude, killing fresh and brackish water marshes.Governor John Bel Edwards declared a state of emergency for the Louisiana coast in 2017 due to coastal land loss.[facebook+5]
Critical Ecosystems at Risk
Coastal wetlands offer tremendous benefits, providing essential ecosystem services to both people and the environment. They serve as critical habitats, offering breeding grounds, nurseries, shelter, and food for fish, birds, and other wildlife. Many endangered species and migratory birds depend on these ecosystems.[fisheries+3]
These wetlands also play a crucial role in protecting human communities. They absorb storm surges and reduce flood heights, shielding homes, infrastructure, and agriculture from devastating damages. This protection saves vulnerable coastal communities an estimated $23 billion each year. During Hurricane Sandy, for example, wetlands protected parts of the East Coast from over $625 million in direct flood damages.[fisheries+4]
The continued loss of these natural buffers means less protection for coastal communities from strong storms. For New Orleans, physical damage from coastal erosion could reach $1.3 billion in 25 years and $1.7 billion in 50 years. More than 9,000 jobs and $568 million in wages could also be lost within 50 years in the region.[ready]
Wetlands also help maintain clean water by filtering harmful pollutants, nutrients, and sediments before they reach the ocean.Their degradation and loss reduce the size and diversity of fish populations, impacting commercial and recreational fisheries.[fisheries+2]
A Call for Action
The future of U.S. coastal wetlands largely depends on human choices. If carbon pollution remains unchecked and development continues to block areas where wetlands could migrate inland, 75 percent of U.S. coastal wetlands could be lost by 2100.A probable 1-meter rise in sea level by 2100 could lead to the loss of approximately 6,441 square miles, or 65 percent, of coastal marshes and swamps.[climatecentral+1]
However, there is still a chance to mitigate these losses. Conserving undeveloped land adjacent to wetlands is a decisive factor, allowing these ecosystems to migrate inland as sea levels rise.Balancing sediment levels, removing manmade structures like dikes, and protecting inland areas from development are also critical interventions.[ecomagazine+4]
Organizations like the NOAA Restoration Center and the U.S. Fish & Wildlife Service provide funding and technical assistance for wetland restoration projects across the country.Programs such as the Agricultural Conservation Easement Program – Wetland Reserve Easements (ACEP-WRE) also support landowners in protecting, restoring, and enhancing wetlands. These focused protection strategies are required to reverse the alarming trend of wetland disappearance.[fisheries+3]
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