WASHINGTON, D.C. — A groundbreaking study published in Nature Water has quantified a staggering economic consequence of environmental degradation across the United States. The research reveals that the destruction of wetlands between 1985 and 2023 directly drove up residential flood insurance claim payments by more than $10 billion, accounting for a notable 9% of all riverine flood loss payments nationwide.
The report, spearheaded by researchers from the Environmental Defense Fund and the University of North Carolina, underscores the critical function wetlands serve as “natural infrastructure.” Operating like sponges, these ecosystems absorb heavy rainfall and slow stormwater runoff before it can inundate downstream communities. However, decades of development and agricultural expansion have stripped away at least 40% of the country’s historic wetland acreage since 1700, leaving communities vastly exposed to intensifying climate threats.
By pairing individual National Flood Insurance Program (NFIP) property claims with spatial tracking of upstream subwatersheds, the authors isolated the financial damage left in the wake of wetland clearing. According to the study, the economic burdens are heavily concentrated in regions with high downstream flood exposure. The metropolitan area of Houston, southeastern Louisiana, and coastal Florida emerged as the nation’s most costly hotspots.
On average, a single hectare (about 2.5 acres) of wetland provides roughly $15,738 in avoided residential flood damage. In the top 10% of high-value subwatersheds, that protective value climbs to $24,783 per hectare. In the most critical 1% of subwatersheds located along the Gulf Coast, Appalachia, New England, and parts of the Pacific Northwest a single hectare of wetland prevents an astonishing $301,268 in property damages.
“That number is actually a large underestimate of how much wetland loss has increased flood damages in total,” warned Jesse Gourevitch, a lead author and former economist with the Environmental Defense Fund.
Because the NFIP underwrites only about 30% of average annual domestic flood losses, the researchers project that the true economic toll of historical wetland loss including uninsured properties and commercial assets likely exceeds $33 billion.
Policy Shifts Threaten Vulnerable Communities
The study arrives at a tense moment for environmental policy. Following the Supreme Court’s 2023 ruling in Sackett v. EPA which stripped federal clean water protections from non-tidal wetlands lacking a continuous surface connection to larger bodies of water, further regulatory pullbacks have been proposed. Environmental agencies estimate that ongoing federal rules could exclude up to 80% of wetlands in the contiguous United States from federal protections.
The researchers calculate that the specific wetland areas currently losing protection would otherwise provide $177 billion in cumulative flood mitigation benefits to residential properties.
Furthermore, the data shows that this environmental and financial fallout is not distributed equally. Historical wetland degradation has disproportionately funneled heightened flood risks into lower income neighborhoods and communities of color areas historically relegated to low-lying, flood prone zones due to systemic discriminatory zoning policies.
To assist local leaders, planners, and residents in identifying the immediate financial trade offs of land development, the research team has released an accompanying interactive mapping tool. The platform visualizes localized subwatersheds where the financial benefits of keeping upstream wetlands intact drastically outweigh the local costs of land conservation.