Wetlands occupy only a small share of Earth’s land surface, yet they support an outsized share of biodiversity, store substantial carbon, and help protect communities from floods. The statistics below show the scale of the world’s remaining wetlands, the pace of loss, and the measurable changes documented in the United States.
Contents
- Global wetland extent and loss
- Ecological value and ecosystem services
- Biodiversity and human well-being
- Climate, peatlands, and restoration
- Wetlands in the United States
- U.S. wetland change from 2009 to 2019
- Wetland records and monitoring
Global wetland extent and loss
The Global Wetland Outlook 2025 reports that about 1.4 billion hectares of wetlands remain worldwide. A more precise figure in the outlook briefing paper is 1.425 billion hectares. These figures describe the remaining global wetland estate, rather than a forecast of future area.
Wetlands cover just 6% of Earth’s land surface, according to the Global Wetland Outlook 2025. Despite that limited physical footprint, 411 million hectares of wetlands have been lost worldwide since 1970. The outlook equates that loss to approximately 22% of the global wetland total. The percentage is a comparison with the reported remaining total, while the underlying loss figure covers the period since 1970.
The decline is continuing at an annual rate of 0.52%. Around 25% of the wetlands that remain are in poor ecological condition. Together, these figures describe two related pressures: the reduction of wetland area and the degradation of a portion of the area that is still present.
Earlier global assessments use different dates and baselines. A Ramsar 2018 news release reported that the world’s wetlands covered more than 12.1 million square kilometers in 2018. The same release said that about 35% of the world’s wetlands disappeared between 1970 and 2015. Ramsar’s climate change statement reported that about 64% of the world’s wetlands had been lost in the last century, while a Ramsar/IPBES note reported that more than 85% of the wetlands present in 1700 had been lost by 2000. These measurements should be read as findings from distinct assessments, periods, and methods rather than as interchangeable totals.
The outlook’s figures can be placed beside the Ramsar historical measures without treating them as a single time series:
| Measure | Reported statistic | Period or reference |
|---|---|---|
| Remaining global wetlands | 1.4 billion hectares | Global Wetland Outlook 2025 |
| More precise remaining estimate | 1.425 billion hectares | Global Wetland Outlook 2025 briefing paper |
| Wetland loss since 1970 | 411 million hectares | Global Wetland Outlook 2025 |
| Wetland area reported globally | More than 12.1 million km² | 2018 Ramsar release |
| Wetlands lost | About 35% | 1970–2015, Ramsar 2018 release |
| Wetlands lost | About 64% | Last century, Ramsar climate statement |
Ecological value and ecosystem services
Wetlands provide services tied to flood protection, clean water, food, carbon storage, and recreation. The Global Wetland Outlook 2025 says these services are critical to billions of people. The outlook’s 1.425-billion-hectare remaining estate generates ecosystem services worth a median USD 7.98 trillion, according to its briefing paper. The same briefing paper reports an upper value of up to $39 trillion annually.
The two values describe different points in the reported valuation range: one is a median estimate and the other is an upper estimate. They are not separate annual totals to add together. The outlook also says that the world is losing value equivalent to billions through wetland degradation and loss, with societal costs escalating.
The remaining wetlands are described by the outlook as crucial for water and food security, climate stability, biodiversity, and community resilience. Ramsar describes wetlands as among the world’s most productive environments and says they support countless species. Their importance therefore extends beyond mapped area: a relatively small land coverage can deliver services across watersheds, coastlines, settlements, and agricultural landscapes.
The Convention on Wetlands has 172 Parties, according to Ramsar’s overview of wetland importance. That figure describes the number of Parties to the international convention and provides a measure of the treaty’s global institutional reach.
Biodiversity and human well-being
Wetlands support 40% of known plant and animal species, according to the Global Wetland Outlook 2025. Ramsar’s biodiversity infographic gives more specific figures for freshwater wetlands: they host almost all amphibians, half of all fishes, and more than one third of vertebrates.
These figures use different descriptions of wetland biodiversity. The 40% statistic refers to known plant and animal species associated with wetlands broadly, while the freshwater figures identify groups supported by freshwater wetlands. They should not be combined into a single count of species.
Wetlands also play a direct role in food and water security. Fish are the main source of protein for 1 billion people and depend on coastal wetlands for part of their life cycle, according to a Ramsar recovery event source. A Ramsar/IPBES note reports that about 40% of the global population lacks access to clean and safe drinking water. The sources present these as connected areas of concern, but the water-access statistic is not limited to people living near wetlands.
Wetlands lock away more than a third of the world’s soil carbon, according to the Global Wetland Outlook 2025. A Ramsar briefing note reports that wetlands store about 30% of global soil carbon. Because the two sources use different wording and precision, both figures are best retained with their original source labels rather than averaged or treated as exact duplicates.
Climate, peatlands, and restoration
Peatlands are a major part of the climate statistics associated with wetlands. Ramsar reports that drained peatlands are responsible for 5% of global greenhouse gas emissions. A separate Ramsar climate change message says drained or burned peatlands account for 10% of annual fossil-fuel carbon dioxide emissions. These are different comparisons: one concerns global greenhouse gas emissions, while the other compares emissions with annual fossil-fuel CO2 emissions.
The Global Wetland Outlook 2025 resources warn that one fifth of the world’s remaining wetlands could vanish by 2050 without urgent action. This is a stated outlook or risk scenario, not a measurement of area already lost. The outlook’s key messages also say that at least 123 million hectares of wetland restoration are required to meet current global targets.
The same key messages place the value of wetlands lost in the last 50 years above $5.1 trillion. That is a reported valuation of lost wetland value, not an estimate of the current annual value of all remaining wetlands. Keeping the time period and valuation basis visible is important when comparing it with the $7.98 trillion median and up-to-$39 trillion annual service estimates for the remaining estate.
The historical comparisons also show why dates matter. Ramsar reported that wetlands disappeared three times faster than forests, in percentage terms, between 1970 and 2015. This is a relative rate comparison for that period, not a claim that wetlands disappeared three times faster in every subsequent period.
Wetlands in the United States
In the 48 contiguous states, wetlands covered 5.5% of the land, according to the U.S. Environmental Protection Agency. The EPA estimates that 95% of wetlands in those states are freshwater. The U.S. Fish and Wildlife Service’s 2009–2019 Status and Trends report similarly found that 95% of wetlands in the conterminous United States were freshwater in 2019.
The 2019 FWS estimate counted 116.4 million acres of wetlands in the conterminous United States. That area represented less than 6% of the nation’s land area in the study geography. The study found that 92% of freshwater wetlands were vegetated, compared with 80% of saltwater wetlands.
The geography is specific: the FWS estimate concerns the conterminous United States, while the EPA statistic refers to the 48 contiguous states. Neither figure includes Alaska or Hawaii in the stated area.
Older U.S. figures document a much longer history of change. The FWS national wetlands history source reports that about 9 million acres of wetlands were lost in the United States between 1954 and 1974. That historical figure covers a different period and national framing from the later conterminous-U.S. status-and-trends estimate.
U.S. wetland change from 2009 to 2019
From 2009 to 2019, the conterminous United States lost 221,000 acres of wetlands, according to the FWS 2009–2019 Status and Trends report. The report says this loss increased by more than 50% compared with the previous study period.
The overall result hides differences among wetland types. Vegetated wetlands lost 670,000 acres during the decade. Salt marshes experienced the largest net percentage reduction: 2%, or 70,000 acres. Non-vegetated wetlands, by contrast, recorded a net gain of 488 acres. Pond area increased by more than 7%.
| U.S. measure | Reported change | Period |
|---|---|---|
| All wetlands in the conterminous U.S. | Loss of 221,000 acres | 2009–2019 |
| Vegetated wetlands | Loss of 670,000 acres | 2009–2019 |
| Salt marshes | 2% net reduction, or 70,000 acres | 2009–2019 |
| Non-vegetated wetlands | Net gain of 488 acres | 2009–2019 |
| Pond area | Increase of more than 7% | 2009–2019 |
Coastal watershed statistics show additional regional pressure. Coastal watersheds lost more than 80,000 acres of wetlands per year on average from 2004 to 2009, compared with about 60,000 acres per year in the prior coastal study period. In the eastern United States, coastal watersheds lost 59,000 acres per year from 1998 to 2004, or an estimated 361,000 acres across that seven-year period.
The nationwide picture for 1998–2004 differed from the coastal figures: wetlands posted a net gain of about 32,000 acres per year, according to the FWS 1998–2004 report and FWS testimony. A nationwide net gain and coastal losses can coexist because they describe different geographies and include different wetland categories and changes elsewhere.
Wetland records and monitoring
The National Wetlands Inventory data layer contains more than 37 million wetland and deepwater features, according to FWS Wetlands Data. The layer is updated twice a year. As updates are incorporated, the NWI data layer grows by about 50 to 100 million acres annually.
More than 1,000 stakeholders use NWI data every day across the United States. FWS reports that the data were developed through partnerships with more than 165 organizations. These figures describe the reach and maintenance of a national information resource; they are not additional acres of wetlands and should not be added to the 116.4 million-acre 2019 estimate.
Taken together, the records show why wetland statistics need a clear date, geography, category, and source label. Global outlook figures describe a planetary estate and its services; FWS status-and-trends figures measure changes within the conterminous United States; and NWI figures describe mapped features and data maintenance. Keeping those distinctions visible makes the numbers useful for local history, heritage, conservation, and community planning.