Wetlands regulate water, buffer floods, provide food and store large amounts of carbon, yet about a fifth of their area has been lost since 1970 and the loss has not stopped.
Updated October 13, 2026. Written from the sources listed below, not independently peer-reviewed.
Since 1970, roughly what share of the world's wetland area has been lost?
411 million ha
Wetland area lost since 1970
About 22% of the world's wetlands, an average decline of 0.52% a year between about 1970 and 2020. A modelled estimate across 11 natural wetland types.
Data year 2020. Source: Convention on Wetlands, 2025
3.4 million km²
Inland wetland area lost since 1700
About 21% of global inland wetland area (confidence interval 16–23%), mostly converted to cropland. A reconstruction of losses from 1700 to 2020.
Data year 2020. Source: Nature, 2023
4%
Greenhouse gas emissions from drained peatlands
Share of global human-caused emissions each year from about 50 million hectares of drained peatland, around 12% of all peatlands and about 0.4% of the world's land.
Data year 2022. Source: United Nations Environment Programme, Global Peatlands Initiative, 2022
Unit: million hectares
Both values come from the Global Wetland Outlook 2025. The 2020 value combines the latest global mapping studies for each wetland type; the 1970 value is back-calculated by applying average annual rates of change over 50 years, so it is a modelled estimate. Only the two reported values are shown; years in between are not plotted.
SDG target 6.6 aimed to protect and restore water-related ecosystems, wetlands included, by 2020, and loss has continued since. For the 2030 targets of the Kunming-Montreal Global Biodiversity Framework, the Global Wetland Outlook 2025 estimates that wetlands need restoration of at least 123 million hectares, likely an underestimate, and effective conservation of about 428 million hectares. It describes the financing gap as immense: funding for all biodiversity conservation equals only about 0.25% of global GDP.
Five countries account for over 40% of the inland wetland area lost since 1700: the United States, China, India, Russia and Indonesia. In loss hotspots across the United States, Europe, India, China, Japan and Southeast Asia, more than half of all wetlands have disappeared.
Source: Nature, 2023According to national reports, wetland deterioration has increased in five of six world regions since 2011, Asia being the exception, and in the 2024 survey it was particularly high in Latin America and the Caribbean and in Africa.
Source: Secretariat of the Convention on Wetlands, Gland, 2025Inland wetlands account for most of the area lost since 1970: an estimated 177 million hectares of inland marshes and swamps and about 123 million hectares of lakes.
Source: Secretariat of the Convention on Wetlands, Gland, 2025Global mangrove area has been increasing since a reversal towards net gains about a decade ago, but around 65% of the gains are in places where mangroves did not grow before, while old-growth mangroves are still being lost at high rates in many regions. The Philippines lost two-thirds of its mangroves in the last century.
Source: Global Mangrove Alliance, 2026Each country is shaded by its latest available value, so you can see where the gap is widest. Hover or tap a country, search for one, or open the full table.
Loading country values…
Change in mangrove area since a 2000 baseline (estimated from 1996 satellite images), from an earlier release of Global Mangrove Watch reported for SDG indicator 6.6.1; negative values mean net loss and darker shades mean larger losses. The latest year per country is 2020 for all of the roughly 115 countries and territories with mangroves in the data. Mangroves only, not other wetlands; the figures are not nationally validated, and newer maps used in the State of the World's Mangroves 2026 show a global turn towards net gains about a decade ago.
Source: UNEP (SDG 6.6.1, Global Mangrove Watch data), via Our World in Data. Latest year available per country; years differ.
Values load from Our World in Data. Simplified Natural Earth borders; they imply no position on disputed territories.
Instead of one “percent solved” score, DO GOOD rates three separate dimensions. A problem can have mature solutions that still reach too few people. These ratings are an editorial reading of the sources on this page, not a measured index.
Has the situation improved in the real world?
LowWetland area keeps shrinking: an estimated 411 million hectares, about 22% of the total, have been lost since 1970. Mangroves are a partial exception: their global extent turned towards net gains about a decade ago.
How mature and validated are the available solutions?
ModerateProtecting intact wetlands, restoring water flows, rewetting drained peat and restoring mangroves are well understood. Restoration is costly, from about $1,000 to over $70,000 per hectare a year, and conserving healthy wetlands is cheaper than restoring them.
How widely are effective solutions actually used?
LowMore than 2,500 Ramsar Sites cover over 250 million hectares, but listing does not guarantee good management, losses continue, and COP15 in 2025 removed all quantitative targets from the Convention's new strategic plan.
The direction of change is clear, but its size depends on method: a 2023 reconstruction puts inland wetland loss since 1700 at 21%, while earlier global estimates ranged from 28% to 87%. The Global Wetland Outlook's 1970 baseline is back-calculated, many wetland types are hard to map, and condition is self-reported by governments.
Wetland area has declined by about 0.52% a year on average since 1970, and national reports show deterioration increasing in five of six regions since 2011. Mangroves, where losses have slowed and the trend turned towards net gains about a decade ago, are the main exception.
Wetlands include peatlands, marshes and swamps, lakes and rivers, and coastal and marine systems such as mangroves, salt marshes, tidal flats, seagrass meadows, kelp forests and coral reefs. About 1.4 billion hectares of natural wetland remain. They help regulate the water cycle, provide food and protect communities from natural disasters such as floods; the Global Wetland Outlook 2025 puts the median value of their services at about $8 trillion a year, around 7.5% of global GDP, although valuation estimates vary widely. Peatlands cover only 3–4% of the world's land but hold nearly a third of its soil carbon, twice as much as all the world's forest biomass.
Since about 1970 an estimated 411 million hectares, roughly 22% of the world's wetlands, have been lost, most of it inland marshes, swamps and lakes. A separate reconstruction finds that about a fifth of inland wetlands have been lost since 1700, mainly to cropland. Agriculture is the largest driver of loss; urban expansion, pollution, drainage and invasive species add to it, and climate change increasingly amplifies these pressures. The decline affects the livelihoods and wellbeing of people who rely on wetlands for food, water and protection from flooding, and national reports show increasing deterioration particularly in Latin America and the Caribbean and in Africa. Drainage also turns carbon stores into sources: drained peatlands release about 4% of human-caused greenhouse gas emissions each year.
No complete global map of wetlands over time exists, so loss is estimated by combining studies, and different methods give different numbers. Wetlands fall under SDG target 6.6, which covers water-related ecosystems, and SDG target 15.1 on land and inland freshwater ecosystems. The main global estimates rest on four elements:
Natural wetland types
The Global Wetland Outlook 2025, published by the Convention on Wetlands (the Ramsar Convention), assesses 11 natural types, from peatlands, marshes, lakes and rivers to mangroves, salt marshes, tidal flats, seagrass, kelp forests and coral reefs. Some natural wetlands have been lost by being turned into artificial ones with controlled water levels, such as irrigated rice fields.
Loss since 1970: back-calculated
The Outlook takes the most recent global mapping study for each type, treated as representing 2020, and applies published average rates of change from about 1970 onwards over 50 years to estimate the 1970 area. The result is a modelled estimate, not a comparison of two complete maps.
Loss since 1700: reconstructed
A 2023 study in Nature combined national and regional drainage records, historical land-use maps and simulated wetland extent to reconstruct where and when inland wetlands were converted to seven human land uses between 1700 and 2020. It covers inland wetlands only.
Condition: reported by governments
The ecological condition of wetlands comes mostly from national reports by countries that are party to the Convention, which state whether their wetlands are in a good or poor state and whether they are improving or deteriorating. These are self-assessments rather than independent field measurements.
What works
The Convention's 172 parties have listed more than 2,500 Wetlands of International Importance (Ramsar Sites), covering over 250 million hectares. At COP15 in 2025 they also recognised other effective area-based conservation measures, so wetlands conserved outside formal protected areas can count towards conservation goals.
Limits
Listing a site does not stop dams, water abstraction or pollution upstream, and many sites lack the staff and funding to be managed well. Protection lasts only where it is enforced and supported by the people who use the site.
What works
Raising the water table stops drained peat from drying out and breaking down. The Global Wetland Outlook gives indicative emissions of about 50 tonnes of CO₂-equivalent per hectare a year for an average drained peatland, against about 10 tonnes for an intact one.
Limits
Rewetting can cause a short spike in methane, although the Outlook judges it almost always beneficial for the climate in the longer term. Farmers and foresters on drained land need another income, and keeping intact peatland wet is cheaper than restoring it.
What works
Mangrove losses have slowed over the past 40 years, and global extent turned towards net gains about a decade ago. The Global Mangrove Alliance has set a minimum goal of 30% protection and aims to restore half of recently lost mangroves.
Limits
Newly established mangroves need decades before their benefits outweigh the loss of old forests, and around 65% of gains are in places where mangroves did not grow before. Old-growth mangroves are still being cleared at high rates in many regions.
What works
Valuing services such as flood control, water supply and carbon storage can show when keeping or restoring a wetland pays off. At Wicken Fen in England, restoring former farmland to wetland gave a benefit–cost ratio of 4.4, against 1.3 for continued arable farming.
Limits
Valuation results vary widely between methods and places. Many benefits, such as reduced flooding downstream, go to people other than the landowner, so a high value on paper does not change incentives by itself.
What works
Wetlands need enough water at the right times. Planning at the scale of a river basin can reserve water for wetlands, keep floodplains connected to rivers and reduce runoff from farms, which addresses agriculture, the largest driver of wetland loss.
Limits
Food and agricultural production already account for about 70% of global water withdrawals, and many river basins are shared between countries, which makes water agreements slow to negotiate and hard to enforce.
Promising, but not proven at scale. The stage shows how far each approach has come; it is not a recommendation.
Earth observation can track changes in wetland extent more often and more consistently than field surveys; Global Mangrove Watch already maps mangroves worldwide, and at COP15 governments asked the Convention to make greater use of Earth observation in wetland inventories and monitoring. Wetlands whose water extent changes quickly, and submerged habitats such as seagrass, remain hard to map from space.
Payments linked to the carbon stored in mangroves, salt marshes and seagrass could help fund their protection. The Global Wetland Outlook estimates that conserving these ecosystems would avoid about 304 million tonnes of CO₂-equivalent a year (range 141–466 million), but how much of their carbon storage is additional and permanent is still debated.
The Regional Flyway Initiative, launched in 2021, aims to mobilise $3 billion in innovative and blended financing over ten years to protect, restore and manage priority wetlands along the East Asian–Australasian Flyway. Whether such funding reaches its targets and improves sites over the long term is not yet known.
Coordination gap
Draining a wetland brings income to its owner, while flood control, clean water and carbon storage benefit society at large. Upland cropland caused about 62% of the inland wetland area lost since 1700, and losses peaked in the 1950s, when government programmes subsidised drainage.
Implementation gap
The Global Wetland Outlook calls the financing gap for wetlands immense. Funding for all biodiversity conservation equals about 0.25% of global GDP, far below what restoring and conserving at least 550 million hectares of wetlands would require.
Coordination gap
At COP15 in Victoria Falls in July 2025, governments adopted a strategic plan for 2025–2034, but all references to quantitative targets were removed, with Brazil pointing to resistance over mobilising resources. The Convention's budget had stayed the same for 12 years before a 4.1% increase was agreed.
Technology gap
Wetlands are difficult to map by satellite because their water cover changes quickly with seasons and tides, and complete global datasets are missing for many intertidal and submerged habitats such as seagrass. Without such maps, losses cannot be tracked directly.
Knowledge gap
Earlier global estimates of wetland loss since 1700 ranged from 28% to 87%. Current estimates are more consistent, but they still rely on average rates of change applied backwards in time, and wetland condition depends largely on governments' own reports.
Implementation gap
Average restoration costs range from about $1,000 to over $70,000 per hectare a year, conserving healthy wetlands is cheaper, and only a limited number of countries are restoring wetlands at the scale needed.
Unresolved questions, not vetted breakthroughs. Answering any of them would change what is possible.
Global estimates rest on a limited set of studies and on average rates applied backwards in time, and older estimates ranged widely. How much has each region and wetland type actually lost, and how much remains?
How large and how long-lasting is the rise in methane after drained peatlands are rewetted, and how quickly do different peatlands become net carbon sinks again?
Most recent mangrove gains are in places where mangroves did not grow before. How long do these new stands take to provide the carbon storage, fish habitat and coastal protection of the old-growth forests being lost elsewhere?
Which mix of payments, regulation and wet farming on rewetted land can give landowners a fair income without draining, and how can those incentives be kept in place over decades?
Peat sold for gardening is dug from peatlands. Peat extraction is a small share of global wetland loss, but choosing peat-free compost and potting soil avoids adding to it.
Conversion to aquaculture ponds has destroyed mangroves in some regions. When you buy shrimp, look for credible information on where and how it was farmed, and keep in mind that labels vary in quality.
Many conservation groups run waterbird counts, water-quality checks or clean-ups at nearby wetlands. Taking part helps keep watch on local sites and adds to the records used to track their condition.
Decisions about building on floodplains, draining land or allocating water are often made locally. Responding to planning consultations and supporting the protection of nearby wetlands can matter more than individual shopping choices.
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Convention on Wetlands (Ramsar Convention), Scientific and Technical Review Panel, published 2025
Official overview of the Convention's flagship assessment. Source of the headline figures: about 411 million hectares, roughly 22% of the world's wetlands, lost since 1970, an average decline of 0.52% a year, and about 1.4 billion hectares remaining.
Secretariat of the Convention on Wetlands, Gland (full report, DOI 10.69556/GWO-2025-eng; copy in the University of Southampton repository), published 2025
Full report. Source of the extent and loss tables by wetland type (1,837.1 and 1,425.6 million hectares), the methods behind them, regional condition trends from national reports, drivers, the value of wetland services, restoration and conservation needs for 2030, restoration costs, peatland emissions, the Wicken Fen, blue carbon and Regional Flyway Initiative examples, and the link to SDG target 6.6.
Nature (peer-reviewed; open copy on the NASA Technical Reports Server), published 2023
Reconstruction of inland wetland loss from 1700 to 2020. Source of the 3.4 million km² (21%) loss estimate, the drivers of loss, the five countries with the largest losses, loss hotspots, the 1950s peak in drainage and the range of earlier global estimates (28–87%).
United Nations Environment Programme, Global Peatlands Initiative (press release, 17 November 2022), published 2022
Launch of the most recent global peatland assessment. Source of peatland extent (3–4% of land), carbon storage (nearly a third of soil carbon, twice all forest biomass), the area drained or degraded (about 50 million hectares, around 12%) and its emissions (about 4% of human-caused greenhouse gases).
Global Mangrove Alliance (press release by The Nature Conservancy, 30 September 2026), published 2026
Launch of the 2026 edition, based on Global Mangrove Watch v4.1. Source of the shift to net mangrove gains about a decade ago, the share of gains in new areas (about 65%), continued losses of old-growth mangroves, the Philippines example and the Alliance's protection and restoration goals.
Earth Negotiations Bulletin, International Institute for Sustainable Development, published 2025
Independent record of COP15 in Victoria Falls, Zimbabwe. Source of the number of parties and Ramsar Sites, the 2025–2034 strategic plan and the removal of its quantitative targets, the budget decision, and decisions on Earth observation and other effective area-based conservation measures.