The most comprehensive mapping to date of the world's wetlands

Wetlands cover less than 10% of the Earth's land surface. Despite this relatively small area, they are crucial habitats for a large portion of the world's plant and animal species, with the United Nations estimating that 40% of all species live or breed in wetlands. Yet, while we have a sense of the general presence of wetlands, it has been a struggle to have a global map that identifies exactly which type of wetland is where and what the boundaries of those wetlands are.

Now a new study aims to deliver the most accurate mapping of global wetland types to date. The revised Global Lakes and Wetlands Database provides information on the locations and extent of 33 separate wetland types. Led by McGill University with support from WWF and other scientific partners, the study helps us better understand where these wetlands occur across the globe and the water storage potential of the world’s inland water systems.

Why we need wetlands

In the not-too-distant past, wetlands were regarded as wastelands. Many people felt that they were places to be avoided, and it was common practice to drain them, fill them, or treat them as dumping grounds. But across the world, wetlands are crucial for water protection due to their ability to filter water, store water during floods, and regulate water flow. They act as natural filters, removing pollutants and sediments from water, improving its quality and making it safer for both humans and wildlife. Additionally, wetlands help regulate water flow, preventing both droughts and floods by slowly releasing stored water and absorbing excess rainfall.

Wetlands are also a critical component of nature’s solution to climate change. They capture and store more atmospheric carbon than any other ecosystem on Earth. Peatlands, though covering only 3% of the planet’s surface, store about 30% of land-based carbon. Coastal blue carbon ecosystems like mangroves, seagrass beds, and salt marshes account for approximately half of the total carbon sequestered in ocean sediments.

How to use this research

For years, governments and policymakers have been struggling to develop plans that address the protection of water-related ecosystems. Major international policy frameworks, such as the the Ramsar Convention on Wetlands rely on classification systems and ecosystem mapping to propose actions toward sustainable development and restoration activities. The previous wetland mapping effort was completed in 2004, so by taking the 12 categories of wetlands in the 2004 expanding and refining those ecosystems to 33 categories in the new study, government planners and policymakers have more data to inform more intelligent and advanced conservation efforts, as well as deploy freshwater monitoring resources in a more effective manner.

How it fits WWF’s freshwater strategy

WWF seeks to change how water is managed around the world. We encourage states and nations relying on the same river to better coordinate their shared freshwater resources, and we advocate for water security in sustainable development. We also help strengthen the effectiveness of river basin management, working with organizations so they are empowered to protect the natural capital of river basins and ensure climate-smart governance. By partnering with multilateral institutions, we can bring our holistic management and policy solutions to scale. As a supporter of the Freshwater Challenge, we work with governments and others to place water higher on global and regional agendas to ensure that freshwater ecosystem integrity is integral to restoration and protection plans and implementation.

Michele Thieme is WWF's Vice President and Deputy Lead for Freshwater