Save the wetlands – nursery and “kidneys and the world”

The importance of swamps, wetlands and mangroves to nature is increasingly recognized. Yet even though they capture far more carbon than forests, wetlands are disappearing three times faster. Although covering only a fraction of the planet's surface, wetlands are so important that they deserve flattering nicknames: kidneys of the world, sponges of the nature, superheroes of biodiversity. For certain scientists, they are so important for human well-being and life on Earth that they should have legal rights.

Terrestrial ecosystems that are waterlogged, whether permanently or seasonally, are present on all continents, except Antarctica. They come in a variety of forms: from moss- and peat-rich ponds to reed-dotted marshes and tree-dominated swamps. Some are located in freshwater floodplains and inland areas below sea level. Others are coastal, such as tropical mangroves, whose trees are capable of living in salt water.

Wetlands are biological supermarkets, as the combination of shallow water with high levels of nutrients and biomass turns them into a veritable feast for a huge variety of plant and animal species. They are among the most productive ecosystems: despite occupying just 6% of the Earth's surface, they are home to an astonishing 40% of global biodiversity.

In 1971, at a convention in the city of Ramsar, on the coast of Iran, a group of environmentalists defined February 2nd as World Wetlands Day.

Powerful CO2 stores – or emitters

For a long time, wetlands were ignored, considered non-productive areas that should be drained to transform into fuel and arable land, or filled with sediment to create solid ground for the construction of buildings and roads.

Now they are recognized not only as hotspots of biodiversity, but as essential carbon sinks, absorbing, each year, millions of tons of greenhouse gases. They contain a third of all CO2 captured in living vegetation, in addition to that stored in its soil, sediments and peat over millennia. Alone, peatlands retain twice as much carbon dioxide as all the world's forests.

Wetlands can also be considered the kidneys of the world: their plants, fungi and algae help filter and purify water from chemicals, heavy metals and other pollutants. They are also a natural defense against flooding, acting as sponges that absorb heavy rain, and protecting coastlines against erosion during storms.

Consequently, when they are damaged they transform into a powerful carbon source, releasing CO2, methane and nitrous oxide – all gases that cause the greenhouse effect that raises global temperatures. Drained and burned peatlands make up 4% of annual human-caused emissions.

A future for wetlands

Wetlands are the most threatened ecosystem on the planet: they are disappearing three times faster than forests. In the last 50 years, a third of them have been lost, mainly due to drainage for agricultural use and construction. More than half of the wetlands in China, the United States, India and Japan have been destroyed since 1700.

In the meantime, however, it was recognized that restoring and conserving these ecosystems is an important natural solution to limit the increase in global temperature to 1.5ºC in relation to the pre-industrial era, as stipulated in the 2015 Paris Climate Agreement.

Nearly 70% of signatory countries now include some type of wetland in their climate commitments. In 2022, a pioneering global pact to protect nature included measures to recover at least 30% of land-based aquatic bodies and freshwater ecosystems.

Several countries are working to rescue wetlands from extinction. Argentina has an ambitious conservation project to restore thousands of kilometers of Iberá wetlands. In Indonesia, measures to rehydrate peatlands have helped prevent the spread of forest fires.