What are wetlands — and why they matter for life on Earth

Wetlands rarely make headlines in the way forests or coral reefs do, but they quietly keep ecosystems (and societies) functioning. They filter water, buffer floods, feed biodiversity, and lock away vast amounts of carbon. When wetlands disappear, the losses show up everywhere: in water quality, in flood damage, in wildlife decline — and, increasingly, in the climate balance.

The trend: Wetlands move from “local nature” to global security

Growing attention to wetland loss sits inside a broader shift in environmental thinking: biodiversity is no longer viewed as “nice to have”, but as infrastructure for a stable economy and safe communities. A major Nature study reconstructed wetland conversion over the last three centuries and found that humans have drained and converted wetlands on a huge scale — but also clarified how much has been lost, and where the hotspots are. 

One striking takeaway is that losses have been especially concentrated in highly developed, heavily farmed regions — including Europe — largely due to drainage for agriculture and settlement expansion. 

What counts as a wetland?

“Wetlands” is a broad category. Under the Ramsar Convention definition, wetlands include far more than bogs and marshes: lakes and rivers, peatlands, wet grasslands, estuaries and deltas, mangroves, tidal flats — and even some human-made systems such as rice paddies and reservoirs. 

In practical terms, a landscape becomes a wetland when water — permanently or seasonally — is the key factor shaping soils, plants, and animal life.

Why wetlands are so important

Wetlands punch above their weight because they deliver several services at once.

They improve water quality by trapping sediments and breaking down or retaining pollutants. They reduce flood peaks by holding water back, slowly releasing it downstream. They provide critical habitat for birds, fish, amphibians, insects, and many plant communities — and they sustain human livelihoods through fisheries, agriculture, materials, and tourism.

And then there’s the climate role. Peatlands, a type of wetland, are especially significant: they store immense quantities of carbon, commonly described as around twice as much as all the world’s forests. 

On the biodiversity and human-dependence side, widely cited conservation summaries note that wetlands support a very large share of species and that over one billion people depend on wetlands for their livelihoods in direct or indirect ways. 

How much wetland has been lost?

For years, estimates often suggested that up to half of global wetlands might have disappeared. The 2023 Nature reconstruction revised and tightened that picture: it estimated about 3.4 million km² of inland wetlands lost since 1700, a net loss of around 21% globally (with an uncertainty range). 

That is still an area roughly comparable to the size of a major country — and the regional pattern matters. The study highlights that wetland loss has been concentrated in Europe, the United States, and China, reflecting centuries of drainage and land conversion. 

Why this is especially relevant in Germany and the EU

Europe’s relationship with wetlands is shaped by history: many lowland marshes and peatlands were drained to create farmland and protect growing cities. Germany is a clear example of how this legacy now intersects with climate policy.

When peat soils are drained, the stored carbon oxidises and escapes as greenhouse gases. German authorities report that peatlands are responsible for around 7% of Germany’s national greenhouse gas emissions (based on recent inventories). This makes wetland protection and rewetting not only a biodiversity issue, but one of the more direct land-based levers for emissions reduction.

At the EU level, wetlands have moved from “conservation topic” to “policy obligation.” The EU Nature Restoration Law sets a bloc-wide goal to restore at least 20% of land and sea by 2030 and to restore ecosystems in need by 2050. In addition, briefings on the final regulation emphasise specific requirements for drained agricultural peatlands, with restoration targets that rise over time and include a rewetting component. 

The good news: Restoration is real — and it works

Wetland recovery is not theoretical. It is happening, and some of the most convincing projects are the ones that connect ecology to everyday risk reduction.

In the United States, the Everglades restoration effort is often cited as a landmark case: the Comprehensive Everglades Restoration Plan has been described by the US National Park Service as a 35+ year programme with costs of more than $10.5 billion, focused on restoring hydrology while balancing water supply and flood protection. 

In Europe, restoration is increasingly framed as “nature-based infrastructure.” One eye-catching example is the return of beavers in parts of the UK: research shows beaver dams can reduce (attenuate) average flood flows by up to around 60% in monitored catchments, supporting the idea that rebuilding wetland processes can deliver measurable flood protection benefits. 

Germany’s wetland future will likely be built from similar logic: rewetting peatlands for climate, improving water retention to handle drought and heavy rainfall, and enabling land uses that work with wet soils (including paludiculture in some regions).

Bottom line

Wetlands are not “empty land waiting for development.” They are living systems that stabilise water, climate, and biodiversity — and in a warming Europe, those functions are becoming more valuable, not less.

Protecting remaining wetlands is the fastest win. Restoring degraded ones is the strategic investment: it reduces flood risk, strengthens biodiversity, and can cut emissions — especially where drained peatlands are a major source of CO₂.

illuminem Voices is a democratic space presenting the thoughts of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.

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