Wetlands: Our hidden climate superpower

What is a wetland?

A wetland is an environment where the ground is covered by water for most of the year. What’s so special about that you might ask? Look a little deeper and you’ll discover the remarkable power hidden in these underappreciated ecosystems.

From bogs to swamps, wetlands are places shrouded in myth. Throughout human history, they were seen as dangerous places to be avoided and were said to be home to mystical creatures. But we overlooked their true magic...

Over the centuries people began to view wetlands as an unproductive waste of space to drain to make way for agriculture and urban development. We’ve lost as much as 87% of the world’s wetlands since 1700 – an alarming rate of loss even higher than that of global deforestation.

Why should we care?

Well, wetlands:

• lock away more carbon dioxide from our atmosphere than forests
• protect us from floods, wildfires, droughts and storms
• act as natural filters by removing pollutants from our water
• provide a unique habitat for a range of plants and animals

But wetlands can only provide all these benefits if they’re intact. If we don’t look after them, we risk increased levels of carbon dioxide in our atmosphere, accelerated climate change and biodiversity loss.

So, how exactly do wetlands provide these benefits and how can we help protect them?

Peatlands: The carbon conquerors

Peatlands, such as bogs and fens, are a type of wetland that forms peat. A type of carbon-rich soil, peat is made from layers upon layers of dead plant material.

Katy Ross, a bog researcher working on her PhD at the University of Leicester with the UK Centre for Ecology & Hydrology and the Natural History Museum, explains how their carbon-trapping superpower works. It’s all to do with how the water in a bog keeps out the air.

“When bogs are wet there isn’t enough oxygen available for most bacteria to break down the peat,” explains Katy. “This means dead plant matter accumulates more quickly than it decomposes.”

“Plants like Sphagnum mosses take in carbon dioxide from the air as they grow. When they die, rather than releasing their carbon back into the atmosphere, the vegetation just builds up into a carbon-rich layer.”

As more layers are formed, they become compressed, forming peat. With enough time and the right conditions, this peat will eventually turn into coal.

Peatlands cover just 3% of Earth’s land surface but store an estimated 600 billion tonnes of carbon worldwide – much more than any other land ecosystem. However, the drainage and destruction of these carbon sinks means they’re at risk of becoming carbon sources.

Draining peatlands of their water introduces oxygen to the peat, accelerating the decomposition process. This releases all that stored carbon back into the air. These emissions contribute to 4% of all human-driven greenhouse gas emissions annually.

“Even if we stop any further drainage of peatlands, we still need to work to restore the ones we’ve damaged, as otherwise they will continue to emit carbon dioxide,” Katy explains. “To restore these systems, we need to bring water back into them.”

The Flow Country in the north of Scotland is one of the largest areas of blanket bog in Europe. “It’s an area that’s suffered from a lot of drainage for timber production,” says Katy. “Hopefully, by restoring these peatlands we can bring back an effective carbon store.”

Teams working to restore nature are removing trees planted for timber and damming drainage ditches to increase the water level. This is allowing peat-building moss to regrow and start capturing carbon.

Elsewhere in the UK, wetland restoration projects are teaming up with beavers – nature’s engineers. They build dams to slow the progress of rivers and streams, creating flooded areas that make up a complex wetland ecosystem that’s fantastic for biodiversity.

Bogs: The biodiversity builders

You might imagine peatbogs to be barren landscapes, but Natural History Museum scientist Dr Sandy Knapp explains that these places are in fact teeming with life.

“All kinds of interesting plants and critters have adapted to live in these low-nutrient, acidic environments,” she remarks.

“For example, carnivorous plants, like sundew, are often found in peatland environments. In acid environments, nitrogen is quite low and carnivorous plants can capture and digest insects to get that nitrogen,” Sandy adds.

Mangroves: The coastal crusaders

Mangroves are another climate-change-fighting wetland. These tropical, coastal forests grow in seawater. The trees have large, sprawling stilt roots that help them to resist the impact of waves and trap sediment between tides.

Mangroves are also brilliant at capturing and storing carbon. Dead roots and branches are quickly submerged by the sediment, locking carbon away rather than releasing it back into the atmosphere.

“Mangroves are amazing ecosystems that work as a buffer between the sea and the land,” explains Sandy. The roots form a permeable barrier that disperses the energy of waves, helping protect coastal communities from tropical storms and tsunamis.

The tangled network of roots also stabilises sediment, preventing coastal erosion. What’s more, Sandy says that “they act as fish nurseries and hatcheries for crabs, lobsters and all kinds of marine invertebrates”.

Sea-forestation

Mangrove restoration projects are taking place all over the world. The Global Mangrove Alliance has the ambitious goal of completely stopping all human-driven mangrove loss by 2030, whilst also reversing at least half of recent loss through supporting local restoration projects.

Mark Spalding, a senior marine scientist at the Nature Conservancy, believes that for these restoration projects to be successful, they must involve the local community and be nature led. Mangroves are fast-growing, opportunistic trees and so will bounce back if we let them.

If we restore these sea forests, they could even relieve some of our dependence on building expensive seawalls to protect us from coastal flooding.

Time to turn the tide for wetlands

Wetlands are not just home to amazing plants and animals. Their unique superpowers protect us in so many other ways too, from capturing carbon to defending against extreme weather and boosting biodiversity. It’s now our turn to protect them, or we risk losing it all.