Swamp wetlands: how wetlands can impede climate change

Swamp wetlands could be the face of a hi-tech and low carbon agricultural future.The harvest can provide low carbon energy and home insulation, while at the same time offering a wildlife sanctuary, and a means of depolluting land and waters.

Maintaining the wetland is also key to reducing Europe’s carbon emissions. Peatland makes up just 3% of the continent’s agricultural land but, because of poor management and degradation, is responsible for more than 90% of CO2 emissions from farming.

Globally, ‘paludiculture’ (literally, swamp cultivation) could also help to save the world’s disappearing peat swamp forests, which account for around 5% of global carbon dioxide (CO2) emissions, and an immeasurable loss in biodiversity.

Peatland is waterlogged land with a 30cm top layer of decomposing plant material. Conventional use of the land in agriculture requires draining and clearing, which releases locked in CO2 back into the atmosphere and degrades the land.

“Paludiculture could turn the tide on deforestation in the most literal sense of the phrase,” said Professor Hans Joosten of Germany’s Greifswald University.

“Most peatlands in south-east Asia are drained for oil palm and pulp wood plantations. But almost all of them are located close to the sea, just a few metres above sea level. Because drained peatlands are associated with subsidence of around 5cm a year, unless we start to change towards paludiculture, most drained peatlands currently under use will be swallowed by the sea and lost.”

Joosten estimates that replacing palm oil and acacia plantations in south-east Asia with wet cultivation could cut 500 megatonnes of CO2 emissions, the equivalent of 1-2% of annual global emissions.

Researchers have identified more than 1,500 substitute species that could be grown in rewetted tropical zones, including nut, rubber and gum trees. Because swamp crops can be grown on marginal land – and substitute for food staples – the damaging effects of indirect land use change can be avoided. Pilot schemes are already underway in Indonesia to investigate their potential.

Earlier this month, the gold-standard Ramsar Convention on wetlands of international importance adopted a motion encouraging paludiculture as a way of avoiding carbon emissions. It singled out biomass grown on rewetted organic soil as a promising option for climate change mitigation.

Along the Baltic coasts of Germany and Poland, a small but growing band of farmers are already making use of conservation subsidies and research grants to move in this direction.

Hans Voigt, a reed farmer in Mecklenburg, northern Germany said that many sharecroppers were thinking of joining a subsidised scheme to provide waste straw and reed residues.

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