Wet agriculture could protect peatlands and climate, but remains largely unexplored

Across the globe, peatlands are under threat and their destruction is contributing to climate change. Damaged peatlands are responsible for roughly five per cent of global greenhouse gas emissions.

Thawing permafrost peatlands, such as those in Northern Canada, are an important “tipping element” that could lead to a runaway greenhouse effect. Further south, in Canada, Europe and the tropics, peatlands are being drained for urban, suburban and infrastructure expansion, converted to dryland agriculture and mined for fuel and the horticulture industry.

Peatlands are water-logged areas that slowly decompose plants, locking carbon into the soils. Protecting intact peatlands — and rewetting those that have been drained — must occur if we are to limit global warming to well below 2 C.

As part of our research, we conducted the first international survey on “wet farming,” or paludiculture, to understand how peatlands can be protected while considering people like farmers who use them. We also organized a workshop in Montréal, for farmers and the public, on the role of peatlands in climate change and to discuss wet farming.

Paludiculture: A necessity-driven innovation

Our survey shows that paludiculture is a necessity-driven innovation. In places where peatlands cannot be fully protected for nature conservation, such as in densely populated areas in Europe, Indonesia and southern Canada, paludiculture allows farmers and others to use the land and keep the carbon in the soil.

A peatland is created by the partial decomposition of plants in bogs and fens. If the land is wet, peat can form; if it is dry, the carbon stored in the peat is released into the atmosphere.

Peatlands cover three per cent of the Earth’s surface, yet they retain 33 per cent of the carbon contained in terrestrial ecosystems. More than half of Québec’s terrestrial carbon stock is stored in peatlands, and their protection is essential to Canada’s plan to achieve net-zero emissions.

Southeastern Québec, the most populated and urbanized area of the province, lost 19 per cent of its peatlands between 1990 and 2011. Peatland drainage for agriculture accounts for an estimated 21 per cent of these losses, approximately 80,000 hectares. We estimate that peatlands drained for agriculture emit between 520,000 and 752,000 tonnes of carbon dioxide equivalent annually, about 10 per cent of the annual emissions from the Québec agricultural sector.