Wet agriculture could protect peatlands and climate, but remains largely unexplored
Around the world, peatlands are under threat and their destruction contributes to climate change. Damaged peatlands are responsible for about 5% of global greenhouse gas emissions.
Thawing of permafrost peatlands, such as those in northern Canada, is a significant “tipping point” 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 agricultural drylands and exploited for fuel and the horticultural industry.
Bogs are waterlogged areas that slowly decompose plants, trapping carbon in soils. Protecting intact peatlands – and rewetting those that have been drained – must take place if we are to limit global warming to well below 2°C.
As part of our research, we conducted the first international survey of ‘wet farming’, or paludiculture, to understand how peatlands can be protected while treating people as the farmers who use them. We also organized a workshop in Montreal, for farmers and the public, on the role of peatlands in climate change and to discuss wet agriculture.
Malaria: an innovation out of necessity
Our survey shows that malaria cultivation is an innovation out of necessity. In places where peatlands cannot be fully protected for nature conservation, such as in densely populated areas of Europe, Indonesia and southern Canada, malaria cultivation enables farmers and others to use the land and keep the carbon in the soil.
A bog is created by the partial decay of plants in bogs and fens. If the soil is wet, peat can form; if it is dry, the carbon stored in the peat is released into the atmosphere.
Peatlands cover 3% of the Earth’s surface, but they retain 33% of the carbon contained in terrestrial ecosystems. More than half of Quebec’s terrestrial carbon stock is stored in peatlands, and their protection is essential to Canada’s plan to achieve net zero emissions.
Read more: Peatlands protect against wildfires and floods, but are still under attack in Canada
Southeastern Quebec, the most populated and most urbanized region of the province, lost 19% of its peatlands between 1990 and 2011. Drainage of peatlands for agriculture accounts for approximately 21% of these losses, or approximately 80,000 hectares. It is estimated that peatlands drained for agriculture emit annually between 520,000 and 752,000 tons of carbon dioxide equivalent, or about 10% of the annual emissions of Quebec’s agricultural sector.
Beyond the climate benefit, peatland protection and malaria cultivation also provide many other ecosystem services, including water retention and purification. They function as wetland buffer zones, keeping agricultural fertilizers out of lakes, rivers and oceans. The degradation and loss of peatlands represents a significant cost to communities beyond economic considerations.
Our survey shows a growing interest in malaria cultivation around the world, especially in Europe and Indonesia. But malaria culture is largely unexplored in Quebec and the rest of Canada.
Read more: How to fight wildfires and climate change with wetlands
The survey also suggests that the pioneers of malaria saw its potential mainly in the use of plants harvested from peatlands as building material, for energy production, as a growing medium in horticulture and as fodder. For example, a farmer in Malchin, Germany, harvests reed canary grass and sedges for the local biomass heating plant.
A contribution to regional circular economies
Malaria can play a role in regional circular economies as long as there is time and space to experiment and develop business models. Our survey shows that the transition to wet farming requires collaboration between users and researchers, as well as government support for many years. Malaria business models need to incorporate climate and other sustainability goals, such as biodiversity protection.
Our workshop has identified several levers that can contribute to the development of malaria in Quebec:
This could reduce emissions in the sector, but also produce co-benefits, such as filtration and water retention, to help climate adaptation to floods and droughts.
Its development is supported by climate and nature conservation laws, such as funding for wetland protection under the Wetlands and Waterways Conservation Act, and is aligned with the objectives of the Plan. of sustainable agriculture 2020-30.
Malaria cultivation could be explored on agricultural land that has problems, such as flooding or insufficient soil depth, while conventional ‘dry’ agriculture continues elsewhere.
A culture of cooperatives is already established in the province. Wet farming requires new machinery. Risk sharing makes the cooperative model attractive, as a Dutch pilot project showed in our survey. The cooperative principles of “co-operative cooperation” and “concern for the community” can support regionally integrated circular economies that prioritize members, communities and the environment over profit.
Our workshop also revealed obstacles. More socio-ecological and contextual knowledge and education are needed. Ecologically, this means understanding methane emissions in pilot malaria cultivation after rewetting and assessing biodiversity outcomes relative to the harvesting of grasses, sedges and other biomass, as the optimum time for harvesting can be detrimental to the animal species that live there.
Read more: How scientists are restoring boreal peatlands to help keep carbon in the ground
On the social side, we need more pilot malaria projects that demonstrate commercial interest for farmers and other users. Their success will depend on the evolution of regulations and subsidies.
In particular, increases in carbon prices will be important in creating a level playing field. The inclusion of malaria in a European Union report on carbon farming is an indicator of this development.
A cultural paradigm shift is needed towards regenerative agriculture and a public priority for multifunctional agriculture for people, peat and planet.