Human activities have fundamentally altered our landscape, and the outcome has been degradation of the earth's natural processes and cycles. Conservation practices are used to restore the natural hydrology and ecosystems in a patchwork of promise across the landscape. Can these conservation practices also help to capture carbon in the atmosphere, reducing greenhouse gases and helping to combat climate change?
The answer is all too familiar - it depends. Practices like turning marginal cropland into restored wetlands does increase the permanent land cover and can encourage the growth of woody plants, but wetlands also emit methane, a more potent greenhouse gas than carbon dioxide. This 2019 report by the Minnesota Board of Water and Soil Resources finds "... Drainage of wetlands and conversion to cropland can release significant amounts of long-stored carbon through organic matter decomposition. However, wetlands also emit methane, making it difficult to assess their role relative to GHG emissions. Methane emissions are highest in wetlands that are permanently or frequently inundated, while less frequently inundated wetland types such as wet meadows appear to sequester more GHGs (green house gases) than they emit. "
Similarly, the role of other conservation measures - for example cover crops - has to be carefully considered before values for carbon capture are assigned. This UMRR blog post from December, 2020, outlines a growing experiment in development of a carbon market in Minnesota. Now, the budget proposed by Minnesota Governor Tim Walz for the Board of Water and Soil Resources includes funding for expansion of carbon markets in Minnesota - see page 46 here.
Let's be clear here. Conservation practices are a good thing. LWV UMRR strongly agrees that cover crops and reduced tillage are vital climate adaptation and resilience measures, providing undeniable benefits to soil health and farm resilience. Improved soil health, keeping water on the land, and restoring habitat will have benefits broadly, including making our landscapes more resilient to the added stresses of our changing climate. Our concern is that cover crops and no-till may play a minimal role in sequestering carbon. LWV UMRR is joining with other environmental organizations in Minnesota in requesting that more consideration be given to scientific data on carbon capture before the state more strongly commits to including cover crops and no-till as eligible practices in a carbon market.
Watch the LWV UMRR Blog for continued reporting on this issue.
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