Peatlands, one of the most powerful carbon sinks in nature, have been drained by thousands of kilometers of Minnesota ditches for about 100 years. To inform prioritization of peatland restoration, Northern Research Station scientists and partners estimated and mapped peat loss from ditching of Minnesota peatlands, establishing that loss of about 165 million cubic meters of peat has resulted in a loss of 3.8 million metric tons of carbon. Scientists developed a map that could inform prioritization of peatland restoration projects as part of natural climate solutions.

Peatlands play a critical role in the global carbon cycle and climate regulation, containing approximately 30 percent of global soil carbon—as much as the pre-industrial atmosphere—despite occupying only about 3 percent of global land area. However, peatland drainage has led to widespread degradation and loss of carbon storage. Restoration of peatlands is part of recommended natural climate solutions, but information to prioritize restoration is lacking. Northern Research Station scientists led a team that studied historic ditches in northern Minnesota peatlands to assess impacts and potential for restoration. The team modeled pre-ditch surface elevations and compared them to present day elevations to calculate peat volume loss. Next, researchers established relationships between volume loss and site characteristics from existing geographic information systems datasets, scaling volume loss to all mapped peatland ditches in northern Minnesota. Researchers estimate that approximately 165 million cubic meters of peat have been lost along almost 4,000 km of ditches, for a total historic loss of approximately 3.8 million metric tons of carbon. Assuming a constant decomposition rate during the roughly 100 years since drainage, annual carbon dioxide emissions from ditched peatlands were equivalent to emissions from about 55,000 personal vehicles. The map of peat loss estimates could be incorporated into decision support tools to inform management decisions regarding peatland restoration.