A groundbreaking new study from Saskatchewan universities has put a startling price tag on the environmental cost of draining Prairie wetlands: an estimated $171 million in annual carbon emissions.
The High Cost of Drained Land
Published in the multidisciplinary science journal FACETS, the peer-reviewed research is the first to quantify greenhouse gas (GHG) emissions from wetland drainage across the entire Canadian Prairie Pothole Region (CPPR). The study, a joint effort by the University of Regina and the University of Saskatchewan, found that draining these wetlands results in 2.1 million tonnes of GHG emissions each year.
Lead author Dr. Kerri Finlay, director of the Institute for Environmental Change and Society at the U of R and Canada Research Chair in Water in a Changing Environment, emphasized the significance of the findings. "When we drain these wetlands, there are costs associated with it, and we need to be cognizant of that and factor that into our decision making," she stated.
The $171 million figure is based on applying Canada's minimum national carbon price for 2024 to the volume of emissions. This research provides a crucial, large-scale perspective that was previously missing, as earlier studies were only localized.
Exposed Sediments: The Major Culprit
The study pinpointed the mechanism behind the massive carbon release. When wetlands are drained to maximize agricultural land, the previously submerged sediment is exposed to the air. These sediments store vast quantities of organic carbon, which then oxidizes and is released as carbon dioxide.
"The magnitude of that carbon release when you expose the sediments, I really didn't expect it to be as high as it was," admitted Dr. Finlay, who began the project roughly two years ago with uncertain expectations. The research compared these drainage emissions against the baseline methane naturally released by intact wetlands and the extra diesel fuel farmers use to navigate around preserved wetlands.
A Conservative Estimate with Broad Implications
Notably, the researchers believe their alarming figures might actually be an underestimate. The study used data on drainage rates from 2001 to 2011, a period that was relatively dry.
Co-author Colin Whitfield, an associate professor at the U of S School of Environment and Sustainability, explained: "It's possible that we've underestimated the amount of drainage because there's been an increasing movement towards drainage in the subsequent years after that research was done."
The 2.1 million tonnes from wetland drainage represents a significant portion of the Prairies' agricultural emissions. For context, Environment and Climate Change Canada's National Inventory Report estimates total annual agricultural emissions for the region at 34.9 million tonnes in recent years.
The research was funded by the National Farmers Union and supported by Ducks Unlimited Canada's Institute for Wetland and Waterfowl Research. It underscores the critical ecosystem services wetlands provide and the substantial, often hidden, economic and environmental cost of their loss.
