Researchers from Lakehead University have found that freshwater wetlands are important nature-based solutions for the mitigation of greenhouse gas emissions.
In a recent study published in the Journal of Geophysical Research: Biogeosciences, Dr. Florin Pendea and co-authors Dr. Nanda Kanavillil and Dr. Sree Kurissery from Lakehead, and Dr. Gail Chmura of McGill University, found that wetlands within the Lake Simcoe watershed were 50 percent more effective in storing carbon than other wetland ecosystems, second only to salt marshes that form along the shores of temperate seas.
“Wetlands are important ecosystems because they have an enhanced capacity to extract carbon dioxide – a greenhouse gas – from the atmosphere and store it in the ground,” says Dr. Florin Pendea, lead researcher and associate professor in the departments of sustainability sciences and geography and the environment at Lakehead University. “This ground storage is vital because it keeps carbon dioxide from increasing in the atmosphere where it causes global warming.”
Pendea says that this research comes at an important time as countries around the world are looking at ways to mitigate climate change, including the federal government’s commitment to net-zero carbon emissions by 2050.
“The research is telling us that if freshwater marshes and swamps are protected, they can be important natural solutions in the mitigation of carbon dioxide emitted by human activity.”
Pendea’s team, which included several undergraduate students from Lakehead, spent three years collecting and examining soil properties and carbon accumulation rates over the last 100 years in swamps and marshes in the Lake Simcoe watershed. These wetland areas – Beaver River Wetlands, Black River-Zephyr Creek Wetlands, and the East Holland River Wetlands – are under increasing pressure from farming and urban development, a trend impacting much of Southern Ontario.
“We found that wetlands flooded more regularly are 60 percent more efficient in storing carbon long-term” explains Pendea. “This means that wetland conservation, particularly preventing drainage of wetlands, is critical in maintaining vital ecosystem services they provide, such as carbon storage.”
For Pendea, it also lends support to the case for wetland restoration through re-wetting as an important nature-based climate solution for mitigation of greenhouse gas emissions in areas where they were already drained for agriculture and other purposes.
While this research already has important policy implications, the work is far from over. This summer, Pendea started a new project in collaboration with Chmura and the Lake Simcoe Region Conservation Authority, which explores the value of constructed wetlands – wetlands purposefully created in areas not suitable for other uses – as a way to increase the Lake Simcoe region’s capacity to mitigate future greenhouse gas emissions for generations to come. In addition to evaluating soil carbon storage capacity, this project will directly document the greenhouse gas balance in these novel ecosystems.
“We hope to provide a baseline for Southern Ontario and ascertain whether constructing new wetlands is a good idea from a climate perspective, particularly with respect to methane and nitrous oxide emissions” explains Pendea. “These greenhouse gases have a much higher global warming potential than carbon dioxide”.
“We’ve always known that wetlands are really important for biodiversity and for water quality,” explains Bill Thompson, Manager, Watershed Plans and Strategies, Lake Simcoe Region Conservation Authority. “This research demonstrates that they’re also really important in addressing greenhouse gas emissions, even in an area like the Lake Simcoe watershed, which is undergoing rapid land use change. We’re hoping to use this information to assist municipalities in our watershed, and across the GTA, in incorporating ‘nature-based climate solutions’ in their climate change strategies.”
This research was funded in part by the Lake Simcoe Region Conservation Authority.