Wetland drainage produces substantial greenhouse gas emissions in the Canadian Prairie Pothole Region

The Prairie Pothole Region of central North America has land use dominated
by agriculture and is characterized by many small mineral-soil wetlands
that are commonly drained to increase the land available for crop
production. Here, we synthesize the available data regarding Canadian
prairie mineral wetland carbon storage and greenhouse gas (GHG) emissions,
along with other aspects of land-use change GHG emissions, in a full
life-cycle assessment to estimate the net effect of ongoing wetland
drainage on Canada’s GHG budget. Our analysis found that 2.13 Tg CO2-eq
are released from one year’s worth of prairie wetland drainage, and this
is dominated by CO2-eq lost through exposure of wetland sediment to
atmospheric conditions. Our estimated emissions from wetland drainage
increased to 3.38 Tg CO2-eqwhen natural emissions from the intact wetlands
were excluded. Other land-use changes associated with wetland drainage,
including eliminating nitrous oxide emissions from double fertilization of
the areas around wetlands, did not appreciably offset GHG emissions from
wetland carbon loss. GHGs from mineral-soil wetland loss are not currently
included in Canada’s National Inventory Report — incorporation of these
emissions would necessitate substantial reductions in emissions from other
agricultural activities to achieve overall emissions reductions targets.