What is the Hudson Bay Lowlands?

The Hudson Bay Lowlands are a vast wetland region around the southern shore of Hudson Bay and James Bay, covering about 320,000 square kilometres of northern Ontario, northern Manitoba, northeastern Quebec, and southern Nunavut. The Lowlands are the second-largest contiguous wetland in the world after the West Siberian Lowland in Russia and one of Canada's seven physiographic regions. The region is dominated by bogs, fens, shallow lakes, and coastal salt marshes underlain by permafrost and ancient marine clays.

The Hudson Bay Lowlands were once submerged beneath the Tyrrell Sea, an inland marine sea that formed about 8,000 years ago when the Laurentide Ice Sheet retreated and depressed the underlying continental crust. The land is still rebounding (isostatic rebound) at one of the fastest rates in the world, about 1 to 1.3 centimetres per year, and the Hudson Bay coast is migrating northward as the land rises. Marine clays underlie the wetlands and contain abundant fossil walrus, ringed seal, and bowhead whale remains.

The Lowlands store an estimated 30 to 47 billion tonnes of carbon in their peatlands, making them one of the largest single-region carbon stores in the world. About 200 to 500 metres of peat deposits accumulated since the end of glaciation, with peat continuing to accumulate today. Climate change threatens to destabilise the carbon store through permafrost thaw, drying of peat, and increased fire frequency. The Ring of Fire mineral deposit in northern Ontario (chromite, nickel, copper, platinum, and palladium) is located within the Lowlands, with proposed development raising significant Indigenous-led environmental concerns.

The Lowlands support distinctive wildlife and the homelands of several First Nations and Cree communities. The Polar Bear Provincial Park (designated 1970, covering 23,552 square kilometres in Ontario) protects the southernmost regular polar bear denning area in the world (the Western Hudson Bay polar bear population). Wapusk National Park in Manitoba (11,475 square kilometres) protects additional polar bear habitat. The Mushkegowuk Cree communities of Attawapiskat, Fort Albany, Kashechewan, and Moose Cree (in northern Ontario), and the Eeyou (James Bay Cree) communities of Eeyou Istchee in Quebec hold treaty and Aboriginal title interests across the Lowlands. Treaty 9 (1905 to 1906) covers the Ontario portion. The Mushkegowuk Council represents seven Cree communities in northern Ontario.