Greenhouse gas emissions in Canada 1990-2021, by province

Alberta was Canada’s most polluting province by far in 2021, having emitted over 256 million metric tons of carbon dioxide equivalent (MtCO₂e). This was an increase of 55 percent compared to 1990 levels. Ontario – Canada's most populous province – was responsible for the second largest volume of greenhouse gas emissions in 2021, at 150.6 MtCO₂e. Unlike Alberta, Ontario’s emissions have fallen since 2005.

Canada’s oil sands emissions

Alberta’s large oil and gas industry is the main contributor to the province’s high emissions. Alberta is home to vast oil sands where some of the most carbon polluting sites in Canada are located – such as the Syncrude project on the Athabasca Oil Sands Deposit. The Syncrude Project is a joint venture between Suncor Energy, Imperial Oil, Sinopec, and CNOOC.

COVID-19 impact on Canada’s emissions

The outbreak of COVID-19 in 2020 and resulting lockdowns and restrictions caused Canada’s carbon dioxide emissions to plummet nearly nine percent to 535 million metric tons that year. This was Canada’s lowest annual emissions for more than two decades. Nevertheless, Canada was still one of the world’s largest emitters in 2020.