Wildfires burning through large swathes of eastern and western Canada have released a record 160 million tonnes of carbon, the EU's Copernicus Atmospheric Monitoring Service said June 27.

The wildfires have so far scorched British Columbia, Alberta, Saskatchewan and the Northwestern Territories in the west; Ontario, Quebec, and Nova Scotia in the east. As of June 26, the annual emissions from these fires are now the largest for Canada since satellite monitoring began in 2003 — roughly equivalent to Indonesia's annual carbon dioxide emissions from the burning of fossil fuels.

"Our monitoring of the scale and persistence of the wildfire emissions across Canada since early May has shown how unusual it has been," Copernicus senior scientist Mark Parrington said in a statement.

The smoke blanketed several major urban centres in June, including New York City and Toronto. Public officials expressed concern about the health impacts of the plume. Wildfire smoke is linked to higher rates of heart attacks, strokes, and more visits to emergency rooms for respiratory conditions.

Forests also act as a critical sink for carbon. When they burn, that carbon is released into the atmosphere, making global warming worse.