Not made up, but estimated. Rather than find the exact article, here are the numbers after all was said and done:

https://www.canada.ca/en/environment-climate-change/services/climate-change/greenhouse-gas-emissions/sources-sinks-executive-summary-2023.html

In 2021, Canada’s greenhouse gas (GHG) emissions were 670 megatonnes of carbon dioxide equivalent (couldn't find 2023 quickly on mobile but it will be close)

https://atmosphere.copernicus.eu/copernicus-canada-produced-23-global-wildfire-carbon-emissions-2023

The wildfires that Canada experienced during 2023 have generated the highest carbon emissions in record for this country by a wide margin. According to GFASv1.2 data, the wildfires that started to take place in early May emitted almost 480 megatonnes of carbon

470 / 670 = 72%

To be fair this is not 72% of total emissions including wildfire smoke, but wildfires emitted 72% as much as the Canadian economy did.

So yes, it's not 80% of total emissions - but it's still a massive amount. Putting out these fires would have had nearly the same effect as shutting down our entire country and letting them burn.

Or you could say letting them burn nearly doubled our emissions, and in the hand-wavey world of emissions accounting you would be pretty close.