What are the CO2 emissions of wildfires?

James Tytko asked Jim Dale from British Weather Services to help with the answer...

Unfortunately, there can be no definitive answer to your question, Jon.

The first thing to say is every wildfire is different. Different locations, different combustible fuel, different meteorological factors, different acreage burned, and different actions taken to quell the fires, if any.  The Canadian wildfires of last year and this were much bigger than the Athens fire of now, and even when the spread is curtailed the underlying moss/peat can continue to ‘quietly burn’, releasing further carbon and other gases over time.

We can’t yet assess the carbon release damage from the 2024 Athens fire or indeed the US & Canadian fires of this season as they are ongoing, but the 2023 Canadian wildfire that put masses of smoke into the Great Lakes area and North East US region was off the scale and produced as much greenhouse gas emissions in a single season as would normally occur over 10 seasons, according to the collated data.

The Canadian fires produced about 2bn tonnes of CO2 alone, or ¼ of the total global wildfire emissions.  In 2023 it is estimated that 8.6bn tonnes of Carbon dioxide was released globally through wildfires alone, near doubling the estimated 4.8bn annual emissions of the US from all other sources. 

So, on that comparison alone, wildfires as a result of climate change have the capacity to overhaul traditional emissions and undo all forms of manmade or even natural climate mitigation. However, in all the short term negatives there is a longer term positive in that the regrowth of vegetation across burned areas takes up much of the carbon released in the fires.

So, it’s very much an ongoing and ever changing situation. However, there is sound evidence that wildfires are potentially doubling the conventional carbon release of human beings worldwide. It’s a worrying scenario for all the reasons given and it’s very likely to become worse within our lifetimes.