In the savanna primarily grass burns, resulting in relatively low CO2 emissions in the burned area, according to Veraverbeke. However, in forest fires like those in Canada, a relatively large amount of carbon is released, not only from trees but also from organic soils and even from permafrost. "If the soot particles travel northward and reach the Greenland ice cap, it can accelerate the melting process. With the current wildfires in the east of Canada, the smoke spread mainly southward and eastward."
Veraverbeke speaks of a self-amplifying effect in the north. Climate change increases the likelihood of lightning strikes, which are by far the most common cause of wildfires in northern areas. And the CO2 subsequently released contributes to climate change. "That linkage is very strong: climate change leads to more wildfires in northern areas. The number of fires we're currently seeing there was actually expected to occur in a few decades."
Haze of smog
Wildfires are not only detrimental to the climate but also to human health: indirectly, over 200,000 people worldwide die each year due to wild fires. And the impact on air quality is literally boundless, as demonstrated early June in New York. Smoke originating from Canadian forest fires enveloped the city in an orange haze of smog.
However, it's important to note that wildfires are not inherently bad, emphasized Veraverbeke. "They help renew and rejuvenate those forests. So we don't want to prevent all fires but rather ensure that their numbers don't increase."
He expects the fires in Canada to continue this summer. "These are massive forests, so if it remains warm and dry, they will keep growing." And even if precipitation largely extinguishes the fires, Veraverbeke says the fire can smolder under the snow and reignite in the spring—what is known as zombie fires. "It's very rare, but it does happen."