Challenging What We Think We Know: Wildfires Reveal the Power of Science

Large wildfires make headlines that spread across the world. This certainly does nothing to lessen the negative stigma attached to them.

That is why it was so interesting to come across a study examining the impact of wildfires in the western United States on air quality in other parts of the country. The researchers’ hypothesis was that wildfires would worsen air quality simply because of smoke transport.

However, the hypothesis turned out to be incorrect. Ma and colleagues showed that extreme wildfires in the West actually reduce fine particle concentrations in the eastern United States by roughly the same amount as they increase them in the West.

This surprising result was explained by the fact that heat-induced convection from the fires weakens eastward transport of smoke and enhances the removal of air pollutants through precipitation. In fact, this mechanism reduces human mortality and economic losses nationwide!

Of course, it is welcome news that the health effects of wildfires may not be as dramatic as feared. Yet in my view, the real lesson of this study lies elsewhere. It once again demonstrates that ordinary and seemingly logical assumptions people make do not necessarily correspond to reality. At the same time, it helps to highlight why systematic science is very likely one of humanity’s most important institutions.

Previous thoughts on the same topic:
Control of Douglas fir beetles by woodborer beetles
Forests in Indonesia and Finland
Scientific misconduct on prevailing theories is too attractive

Why are boreal forest fires on the rise everywhere but in Finland?

A research article published in Science showed that carbon dioxide emissions from fires in boreal forests have been increasing during this century, reaching a new high in 2021. Although boreal fires typically account for only one tenth of global carbon dioxide emissions from all wildfires, in 2021 they produced nearly one quarter of the total emissions.

The reason for this increase was the rare concurrence of water deficits in North America and Eurasia. This problem is exacerbated by the fact that increasing numbers of extreme weather events contribute to global warming, making it even more challenging to mitigate the effects of global change.

It is interesting to compare Finland and Sweden, two neighboring countries that are highly similar in many ways. Both countries experience relatively low levels of forest fire activity compared to other countries, but there is still a notable difference. In Sweden, 3 000 to 4 000 fires burn approximately 2 000 to 5 000 hectares annually. In contrast, Finland has a considerably lower average number of forest fires, around 1 000 per year, with each fire covering an average burnt area of only 0.5 hectares.

So, why do we see this difference? 

There are three main reasons for Finland's success in managing forest fires. Firstly, the country experiences weaker winds, which slows down the spread of fires in burning forests.

Secondly, Finnish society is well-equipped to recognize forest fires, thanks to the presence of volunteer fire brigades with superior local knowledge compared to municipal firefighters. This enables faster site location and response times.

Thirdly, the abundance of forest roads in Finnish forests allows firefighters to quickly reach burning sites. Despite being narrow, these roads are effective in slowing down the spread of fires by creating breaks in the continuous forest cover.

Given that forest fires pose a continuous risk to the global climate, other nations could benefit from adopting Finnish practices and techniques to manage such disasters.

Previous thoughts on the same topic:
Fair policy will build a strong Union
A new justification is needed for environmental activists
Historical context of forest fires in Kalajoki (Written in Finnish, but readable in English using Google Translate)