The link between climate change and forest fires

Fire is a recurring disaster story in the news, whether in California, Greece, Brazil or Australia. Other fires don’t get our attention – such as the extensive fires in Africa. While fire seasons are familiar in many parts of the world, there have been new and unprecedented extremes, and these are linked to climate change.

In a recent episode of the BBC radio series Costing the Earth, professor Mike Flannigan explained that there are three reasons why climate change leads to more fires.

1. The fire season is longer. That’s the time between the first and the last major fire, and in Canada the fire season used to start on the 1st of April. It now starts on the 1st of March. In the US the season has extended from five months long in the 1970s to seven months long today.
2. Warmer temperatures cause more extreme weather, and that means more lightning and more forest fires. “For every degree of warming, there is a 12% increase in lightning activity”, says Flanagan. Nine out of ten forest fires are caused by human carelessness, but the ones started by lightning tend to do far more damage. They’re more likely to be in more remote areas, and could get well established before they are reported.
3. Most importantly, warmer temperatures mean more evaporation, which means that forests and wood is drier. Dry fuel is obviously more combustible, and is more likely to ignite.

With these three factors in play, the number of wildfires in the Western US is rising. There were 140 large fires in the 1980s, 160 in the 90s, and 250 in the years 2000 to 2012. It’s an increasing problem.

That’s not true everywhere. As we should know by now, climate change is non-linear and complicated. In some places the rise in temperatures is causing more rainfall and reducing fire risk. There are also changing agricultural patterns to consider. Traditional slash and burn farming practices are in decline in Africa for example, reducing the number of wildfires on the continent. Overall, the number of wildfires has been a mixed picture at the global level. You will find climate skeptic blogs using global statistics to claim no correlation between climate change and forest fires. But it depends on local conditions and in the Western US, there’s a clear trend.

When California burns, its national government’s position of official denial is fails its citizens. When Australia burns and its politicians and press claim no correlation with climate change, they fail them too. Climate change is happening, and fire is one of its most visible and most visceral effects.