Its mid November, just a couple of weeks until the start of winter in the northern hemisphere. After a horror summer of fires across the North of the planet, fires continue to threaten communities and landscapes in many areas. This week, mandatory evacuations were announced in the area of Estes Park in Colorado, as some ski resorts in that state prepare to open. The Larimer County Sheriff’s Office announced “evacuate the area immediately and as quickly as possible. Do not delay leaving to gather belongings or make efforts to protect your home or business.” Meanwhile, the city of Denver is getting close to its record for latest First Snow of the season. And after a summer of extreme weather, the north west of North America has been hit by massive floods.

What we do know is that climate change influences wildfire now. The evidence for this is so widespread and compelling that there is really no point in even trying to argue its not a real phenomena. Here is a quick recap of some of the most recent research into climate change and wildfire.

Climate controls fire

As noted recently in research which was published in the Proceedings of the National Academy of Sciences, ‘California researchers say that climate change is now the overwhelming cause of conditions driving extreme wildfire behavior in the western United States.’

In short, warmer temperatures cause a ‘vapor pressure deficit’, which basically describes how thirsty the atmosphere is.

The researchers found this to be the leading meteorological variable that controls how much land burns in the western U.S. during a given fire season. The higher the deficit, the more moisture the atmosphere saps from soil and plants, priming the landscape to burn. Any firefighter will know that hot and dry conditions makes the available fuel in a forest more ‘ready’ to burn.

Rong Fu, a UCLA professor of atmospheric and oceanic sciences and one of the report’s authors, said the trend is likely to worsen in the years ahead. “I am afraid that the record fire seasons in recent years are only the beginning of what will come, due to climate change, and our society is not prepared for the rapid increase of weather contributing to wildfires”.

The report (Quantifying contributions of natural variability and anthropogenic forcings on increased fire weather risk over the western United States) is available here.

Climate is making forests more flammable

Other research notes that this ‘fuel aridity’ combined with ‘fire-weather extremes’ as a result of continued climate change ‘portend increased wildland fire activity where biomass is abundant and flammability is a primary constraint’. That is, even though forests are burnt and reburnt, they will keep burning (this is slightly counter intuitive because you would expect that repeat burning will mean less growth and hence less fuel for subsequent fires). ‘Fuel limitations from fire-fuel feedbacks are unlikely to strongly constrain the profound climate-driven broad-scale increases in forest-fire area by the mid-21st century’. In other words: Climate trumps fuel availability when it comes to fire because the remaining trees and wood are more likely to burn. This is a feedback loop that potentially locks in more regular fires until the forest ecosystem collapses.

Report authors say there are a number of factors at play (this study is based in the western USA):

‘Several anthropogenic factors underpin growing wildland fire area, including historically high fuel loads due to a century of fire suppression and outlawing of Indigenous burning; less direct suppression tactics to support firefighter safety, and increased fuel aridity due to human-caused climate change’.

Fires are getting bigger

As in Australia, the area burnt each fire season continues to grow: ‘The annual area burned by forest fires in the western United States (US) has increased ten-fold over the past half-century’. In Victoria, there has been a 170% increase in fire ignitions over the past 50 years. There have been 8 ‘megafires’ in that state since the start of the 21st century.

What should we do?

Of course there is much we can do to reduce the impact of fires. ‘More fuel reduction’ burning is often waved around as the ‘solution’ to increased fire threat, but it can be a blunt tool when used in the wrong place at the wrong time. Certainly fuel reduction (also called hazard reduction and proscribed burning) has a role but it would be dangerous to apply it as a panacea.

Research from the USA highlights some of the options:

‘After reviewing more than 1,000 papers representing over a century of research and observations, the researchers concluded there are several strategies that can make wildfires less destructive under certain circumstances. These include thinning dense forests that haven’t recently burned, removing some flammable shrubs and bushes, allowing wildfires to burn when conditions are appropriate, and ramping up Indigenous fire stewardship practices, including prescribed burns. If forests are managed well, they’ll still burn — but the fires won’t be so devastating’.

They note that ‘no one thing is guaranteed to work in every forest’. That’s why we need to be very careful about applying simple solutions to complex landscapes.

We need more fire fighting capacity

We also know that when the fires are happening in bad seasons, we need to stop them. ‘The fires that do end up burning in the height of fire season are too big, too hot and too severe to help keep an ecosystem healthy’.

That’s why we need to build our capacity to fight fire on public lands, to ensure we can limit the ecological impacts of wildfire.

Here’s a few ideas on what we need to do.

1/ Build our fire fighting capacity

Remote area firefighting. It’s great that the Victorian government has invested in more career firefighters. We need to also establish a remote area firefighting team responsible for tackling fires in our national parks and state forests. NSW, Tasmania and the ACT already have volunteer units. Victoria should do the same.

Background information is available here.

2/ A national, publicly owned air fleet.

One of the recommendations of the recent Bushfire Royal Commission report recommends the creation of a national publicly-owned aerial firefighting fleet, which can then be allocated to the states “according to greatest national need”. The federal government has refused to adopt this recommendation.

To add your voice to the call for a national air fleet, please check here.

For background information on fires and the need for a fleet, please check here.

IMAGE: Smoke from a 2019 Northern California wildfire could be seen by astronauts aboard the International Space Station.