Fires can be a natural and positive part of the healthy functioning of many ecosystems. However, the pattern of large or unusual fires - known as wildfires - is changing, and there is scientific consensus that climate change is promoting the conditions on which they depend, such as the frequency and intensity of fire weather.
Fires mostly result from the interaction between climate conditions (such as temperature, moisture, and lightning), vegetation (fuel availability and dryness) and people (through land-use change, ignition, and suppression), and changes in these factors are leading to shifts in fire patterns in many regions of the world.
It is widely known that the overall global burned area is decreasing, as explored by one report from Science magazine in 2017. This is mainly driven by land-use change from natural savannah and grasslands to agriculture. However, changes in land use can act as a driver for fires in different areas such as tropical forests, and in other regions such as high-latitude forests wildfires are increasing more in line with fire weather and fire season length. Extreme weather, a warming climate, and a build-up of dried-out vegetation acting as fuel, can also result in fires that are larger, more intense, or more frequent than normal, which can lead to the destruction of habitats (wildlife and vegetation) and negative impacts on society (destruction of infrastructure, displacement of people, and air pollution), as well as impacting carbon sinks.
A negative cycle
Wildfires and climate change can be part of a negative cycle. Fires can contribute to climate change through releasing carbon from soils and vegetation but are also affected by climate change through hotter and, in places, drier conditions.
Climate change can lead to plant life drying out more quicky, which creates more flammable vegetation to burn. In turn, this burning contributes to climate change by the release of carbon and the destruction of natural carbon sinks, such as forests. The effects of climate change on wildfires have been apparent in many regions of the world in recent years. For example, climate change more than doubled the likelihood of extreme fire weather in Eastern Canada in 2023 (WWA), and extreme wildfires are moving into unexpected places – like the Arctic, wetlands, peatlands and rainforests that would not previously have been expected to burn easily (UNEP 2022). The vegetation in these are places is not adapted to fire and these locations also hold huge amounts of carbon. Fire's overall contribution to the carbon cycle though is complex, including carbon uptake in plant regrowth, phytoplankton blooms in the ocean, storage of burnt carbon in soils, as well as variable effects from aerosols.
It is important to note that climate change will not impact all environments in the same way. In some areas climate change may lead to changes in precipitation and fuel availability, which may decrease flammability, but in other areas climate change may increase fires (e.g., extreme fires in Europe). Higher temperatures alone will not necessarily lead to more fires in all cases; however, our climate system is finely balanced, and small changes can have significant consequences. At 2 °C of warming, models calculate that more areas globally would be at risk of higher fire danger compared to today. Overall, the changing and warming of the climate has increased the scale, intensity, and impact of extreme events in many regions across the globe.
Met Office research
The Climate Science for Service Partnership Brazil (CSSP Brazil) research project aims to build strong partnerships between research institutes in the UK and Brazil. As part of this project, scientists from the UK and South America have worked together to develop a seasonal fire probability forecasting service. This delivers forecasts of fire probability for South America several months in advance and enables communities to prepare for these events and mitigate some of the risks posed.
Dr Chantelle Burton, climate scientist at the Met Office, said: "We are already seeing the impact of climate change on weather patterns all over the world, and this is disrupting normal fire regimes in many regions. It is important for fire research to explore what is changing, what effect this could have on people and the environment, and what communities need to do to prepare."
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