Increasing wildfires a threat to new species

As global temperatures rise, the incidence of wildfires is increasing in many regions. This is mainly because higher average temperatures and changing weather conditions are drying out land and vegetation, making them more flammable. The study in Nature Climate Change shows that wildfires can break out closer to the poles than before. In some areas, the fire seasons may also double in length. This is under a medium scenario where the emissions don't sharply increase or get cut till the end of this century.

"Our research shows that wildfires pose an ever-increasing threat to biodiversity. We find that nearly 84 per cent of species vulnerable to wildfires will face a higher risk by the end of this century," says Xiaoye Yang, a researcher at the University of Gothenburg and the study's lead author.

Another author, Ziqian Zhong at Chalmers, focused his part of the research on the ecological side, where he contributed to interpreting what the projected wildfire changes mean for species and biodiversity.

"What surprised me most was how uneven the pattern is. It is not a simple story of wildfire increasing everywhere in the same way. South America was especially notable, but at the same time the signal in high-latitude regions was also striking, because those are places where wildfire risk has often been underestimated from a biodiversity perspective".

Combines 13 climate models and machine learning

Previous research into how biodiversity is affected by global climate change has mainly focused on gradual changes to habitats. Less attention has been paid to how climate-driven wildfires affect the long-term survival of plants and animals.

The research team combined 13 climate models with a machine learning-based method to forecast changes in the wildfire burned area and the length of the fire season up to the end of this century. They then assessed how these changes affect the risk to species worldwide, based on a Red List from the IUCN (International Union for Conservation of Nature). The Red List includes 9,592 species whose survival is currently threatened by the increasing occurrence and severity of wildfires.

"This combination of machine learning and climate models allows us to move beyond regional case studies and take a much more systematic and global view. Instead of relying only on individual case studies or a single model framework, we can combine information from multiple climate models with machine learning to project burned area and then connect that directly to species exposure. This makes it possible to compare different future emissions pathways and identify where biodiversity risks are likely to increase the most", says Ziqian Zhong.

"Species with small ranges are particularly vulnerable. The most affected species are concentrated in South America, South Asia and Australia, and a large proportion of them are already endangered. An increase in the frequency of wildfires could push some of them closer to extinction", says Xiaoye Yang.

Even species that have previously been spared from wildfires are facing a new threat, but there is a lack of research to assess how serious that threat is.

Global trends of increasing risk

The researchers calculated the increase in wildfires based on the IPCC's various global warming scenarios. Under a moderate scenario involving a temperature rise of around 2.7 degrees compared with pre-industrial levels, the study shows that:

• The global area affected by wildfires could increase by around 9.3 per cent
• Fire seasons could be extended by 22.8 per cent
• Almost 84 per cent of species vulnerable to fire will face an increased risk of wildfires

The study highlights significant regional differences. Whilst the risk of wildfires is increasing in many parts of the world, certain regions in Africa may see a reduction in the area affected by fires due to a wetter climate in the future.

Climate action can reduce risk

The researchers also show that measures to limit emissions can significantly reduce the occurrence of wildfires. Compared with a high-emissions scenario, a future with moderate emissions could reduce the increase in species' vulnerability to wildfires by more than 60 per cent. Regions such as New Zealand, South America and areas near the Arctic would benefit most from reduced emissions.

"The main message is that we cannot focus only on species or regions that are already recognized as fire-threatened today. We also need to prepare for emerging risks-especially in high-latitude regions - and pay close attention to narrowly distributed species, because they seem to be especially vulnerable", says Ziqian Zhong.

"This research connects very naturally to broader work on climate change impacts, Earth system science, and ecological risk assessment that we do here at Chalmers. The next step could be to develop higher-resolution assessments in hotspot regions and integrate more species-specific ecological information, such as sensitivity and adaptive capacity", concludes Ziqian.

More information:

Read the scientific study in Nature Climate Change: Wildfire Risk for Species under Climate Change

This text is based on a press release from The University of Gothenburg.

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