The occurrence of fires in the Arctic is linked not only to warming temperatures and increasingly dry conditions, but also human activity in the region. An international research team led by the University of Zurich found that fires occurred 2.5 times more often in lit areas associated with human activity than in climatically similar unlit areas. Effective fire prevention and response can help reduce risks whose impacts extend far beyond the Arctic.

Fires in the Arctic are not solely a regional issue, as shown by the hazy skies in Switzerland last summer despite otherwise sunny weather. Smoke from major fires in northern Canada crossed the Atlantic and reached Europe. Until now, large-scale studies of Arctic tundra fires have focused primarily on rising temperatures and drought as the main drivers. The role of human activity has received much less attention, even as industrial development, settlements, roads, and other infrastructure expand rapidly in parts of the Arctic, particularly in connection with extractive industries such as oil and gas production and mining.

Comparing artificial light at night and fire occurrence
An international team of researchers led by the University of Zurich (UZH) has investigated for the first time at the pan-Arctic scale whether human activity is linked to fire occurrence between 2001 and 2013. Study leader Gabriela Schaepman-Strub from the Department of Evolutionary Biology and Environmental Sciences at UZH collaborated with colleagues from NASA’s Goddard Space Flight Center, USA, and the University of Münster, Germany. Since direct and consistent data on human activities across the entire Arctic are difficult to obtain, the researchers used artificial light at night as a satellite-based indicator of human presence, including settlements and industrial activities.

"Our results show that in the Arctic, fires occurred 2.5 times more often in areas illuminated by artificial nighttime light than in climatically similar unlit areas. We also found that fire occurrence was higher closer to lit areas, suggesting a strong spatial association between light-emitting human activity and Arctic fire occurrence," says Cengiz Akandil, a postdoctoral researcher at UZH and first author of the study. He notes that this does not mean that human activity is the only driver of fires in the Arctic, as changing temperature, moisture, and drought conditions remain major factors. The findings nevertheless show that human activity also plays an important role.

According to Miguel Román, Deputy Director for Atmospheres and Data Systems at NASA Goddard and co-author of the study, earth observations are most powerful when they help scientists understand how environmental conditions and human activity interact. "This study underscores the importance of interdisciplinary Earth system science that includes human systems as part of the interconnected whole, rather than treating them as separate from the environment,” says Román.

Different strategies for fire prevention and response
The researchers also found large regional differences in fire occurrence near lit areas. This suggests that fire management, prevention measures, and firefighting capacities may help explain regional differences in fire occurrence associated with human activity. "Better fire prevention and management around settlements, industrial sites, roads, and other lit areas could therefore help reduce ignition risks and limit fire damage," says Akandil.

The study findings are highly relevant to Arctic communities. Fires can threaten homes, infrastructure, transport routes, public health, and livelihoods, as well as culturally important landscapes and valuable ecosystems that support local ways of life and Arctic biodiversity. They can accelerate permafrost thaw and shift tundra ecosystems into new, more fire-prone states. "Reducing human-related ignition risks is therefore important not only for protecting infrastructure, but also for strengthening the resilience and safety of Arctic communities," emphasizes senior author Gabriela Schaepman-Strub.

Impact extends far beyond the Arctic
Because Arctic fires release carbon and can accelerate permafrost degradation, they contribute to feedbacks that affect the global climate. The impact extends far beyond the Arctic. Managing fire risk associated with human activity in the Arctic is therefore a local and a global issue, as Schaepman-Strub concludes: "As Arctic development continues and climatological conditions become more fire-prone, integrating fire prevention into land-use planning, industrial operations, and community protection strategies will become increasingly important."