Particulate matter from wildfires causes globally over 100,000 annual deaths – impacts of fire smoke and desert dust are unevenly distributed between continents

As part of the report, researchers from the Finnish Meteorological Institute modeled how the fine particles from forest fires spread in the atmosphere and estimated how much people are exposed to harmful concentrations. The analysis is based on the satellite-based observations of fires that were used as an estimate for smoke emissions.

The year 2024 was the peak year for mortality with approximately 154,000 deaths due to fire smoke, slightly exceeding the previous year 2023. Compared with the previous report, the fire smoke indicator currently estimates also the total mortality from fire smoke. From 2003–2012 to 2015–2024, the average mortality increased by 9%, with low Human Development Index (HDI) countries seeing the biggest increase (46%). However, the increasing trend in mortality from fire smoke is mainly caused by the growing population exposure rather than worsening smoke conditions. While local fire activity has intensified in some areas, such as western parts of Canada and the United States, the global average wildfire smoke particle concentration did not show a clear increasing trend.

Fire risk, however, continues to grow regionally, with strength and smoke exposure depending on the efficiency of fire management measures and the impacts of climate change.

Apart from the fire indicator, SILAM model calculations of global desert dust were included in the Dust ensemble, together with Copernicus, Naval Research Laboratory, and NASA models. Climate change and population growth also leads to increasing exposure of population with dust, with particularly significant rise in Africa and Asia.

Climate and health are closely linked

The published global report is part of the Lancet Countdown project that tracks the relationship between health and climate change using over 50 indicators. The 2025 report emphasizes that urgent action is needed to mitigate and adapt to climate change to avoid the most severe health effects.

The Lancet Countdown has been selected as one of the 15 finalists for the GAEA awards. The winner will be announced at the World Economic Forum in January 2026. The nomination itself is a significant recognition of the project’s impact on both climate research and policymaking.