March 2025 Japan and South Korea wildfires have been fueled by meteorological conditions likely strengthened by human-driven climate change in March 2025

Contact Authors

• Davide Faranda, IPSL-CNRS, France  📨davide.faranda@lsce.ipsl.fr 🗣️English,French, Italian, 

• Carmen Álvarez-Castro, UPO, Spain 📨 mcalvcas@upo.es 🗣️Spanish, English, Italian

• Tommaso Alberti, INGV, Italy 📨 tommaso.alberti@ingv.it 🗣️Italian, English

• Greta Cazzaniga, IPSL-CNRS, France  📨greta.cazzaniga@lsce.ipsl.fr  🗣️Italian, English, French 

Citation

• Faranda, D., Alvarez-Castro, M. C., Alberti, T., & Cazzaniga, G. (2025). March 2025 Japan and South Korea wildfires have been fueled by meteorological conditions likely strengthened by human-driven climate change. ClimaMeter, Institut Pierre Simon Laplace, CNRS. https://doi.org/10.5281/zenodo.15083384

Press Summary

• Meteorological conditions leading to the March 2025 wildfires in Japan and South Korea were significantly warmer, drier, and windier than they would have been in the past. Present-day conditions are up to 2°C hotter, up to 2 mm/day drier (up to 30%), and up to 4.8 km/h windier (up to 10%) compared to similar past events. 

• This event is associated with exceptional meteorological conditions. 

• We mostly ascribe the increased fire-conducive conditions to human-driven climate change, with natural climate variability likely playing a limited role.

Event Description

Large-scale wildfires broke out in Southwestern Asia between March 21 and 23, 2025, causing significant damage in Japan and South Korea, including burned land and human casualties. In Japan, separate wildfires hit Okayama and Ehime prefectures, injuring at least two people, forcing thousands to evacuate, and damaging multiple homes. By March 24, the fires had burned at least 370 hectares. This follows another major wildfire in Iwate Prefecture in February/March 2025, which destroyed 2 900 hectares. In both cases, the affected areas had experienced very dry weather in the days before the fires. In South Korea, wildfires in the region around Jinju and Busan caused the death of four individuals and triggered a national emergency response. The Central Disaster and Safety Countermeasures Headquarters reported that 7,778 hectares of forest were burned due to simultaneous wildfires across the country. The fires spread rapidly due to persistently dry soils, strong winds, and unusually high temperatures during the days of the event.

The meteorological conditions were characterized by an unusual pattern of surface pressure anomalies, with negative pressure over the inland and the sea between Japan and Korea, with positive anomalies to the south helping to sustain a strong pressure gradient across the affected regions. Temperature anomalies reached up to +2°C across Honshu and southern Korea. Precipitation during the event was extremely low, with large areas receiving less than 1 mm/day, while sustained winds over 50 km/h created favorable conditions for fire ignition and spread. The dry and windy conditions were particularly pronounced in coastal and mountainous areas. The data used in this analysis come from the ERA5 reanalysis, which combines model output with available observational data, including ground stations and satellite measurements. Differences with localized station observations may occur.

Climate and Data Background for the Analysis

Wildfires are responsible for 70% of global biomass burning each year and they release vast amounts of atmospheric trace gases and aerosols (van der Werf et al., 2017). Extreme weather conditions, such as heatwaves, droughts, and strong winds contribute to the conditions that favor wildfires. Although fires are part of natural ecosystems, the IPCC AR6 WG1 highlights the growing influence of climate change on wildfire frequency and extension. Indeed, the effect of climate change on the frequency and intensity of climate extremes contributes, in turn, to the change in the frequency and intensity of wildfires.  The IPCC report states with medium to high confidence that human-induced climate change has significantly increased areas burned by wildfires in certain regions (including Eastern Asia) and lengthened fire weather seasons. Furthermore, wildfires now affect regions previously unexposed to such risk (Jolly et al., 2015, Artés et al., 2019). Chang et al., 2024 showed that in South Korea, climate change has contributed to a shift from cold, wet winters to warm, dry conditions, creating more fire-prone environments and consequently increasing wildfire risks. 

Our analysis approach rests on looking for weather situations similar to those of the event of interest having been observed in the past. For this event, we have medium-low confidence in the robustness of our approach given the available climate data, as the event is exceptional in the data record.

ClimaMeter Analysis 

We analyze here (see Methodology for more details)  how events similar to the meteorological conditions leading to the March 2025 wildfires have changed in the present (1987–2023) compared to what they would have looked like if they had occurred in the past (1950–1986) in the region [126°E 146°E 30°N 41°N]. Surface pressure changes show a more pronounced land-sea contrast in the present, enhancing easterly winds inland. Temperature changes show increases of up to 2°C in the wildfire-affected regions. Precipitation changes reveal widespread drying, with present-day conditions up to 2 mm/day drier in parts of Honshu and southern South Korea. Wind speed changes show increased windiness inland, with up to 4.8 km/h stronger winds, especially near coastal areas of South Korea and northern Japan.

Similar past events show a seasonal shift, with events in the recent period occurring more frequently in March compared to the past, when they were more common in February and April. Changes in urban areas reveal that Imabari, Okayama, and Busan experienced significantly warmer and drier conditions during this event compared to similar past conditions. Busan also experienced stronger winds, while the increase in temperature was most pronounced in Imabari.

These results suggest that meteorological conditions similar to those of the March 2025 wildfires are becoming more intense, in line with what would be expected under continued global warming. Our results also suggest that sources of natural climate variability, such as the El Nino Southern Oscillation, may have played only a secondary role in shaping the observed event.

Conclusion

Based on the above, we conclude that meteorological conditions leading to the March 2025 wildfires in Japan and South Koreare up to 2°C hotter, up to 2 mm/day drier (up to 30%), and up to 4.8 km/h windier (up to 10%) compared to similar past events. We interpret this event as an exceptional meteorological occurrence whose characteristics were mostly strengthened by human-driven climate change.