Evidence of this is how fires responded to different degrees of mobility loss, based on the number of fires in 0.5 degree grid cells. In countries with fewer fires, fires declined almost linearly as mobility decreased. But countries with more fires saw a slow increase, leveling off at an average of about 27 percent as mobility fell. The researchers interpreted this as a sign that different mechanisms were at work. The steady decline suggests less human-caused ignitions, while the gradual increase suggests weaker suppression. But Wang mentioned that there could also be other reasons, such as changes in local land use.
Mobility restrictions may also have led to a disruption in fire safety measures, which could result in fewer fires being set for firefighting purposes. Researchers looked at 12 countries with prescribed burn records. The area burned by prescribed fires fell by about half in 2020 compared to the 2013-2019 average. Of course, the locations and sizes of prescribed burns also change from year to year with fire return intervals and land management cycles, complicating this analysis.
If you exclude areas where prescribed burning occurs in these twelve countries, the decline in fires there decreases from 45.3 percent to 27.8 percent.
This research has limitations in part because it relied on cell phone data to track human movements. This type of data may not capture human activity in rural areas where coverage may be limited. Additionally, the analysis only focused on the first half of the year, so the impact on regions where fires occur more frequently in the second half of the year, such as the western United States, may not have been fully captured.
Wang explained that this quasi-experimental design provides strong association evidence but is not a controlled experiment.
Understanding human influence
Wang emphasized that the study is not an assessment of fire safety policy. However, the analysis suggests that there is no single ideal policy response. Where fires have declined, human ignition appears to dominate. In these areas, it may be important to reduce accidental ignitions through public education and maintain beneficial prescribed burning. On the other hand, areas where fires have occurred may require fewer monitoring and extinguishing measures. Maintaining firefighting and patrol capacities in the event of disruptions can be important.
Wang added: “Overall, a one-size-fits-all policy is unlikely to work, and strategies should be tailored to local human-fire relationships.” Fire risk predictions could benefit from taking human behavior into account. This allows more accurate fire forecasts to be made, even as weather and society changes.
Cell Reports Sustainability, 2026. DOI: 10.1016/j.crsus.2026.100860
