A new study published in Science Advances warns that wildfire seasons around the world are increasingly overlapping, making it harder for countries to share firefighting crews and equipment. Researchers found that extreme fire weather days have grown more frequent since 1979, driven largely by human-caused climate change.

Historically, different regions experienced wildfire seasons at different times, allowing nations to assist one another during emergencies. But as fire seasons lengthen and converge, that window for cooperation is shrinking. Areas such as South America, parts of Africa, North America, Europe and the Middle East have seen especially large increases in overlapping days of severe fire weather.

The growing synchronicity raises concerns about resource shortages and cascading effects if multiple regions face major fires at once. Experts say that while global resource sharing still functions, increasing strain could test its limits. The findings highlight the need for better forecasting, expanded local firefighting capacity and long-term efforts to address climate change and reduce fire risk.