The study examines the impact of climate change on global wildfire activity from 1979 to 2013. Using three daily global climate datasets and three fire danger indices, the researchers developed a metric to measure the length of fire weather seasons and mapped spatio-temporal trends. They found that fire weather seasons have lengthened across 29.6 million km² (25.3%) of the Earth's vegetated surface, increasing the global mean fire weather season length by 18.7%. The area affected by long fire weather seasons (>1.0 σ above the historical mean) doubled (108.1% increase), and the frequency of such seasons increased across 62.4 million km² (53.4%) during the second half of the study period. These changes, coupled with ignition sources and available fuel, could significantly impact global ecosystems, societies, economies, and climate. The study highlights the importance of understanding these changes to effectively manage wildfires and mitigate their negative socio-economic impacts.The study examines the impact of climate change on global wildfire activity from 1979 to 2013. Using three daily global climate datasets and three fire danger indices, the researchers developed a metric to measure the length of fire weather seasons and mapped spatio-temporal trends. They found that fire weather seasons have lengthened across 29.6 million km² (25.3%) of the Earth's vegetated surface, increasing the global mean fire weather season length by 18.7%. The area affected by long fire weather seasons (>1.0 σ above the historical mean) doubled (108.1% increase), and the frequency of such seasons increased across 62.4 million km² (53.4%) during the second half of the study period. These changes, coupled with ignition sources and available fuel, could significantly impact global ecosystems, societies, economies, and climate. The study highlights the importance of understanding these changes to effectively manage wildfires and mitigate their negative socio-economic impacts.