A new study shows hot, dry and windy weather that fuels extreme wildfires has nearly tripled worldwide in 45 years. Researchers report the rise has sped up especially in the Americas. Wednesday's journal Science Advances shows that globally, big fire-prone days have nearly tripled from about 22 days a year in the 1980s to about 60 days a year lately. Scientists say climate change drives more than half the increase. The study team tracks “synchronous” fire weather, when many places face dangerous conditions at the same time. That overlap strains firefighters and worsens smoke and air quality.