BOGOTA, Colombia — Chile is reeling from one of its most serious wildfire emergencies in years. Deadly flames sweeping across central and southern parts of the South American country have turned large swaths of forest and towns to ash. Fire scientists say the blazes are being driven not only by extreme heat, drought and wind, but also by how human-shaped landscapes interact with changing climates — a lethal mix that makes fires harder to control. …The fires have razed forests, farmland and hundreds of homes. …What distinguishes Chile’s current fire season isn’t an unusual surge in the number of fires, but the amount of land they are burning. …Miguel Castillo, at the University of Chile… “almost tripling the amount of affected area,” even though the number of fires so far is “within normal margins.” That means fewer ignitions are causing far greater damage — a pattern increasingly seen in extreme wildfire seasons around the world.