At the turn of the 2000s, Valley fever was an obscure fungal disease in the United States, with fewer than 3,000 reported cases per year, mostly in California and Arizona. Two decades later, Valley fever cases exploded, increasing more than sevenfold and spreading to other states. And Valley fever is not alone. Fungal diseases are generally appearing in places where they haven’t been before, and previously harmless or mildly harmful fungi are becoming deadly to humans. One likely reason for this worsening fungal situation, scientists say, is climate change. Changes in temperature and precipitation are expanding where disease-causing fungi are found; climate-induced disasters can help fungi spread and affect more people; and warmer temperatures create opportunities for fungi to evolve into more dangerous disease-causing agents. (DANA SMITH)