On June 4, 2021, amid flowering saguaros and prickly pear cacti, a wildfire bloomed in the Sonoran Desert in central Arizona. Its nascent flames gorged on nonnative grasses desiccated by a long, severe drought, and the fire was further nourished by the weather. A nearby weather station recorded a temperature of 36° Celsius (97° Fahrenheit). And it was so dry that the blades of firefighters’ bulldozers — used to clear brush — sparked small flames as the heavy vehicles dragged on rocks. Fire ecolo...