1. In Northern California, the death toll from the Carr Fire rose to six, and seven people are missing. The fire is only 20 percent contained, and it’s just one of about a dozen that emergency response crews have battled around the state in recent days. Above, a scene in Redding.

Scientists link the new frequency and intensity of the state’s fires to climate change, which is also a driver of record-breaking heat waves around the world.

We talked to people experiencing extreme temperatures on four continents, including a worker at an Algerian oil plant who walked off the job as the temperature hit 124 degrees Fahrenheit. “We couldn’t keep up,” he recalled. “It was impossible to do the work. It was hell.”