Here in the United States, more than 88 million people are under excessive heat warnings and advisories again today. Smoke from hundreds of Canadian wildfires is triggering “unhealthy” air quality alerts across New England and as far south as Atlanta, Georgia, and Birmingham, Alabama. Today Phoenix, Arizona, is forecast to record its 18th consecutive day over 110 degrees Fahrenheit, with no respite in sight. A recent study found that a loss of the power grid in Phoenix during a heat wave would cause at least 12,000 deaths, with hundreds of thousands more needing treatment for heat-related illnesses.