Heat waves fueled by climate change fueled more than 100 wildfires across Ontario and northern Minnesota.By Phil McKenna, Keerti GopalSmoke from climate change-fueled wildfires in Canada and northern Minnesota blanketed skies across much of the Midwest and East Coast, exposing millions of Americans to dangerous levels of air pollution. The National Weather Service warned residents in exposed areas to stay indoors as researchers began to assess the death toll.