This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration. The morning temperature is nearing 100 degrees Fahrenheit as Keith Seaman sweats beneath his bucket hat, walking door to door through the cookie-cutter blocks of a subdivision in Casa Grande, Arizona. Seaman, a Democrat who represents this Republican-leaning area in the state’s House of Representatives, is trying to retain a seat he won by a margin of around 600 votes just two years ago.