In the three years that Nicole Rae and Brian Mastenbrook lived in the San Francisco Bay Area, they grew increasingly concerned about California’s wildfires. The skies would turn orange, ash would settle on plants and porch railings, and Ms. Rae, a 30-year-old teacher who has asthma, would have trouble breathing.So in May, she and Mr. Mastenbrook, a 37-year-old tech worker, sold their home and moved to Ann Arbor, Mich. Mr. Mastenbrook has family in Michigan, and officials in Ann Arbor were taking steps to lower the city’s carbon footprint.They admired plans for a “net zero” community there, Veridian at County Farm, to be filled with solar-powered, all-electric homes that would be free of the fossil fuels whose greenhouse gas emissions have contributed to climate change.“If those homes were built and ready to buy today,” Ms. Rae said, “we already would have purcha …
