By  Priyanka Runwal , data and science reporter, Climate Central and  Lori Valigra , Bangor Daily News A man crosses the street in downtown Biddeford on a scorching Thursday, Aug. 12, 2021. Credit: Troy R. Bennett / BDN BIDDEFORD, Maine — Duane Dennison knows more than most about the effects of hotter summers and heat lingering into the night: He lives near the Saco River in a tent community of about 20 people experiencing homelessness. As temperatures soared into the mid-90s Aug. 12, the 61-year-old painter sought relief at the Seeds of Hope Neighborhood Center, which offers air conditioning, snacks and a place to socialize for up to 30 people at a time. His options to cool off in the summer are the cooling shelter, swimming in the river or hanging out at the local supermarket’s meat department. “It’s harder in summer than the winter,” Dennison said of trying to stay comfortable outside.…