How heatwaves make life harder for homeless people

River Tiber in central Rome, Italy. LifeCollectionPhotography/Shutterstock Cities are getting hotter. Building materials like concrete or asphalt trap and radiate heat. Heat emissions from vehicles and air conditioning units are concentrated in urban areas, and there’s less of a breeze in built-up places. Alongside fewer trees or the absence of cooling rivers, heatwaves can feel harsher in urban areas, where homeless people are among the most vulnerable to extreme heat. Researchers like me…