DALLAS — It’s the middle of June and just shy of 11 a.m. on a Wednesday. The track and infield at David W. Carter High School is bustling. The sky is mostly clear and bluer than a teenager’s tongue after a Jolly Rancher. The Texas heat is already sweltering, as if the sun rose from the East and loitered just south of I-20. It was hot enough to laminate skin with sweat. To dehydrate the dandelions on the barren grassy field across the street. To wonder if Willis Carrier deserved a Nobel Prize for his 1902 invention of the modern air conditioner.