heat island
This has been known for years. It is very frustrating to see people ask questions like "well, what we don't know is what will global warming do?" Global warming has done, already, quite a bit and it is insulting to our collective intelligence and an affront to the families of those who have died from it to pretend nothing has happened. From desertification in Africa to heat waves in Chicago, global warming has killed people. Perhaps the following video from PBS will make this a bit more palpable to those who can't grasp this concept.