greece, where more than 90 people died. record heat there and here caused by a loopy weakened jet stream that's not moving hot air along. yet, scientists blame climate change, too. >> when you melt the sea ice in the arctic and you change the temperature patterns in the atmosphere, you actually change the jet stream him you change it in a way that you slow it down. >> reporter: fire and heat altering landscapes in the northern half of the world. anne thompson, nbc news, new york. >> bill, it's a scary thought that this fire season is now a year-round season and the weather doesn't seem to be helping out there on the west coast. >> you think of the climate change on the jet stream. there is a lot of unknown. there's theories out there about what will happen. stalled out jet stream increases to areas of flooding and drought