"Heat rising up from cities such as New York, Paris and Tokyo might be remotely warming up winters far away in some rural parts of Alaska, Canada, and Siberia, a surprising study theorizes."
"In an unusual twist, that same urban heat from buildings and cars may be slightly cooling the autumns in much of the Western United States, Eastern Europe and the Mediterranean, according to the study published Sunday in the scientific journal Nature Climate Change.
Meteorologists long have known that cities are warmer than rural areas, with the heat of buildings and cars, along with asphalt and roofs that absorb heat. That's called the urban heat island effect and it's long been thought that the heat stayed close to the cities.
But the study, based on a computer model and the Northern Hemisphere, now suggests the heat does something else, albeit indirectly. It travels about half a mile up into the air and then its energy changes the high-altitude currents in the atmosphere that dictate prevailing weather."