WASHINGTON (AP) - 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.

At least that's what a surprising study suggests.

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.

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. It's long been thought that the heat stayed close to the cities.

But the study in the journal Nature Climate Change suggests the heat travels about half a mile up and its energy changes air currents.