City Heat May Change Temps Thousands of Miles Away

You may not be able to see it, but heat from cars, trucks, buildings rises up to the atmosphere where it can increase local temperatures on the ground. It’s called waste heat and big cities are major sources of it. Waste heat can affect local weather patterns, and weather patterns hundreds and even thousands of miles away.

“It does affect the regional climate by changing the atmospheric circulation,” said Aixue Hu, an atmospheric scientist at the National Center for Atmospheric Research in Boulder, Colo.

For the first time researchers have learned that waste heat can influence winter weather patterns and cause warming across large areas of the northern U.S. and into northern Asia.

It has been shown to cause an increase in temperatures in some areas by as much as 1.8 degrees Fahrenheit. The “waste heat” may also widen the flow of the jet stream – changing the way warm and cold air move around the globe.

“We see the jet stream location actually is slightly moved southward; that means the jet stream has become stronger,” said Hu.

Waste heat’s influence on local temperatures may explain why some areas have more winter warming than projected by climate models – giving meteorologists a better understanding of human impact on the weather.