Cities Affect Global Weather Currents

The heat emanating from large metropolitan areas may be changing weather patterns thousands of miles away.

Jan 28, 2013
Edyta Zielinska

A composite image of Earth at night, compiled from over 400 satellite images, shows the locations of major cities, which new research suggests can have far-reaching effects on temperature. NASA AND NOAAEscaped heat from buildings, cars, and other sources can change the weather in other parts of the country, say the authors of a study published yesterday (January 27) in Nature Climate Change. According to the climate models, city-generated heat may be causing warming by 1 degree Celsius in North America and northern Asia mostly over the winter and fall months, by warming the jet stream currents flowing over cities. On the other hand, parts of Europe may experience decreases in temperature by the same amount, due to changes in atmospheric circulation caused by the warmed currents.

“The world’s most populated and energy-intensive metropolitan areas are along the east and west coasts of the North American and Eurasian continents, underneath the most prominent atmospheric circulation troughs and ridges,” co-author Ming Cai of Florida State University said in a press release. “The release of this concentrated waste energy causes the noticeable interruption to the normal atmospheric circulation systems above, leading to remote surface temperature changes far away from the regions where waste heat is generated.”

The study helps explain why some areas have been experiencing warmer winters than predicted by current climate change models.