Think of a cooling system in a big mall, or Hollywood sightseeing buses on a freeway. It takes energy to run them, and burning coal and oil to do that generates waste heat.
Scientists who study energy use in big cities have concluded that everyday activities like driving cars or heating buildings – activities that generate waste heat – influence the weather.
A new study published in Nature Climate Change, by researchers from the National Center for Atmospheric Research, the Scripps Institute of Oceanography, and Florida State University, analyzed global energy consumption to learn more about waste heat.
They found that the energy people use every day can widen the jet stream - changing global atmospheric systems, and influencing temperatures, with a noticeable effect in Europe.
“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,” FSU’s Ming Cai said in a written statement. “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.”
Globally, the change in temperature attributable to waste heat is pretty small – on average, a tenth of a degree Fahrenheit. But scientists say the findings sharpen their understanding of the ways people in big cities influence climate and weather patterns. They believe the new research will deepen the resolution of computer models other scientists use to predict climate, strengthening predictive tools.