Cooling measures are big and getting bigger: The global impact of air conditioning

Jul 29, 2016 by

More AC means billions of tons of increased carbon dioxide emissions into the atmosphere

, The Conversation  VIA SALON.COM

Cooling measures are big and getting bigger: The global impact of air conditioning

This article was originally published on The Conversation.

With a heat wave pushing the heat index well above 100°F (38°C) through much of the United States, most of us are happy to stay indoors and crank the air conditioning. And if you think it’s hot here, try 124°F in India. Globally, 2016 is poised to be another record-breaking year for average temperatures. This means more air conditioning. Much more.

In a paper published in the Proceedings of the National Academy of Science (PNAS), Paul Gertler and I examine the enormous global potential for air conditioning. As incomes rise around the world and global temperatures go up, people are buying air conditioners at alarming rates. In China, for example, sales of air conditioners have nearly doubled over the last five years. Each year now more than 60 million air conditioners are sold in China, more than eight times as many as are sold annually in the United States.

A ‘heat dome’ arrives in the U.S. NOAA Forecast Daily Maximum Heat Index

This is mostly great news. People are getting richer, and air conditioning brings great relief on hot and humid days. However, air conditioning also uses vast amounts of electricity. A typical room air conditioner, for example, uses 10 to 20 times as much electricity as a ceiling fan.

Meeting this increased demand for electricity will require billions of dollars of infrastructure investments and result in billions of tons of increased carbon dioxide emissions. A new study by Lawrence Berkeley Lab also points out that more ACs means more refrigerants that are potent greenhouse gases.

Evidence from Mexico

To get an idea of the global impact of higher air conditioner use, we looked at Mexico, a country with highly varied climate ranging from hot and humid tropical to arid deserts to high-altitude plateaus. Average year-round temperatures range from the high 50’s Fahrenheit in the high-altitude plateaus to low 80’s in the Yucatan Peninsula.

Graphic shows the range of average temperatures in Fahrenheit in different parts of Mexico. Davis and Gertler, PNAS, 2015. Copyright 2015 National Academy of Sciences, USA.

Patterns of air conditioning vary widely across Mexico. There is little air conditioning in cool areas of the country — even at high-income levels, penetration never exceeds 10 percent. In hot areas, however, the pattern is very different. Penetration begins low but then increases steadily with income to reach near 80 percent.

Davis and Gertler, PNAS, 2015. Copyright 2015 National Academy of Sciences, USA.

Davis and Gertler, PNAS, 2015. Copyright 2015 National Academy of Sciences, USA.

As Mexicans grow richer, many more will buy air conditioners. And as average temperatures increase, the reach of air conditioning will be extended, even to the relatively cool areas where saturation is currently low. Our model predicts that near 100 percent of households will have air conditioning in all the warm areas within just a few decades.

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