Contribution of air conditioning adoption to future energy use under global warming

Lucas W. Davis; Paul J. Gertler

doi:10.1073/pnas.1423558112

New Research In

Edited by B. L. Turner, Arizona State University, Tempe, AZ, and approved March 27, 2015 (received for review December 9, 2014)

Significance

The use of air conditioning is poised to increase dramatically over the next several decades as global temperatures go up and incomes rise around the world. In this paper, we use high-quality microdata from Mexico to characterize empirically the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Overall, our results point to air conditioning impacts being considerably larger than previously believed.

Abstract

As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change.

Footnotes

↵¹To whom correspondence may be addressed. Email: ldavis{at}haas.berkeley.edu or gertler{at}haas.berkeley.edu.

Author contributions: L.W.D. and P.J.G. designed research, performed research, analyzed data, and wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
^¶Deschênes and Greenstone predict an 11.0% increase in US residential energy consumption by end of century (6). This prediction uses an older emissions scenario (A1FI) that is comparable to RCP 8.5.
*Energy demand studies have long made this distinction between the intensive and extensive margins (4, 5).
^†This specification follows recent studies of the effect of temperature on electricity consumption in the United States (6, 8) and related studies on the effect of temperature on other outcomes (16–21).
^‡Deschênes and Greenstone find that each >90 °F day increases monthly consumption by 4.4%, and each 80–90 °F day increases monthly consumption by 2.0% (6). Their estimate for >90 °F is a bit higher than our estimate, but their estimate for 80–90 °F is right in the middle of our estimates for 80–85 °F and 85–90 °F.
^§Previous studies have also shown that warmer temperatures increase electricity consumption by refrigerators (22) and can lead households to watch more television and engage in other indoor activities (23).
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