The amount of energy needed to cool (or warm) buildings is proportional to cooling (or heating) degree days. The figure shows increases in population-weighted cooling degree days, which result in increased air conditioning use, and decreases in population-weighted heating degree days, meaning less energy required to heat buildings in winter, compared to the average for 1970-2000. Cooling degree days are defined as the number of degrees that a day’s average temperature is above 65°F, while heating degree days are the number of degrees a day’s average temperature is below 65°F. As shown, the increase in cooling needs is greater than the decrease in heating needs (Data from NOAA NCDC 2012da636886-4bc3-400b-8ce8-dc51f16ac54f).