The Relative Effects of U.S. Population Shifts (1930-80) on Potential Heating, Cooling and Water Demand

Abstract

The effects on potential heating, cooling and water demand induced by the shift and growth of population from cooler and wetter regions of the country to warmer and drier areas were examined. Heating and cooling degree day totals for each of the 48 contiguous states were weighted by population to obtain national totals using U.S. Census figures starting with the 1930 Census. We also developed categorical measures of population in relation to mean annual precipitation and precipitation variability. The water year October to September was used instead of the calendar year to take into account seasonal factors. The shift in population from the Northeast and Midwest to the South and Southwest United States has resulted in relatively lower heating but greater cooling demand on a national basis in the 1980s as compared with the results obtained using the 1930 Census. The increase in population in the arid West has increased the region's sensitivity to precipitation, and hence streamflow fluctuations.