Climate and Energy Action Plan (CEAP)

CLIMATE TRENDS & PRO JECTIONS | CITY OF ASHLAND, OREGON | FINAL REPORT | 18 Heating & Cooling Degree Days The amount of heating or cooling required in buildings is partially determined by how much the air temperature is below or above 65°F, and for how long, defined as heating or cooling degree -days. For example, one day with an average temperature of 64°F counts as one heating degree -day. With projected warming tem peratures, the need for heating as expressed by the number of heating degree -days is projected to decline while the need for cooling as expressed by the number of cooling degree -days is projected to increase ( see Figure 10). The r ange across all models and both emissions scenarios of future changes in heating degree -days in Ashland is -473 to -1600 °F -days for the 2050s and -641 to -2455 °F-days for the 2080s (Table 2 ). For future changes in cooling degree -days in Ashland, the rang e across all models and both emissions scenarios of future changes is +200 to +762 for the 2050s and +279 to +145 5 °F-days for the 2080s ( refer to Table 2). The multi -model mean projects a decrease of 2008 heating degree -days , a 37% decrease, and an increase of 994 cooling degree -days , a 303% increase, by the 2080s under the high emissions scenario compared to the historic baseline (1950 -2005). Thus, as the climate changes, less heating will be required to heat buil dings, but much more air conditioning will be required to cool buildings. Figure 10. Projections of heating degree days (top) and cooling degree days (bottom) with a base of 65°F for average temperature for Ashland as simulated by 18 downscaled global climate models for the historical period (1950 -2005) and future (2006 -2099) under a low (RCP4.5) and high (RCP8.5) greenhouse gas emissions scenario. Solid line and shading depicts the 18 -model mean and range, respectively . The multi -model mean differences for the 2050s (2040 -2069 average) and 2080s (2070 -2099 average) compared to the historical baseline (1950 -2005) are displayed . Ashland Ann ual (J ul−Jun) T otal Heating Degree Da ys Base 65°F°F−Day Histor ical Low (RCP4.5) High (RCP8.5) 2050s −976 °F .day 2050s −1240 °F .day2080s −1256 °F .day 2080s −2008 °F .day200030004000500060007000 1950 1970 1990 2010 2030 2050 2070 2090 Ashland Ann ual (Jan−Dec) T otal Cooling Degree Da ys Base 65°F°F−Day Histor ical Low (RCP4.5) High (RCP8.5) 2050s +368 °F .day2050s +526 °F .day 2080s +506 °F .day2080s +994 °F .day 0200400600800100012001400160018002000220024002600 1950 1970 1990 2010 2030 2050 2070 2090