Climate and Energy Action Plan (CEAP)

CLIMATE TRENDS & PRO JECTIONS | CITY OF ASHLAND, OREGON | FINAL REPORT | 3 Summary of Key Findings Temperature . Ashland has experienced significant warming over the last 120 years. Going forward, the temperatu re is projected to increase by 5 °F on average by the 205 0s and 8°F by the 2080s under the high emissions scenario. Warming may be more pronounced in the summer. Extreme Heat . The hottest day of the year in Ashland is projected to increase by about 7°F by the 2050s and 12°F by the 2080s under the high emissions sce nario. Warm spells are projected to comprise about 40 more days of the year by the 2050s and 90 more days of the year by the 2080s compared to the historical baseline. The number of daytime high temperatures reaching 100°F or more is projected to increase by 11 days by the 2050s and 27 days by the 2080s . The number of nighttime low temperatures staying above 60°F is projected to increase by 15 days by the 2050s and by 38 days by the 2080s. Cold Extremes. The coldest night of the year in Ashland is projected to increase by about 5°F by the 2050s and by about 8°F by the 2080s under the high emissions scenario. The number of days in which the temperature drops below freezing are projected to decline by about 50 days by the 2050s and by about 80 days by the 2080 s compared to the historical baseline . Degree Days . Degree days measure how much heating or air conditioning is required for buildings to maintain a comfortable temperature. With projected increasing temperatures, the need for heating will decrease, wi th projected declines in heating degree days of about 1240 °F-days by the 2050s and about 2,000 °F -days by the 2080s under the high emissions scenario. Meanwhile, the need for air conditioning will increase, with projected increases in cooling degree days of about 530 °F-days by the 2050s and about 1,000 °F -days by the 2080s . Precipitation . There was no significant change in total precipitation in Ashland over the last 120 years. Future projections are split: some models project an increase in total annu al precipitation and others project decreases. Cool season precipitation may increase and warm season precipitation may decrease in the future. Changes in precipitation have been and will continue to be dominated by natural variability, rather than climate change. Extreme Precipitation . It is generally expected that heavy precipitation events wil l become more common. Under the high emissions scenario, the number of days with more than 20 mm of precipitati on is projected to increase by 0.3 days by the 205 0s and 0.7 days by the 2080s . Meanwhile, the total amount of rainfall during the year that falls during the heaviest 5% of days is projected to increase by more than half an inch by the 2050s and more than an inch by the 2080s for the multi -model mean. In addition, the longest dry spell in a ye ar is projected to increase by 5 days on average by the 2050s and by 6 days by the 2080s . While the majority of models project increases in these extreme precipitation measures, some project decreases. This report presents future climate projections for Ashl and for the 2050s and 2080s compared to the 1950 - 2005 average historical baseline. T he projections were analyzed for a low greenhouse gas emissions scenario as well as a high greenhouse gas emissions scenario, using multiple models. This summary lists only the mean projections for the 2050s and 2080s under the high emissions scenario. P rojections for both time periods and both emissions scenarios are listed in Table 2 of the report.