addressing climate change adaptation in regional transportation plans

Adaptation ConsiderationsThe Desert region has a large population along its western edge and smallerpopulations to the east. The higher population areas are more prone to climatechange impacts associated with urban areas (heat and air quality). In the desertareas, climate change will have dramatic impacts on the fragile ecosystems.Ecosystems and BiodiversityMany of the species endemic to the inland desert areas of California are adaptedto a specific, often narrow, temperature and precipitation range. Changes tothe seasonal pattern can stress species, particularly aquatic species. Increasedtemperature and reduced precipitation can limit the existence and extent ofhabitats such as intermittent streams or other periodic habitats. For terrestrialspecies, migration becomes a critical point of assessment. Species such as thedesert tortoise have had their habitat fragmented and been stressed by invasivespecies and pest populations (CDFG, 2007).There are extensive federal land holdings in the region. Preserving species reliespartly on managing these lands (for grazing, solar installation, etc and managingthe adjoining lands to accommodate migration corridors.Water SupplySimilar to the South Coast region, the Desert region relies on water fromthe Colorado River and the State Water Project. Both of these sources beginwith mountain snowpack. Climate change will result in drastically reducedsupply from these sources. Declining snowpack in the San Gabriel Mountains,San Gorgonio Mountains, and San Jacinto Mountains will lead to permanentlydiminished local water supply.Public Health, Socioeconomic, and Equity ImpactsRiverside and San Bernardino counties rank fourth and seventh in the state in theabsolute numbers of the elderly and children less than five years of age. Thesetwo populations are most likely to suffer from heat-related illnesses and heatevents (English et al., 2007).Impervious surfaces are increasing in Riverside and San Bernardino counties,increasing the potential impacts of heat islands (English et al., 2007). Foothilland mountainous communities of this region may be particularly subject torespiratory and heat stress due to a combination of higher ozone levels, higherelevations, and increasing temperatures in these areas (English et al., 2007;Drechsler et al., 2006). Those most vulnerable to high levels of ozone andparticulate matter include people who work or spend a lot of time outdoors,such as agricultural employees in Imperial County and employees of the touristAPG: UNDERSTANDING REGIONAL CHARACTERISTICS PAGE 97