Planning for Climate Change Implications of High Temperatures and Extreme Heat for Los Angeles County (CA)

Problem, research strategy, and findings Climate scientists have developed high-resolution climate models to project local effects of climate change. However, such high-resolution climate information is not widely incorporated into climate change adaptation plans. In this study we analyze high-resolution (1.24 x 1.24-mile grid) temperature data generated by a climate model for Los Angeles County (CA). The data include projected surface air temperature and the number of extreme heat days (daily maximum temperature exceeding 95 degrees F) between a baseline period (1981-2000) and a mid-21st-century period (2041-2060). The data assume that human-induced greenhouse gas emissions will continuously increase at the current level and no change in existing built environments. We find significant geographic heterogeneity in terms of climate change effects in Los Angeles County. Also, given the assumptions, we expect inland suburban areas where urban expansion has been occurring to have more severe extreme heat effects than central and coastal areas by mid-century. Takeaway for practice Planners should engage with climate scientists to access and use high-resolution climate data. The use of high-resolution climate data needs to be mandated in plan-making in the era of climate change. Many regions may have different spatial patterns of extreme heat events and require tailored climate adaptation plans. In Los Angeles County, for example, continuing suburbanization in inland valley areas may need to be discouraged, whereas coastal areas with the least effects may consider denser, inclusive redevelopment strategies.