Exploring the Effects of the Built Environment on Heating in LA
It’s no secret that climate change is causing global temperatures to rise. The European Copernicus Climate Change Service now expects the three-year average global temperature from 2023 to 2025 to breach the 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial level threshold for the first time. But it’s not just the burning of fossil fuels on a planetary scale that is raising the mercury in the thermometer. The form of our built environment – full of concrete and buildings that absorb heat during the day and release it at night, and with not enough green spaces that can act as cooling oases – means that urban areas are often hotter than their less built-up surroundings.
Los Angeles County is not immune to this urban heating effect – according to a new Urban Heating indicator on the National Equity Atlas (by PolicyLink and USC Equity Research Institute), 59% of all residents living in urban areas of the county – over 5.7 million people – experience at least eight degrees of additional heating due to the built environment, which is ranked in the top 14% of counties nationwide. This additional heating cuts across demographics, with majorities of every group living in neighborhoods with at least eight degrees of additional heating.
Although most Angelenos are affected at some level by increased urban heating, some have less ability to address or adapt to the issue of extreme heat. According to the National Equity Atlas, about 60% of both children and seniors, who are more susceptible to the health risks of extreme heat like heat stroke, live in neighborhoods with more than eight degrees of additional heating. About 60% of both immigrants and linguistically isolated households in urban LA County, who may have higher barriers to participation in policymaking that could address extreme heat, also live in such areas. Lower-income or renter households may not be able to invest in air conditioning to keep their homes cool. Communities of color in Los Angeles are still feeling the effects of historical redlining through disinvestment, more buildup of industrial areas, and a relative lack of environmental amenities like green space.
Urban heating is intricately linked to tree canopy coverage. Among other benefits, this coverage can directly reduce the urban heat effect by absorbing excess heat without releasing it back into the atmosphere and by providing havens of shade for residents. The National Equity Atlas’ new Urban Tree Canopy indicator shows that nearly 90% of residents living in urban areas in Los Angeles County live in neighborhoods with less than 10% tree canopy cover. Unlike urban heating itself, urban tree canopy coverage in LA County reveals more stark inequities – white Angelenos have significantly more tree canopy in their neighborhoods than do Angelenos of color, as do residents living above the poverty line as compared to those living below poverty.
These heat inequities make the work of local collaboratives like the South LA EcoLab all the more important to the environmental health of Los Angeles County. Funded by the Transformative Climate Communities program, the South LA EcoLab has brought together organizations like T.R.U.S.T. South LA, CicLAvia, Coalition for Responsible Community Development, GRID Alternatives, LA Neighborhood Land Trust, and others to offer numerous environmental initiatives for South Los Angeles. South LA EcoLab initiatives related to extreme heat adaptation include heat-reflective cool roofs and cool pavements, urban greening at an elementary school, and planting over 4,000 trees.
Outside of the South LA EcoLab initiative, these organizations (and many others) are engaging in additional efforts to combat extreme heat in Los Angeles. TreePeople has planted millions of trees throughout Southern California, including shade trees in communities facing extreme heat. SAJE has advocated for increased building decarbonization in Los Angeles, which would both mitigate heat-causing pollution and improve interior cooling systems. Climate Resolve has long advocated for increased cool roofs, pavements, and other surfaces in Los Angeles to directly reduce the urban heat effect. As with most environmental issues, it will take a combination of both mitigating and adaptive measures to combat the issue of extreme heat and the urban heat effect in Los Angeles – but organizations across the county are stepping up to the plate in keeping LA cool.
To learn more about urban heating and urban tree canopy, as well as lead exposure and toxic flood risk, visit the National Equity Atlas’ new environmental justice indicator pages. This data can support public officials, advocates, researchers, and residents concerned with environmental well-being, and each of the individual indicator pages contains additional context, key data trends, and strategies for addressing each issue.