The burden of heat-related mortality attributable to recent human-induced climate change

Medical Research Council-UK (Grant ID: MR/M022625/1); Natural Environment Research Council UK (Grant ID: NE/R009384/1); European Union’s Horizon 2020 Project Exhaustion (Grant ID: 820655); N. Scovronick was supported by the NIEHS-funded HERCULES Center (P30ES019776); Y. Honda was supported by the Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency, Japan (JPMEERF15S11412); J. Jaakkola was supported by Academy of Finland (Grant No. 310372); V. Huber was supported by the Spanish Ministry of Economy, Industry and Competitiveness (Grant ID: PCIN-2017-046) and the German Federal Ministry of Education and Research (Grant ID: 01LS1201A2); J Kysely and A. Urban were supported by the Czech Science Foundation (Grant ID: 20-28560S); J. Madureira was supported by the Fundação para a Ciência e a Tecnologia (FCT) (SFRH/BPD/115112/2016); S. Rao and F. di Ruscio were supported by European Union’s Horizon 2020 Project EXHAUSTION (Grant ID: 820655); M. Hashizume was supported by the Japan Science and Technology Agency (JST) as part of SICORP, Grant Number JPMJSC20E4; Y. Guo was supported by the Career Development Fellowship of the Australian National Health and Medical Research Council (#APP1163693); S. Lee was support by the Early Career Fellowship of the Australian National Health and Medical Research Council (#APP1109193)

Household accessibility to heat refuges: Residential air conditioning, public cooled space, and walkability

Access to air conditioned space is critical for protecting urban populations from the adverse effects of heat exposure. Yet there remains fairly limited knowledge of the penetration of private (home air conditioning) and distribution of public (cooling centers and commercial space) cooled space across cities. Furthermore, the deployment of government-sponsored cooling centers is likely to be inadequately informed with respect to the location of existing cooling resources (residential air conditioning and air conditioned public space), raising questions of the equitability of access to heat refuges. We explore the distribution of private and public cooling resources and access inequities at the household level in two major US urban areas: Los Angeles County, California and Maricopa County, Arizona (whose county seat is Phoenix). We evaluate the presence of in-home air conditioning and develop a walking-based accessibility measure to air conditioned public space using a combined cumulative opportunities-gravity approach. We find significant variations in the distribution of residential air conditioning across both regions which are largely attributable to building age and inter/intra-regional climate differences. There are also regional disparities in walkable access to public cooled space. At average walking speeds, we find that official cooling centers are only accessible to a small fraction of households (3% in Los Angeles, 2% in Maricopa) while a significantly higher number of households (80% in Los Angeles, 39% in Maricopa) have access to at least one other type of public cooling resource such as a library or commercial establishment. Aggregated to a neighborhood level, we find that there are areas within each region where access to cooled space (either public or private) is limited which may increase heat-related health risks

Integrated Assessment of Urban Overheating Impacts on Human Life

10.1029/2022EF002682EARTHS FUTURE10

Heat/mortality sensitivities in Los Angeles during winter: a unique phenomenon in the United States

Abstract Background Extreme heat is often associated with elevated levels of human mortality, particularly across the mid-latitudes. Los Angeles, CA exhibits a unique, highly variable winter climate, with brief periods of intense heat caused by downsloping winds commonly known as Santa Ana winds. The goal is to determine if Los Angeles County is susceptible to heat-related mortality during the winter season. This is the first study to specifically evaluate heat-related mortality during the winter for a U.S. city. Methods Utilizing the Spatial Synoptic Classification system in Los Angeles County from 1979 through 2010, we first relate daily human mortality to synoptic air mass type during the winter season (December, January, February) using Welch’s t-tests. However, this methodology is only somewhat effective at controlling for important inter- and intra-annual trends in human mortality unrelated to heat such as influenza outbreaks. As a result, we use distributed lag nonlinear modeling (DLNM) to evaluate if the relative risk of human mortality increases during higher temperatures in Los Angeles, as the DLNM is more effective at controlling for variability at multiple temporal scales within the human mortality dataset. Results Significantly higher human mortality is uncovered in winter when dry tropical air is present in Los Angeles, particularly among those 65 years and older (p < 0.001). The DLNM reveals the relative risk of human mortality increases when above average temperatures are present. Results are especially pronounced for maximum and mean temperatures, along with total mortality and those 65 + . Conclusions The discovery of heat-related mortality in winter is a unique finding in the United States, and we recommend stakeholders consider warning and intervention techniques to mitigate the role of winter heat on human health in the County