A collaborative research project between Arizona State University and the University of California, Los Angeles funded by the National Science Foundation's Infrastructure Management and Extreme Events program (Awards 1335556 and 1335640).

coolme.today website
Extreme Heat Futures
Electricity Generation Vulnerability Presentations

ASU & UCLA Researchers

Prioritizing Cooling Infrastructure Investments for Vulnerable Southwest Populations

The vulnerability to heat of urban Southwest populations is a combination of social and built environment (infrastructure) factors. To date, heat vulnerability research has largely been focused on social factors (including age, chronic disease, poverty level, and English proficiency, among others) and few studies have considered how infrastructure enables or restricts access to cooling. New methods are needed for i) categorizing and quantifying the significance of infrastructure systems in providing protection from heat, and ii) joining social and infrastructure vulnerability to heat indices into a single framework that will allow city agencies to prioritize investments.

The Southwest is expected to experience more heat days and water shortages in the future which magnifies the need to characterize the vulnerability of population subgroups to heat events as a function of both socio-demographic and built environment characteristics. Social vulnerability analysis has provided valuable insight into the socio-demographic factors that put communities at risk during heat events, but little is known about how infrastructure systems amplify vulnerability. Building construction practices, home air conditioning, electricity generation and transmission, and cooling centers can contribute to a community’s heat-related vulnerability. This project will develop methods for joining social and built environment vulnerability into a single framework, and will create a prioritization framework for selecting investments in cooling infrastructure that maximize the reduction in vulnerability across two Southwest counties: Los Angeles and Maricopa (Phoenix metro area).

The proposed integrated social and infrastructure vulnerability framework will produce novel methods for estimating the additional risk to heat that result from built environment characteristics, and will identify efficient cooling infrastructure investment strategies for reducing this risk. The project will focus on two urban areas that are highly vulnerable to heat, with large socio-economic disparities, immigrant communities, linguistic isolation, and increasingly uncertain water supplies, as well as very different infrastructure (Los Angeles grew largely between 1940-1980 and Phoenix from 1980 on). (a) Environmental, social, and infrastructure vulnerability indices will be developed. The infrastructure indices will include building shell analysis, home air conditioning, electricity generation and transmission, and cooling centers, at a census tract resolution. (b) The indices will be joined to create a socio-technical vulnerability index (STVI). (c) The STVI will weigh the infrastructure vulnerability indexes against the social and each other to account for the relative impacts of infrastructure services on morbidity and mortality outcomes, using two approaches for weight estimation: regression and stochastic assessment. The use of two approaches will provide the research team with an opportunity to i) assess the feasibility of developing infrastructure index weightings from existing urban built environment and morbidity/mortality data and ii) develop novel stochastic weighting methods for cities when low quality data exist to assess the likelihood that one infrastructure characteristics is more or less significant than another. (d) The weighted STVI index will be used to develop a framework for assessing how cities should prioritize infrastructure investments by considering building weatherization, air conditioning rebates, rooftop solar, tree planting, and cooling center placement. (e) The STVI and prioritization strategies for Los Angeles and Maricopa will be compared to understand the socio-demographic and built environment differences between each county and identify the key drivers that other cities should focus on


We have developed an interactive web-based map for cities to advertise cooling centers and hydration stations: coolme.today. The map launched in Spring 2014 for Phoenix and Los Angeles and has since been expanded to include heat refuges in San Diego.

Estimating Future Extreme Heat Events in the U.S. Southwest

Already the leading cause of weather-related deaths in the United States, extreme heat events (EHEs) are expected to occur with greater frequency, duration and intensity over the next century. However, not all populations are affected equally. Risk factors for heat mortality—including age, race, income level, and infrastructure characteristics—often vary by geospatial location. While traditional epidemiological studies sometimes account for social risk factors, they rarely account for intra-urban variability in meteorological characteristics, or for the interaction between social and meteorological risks. This study aims to develop estimates of EHEs at an intra-urban scale for two major metropolitan areas in the Southwest: Maricopa County (Arizona) and Los Angeles County (California). EHEs are identified at a 1/8-degree (12 km) spatial resolution using an algorithm that detects prolonged periods of abnormally high temperatures. Downscaled temperature projections from three general circulation models (GCMs) are analyzed under three relative concentration pathway (RCP) scenarios. Over the next century, EHEs are found to increase by 340-1800% in Maricopa County, and by 150-840% in Los Angeles County. Frequency of future EHEs is primarily driven by greenhouse gas concentrations, with the greatest number of EHEs occurring under the RCP 8.5 scenario. Intra-urban variation in EHEs is also found to be significant. Within Maricopa County, “high risk” regions exhibit 4.5 times the number of EHE days compared to “low risk” regions; within Los Angeles County, this ratio is 15 to 1.

Additional information is available at urbantransitions.org/extremeheat.
Background report: Matthew Bartos and Mikhail Chester, 2014, "Assessing Future Extreme Heat Events at Intra-Urban Scales: A Comparative Study of Phoenix and Los Angeles", Arizona State University Report No. ASU-CESEM-2014-WPS-001.


Electricity and the environment are inextricably linked and with climate change there is potential that energy generation systems become vulnerable. Through modelling of changes in climate and hydrology the impacts on thermoelectric and hydroelectric power generation are assessed. As surface water flows change, electricity generation technologies become vulnerable and may operate with reduced margins between supply and demand. We explore this uncertainty in this project theme.

Deepak Sivaraman, Matthew Bartos, Mikhail Chester, and Stephanie Pincetl 2014, "Future Electricity Supply Vulnerability and Climate Change: A Case Study of Maricopa and Los Angeles Counties", Arizona State University Report No. ASU-CESEM-2014-WPS-003.

Matthew Bartos and Mikhail Chester, 2014, "Methodology for Estimating Electricity Generation Vulnerability to Climate Change Using a Physically-based Modelling System", Arizona State University Report No. ASU-CESEM-2014-WPS-002.

Research Team

Mikhail Chester, Ph.D.
Assistant Professor, Civil, Environmental, and Sustainability Engineering
Arizona State University

Matthew Bartos
Arizona State University

Paul English, Ph.D.
Branch Science Advisor for the Environmental Health Investigations Branch
California Department of Public Health

David Eisenman, M.D., M.S.H.S.
Director of the Center for Public Health and Disasters and an Associate Professor in Residence in the David Geffen School of Medicine and the Fielding School of Public Health
University of California, Los Angeles

Andrew Fraser
Graduate Student
Arizona State University

Holly LeClair
Senior Statistician in the Department of Medicine Statistics
University of California, Los Angeles

Stephanie Pincetl, Ph.D.
Adjunct Professor and Director of the California Center for Sustainable Communities, Institute of the Environment and Sustainability
University of California, Los Angeles

Thomas Seager, Ph.D.
Associate Professor in Civil, Environmental, and Sustainability Engineering
Arizona State University

Deepak Sivaraman, Ph.D.
Energy Economist and Analyst
Pacific Northwest National Laboratory


Technical Advisory Committee presentation to Los Angeles stakeholders on September 28, 2015:

Technical Advisory Committee presentation to Phoenix stakeholders on August 3, 2015: