Impacts of Multiple Climate Change Stressors on Health in California
To apply for this project, see the pre-proposal solicitation requirements on the solicitation landing page.
Scope of Work
Understanding the overall impacts of climate events and stressors on health is an important new direction of focus for CARB. CARB is developing a tool, the Climate Vulnerability Metric, that will quantify the cumulative community-level impacts of a warming climate on human welfare. This study is focused on a different aspect of cumulative impacts and will not be developing a tool or cumulative score of climate effects. This study will instead seek to assess the cumulative and interactive effects of multiple climate stressors in different regions of the state. The goal for this project is to understand the cumulative impact of multiple climate stressors of combined climate stressors (i.e., heat, air pollution, wildfires, drought) in regional contexts alongside environmental justice, racial equity, and social vulnerability factors. The cumulative impact assessment here refers to the evaluation of exposures to more than one climate stressor (including chemical, physical, and social factors that may have a role in the exposures) and/or their pathway by considering the interactions among stressors.1 By examining the cumulative health impacts in regional contexts, this project can help determine which climate stressors are driving the health impacts in different regions. The characterization of the dominant climate stressors and the information on health effects from interactions of climate impacts in different California regions will expand CARB’s ability to analyze health effects of actions to reduce greenhouse gases, particularly in vulnerable communities. This study would provide additional information to supplement and improve CARB’s health analysis of climate actions, going beyond, for example, the analysis in the health appendix included in CARB’s 2022 Scoping Plan.2 CARB expects the study will help inform CARB’s programs and policies on the need for health and equity benefits in the face of multiple, and increasingly co-occurring, climate change stressors.
Climate change is considered the greatest threat to global public health.3 In California, more frequent and severe wildfires, extreme heat waves, drought, and a variety of other direct and indirect impacts are already significantly harming human health and well-being. Notably, vulnerable communities/populations are disproportionately affected by climate change due to their increased exposure to pollution, less capacity for adapting to climate hazards, and higher levels of pre-existing medical conditions and other socioeconomic and structural stressors. There is an array of health literature on individual climate impacts. For instance, exposure to wildfire smoke has been linked to a greater risk of respiratory and cardiovascular diseases, specifically for more susceptible groups such as children, seniors, and those with underlying chronic diseases.4 Hotter temperature or heat is another widely studied climate stressor. Heat exposure is associated with increased risks of mortality and morbidity (e.g., hospitalization for various diagnoses including cardiovascular disease, acute renal failure, respiratory disease, and birth outcomes).5,6,7,8 Children, the elderly, those with pre-existing conditions, outdoor workers, and low social economic status groups are found to be more vulnerable to heat-related health risks.9
Hotter temperatures not only lead to heat-related illness, but they can also lead to increased air pollution related illness and elevated health effects from the combined health risks. Zhu et al.’s study predicted the future air quality for ozone and PM2.5 in three major California air basins and reported a strong likelihood of poorer air quality due to the warmer weather, specifically in the areas that have been disproportionately affected by these pollutants.10 Schwarz et al.’s study investigated the joint effects between heat and ozone exposure on respiratory hospitalizations in California communities, and found the joint effects varied geographically (i.e. some zip codes had stronger joint effects than others).11 The combination of exposures to extreme heat and air pollution episodes leads to increased health burdens on communities.
However, the cumulative health impacts of multiple climate stressors are under-examined. This is particularly true in assessing cumulative climate change-related health burdens on populations and communities experiencing climate vulnerabilities, racial and health inequities, and long-standing environmental injustices. By applying a racial equity assessment lens,12 this project aims to assess the cumulative and interactive health impacts of multiple climate stressors (e.g., heat, air pollution, wildfires, and drought) and social determinants of health. CARB will use the results of this project to deepen and broaden our understanding of cumulative climate-health risks and climate vulnerability13 in California, and further inform and prioritize California’s climate actions and mitigation programs.
III. Scope of Work
The study will estimate the cumulative and interactive health impacts from increased temperature, air pollution, wildfire smoke, and drought (if possible) for different regions and/or communities throughout California and include effects of social determinants of health (e.g., race/ethnicity, income levels, etc.). Since California includes areas that are impacted by different climate stressors, it will be important to conduct the study in multiple regions of the state, including but not limited to the San Joaquin Valley and the South Coast as well as other areas. This project will not only investigate the interaction of climate stressors on health but will also study how social determinants of health influence the cumulative health risks and effects associated with multiple climate impacts. Furthermore, this project will attempt to quantify and if possible, monetize the cumulative health impacts of multiple climate change stressors. CARB is requesting a multidisciplinary team consisting of researchers with exposure, health, and racial equity expertise and skills to design a study that not only fulfills the research goals but also incorporates a racial equity assessment lens. CARB expects that the results of this study will provide information that can assist CARB in understanding regionally dominant climate stressors and associated health impacts, as well as cumulative impacts, and expand CARB’s ability to analyze health effects of actions to reduce greenhouse gases in different regions. This information would, for example, assist CARB in conducting health analysis such as the health appendix included in CARB’s 2022 Scoping Plan. The study approaches could include some or all of the following: quantitative research (preferred; such as an original epidemiology study or a meta-analysis) and qualitative research (i.e. exploring how different climate stressors interact/enhance the associated health effects). Conclusions should include an evaluation, on a regional and local basis for areas across California, of the dominant climate stressors and related cumulative health impacts.
Task 1. Identify research needs in climate-health studies
The investigators will conduct a comprehensive literature review on recent research that investigates how individual and combined climate stressors (e.g., heat, air pollution, wildfires, drought, etc.) affect health outcomes. Population and epidemiology studies are preferable but not exclusively. A gap in previous research, particularly for health impacts of combined climate stressors, should be identified. Suggested sub-tasks include:
- Climate stressors that are most important in California.
- Key climate stressors to include in this study and key focus regions of California.
We expect the results of this task would be region-specific climate stressors and the research gaps that would help to prioritize the climate stressors and California regions assessed in the following tasks.
Task 2. Assess exposure to combined climate stressors
The investigators will conduct region-specific assessments of combined human exposure to multiple climate stressors (e.g., heat, air pollution, wildfires, drought, etc.) across multiple areas in California and over the past years/decades by using state-of-the-art techniques and/or leveraging their previous work and available online resources/tools. Suggested sub-tasks include:
- Conduct exposure assessments for selected climate stressors in different California regions to identify regionally dominant and impactful climate stressors;
- Investigate the interaction and enhancements of different climate stressors;
- Examine the differences of exposure to climate stressors among racial/ethnic subgroups that may be more vulnerable to climate effects due to reduced resources such as air conditioning for reducing heat effects.
We expect the results of this task would be characteristics of the most dominant and impactful climate stressors, their interaction and distribution among racial/ethnic subgroups within different regions of California. The exposure assessment would be used in Task 3 for the estimations of cumulative health impacts.
Task 3. Estimate cumulative health impacts of combined climate stressors
Suggested sub-tasks include:
- The investigators will obtain population data from available datasets on health outcomes that have been previously linked to the identified key climate stressors (i.e. the findings from Task 1), including but not limited to the disease burden of respiratory, cardiovascular, and heat-related illnesses, emergency department visits, hospitalizations, mortality, birth outcomes, and mental illness. When selecting health datasets, the investigators should consider whether the datasets are representative of diverse demographic and socioeconomic groups, particularly for vulnerable populations. Covariates identified in previous research need to be included.
- The investigators will utilize the exposure assessment conducted in Task 2 to estimate the cumulative health impacts of combined climate stressors by California regions. The region-specific health impact assessments need to consider interaction effects of multiple climate stressors, for example in the context of increasing temperatures. The investigators will also control confounding factors, perform sensitivity analyses, and test statistical validity (if applicable).
- If applicable, by using the health impact estimates found in this study (Task 3-B), the investigators should seek to quantify and if possible monetize the impacts of the cumulative health impacts of combined climate stressors , e.g., a cost saving from averted premature deaths due to temperature increases in combination with exposure to worsen air pollution and wildfire smoke (investigators are not requested to estimate health and economic impacts for future scenarios).
We expect to obtain region-specific health impact estimates for multiple health endpoints of interest. If possible, we would like to have the estimation of health and economic impacts based on the health impact estimates developed in this study (but we are not asking for future predictions).
Task 4. Investigate social determinants of climate-health equity
Building upon Task 3, the investigators will identify social determinants of climate health (e.g., racism or discrimination based on race/ethnicity, income, proximity to air pollution sources, ownership and use of air conditioning, housing access, lengthy commuting to places of employment, social isolation, loss of community, food deserts, urban/rural divide, availability of neighborhood tree canopy and shade, and other factors) and investigate whether and how these social determinants would modify, interact, or mediate the cumulative health risks of combined climate stressors.
We expect the results would be region-specific health impact estimates for the dominant climate stressors and health endpoints of interest tailored to vulnerable groups and/or other social determinants sub-groups.
Task 5. Deliver reports, data, and meetings
The investigators will submit quarterly progress reports, a draft final report and final report to CARB, participate in progress update meetings and a seminar geared toward a wide audience at the conclusion of the project. The investigators will provide raw data, modeled data, and all data analyses results generated through the course of the project in electronic format. Specifically, in reports, the investigators will include the following expected results from Tasks 1 to 4:
- Task 1 - Literature review on region-specific climate stressors and the research gaps;
- Task 2 - Regional exposure assessments for characterizing the most dominant and impactful climate stressors, their interaction and distribution among racial/ethnic subgroups within different regions of California;
- Task 3 - Region-specific health impact estimates for the dominant climate stressors, and associated health and economic impacts estimations (if possible);
- Task 4 - Region-specific health impact estimates tailored to vulnerable groups and/or other social determinants sub-groups.
Additionally, the investigators will prepare peer-reviewed journal articles as appropriate and provide a preview of the manuscript to CARB for their comments prior to submission. Submitting articles to open-access journals is recommended. Lastly, CARB requires new research contracts to incorporate racial equity components in the deliverables (see details in IV. Deliverables).
The project proposal must include but is not limited to the following deliverables:
At the Beginning of the Contract
- All researchers must undergo cultural competency training (examples include implicit bias training, racial equity training, etc.). Trainings should be completed or scheduled within 30 days of contract execution.
- Work with CARB staff at the beginning of the project to create a 1-page plain-language outreach deliverable and to hold a lay-oriented webinar for public describing the project’s goals, process, and planned deliverables (available in multiple languages, template will be provided) in combination with the kickoff of the contract.
During the Active Contract Period
- Quarterly Progress Reports and conference calls; The progress reports will include plain-language summaries that can be posted publicly. A progress report template will be provided.
- Consultation calls with CARB as needed in addition to quarterly calls
Prior to Contract Close
- All data, analyses and analytical tools generated through the course of this project.
- Draft final report.
- Include a plain language summary in draft final report.
- Include an equity implications section in draft final report.
- Work with CARB to create plain-language outreach deliverables for public such as fact sheets or other formats summarizing results and impact of project (available in multiple languages).
- Final Report.
- Virtual or in-person seminar that communicates the research project and results to a broad public audience that includes people with both academic and non-academic backgrounds.
- Peer reviewed publications should be publicly available (please budget for this expense; submission-ready publications shall be reviewed by CARB staff).
- Additional deliverables to be determined in consultation with CARB staff.
It is anticipated this project will be completed in 24 months from the start date. This allows 18 months for completion of all work through the delivery of a draft final report. The last 6 months are for review of the draft final report by CARB staff and the Research Screening Committee (RSC), modification of the report by the contractor in response to CARB staff and RSC comments, and delivery of a revised final report and data files to the CARB. Cost shall not exceed $500,000.
- US EPA. Exposure Assessment Tools by Tiers and Types – Aggregate and Cumulative. https://www.epa.gov/expobox/exposure-assessment-tools-tiers-and-types-aggregate-and-cumulative
- CARB. 2022 Scoping Plan Documents. https://ww2.arb.ca.gov/our-work/programs/ab-32-climate-change-scoping-plan/2022-scoping-plan-documents
- The Lancet Countdown on health and climate change. https://www.thelancet.com/countdown-health-climate
- Liu JC, Pereira G, Uhl SA, Bravo MA, Bell ML. A systematic review of the physical health impacts from non-occupational exposure to wildfire smoke. Environ Res. 2015 Jan;136:120-32. doi: 10.1016/j.envres.2014.10.015. Epub 2014 Nov 20. PMID: 25460628; PMCID: PMC4262561.
- Benmarhnia T, Deguen S, Kaufman JS, Smargiassi A. Review Article: Vulnerability to Heat-related Mortality: A Systematic Review, Meta-analysis, and Meta-regression Analysis. Epidemiology. 2015 Nov;26(6):781-93. doi: 10.1097/EDE.0000000000000375. PMID: 26332052.
- Guirguis K, Basu R, Al-Delaimy WK, Benmarhnia T, Clemesha RES, Corcos I, Guzman-Morales J, Hailey B, Small I, Tardy A, Vashishtha D, Zivin JG, Gershunov A. Heat, Disparities, and Health Outcomes in San Diego County's Diverse Climate Zones. Geohealth. 2018 Jul 3;2(7):212-223. doi: 10.1029/2017GH000127. PMID: 32159015; PMCID: PMC7007153.
- Malig BJ, Wu XM, Guirguis K, Gershunov A, Basu R. Associations between ambient temperature and hepatobiliary and renal hospitalizations in California, 1999 to 2009. Environ Res. 2019 Oct;177:108566. doi: 10.1016/j.envres.2019.108566. Epub 2019 Jun 29. PMID: 31323396.
- Bekkar B, Pacheco S, Basu R, DeNicola N. Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the US: A Systematic Review. JAMA Netw Open. 2020 Jun 1;3(6):e208243. doi: 10.1001/jamanetworkopen.2020.8243. Erratum in: JAMA Netw Open. 2020 Jul 1;3(7):e2014510. PMID: 32556259; PMCID: PMC7303808.
- Ebi KL, Capon A, Berry P, Broderick C, de Dear R, Havenith G, Honda Y, Kovats RS, Ma W, Malik A, Morris NB, Nybo L, Seneviratne SI, Vanos J, Jay O. Hot weather and heat extremes: health risks. Lancet. 2021 Aug 21;398(10301):698-708. doi: 10.1016/S0140-6736(21)01208-3. PMID: 34419205.
- Zhu S, Horne JR, Mac Kinnon M, Samuelsen GS, Dabdub D. Comprehensively assessing the drivers of future air quality in California. Environ Int. 2019 Apr;125:386-398. doi: 10.1016/j.envint.2019.02.007. Epub 2019 Feb 8. PMID: 30743145.
- Schwarz L, Hansen K, Alari A, Ilango SD, Bernal N, Basu R, Gershunov A, Benmarhnia T. Spatial variation in the joint effect of extreme heat events and ozone on respiratory hospitalizations in California. Proc Natl Acad Sci U S A. 2021 Jun 1;118(22):e2023078118. doi: 10.1073/pnas.2023078118. PMID: 34031244; PMCID: PMC8179213.
- CARB. Update on CARB’s Racial Equity, and Diversity Efforts- slide 11. 2022. Available at https://ww2.arb.ca.gov/sites/default/files/barcu/board/books/2022/051922/22-7-1pres.pdf
- Climate vulnerability: “the degree to which people or communities are at risk of experiencing the negative impacts of climate change.” (U.S. Global Change Research Program (USGCRP). Climate Change Impacts in the United States: The Third National Climate Assessment. 2014. http://nca2014.globalchange.gov/)
Responsiveness to the Goals and Objectives Outlined in the Proposal Solicitation(15 points)
Proposers should demonstrate a clear understanding of the policy objectives and research needs that CARB seeks to address with this project and should convey their knowledge of the subject. The proposal should have a clear research question or testable hypothesis. The proposal should consider various aspects of the research need and identify or acknowledge biases. The proposal should spell out, in adequate detail, exactly what the Proposer proposes to do to satisfy the requirements of the Solicitation. The draft proposal must propose work that would satisfy the objective(s) stated in the Research Solicitation: To understand the cumulative impact of combined climate stressors (i.e., heat, air pollution, wildfires, drought) alongside environmental justice, racial equity, and social vulnerability factors.
Policy Relevance/Benefits to the State (10 points)
Does the proposal describe how the project will provide data, information, and/or products to help CARB accomplish its mission?The characterization of the dominant climate stressors and the information on health effects from interactions of climate impacts in different California regions will expand CARB’s ability to analyze health effects of actions to reduce greenhouse gases, particularly in vulnerable communities. This study would provide additional information to supplement and improve CARB’s health analysis of climate actions, going beyond, for example, the analysis in the health appendix included in CARB’s 2022 Scoping Plan. CARB expects the study will help inform CARB’s programs and policies on the need for health and equity benefits in the face of multiple, and increasingly co-occurring, climate change stressors.
Previous Work (15 points)
Do the researchers have relevant experience in this area? Is the team composed of a multidisciplinary team of experts? Do they discuss how they will build upon previous relevant work that was funded by CARB, other state agencies, and the U.S. Environmental Protection Agency, etc.? 5 points will be reserved for project teams that meet at least one of the following criteria:
- The project has a multidisciplinary team consisting of researchers with exposure, health and racial equity expertise and skills to design a study that not only fulfills the research goals but also incorporates a racial equity assessment lens.
- The project team members come from various universities or include non-academic institutions or community-based organizations.
- The project team includes one or more members, contributing significantly to the project (i.e. a principle investigator, co-principle investigator or co-investigator, contributing 25% or more of their time to the project) who have not worked with CARB in the past 5 years.
Technical Merit (25 points)
Describe the submission's technical strengths and/or weaknesses. Proposers should demonstrate the logic and feasibility of the methodology and technical approach to the project, spell out the sequence and relationships of major tasks, and explain methods for performing the actual work. The proposal should provide an explanation of how the proposed methods are robust and how results will be validated. Please factor in how well the draft proposal describes these areas:
- Materials and Methods:
- State-of-the-art techniques for exposure assessment of the most dominant and impactful climate stressors, their interaction and distribution among racial/ethnic subgroups within different regions of California.
- Relevant health outcomes for multiple health endpoints, social determinants of climate health (particularly for race/ethnicity), and sufficient covariates; individual-level data are preferred. When selecting health datasets, the investigators should consider whether the datasets are representative of diverse demographic and socioeconomic groups, particularly for vulnerable populations.
- Advanced approach to estimate the cumulative health impacts of combined climate stressors by California regions. The analysis needs to consider interaction effects of multiple climate stressors, for example in the context of increasing temperatures.
- Quantifying and if possible, monetizing the impacts of the cumulative health impacts of combined climate stressors.
- Does the proposed work address all the deliverables required in section “Deliverables”? If not, the proposal should not be considered for funding.
- The review team will be selecting only one draft proposal for development into a full proposal. If this draft proposal has potential, what areas or topics should be prioritized or better explained in the full proposal?
Level and Quality of Effort to be Provided (15 points)
Does the proposal allocate time and resources in such a way that the objectives of the study will be met? Is supervision and oversight adequate for ensuring that the project will remain on schedule? Is the distribution of workload appropriate for activities such as research, evaluation and analysis, data reduction, computer simulation, report preparation, meetings, and travel?
Cost Effectiveness (20 points)
Does the cost seem appropriate for the proposed work? Does the proposed work seem feasible within the requested budget? Projects that provide co-funding should be evaluated more favorably.