Abstract
Heat waves are increasing in frequency, intensity, magnitude, and duration, causing a disproportionate impact on marginalized communities exposed to urban heat islands. Newly emerging spaceborne thermal sensing instruments, such as ECOSTRESS and Hydrosat, now have the capabilities to measure urban surface temperatures accurately at the block level (<100 m) and with enough frequency to capture transient heat waves (daily to subweekly). Such data are critical for monitoring and informing policy and mitigation efforts, such as resurfacing, green space, cooling stations, and medical mobilization. These serve to advance environmental justice and reduce health risks—and deaths—among the most vulnerable: minority, low-income, elderly, those with physical- and mental-health preconditions, unhoused, children, and outdoor workers. While scientists have increasingly used satellite data to quantify urban heat islands and risks to communities, there remains a significant gap in action resulting from such analyses—a figurative and literal “valley of death.” Reviewing over 500 scientific publications, we identify a critical lack of engagement with the communities being analyzed (10.9%; n = 58); yet, community engagement is key to bridging such analysis with subsequent action. Here, we demonstrate how participatory community engagement directly with data and analysis leads to increased policy changes and mitigation efforts. Our framework has immediate implications for how scientists may augment their work and thought processes to achieve objectives and impact from urban heat research, needed now in the face of accelerating climate change.
Keywords
URBAN HEAT ISLANDS AND ENVIRONMENTAL HEALTH DISPARITIES
The single leading cause of weather-related human mortality is extreme heat. 1 Heat waves continue to increase in frequency, intensity, magnitude, and duration, with records now set nearly every year. 2 For instance, in 2024, the heat index reached 82°C/180 °F in the Middle East, and surface temperatures exceeded 81°C/177 °F in India—our infrastructure melts at these temperatures, including roads, shoes, and electrical housing—and this is past the limit for human survival (Fig. 1). 3 More people died from heat in 2023 in the United States than any other year. 4 A total of 500,000 people die each year globally from extreme heat, with a projected 370% increase by 2050, culminating in 3.4 M heat-related deaths per year expected by the end of the century. 5
High-resolution satellite measurements of surface temperature can detect extreme heat waves and urban heat islands.
Excessive heat leads to a continuum of health impacts with both immediate and cascading downstream effects. 6 These are exacerbated by physical (respiratory and cardiovascular) and mental health preconditions, compounded by other environmental stressors, such as air pollution. Direct heat exposure can lead to fatigue, 7 heat stress, 8 heat stroke, 9 dehydration and kidney stress, 10 gastrointestinal hemorrhage, 11 respiratory distress, 12 cardiovascular stress, 13 and, ultimately, an increase in morbidity and mortality (Åström et al., 2011; Matthews et al., 2025). In combination with air pollution, excessive heat can trigger respiratory reactions such as asthma attacks 14 and respiratory tract irritation 15 and can increase exposure to lung-damaging surface ozone 16 and carcinogens 17 ; children, outdoor workers, and unhoused individuals are particularly susceptible 18 . People with mobility constraints (elderly, people with physical disability, and pregnant women) are highly vulnerable to heat waves. 19 Some mental health conditions feed back into physical well-being and self-regulation, which are further decoupled under excessive heat. For instance, schizophrenia is frequently associated with anosognosia, which inhibits a person’s insight into their own health status. 20 Many mental health conditions are intensified under heat waves: Depression and schizophrenia are associated with nearly double and triple the likelihood of heat-related mortality, respectively. 21
Urban areas are hotter than their surrounding suburban and rural landscapes by as much as 9°C due to the predominant surface of concrete/asphalt, giving them the name “urban heat islands (UHIs).” 22 Solar energy is absorbed by these surfaces and reemitted as sensible heat, in contrast to vegetated areas that absorb energy in water that is evaporated away. 23 Airflow may also be blocked by buildings in urban settings, which reduces the ability to dissipate heat. 24 Moreover, additional heat is generated by vehicles and energy consumption with an escalating heat feedback, as electricity demand for air conditioning increases by 1–9% for each 1°C increase in temperature. 25 Fossil fuel burning that supplies this electricity, in turn, results in more greenhouse gases, which then trap more energy and heat. 26
Those living in urban areas are therefore disproportionately exposed to elevated heat. Three billion people are estimated to live in urban areas, and growing. 27 Because of a history of “white flight” (US and global analogs) and systematic redlining and other city planning discriminatory measures, inner cities have been predominantly low-income communities of color. 28 Limited access to health care and resources exacerbates health impacts caused by the compounding of heat and air pollution, among other environmental pollutants (e.g., water, building materials). 29 Heat-related health impacts result in decreased productivity (work and school) and risk of job loss and health insurance (United States), leading to cascading physical and mental stresses and health impacts. 30 As such, this combination of demographic, environmental, and health inequities makes urban heat an environmental justice issue (Fig. 2). 31
Urban heat islands impact a wide range of people through multiple immediate and cascading respiratory and cardiovascular health impacts, compounded by air pollution. Concrete/asphalt surfaces absorb solar energy and reemit it as sensible heat, and air flow is blocked by buildings, which generate heat through energy consumption in addition to vehicles. Children, outdoor workers, unhoused individuals, people with mobility constraints, and those with physical and mental health preconditions are particularly susceptible. Urban areas are predominantly low-income communities of color with reduced access to resources, health care, and educational/income buffers, making urban heat an environmental justice issue. Credit: DALL-E.
Here, we describe how urban heat islands and heat waves can be monitored, adding new information on using the latest in cutting-edge satellite technology. We then review the literature to determine if scientists using such technology are making an impact on human health, policy, and environmental justice. We illustrate how community engagement can bridge technology and scientific analysis with policy and action within the framework of the central tenets of environmental justice. Finally, we provide an overview of mitigation actions to reduce the impacts of urban heat islands.
MEASURING URBAN HEAT ISLANDS AND HEAT WAVES
To measure and monitor urban heat islands, temperature measurements are required that delineate the heterogeneity of urban structures, including buildings, roads, parking lots, schools, and recreational and green spaces, which exist on length scales of 10s of meters. 32 Measurements that otherwise blend surrounding suburban areas or mix green and nongreen spaces do not correctly reflect the lived experiences of people within urban settings. 33 Of relevance to public health is the “apparent temperature” (heat index) felt by humans, which is a combination of air temperature and relative humidity (which itself is a function of air temperature). 34 In situ air temperature and humidity measurements provide good detail, but are subject to inadequate coverage, inconsistent calibration, and uneven representation (e.g., sensors that are only in the shade, or vice versa). 35 Spaceborne measurements of air temperature and humidity are too coarse to differentiate urban heterogeneity. 36
The measurements that provide the best coverage with consistent high spatial resolution are spaceborne thermal infrared (TIR) measurements of surface temperature. 37 Not only do they correlate with air temperature (though with caveats including lags, advection, and scaling), 38 but they also provide additional health risk insight of direct surface contact that can lead to burns, as well as infrastructure risk of temperature-induced degradation. 39 Moreover, elevated indoor air temperatures, especially at night, are usually due to absorbed energy by buildings that continue to reradiate internally throughout the night. 40 High-resolution spaceborne TIR measurements have existed for decades from Landsat and ASTER at ∼100 m, and since 2018 from ECOSTRESS at ∼70 m. 41 These measurements should continue with planned missions TRISHNA, SBG, LSTM, and Landsat Next. 42 Still, these measurements are only on the cusp of matching the length scales of urban features; frequently, downscaling techniques must be employed to align the data with the urban surface features (e.g., < 30 m), but downscaling typically relies on assumptions of nonthermal data representing thermal conditions. 43 The recent launches of the first stages of the Hydrosat constellation are bringing the TIR resolution down further to 25 m, and new capabilities from SatVu and Albedo offer unprecedented < 5 m resolution. 44
While spatial resolution is key to measuring urban heat islands, temporal resolution is critical to capturing heat waves. Heat waves are transient, lasting on average 4 days in duration (with some definitional debate), and the extreme heat during this short duration exerts the greatest toll on human health and deaths. 45 Consequently, measurements of surface temperature need to be more frequent than ∼4 days, otherwise the heat wave may be missed entirely, even more so if there are clouds. 46 Landsat and ASTER, at 16 days repeat, inevitably miss many heat waves; Landsat Next aims to have a 6-day repeat. SatVu and Albedo do not provide regular large-scale/global coverage (used for tasking). ECOSTRESS, at 3–5 days repeat tends to provide at least one image during most heat waves, though this repeat cadence is inconsistent owing to precession orbit characteristics of the International Space Station, and the coverage may be at different times of day; 47 for example, two of the largest recent heat waves in southern California in 2020 and 2024 were captured by ECOSTRESS only at night. TRISHNA, SBG, and LSTM will improve this further with consistent 3-day frequency. Hydrosat will have the highest combination of spatial and temporal global coverage at 1-day temporal resolution. Until the planned missions are fully in orbit, the best current capability to measure urban heat islands during heat waves is ECOSTRESS, though Hydrosat will soon be the optimal data for monitoring urban heat waves (Fig. 3).
Urban heat features in Las Vegas are clearly delineated by
REVIEW OF SATELLITE-BASED URBAN HEAT ISLAND AND HEAT WAVE ANALYSES
Here, we ask how satellite-based urban heat island and heat wave analyses have linked to human health impacts and environmental justice, leading to policy changes or other community-based action. We reviewed 538 scientific articles on satellite-based urban heat island and heat wave analyses, subjectively scoring them on a 0–3 scale for relevance within four categories: 1) health implications, 2) environmental justice issues, 3) community engagement, and 4) policy/action outcomes (Supplementary Table S1). Specifically, we evaluated if articles simply discussed health or more thoroughly analyzed health data, mentioned environmental justice or linked analyses to multiple tenets of environmental justice with discussion of solutions, noted the communities impacted versus included community members and explicit methodological direction from the community, and suggested public policy/action outcomes or described actual policy/action changes. This methodological approach supported a literature-backed hypothesis of what characteristics of a given study led to high-impact environmental justice outcomes on extreme urban heat.
We also tracked geography, data used, the stated limitations/future research needs, and citation count at review date, among the full bibliographic information. We focused only on high-resolution data, that is, ∼100 m, which excludes MODIS-based and other similar coarser resolution data. A key limitation to contextualize our results is that, especially in categories 3 and 4, these may come after the publication of a article. Another limitation is that the scoring is subjective and considered linear, though generally the score distributions were bimodal between 0 and 1–3. We trained a set of artificial intelligence tools, TypeSet and Copula, to search for key phrases and terms, cross-validated with our primary human evaluation, to expedite review, though these may also contain biases and errors. 48 Finally, although our review on this topic is among the largest to date, it is inevitably nonexhaustive and likely misses some important literature. We next present the findings, but they should be interpreted within the limitations and caveats stated above.
Most satellite-based urban heat island and heat wave studies focused geographically on East Asia (e.g., China, South Korea, Japan) (27.8%; n = 147) and North America (United States, Canada, Mexico) (19.1%; n = 101), followed by South Asia (15.2%; n = 80), Europe (13.8%; n = 73), Other (e.g., South America, sub-Saharan Africa) (10.9%; n = 58), Middle East and North Africa (10.6%; n = 56), and Australia (2.3%; n = 12) (Fig. 4a). Studies focusing on East Asia have been increasing in relative proportion (0.5 year−1), likely due to the overall increase in scientific productivity from China in recent years, though also perhaps due to the proliferation of UHIs and heat waves in China. 49 Some implications of this geographic shift are how these analyses are translated to environmental justice and policy contexts, which are often geographically and politically dependent. 50
The studies used mostly Landsat (79.9%; n = 238), followed by ECOSTRESS (17.2%; n = 91) and ASTER (0.3%; n = 16); studies that used ECOSTRESS have been increasing in relative proportional use to other sensors since its launch in 2018 (3.2 year−1) (Fig. 4b). Typically, there is a lag following any new sensor and its adoption for scientific applications, which we see here, for example, for ECOSTRESS. A future direction implication is that it would behoove the science and outreach teams of new sensors (e.g., Hydrosat, TRISHNA) to expedite and facilitate ease of use of the new data, especially as time is critical, as heat waves increase in frequency and magnitude.
We found that about a quarter of satellite-based urban heat island and heat wave analyses included relatively strong relevance of public health findings in their results (26.4%; score = 0.99; n = 142), with three-quarters of those having some relevance to environmental justice (20.2%; score = 0.86; n = 109). However, we found a distinct lack of engagement with the communities being analyzed (10.9%; score = 0.47; n = 58), as well as any policy or action outcome from the research reported within the respective article (6.3%; score = 0.87; n = 34) (Fig. 4c). The lack of community engagement is a key finding from this review, helping to explain the disconnect between the analyses and potential policy or action outcomes.
Stated limitations and future research needs or directions within the articles were relatively balanced among six categories: i) lack of detailed data (20.8%; n = 112), ii) lack of community input (24.6%; n = 130), iii) lack of mitigation strategies (14.1%; n = 76), iv) spatial or temporal resolution issues (14.1%; n = 76), v) need for better models (13.2%; n = 71), and vi) other (13.5%, n = 73) (Fig. 4d). The results here are what drove our hypothesis and motivation for this article, which we hope will help the science community improve these shortcomings.
Finally, we report five commonalities within the categories from Figure 4c among the few most high-scoring articles, specifically to highlight what elements made for impact, which were: i) incorporated community input, ii) outlined clear opportunities for heat mitigation, iii) addressed urban heat islands and heat waves at finer scales (often using downscaling techniques or other models), iv) incorporated direct links to human health impacts, and v) clearly identified priority and policy/action-oriented areas (Fig. 4e).
COMMUNITIES FOR A BETTER ENVIRONMENT (CBE)—BRIDGING ANALYSIS AND ACTION
In a landscape where social and environmental inequities persist, collaboration that connects data with environmental exposures by affected residents can empower residents to gather, interpret, and act on data, informed by lived experiences, to advocate for a just transition toward sustainable development, job growth, environmental change, and overall collective well-being. Here, we illustrate how this empowering community-based participatory research (CBPR) approach can connect satellites with action by fortifying this bridge within the central tenets of environmental justice—distributional, procedural, and recognitional. 51 CBPR emphasizes equitable partnerships that recognize community members as co-investigators with critical expertise, build community capacity through the co-production of knowledge, and commit to action-oriented outcomes, such as achieving structural changes that attend to resident interests. 52 As an emerging successful example, we introduce a CBPR case study in Southeast Los Angeles (SELA), which has endured an uneven burden of social and environmental inequities for decades, intersecting to create one of the most disadvantaged areas of Los Angeles County. 53 SELA communities face dense urbanization and industrial zoning that exacerbate urban heat and limit access to green spaces, manifesting stark health disparities, such as escalated rates of asthma and cardiovascular disease. 54
CBE is a community-based organization that leverages community organizing, research, and legal action to address environmental injustices in California’s underserved communities; SELA is a CBE target community. 55 With support from the National Aeronautics and Space Administration (NASA)’s Equity and Environmental Justice program, CBE partnered with local and partner academic institutions (University of California Irvine and Chapman University; Tennessee State University) to form a Research Leadership Academy to enable community residents to engage and learn from environmental scientists and public health researchers on how to use NASA data to address the specific environmental justice needs of SELA residents. This initiative integrated high-tech data and ground truthing efforts to develop community-centered solutions for urban heat and air pollution reduction, climate adaptation, and community health promotion.
Specifically, the team employed: 1) satellite remote sensing and participatory geographic information systems to capture, quantify, and examine environmental, health, and socioeconomic data; and 2) participatory mapping to ground truth resident exposure to UHIs (e.g., high roadway and housing density areas), access to green space (e.g., public parks), and distribution of environmental health disparities (e.g., asthma and cancer). 56 To capture and disseminate SELA residents’ experiences of environmental health disparities in an accessible, data-driven format, they developed an open-access, layperson-accessible, web-based, GIS-enabled decision-making dashboard that visualizes Los Angeles County and local-level (cities, neighborhoods) data on socioeconomic and health, UHIs, air pollution hotspots, and green space access (Fig. 5). 57
An open-access GIS dashboard consolidates data for community organizers to analyze environmental inequities and mobilize changes in policy and management. Here, an example is shown from Communities for a Better Environment (CBE) in Southeast Los Angeles illustrating data for cardiovascular disease overlain by residents’ exposure to urban heat.
Distributional justice concerns the equitable distribution of environmental benefits and harms. 58 Using this effective CBPR approach, which aligns community knowledge with scientific data, SELA residents mapped the spaces and places where they experienced environmental exposures and the social and environmental factors that contribute to said exposures. The satellite data were then used to confirm and spatiotemporally quantify not only that the community-identified spaces, such as public parks and schools, were excessively absorbing solar energy and emitting heat, but that they were disproportionately hotter than the same types of places in more affluent adjacent communities (Fig. 6). 59 This work confirmed with data the distributional inequities residents have voiced concerns over for decades, which is often what regulatory agencies need to enact policies, enforcement, and change for distributional justice. 60
Satellite data on urban heat are integrated into a community-driven GIS dashboard, enabling hotspots to be identified, quantified, and targeted for mitigation efforts such as resurfacing or green space. Data shown here are from NASA’s ECOSTRESS mission in Southeast Los Angeles, as part of the CBE project.
Procedural justice emphasizes the right of underserved communities that bear a disproportionate burden of environmental exposures to meaningfully participate in policy-making, environmental governance, and enforcement. 61 Our partnership embodied this central tenet through CBPR’s commitment to shared partnership and decision-making. 62 Residents participated in determining research priorities, interpreting data, and designing the dashboard to ensure that the tool reflected community interests rather than purely academic perspectives. Consistent with CBPR’s core principle of capacity building, the Research Leadership Academy equipped residents and community organizers with the data and tools, including our GIS-enabled data dashboard, to advocate for their inclusion in environmental decision-making. 63 Importantly, residents and community organizers have used the dashboard to present critical data and information to local policy- and decision-makers (see Conclusions and Call to Action below).
Building on this foundation of capacity and demonstrated impact, over 100 SELA residents highlighted the power of the data and dashboard to advocate for procedural justice. For example, one resident noted that they will use the data to identify and compare temperature measurements from the satellites and to unite the community to enhance their proposals to the city council. 64 This action was echoed by a different resident in structurally creating a committee to review the data and put forth recommendations to be considered by the city. 65 A third resident stated, “We can use maps to bring more awareness to people or government officials who choose to ignore the issue. It can also be used to give evidence for such improvements or a reason for them in specific places.” Finally, multiple residents expressed interest in applying reflective paint on roads and buildings to reduce heat. These narratives revealed that residents, having built the new Research Leadership Academy and dashboard-enabled capacity, were empowered to use data promoting procedural justice. The residents generated ideas and approaches that leveraged the data and dashboard toward procedural justice.
Finally, recognitional justice acknowledges and respects the diverse experiences and histories of underserved communities’ relationship with nature and the environment; it challenges the dominant narratives that often devalue their environmental knowledge and rights. 66 Our CBPR partnership exemplified this central tenet, operationalizing CBPR’s foundational principle that community members are local experts with grounded knowledge of place that must inform research questions and methods. 67 Our participatory mapping sessions documented SELA residents’ experiences of place, and these experiences, along with ongoing data analysis and review with the Research Leadership Academy and broader community, were used to inform the use of satellite data, resulting in a data dashboard shaped by community residents’ lived experience.
For example, several residents noted their experiences at local schools and parks, with one stating that, “There are no trees, shade, or grass. It is made of pure asphalt. The kindergarten place has no shade for the children; it feels very hot. The trees that you have are dry. There is a pond with green water, and there are many mosquitoes.” These observations directed our analysis to prioritize public schools and parks, with the satellite data confirming that these community-identified sites were indeed experiencing disproportionate extreme heat exposure (Fig. 6). By documenting these experiences on the dashboard and working with residents to shape research questions and analyses throughout the project, our combined in situ and spaceborne data recognize and make actionable the lived experiences of underserved communities.
As reflected by one resident: “We can use the maps to see what areas we can go to cool down, spots in our community that are safe areas, or we can show all the impacted areas so that our communities can have knowledge to inform themselves so they know the conditions in their neighborhoods.” Furthermore, the maps of temperature and green space can direct targeted green space improvements and widespread communication for support and expansion. 68 Another resident summarized the recognitional justice for urban heat advanced by the community engagement with the data, “To reduce high temperatures in our community, we can reduce the amount of places that have materials that absorb heat rather than releasing it. Parks and gardens can help by allowing for places that don’t allow heat to build up and for people to cool down.” These statements (also a form of “data”) provide data-backed and action-guided knowledge and direct understanding of the importance of green spaces, where they are needed, and their health impacts.
MITIGATION SOLUTIONS
Urban heat islands and heat waves, and their corresponding public health impacts, can be mitigated through proactive and reactive measures. Because urban heat islands form primarily due to their energy-absorbing/heat-emitting concrete/asphalt surfaces, measures that change these surfaces can have immediate heat reduction impacts. Energy either needs to be: i) not absorbed into heat-emitting surfaces (i.e., reflected); ii) absorbed into water that dissipates heat through latent heat flux; and/or iii) absorbed into heat-emitting surfaces that effectively ventilate.
Streets, parking lots, and building tops can be painted with a coating that increases reflectance of incoming solar radiation, thereby reducing absorbed energy and reemitted heat. 69 Such mitigation is potentially the easiest and cheapest option for large-scale implementation. 70 These solutions were also identified by residents in our case study example. Reflective shade structures may also be installed over surfaces, which provides additional shading benefits, though it is more costly than surface coating. 71 Surface temperatures can be reduced by as much as 4°C, depending on coating and preexisting surface characteristics. 72 Costs for reflective coating may be < $100 kg−2; costs for shade structures may be < $1 K depending on size and material. 73 Such implementations must first be modeled to ensure that the reflected energy effectively exits the urban setting back to the atmosphere and does not bounce laterally into homes, buildings, or topographic features. 74
Green scaping, or increasing vegetation cover (“green space”), can be very effective at reducing urban heat island impacts. 75 Expansion of parks, tree-lined streets and parking lots, other landscaping, and plants on roofs (“green roofs”) enable solar energy to be absorbed into vegetation water and redirected back to the atmosphere through transpiration via the latent heat flux, assuming sufficiently watered and live vegetation. 76 Like human-made reflective shade structures, trees and parks can also provide shade. Moreover, there are a multitude of additional benefits provided by green space, including: improvement in mental health, crime reduction, food and material sustenance, increases in property value, education, and wildlife and biodiversity, including migratory corridors. 77 Green space measures have been demonstrated to reduce air temperatures by up to 4°C. 78 Green scaping efforts have been a focus of mitigation solutions by residents in our case study. Costs for green space implementation start on the order of $10 per tree, but often require initial and/or long-term installation, irrigation, and maintenance. 79
Blue scaping, or increasing blue space cover, is also very effective at reducing urban heat islands. 80 Ponds and artificial lakes, as well as flowing water over roofs (“blue roofs”), can have immediate heat reduction impacts by up to 3°C for their adjacent human-populated surfaces. 81 Like green spaces, blue spaces can provide: improvement in mental health, crime reduction, food and material sustenance, increases in property value, education, and wildlife and biodiversity, including migratory corridors. 82 Costs for blue scaping implementation may be tens of thousands of dollars, which is orders of magnitude more than green scaping, and often require long-term water supply and maintenance. 83
Surface coating and shading, green scaping, and blue scaping all serve to reduce the amount of energy absorbed into urban surfaces and reemitted as heat. Additionally, and/or where those are not options, improvement of ventilation both within and among urban structures can reduce the heat load on people. 84 Improvements in air conditioning, fans, windows, and cross-breeze (horizontal and vertical), as well as improvements in building materials, can effectively move heat out of buildings. 85 Improvements in energy efficiency of air conditioning, lighting, and other energy-consuming appliances can reduce within-building heat. 86 Improved ventilation also provides additional benefits by reducing transmission of airborne diseases (e.g., COVID) and improving productivity and mental focus, especially where indoor CO2 levels concentrate. 87 Beyond individual buildings, urban planners should model air flow impacts so that urban heat can effectively dissipate through city crosswinds. 88 Other measures, such as public transit and energy-efficient vehicles, can also reduce some urban heat. 89 Overall, a reduction in reliance on fossil fuel burning will reduce the greenhouse gases that contribute to trapped energy in the global system and lead to increased heat waves. 90
Additionally, and/or where none of these measures are options, municipalities may provide cooling stations and medical mobilization deployed where significant hotspots intersect with high population densities in vulnerable communities. 91 These areas can be identified and targeted using remote sensing monitoring. Overall, improving access to health care and resources can reduce the health impacts of urban heat islands and heat waves. 92 Further, and perhaps most importantly, making data, analysis tools, and information resources available and accessible to affected communities can advance environmental justice and inform community empowerment. 93
It should be noted that cost is a primary consideration for all these measures. Yet, the benefits far outweigh the costs in increased productivity and reduced health impacts. 94 In the United States alone, urban trees ontribute to $73B year−1 in environmental benefits, 95 and the Federal government recently granted $1B for urban green projects through the U.S. Inflation Reduction Act. 96 U.S. cities overall have recently invested $1.6B year−1 for +1 M new trees. 97 Cool pavement investments are increasing; for example, the City of Los Angeles has spent over $4 M on cool pavement resurfacing. 98 Globally, the World Bank has been investing $2B year−1 in urban resilience with plans to increase that investment to $25B year−1. 99
CONCLUSIONS AND CALL TO ACTION
We showed how urban heat islands and heat waves may be monitored with different types of data, that there is a significant gap in connecting those data to the affected communities, and a framework for engaging communities to advance mitigation solutions and environmental justice (Fig. 7*). For monitoring urban heat islands and heat waves, we recommend using ECOSTRESS and Hydrosat data. To bridge analyses of these data to policy and action, community engagement is key. Co-developed recommendations between communities and research institutions for bridging the gap between analysis and action include: 1) making satellite data accessible to the general public (i.e., procedural justice), 2) providing information about how residents experience environmental injustices (i.e., recognitional justice), and 3) presenting these data to public officials (i.e., procedural justice) toward achieving environmental change, such as improving green space infrastructure in environmental justice communities ([i.e., distributional justice).
Combining cutting-edge science and technology with community engagement and empowerment can move society away from urban heat islands and the associated environmental health inequities toward healthy cities resilient to climate change. Credit: DALL-E.
In our example case study, the community took their data-enabled partnership and dashboard to the U.S. Environmental Protection Agency and to the City of Cudahy and the Los Angeles Unified School District officials (https://www.cbecal.org/community-organizing/southeast-la/). As a result, officials decided to support the renovation of existing and development of new public parks and recreation spaces in the key hotspots of this critical UHI. The data and information were openly received by officials, leading to support for the greening in Southeast Los Angeles, thereby providing a promising example of how community was the bridge between data and action to proactively support environmental justice initiatives. The framework we provide here may be a blueprint for other researchers and communities working to build bridges to drive data toward action.
AUTHORS’ CONTRIBUTIONS
J.B.F. and J.A.D. formulated the idea; J.B.F. and J.A.D. designed the research; J.B.F., A.C., A.A., K.T., S.S., A.M., and R.E.F. performed the research; all authors contributed to the writing of the article. Conceptualization: J.B.F. and J.A.D. Data curation: A.C., A.A., R.E.F., K.T., S.S., A.R., and J.A.D. Formal analysis: J.B.F., A.C., J.A.D., A.A., and R.E.F. Funding acquisition: J.A.D., J.B.F., R.A., and A.C. Investigation: all authors. Methodology: J.B.F., J.A.D., A.C., R.A., and A.R. Project administration: J.A.D., J.B.F., and A.R. Resources: J.B.F. and J.A.D. Software: A.C., A.A., K.T., and S.S. Supervision: J.B.F. and J.A.D. Validation: J.B.F. and J.A.D. Visualization: J.B.F., A.A., A.C., K.T., S.S., R.A., A.R., and J.A.D. Writing—original draft: J.B.F., A.C., and J.A.D. Writing—review and editing: all authors. We thank Z. von Allmen for preliminary analysis and the Southeast Los Angeles residents and CBE’s Research Leadership Academy for knowledge contributions.
Footnotes
AUTHOR DISCLOSURE STATEMENT
No competing financial interests exist.
FUNDING INFORMATION
This work was supported by NASA Equity and Environmental Justice (EEJ) (80NSSC22K1700; 80NSSC25K7035) and NASA ECOSTRESS Science and Applications Team (ESAT) (80NSSC23K0309).