Writing in Nature Climate Change, the researchers describe this approach as “Thermal Justice,” an application of environmental justice designed specifically for a warming world. The concept recognises that heat is not experienced equally, even within the same neighbourhood or building. Physiological sensitivity, working conditions, housing quality, access to shade, energy affordability and social isolation all influence whether a hot day becomes uncomfortable, dangerous or fatal. “The question is not only whether a measure lowers temperatures, but whether people can actually sleep, work, move, care for others, and remain healthy during heat,” says lead author Lucas Gobatti, an environmental engineering researcher. The framework is intended to help cities evaluate adaptation policies through a broader social and ecological lens, rather than treating temperature reduction as the sole measure of success.

Thermal Justice combines five connected dimensions. The first concerns the distribution of thermal burdens and benefits: cooling should reach those facing the greatest exposure, not simply those with the greatest ability to pay. The second is recognition, which requires authorities to identify vulnerabilities created by structural conditions such as poverty, discrimination, insecure housing, age, disability and precarious employment. The third is participation, meaning that residents affected by heat policies should have a meaningful role in shaping them. The fourth focuses on capabilities—the real ability of individuals and communities to function safely, including sleeping, working, travelling and caring for others during extreme heat. The fifth extends justice beyond people alive today by considering ecosystems and future generations that may bear the consequences of energy-intensive or water-intensive interventions.

The framework highlights a phenomenon the researchers call thermal displacement: efforts to cool one location or group can transfer heat-related burdens elsewhere. Air conditioning illustrates the problem. It can reduce indoor temperatures and protect occupants from heat stress, but conventional systems expel waste heat into the outdoor environment. When deployed widely, they can intensify local heat, increase electricity demand and place additional pressure on power grids. Their benefits are also unevenly distributed because households facing high energy prices, renters unable to install equipment or residents in unreliable buildings may be excluded. During a power outage, people who depend on mechanical cooling can become especially vulnerable, demonstrating why individual technologies cannot substitute for resilient, accessible public infrastructure.

Urban greening can also produce unintended consequences. Trees, parks, green roofs and vegetated corridors can lower surface and air temperatures through shade and evapotranspiration, the process by which plants release water vapour and remove heat from their surroundings. They can improve air quality, reduce stormwater runoff and create cooler routes through dense neighbourhoods. Yet new green amenities may increase property values and rents, encouraging so-called green gentrification. Residents who helped create or live near a cooling project may eventually be displaced to areas with fewer trees and higher temperatures. In this situation, a policy that improves the thermal environment of one place may indirectly increase exposure among the people it was supposed to protect.

Other adaptation measures can shift risk through resource use. Vegetation selected without considering local water availability may require intensive irrigation during drought, weakening water security and reducing the long-term viability of the cooling project. Highly engineered cooling systems may depend on fragile energy networks, scarce materials or maintenance budgets that disappear after a grant ends. Reflective surfaces can reduce the amount of solar radiation absorbed by roads and roofs, but their effectiveness depends on local climate, building form, material performance and maintenance. Some surfaces may also create glare or redirect heat toward pedestrians and neighbouring buildings. Thermal Justice therefore asks policymakers to examine the entire life cycle of an intervention, including its energy, water, financial and social costs.

The authors argue that emergency measures remain essential, particularly as heatwaves become more intense and persistent. Cities can issue clear and timely warnings, open accessible cooling spaces, protect outdoor and overheated indoor workers, provide shaded routes to hospitals and public transport, and organise outreach to older people and those living alone. Public cooling facilities must be physically accessible, affordable or free, culturally appropriate and reachable without exposing people to additional heat during travel. Workplace protections may include adjusted schedules, mandatory rest and hydration breaks, shaded recovery areas and enforceable temperature limits. These measures are most effective when they are designed around the realities of people’s daily lives rather than assuming that everyone can simply remain indoors.

Long-term adaptation requires structural change between heatwaves. Poorly insulated and badly ventilated homes can retain heat after sunset, extending exposure into the night and preventing the body from recovering. Retrofitting housing with insulation, external shading, efficient ventilation and appropriately designed cooling can reduce indoor temperatures while lowering energy consumption. Cities can expand tree canopy and blue infrastructure, such as restored waterways and water-sensitive public spaces, while matching plant species and irrigation needs to future climate conditions. Planning rules can preserve affordable housing in newly improved districts, and public investment can prioritise neighbourhoods with the greatest combination of heat exposure, health vulnerability and limited resources. Such policies treat heat as a housing, labour, transport, energy and public-health issue rather than an isolated weather emergency.

The researchers say that measuring success will require more than counting warnings issued, cooling centres opened or trees planted. Authorities should assess whether heat-related illness and mortality decline among the most exposed groups, whether homes remain safe at night, whether workers can take protective breaks without losing income, and whether residents can reach essential services without crossing dangerous heat zones. They should also monitor electricity demand, water use, displacement, rent changes, maintenance requirements and ecological impacts. This broader accounting can reveal whether a seemingly successful project is reducing risk overall or merely moving it to another community, ecosystem or generation. The Thermal Justice framework is designed as a tool for asking those questions before adaptation projects are implemented, when changes are still possible.

The ideas are also being explored through “Thermal Justice: a serious game,” a collaborative board game developed to simulate the difficult decisions facing cities during extreme heat. Players work together to protect residents while managing limited energy, water, space and financial resources. The game makes trade-offs visible: a project that cools a densely populated district may consume water needed elsewhere; a major greening programme may compete with affordable housing; and a rapid expansion of air conditioning may protect households while increasing grid stress and outdoor waste heat. The game will be presented in a workshop at the Scientifica science festival in Zurich, Switzerland, giving visitors an opportunity to examine how urban heat responses can be effective without making vulnerable people, ecosystems or future generations pay the hidden cost of cooling.

Subject of Research: Urban climate change adaptation and thermal justice

Article Title: Thermal justice in urban climate change adaptation

News Publication Date: 19-Aug-2026

Web References: https://scientifica.ch/en/event/thermal-justice-a-serious-game/

References: Gobatti et al., “Thermal justice in urban climate change adaptation,” Nature Climate Change, DOI: 10.1038/s41558-026-02727-5

Image Credits: Gobatti et al. 2026

Keywords

Thermal justice, extreme heat, heatwaves, climate adaptation, environmental justice, urban climate, public health, heat vulnerability, cooling infrastructure, green gentrification, climate resilience, urban planning

The psychological phenomenon at the heart of this reluctance is contamination aversion—an innate or learned response to perceived risk of infection or germ exposure. This study’s robust datasets, encompassing a representative sample of the German general population as well as a focused cohort of elderly individuals, uncovered a deeply ingrained hesitation to engage with public drinking fountains. Quantitative analysis revealed that each standard deviation increase in individuals’ sensitivity to contamination corresponded to a dramatic reduction in the likelihood of ever having used a drinking fountain: 49% lower odds in the elderly group and 32% lower odds across the general population. These figures underscore how powerful the invisible barriers of perceived microbial threat can be in shaping daily health behaviors.

Understanding the nuances of this contamination aversion is more than an academic exercise; it is a critical step towards designing interventions that could ultimately enhance public health outcomes during heat crises. Notably, the researchers conducted a natural experiment analyzing behavior at 14,128 fountain encounters, which provides a rare real-world behavioral validation beyond self-reported surveys. The intervention involved strategic signage that explicitly communicated the fountains’ safety conditions, highlighting contamination control measures and disinfection procedures. Remarkably, such signage yielded an 82% increase in the odds of individuals drinking directly from the fountain spout and a 37% rise in “cooling behaviors,” such as splashing water on the face or using the fountain to refresh without drinking.

This behavioral shift induced by signage reveals an intriguing interplay between cognitive reassurance and established contamination aversion. By visually signaling safety, the signs alleviate ambiguous fears, encouraging more autonomous and spontaneous usage rather than behavior dictated by social cues or hesitation. Temporal point process modeling of fountain usage data further demonstrated prominent social amplification effects—patterns where individuals’ fountain use was heavily influenced by the actions of others immediately beforehand. However, in the signage condition, these social dependencies weakened, suggesting patrons felt empowered to act independently, unburdened by concern for social norms or indirect pathogen exposure cues.

From a broader perspective, the research highlights that infrastructure alone is insufficient to provoke public use that aligns with intended public health goals. Design strategies must integrate psychological insights about human behavior, particularly regarding contamination fears stemming from both evolutionary and cultural origins. The findings suggest that interventions designed to transparently communicate microbial safety and hygiene measures can directly counteract contamination aversion, thereby enhancing the practical efficacy of public drinking fountains during critical heat events.

Moreover, these results carry significant implications as cities worldwide look towards sustainable, equitable, and resilient urban water provision systems. Establishing trust in public water infrastructure is paramount not only for immediate heat mitigation but also for long-term public health equity, particularly among vulnerable groups like the elderly, who tend to exhibit heightened contamination aversion. The study’s dual focus on both elderly and general populations provides a comprehensive lens on how these psychological factors vary across demographics, emphasizing the need for tailored messaging and infrastructural design.

The use of natural experimental settings combined with advanced temporal modeling further enriches the methodological rigor of the study. By examining over fourteen thousand direct encounters with public fountains, the research accomplishes a granular perspective rarely accessible in social science investigations of public infrastructure use. This methodological approach bridges the gap between controlled lab-based studies on contamination aversion and real-world behavior, offering actionable insights with immediate policy relevance.

Importantly, the findings challenge policymakers and urban planners to consider not only the physical installation of hydration points but also the cognitive and emotional frameworks within which citizens interact with public amenities. Public health campaigns and urban design must be synchronized to dismantle psychological barriers, leveraging clear communication, reassurance, and demonstrable hygiene assurances to foster higher utilization rates. In effect, this would transform the urban landscape into a psychologically safe space that encourages healthy behaviors by design.

As climate-induced heatwaves continue to place unprecedented pressure on urban populations, accessible hydration infrastructure becomes an essential frontline defense. Yet, the success of such interventions is contingent upon a sophisticated understanding of human psychology, including the unconscious avoidance mechanisms that have evolved to protect individuals from disease but may now inadvertently limit life-saving behaviors. This research exemplifies how bridging epidemiology, behavioral science, and urban ecology can produce holistic solutions that better serve public well-being.

Future research building upon these insights might explore additional sensory and informational cues that could mitigate contamination fears, such as realtime water quality displays, public demonstrations of maintenance procedures, or interactive engagement from local health authorities. Moreover, investigating cultural and regional variations in contamination aversion could provide a global framework for designing universally acceptable public hydration infrastructures. Such interdisciplinary and cross-cultural inquiries will be crucial as urban populations worldwide confront the escalating consequences of climate change.

The deliberate integration of psychological safety signals into the design and communication of public water infrastructure may very well serve as a key innovation in public health promotion. Beyond hydration, these principles could extend into other shared urban resources requiring routine human engagement where contamination aversion is a limiting factor. The study thus opens pathways for reimagining how cities can fuse technical infrastructure with behavioral science to cultivate healthier, more resilient communities amidst complex environmental challenges.

In sum, the research conducted in Germany demonstrates that while physical adaptation to rising heat through installing drinking fountains is critical, ensuring their use depends heavily on addressing the invisible psychological barriers rooted in contamination fears. Signage that communicates safety effectively alters these barriers by reducing social dependencies and encouraging independent use. This emphasizes a crucial interdisciplinary insight: successful public health infrastructure must account for human psychological dynamics as integrally as technical design and environmental need.

As urban planners and public health professionals digest these findings, the message is clear—hydration solutions are only as effective as the confidence and comfort they instill in their users. Harnessing behavioral science to complement engineering and infrastructure investments offers a promising avenue toward reducing heat-related morbidity and mortality worldwide. Ensuring widespread and consistent use of public drinking fountains will require ongoing attention to both the tangible and intangible factors influencing human behavior in the urban ecosystem.

This pioneering research not only charts a new understanding of contamination aversion in public infrastructure use but also demonstrates an actionable path forward. By embedding reassurance, clarity, and evidence of safety within the physical environment, cities can promote healthier, more consistent hydration habits. Such integration of psychological mechanisms with infrastructural interventions should become a standard consideration in urban resilience strategies as climate and health landscapes evolve.

Subject of Research: Psychological barriers to public drinking fountain use and strategies to mitigate contamination aversion in urban water infrastructure during heat stress.

Article Title: Understanding and addressing contamination aversion in the use of drinking fountains.

Article References:
Bruckmann, R.W., Sprengholz, P. Understanding and addressing contamination aversion in the use of drinking fountains.
Nat Water (2026). https://doi.org/10.1038/s44221-025-00540-6

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s44221-025-00540-6