As cities confront increasingly frequent and severe heatwaves, scientists are urging authorities to rethink what it means to protect people from extreme temperatures. Conventional heat-health advice—drink water, avoid strenuous activity, keep homes cool and check on vulnerable people—can save lives. But such guidance assumes that everyone has the freedom, money, housing, mobility and social support needed to follow it. A construction worker may not be able to leave work during the hottest hours. A low-income household may be unable to afford air conditioning. An older person may live in an apartment that remains dangerously hot overnight, while a parent may have no practical way to reach a cooling centre. A new framework developed by researchers at ETH Zurich, the Swiss Federal Institute of Aquatic Science and Technology, and partner institutions argues that heat adaptation must be judged not only by how much it lowers temperatures, but also by who benefits, who remains exposed and where the risks go next.
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
