The summer of 2026 served as a brutal awakening for the European healthcare sector. What climate scientists have warned about for decades materialized in hospitals and emergency services across the continent. The frequency, duration, and intensity of extreme heat events are no longer projections for the future; they are immediate, life-threatening realities that hospitals must manage today.
The conversation is no longer solely about mitigating our carbon and ecological footprint (although it remains imperative). It’s equally about climate adaptation and resilience. This blog explores the impacts of heatwaves on public health and emergency systems, and outlines science-based, actionable strategies for hospitals to adapt and build resilience in an increasingly warming world.
The 2026 heat wave
In June 2026, Western and Southern Europe were engulfed by what the World Weather Attribution consortium identified as the most severe heatwave to ever strike the region, characterized by record-breaking temperatures and dangerously high humidity. The physiological toll on the human body was immense. Researchers utilizing the wet-bulb globe temperature metric found that 45% of European cities with over 50,000 inhabitants experienced their worst conditions on record. When ambient air holds too much moisture, sweating becomes an ineffective cooling mechanism, drastically increasing the risk of heatstroke and cardiovascular collapse.
Figure 1: The cities where Wet Bulb Globe Temperature records were broken (or forecast to be broken) during this heatwave (World Weather Attribution, 2026).
Belgium offers a clear picture of this public health crisis and the strain it creates. Between June 17 and June 28, the country endured severe heat, including seven tropical days above 30°C and five nights above 20°C that prevented buildings from cooling down. Sciensano counted 2.112 excess deaths between June 18 and July 1, 31% more than expected. On the peak day of June 27, mortality ran 146% above baseline. It was the deadliest heatwave since Belgium began monitoring mortality, and produced the highest daily death peak since the first wave of COVID-19.
The surge in acute medical cases mirrored the operational pressure seen during peak COVID-19 waves. Government authorities activated the alarm phase of the national Ozone and Heat Plan for the first time since August 2020. The Federal Public Service Public Health monitored emergency call volumes and bed capacity around the clock. Following the crisis, health authorities issued updated guidelines to strengthen 112 dispatch centre capacity during extreme weather events.
Figure 2: Emergency call and intervention volumes during the heatwave,
compared to the rest of the month of June 2026. (De Standaard, 2026)
Interconnected system risks
Hospitals are complex, energy-heavy environments. When outdoor temperatures skyrocket, internal balances break down across multiple fronts. First, vulnerable patients face direct physiological danger. Inpatients with pre-existing conditions struggle to regulate body temperature, driving up clinical risk across wards.
Second, infrastructure gets pushed beyond design parameters. Traditional chillers and HVAC units typically run efficiently when outdoor air stays below 28°C. Once outdoor ambient temperatures cross 35°C or 40°C, these systems lose cooling capacity or trip out entirely. Mechanical cooling failures threaten patient safety, but they also knock out sensitive technology like MRI scanners and server infrastructure. During the 2026 wave, thermal overloads shut down servers hosting patient record systems for the University Hospital of Antwerp and AZ Sint-Lucas in Gent (at their cloud host facility in Paris), briefly cutting clinical staff off from electronic health records.
Third, power grid instability creates constant exposure. Peak air conditioning demand in Belgium pushed wholesale electricity prices to a record peak of €1 per kilowatt-hour during the June wave. Facilities faced both severe cost spikes and the threat of localized brownouts.
Fourth, deaths are only the tip of the iceberg. On 26 June, Belgium’s emergency number 112 received almost 20.000 calls, nearly three times the usual, and ambulance interventions rose from 2,500 to 4,324 a day. Emergency departments struggled with the inflow, and geriatric wards reached full capacity, forcing patient transfers. A Swiss study of 22 years of emergency admissions found that on a 34°C day and the week after, 86% of dehydration cases and 56% of acute kidney injury admissions were attributable to heat. Heat also drives respiratory admissions among older patients, while the ozone that builds up on hot, sunny days triggers asthma and COPD flare-ups. Even this could be an undercount: heatstroke is rarely recognised in European emergency departments and is often coded as something else.
Finally, healthcare staff suffer severe thermal fatigue. Working in overheated wards leads to physical exhaustion, reduced concentration, and an increased likelihood of clinical errors.
6 heat adaptation strategies for hospitals
To move from emergency reaction to structured resilience, healthcare institutions need a comprehensive plan spanning six operational areas.
Predictive heat action plans
Effective emergency management requires predictive action long before ambient temperatures cross critical thresholds. Hospitals should integrate their operational workflows directly with 48- to 72-hour meteorological forecasts, enabling management to adjust staffing levels, reallocate ward capacities, and adapt triage protocols proactively.
Within the hospital, conducting thorough vulnerability assessments allows clinical teams to identify high-risk areas such as geriatric, psychiatric, and intensive care units, and be vigilant for patients with impaired thermoregulation. Alongside patient tracking, facilities must establish clear surge management procedures, including fast-tracking discharge for stable patients and designated expansion zones for heatstroke victims. Finally, educating clinical and administrative staff is essential. Executing heat stress (tabletop) drills prior to peak summer months ensures that personnel can swiftly navigate heat-stroke protocols, backup cooling activations, emergency shift workflows, and other necessary protocols.
Infrastructure and HVAC
Relying solely on adding standard air conditioning units creates a structural trap that overloads local electrical circuits and inflates utility expenses. A resilient building infrastructure requires a layered strategy that prioritizes passive cooling before scaling up mechanical systems.
When mechanical upgrades are necessary, replacing aging chillers with modular water-to-water heat pumps allows cooling output to scale efficiently with demand. Crucially, cooling networks for high-vulnerability spaces (such as operating rooms, intensive care wards, and server rooms) must be decoupled from general comfort lines and protected by redundant backup power systems. Integrating smart building management systems and digital twin technology further optimizes efficiency, allowing facility managers to model thermal loads in real time and pre-cool structural zones during cooler early morning hours before regional power grids experience peak demand.
AZ Zeno’s Knokke-Heist campus shows this layered approach in practice. When the hospital was built on a greenfield site in 2018, the design followed one principle: keep heat out first, then cool what remains as efficiently as possible. The building envelope goes well beyond regulatory requirements, with a K-level of around K20, a double-skin façade that acts as a thermal buffer, and external shading controlled by solar sensors. The remaining cooling demand is met by heat pumps, climate ceilings and cooled ventilation, drawing on a borehole energy storage field more than 100 metres deep beneath the car park.
Clinical adaptation
Extreme heat alters human physiology and pharmacokinetics. Clinical staff must proactively review medication regimens during severe heatwaves, as commonly prescribed pharmaceuticals (such as diuretics, antihypertensives, anticholinergics, and psychotropics) can severely impair thermoregulation or accelerate dehydration. To support proactive care, hospitals should deploy frequent patient monitoring.
Facilities should also establish dedicated, temperature-controlled cool zones equipped with boosted air conditioning, hydrated nutrition stations, and active cooling equipment to provide immediate relief for high-risk patients.
Workforce resilience
A healthcare facility can only remain operational if its clinical workforce is protected from thermal exhaustion and burnout. Safeguarding staff health preserves operational capacity and maintains consistent standards of care.
Management should institute flexible work shifts and schedule adjustments, shifting heavy physical tasks to cooler early morning hours and rotating clinical staff to limit continuous heat exposure. Across wards, hospitals can deploy mobile hydration services that distribute cooled water, electrolyte solutions, and ice directly to staff. Furthermore, institutions should establish cooled staff break areas, provide lightweight and breathable workwear and protective equipment (PPE), and utilize internal communications to broadcast immediate communications.
Greening the campus
Hospital grounds can either amplify surrounding heat through dark surfaces or act as a natural cooling buffer for the facility. Replacing heat-retaining concrete and asphalt with ecological landscaping transforms campus surroundings into a protective thermal barrier.
Figure 3: The Knokke-Heist campus of AZ Zeno exemplifies nature-based climate
adaptation, combining surrounding polder wetlands, open water retention basins,
and extensive solar parking canopies to cool the hospital microclimate while
generating clean renewable energy (AZ Zeno, 2026).
Developing urban canopies by planting native, drought-resistant shade trees and installing vertical green walls along exterior facades blocks direct sunlight, lowering wall surface temperatures and providing natural shading. For ground surfaces, substituting dark asphalt with light-coloured, permeable paving reduces thermal storage while enhancing rainwater infiltration into the soil. Installing solar photovoltaic canopies over outdoor parking areas creates a dual benefit, generating renewable electricity while shading vehicles and pedestrian walkways. Finally, integrating rainwater retention ponds or low-water misting stations near public entryways utilizes natural evaporative cooling to lower ambient air temperatures across hospital grounds.
At AZ Zeno, the campus forms a second protective layer around the building. The hospital is integrated into the surrounding polder landscape, where green areas, open water and rainwater retention zones help cool the surroundings and absorb excess water during heavy rainfall. Solar canopies over the car park generate electricity while shading the asphalt below. At AZ Zeno, each measure should ideally tackle several climate challenges at once.
Safeguarding the supply chain
Hospital readiness founders if external supply chains fail during extreme weather events, as demonstrated when European heatwaves dropped River Rhine water levels to historic lows, restricting cargo barge capacities and delaying raw material shipments to pharmaceutical manufacturers. Temperature excursions during transit and power outages threaten heat-sensitive biologics, vaccines, and blood products. To protect critical medical inventories, healthcare networks must enforce strict supply chain safeguards, including audited active thermal packaging with real-time sensor logging across distribution logistics.
The ROI of climate resilience
Viewing adaptation strictly as an overhead expense overlooks the severe financial losses caused by operational paralysis. Unprepared facilities face substantial costs during severe heat events, including cancelled elective procedures due to server or chiller failures, emergency cooling equipment rentals at premium rates, high electricity costs, mounting staff overtime or ruined pharmaceutical stock.
Being unprepared is expensive. When both data centres of Guy’s and St Thomas’ in London failed during the July 2022 heatwave, restoring the systems took six weeks and £1.4 million in unplanned IT costs, in what a review later called a potentially preventable event. Patients add to the bill: in Portugal, hospital admissions rose by 19% on heatwave days, and in Switzerland heat-related hospitalisations cost six cantons CHF 20.6 million a year. Prevention pays back. The World Resources Institute estimates that every dollar invested in climate services for health, such as early-warning systems and climate-resilient facilities, returns $3.60 to $68.40, mostly through illness and deaths avoided. Efficient HVAC and thermal retrofits also cut energy bills year-round, so resilience investments recover their costs while keeping care running when the next heatwave hits.
Keeping it safe and cool
Extreme heatwaves represent a permanent structural challenge to public health and hospital operations. Transitioning from reactive crisis response to systemic climate adaptation is essential to protect vulnerable patients, shield staff from burnout, and ensure the operational continuity of critical healthcare infrastructure. By implementing pre-emptive measures well before temperatures peak, healthcare leaders can ensure their facilities remain safe, cool, and fully resilient.
- Integrate meteorological forecasts proactively into hospital management systems to trigger predictive staffing and surge-capacity protocols.
- Prioritise passive envelope retrofits alongside modular heat pumps and decoupled backup cooling, ensuring critical spaces remain operational during severe grid stress.
- Establish proactive protocols to screen vulnerable patients, flag high-risk heat-altering medication regimens.
- Adjust shift patterns, provide hydration, and establish dedicated cooling sanctuaries to safeguard staff from fatigue and burnout.
- Replace heat-absorbing asphalt with permeable paving, tree canopies, and solar shade structures to transform hospital grounds into natural microclimate buffers.
References
- Alho et al., 2024, Effect of heatwaves on daily hospital admissions in Portugal, 2000–18: an observational study, The Lancet Planetary Health, https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(24)00046-9/fulltext
- AZ Zeno, 2026, Ons verhaal, https://azzeno.be/over-az-zeno/ons-verhaal
- Belga, 2026, Belgium experienced highest excess mortality in Europe during end of June heatwave
- Brandon, C., Kratzer, B. & Aggarwal, A., 2026, Adapting to climate-related health risks: The economic case for climate services for health, WRI Working Paper, https://doi.org/10.46830/wriwp.25.00120.
- De Standaard, 2026, Hulpverleners reconstrueren het fatale hitteweekend: “We vonden mensen dood in de zetel, op een stoel of in bed”, https://www.standaard.be/binnenland/hulpverleners-reconstrueren-het-fatale-hitteweekend-we-vonden-mensen-dood-in-de-zetel-op-een-stoel-of-in-bed/158560182.html
- European Environment Agency, 1998, Health effects of exposure to ozone, https://www.eea.europa.eu/en/analysis/publications/top08-98/page010.html
- European Environment Agency, 2024, The impacts of heat on health: surveillance and preparedness in Europe
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- Guy’s and St Thomas’ NHS Foundation Trust, 2023, IT critical incident review, https://guysandstthomas.nhs.uk/media/13017/IT%2Bcritical%2Bincident%2Breview
- Health Care Without Harm Europe, 2024, Practical guide for building climate-resilient health systems
- Kpler, 2026, Belgium breaches 1,000 €/MWh as low wind and heatwave spikes evening peak, https://www.kpler.com/blog/belgium-breaches-1-000-eu-mwh-as-low-wind-and-heatwave-spikes-evening-peak
- Michelozzi et al., 2009, High temperature and hospitalizations for cardiovascular and respiratory causes in 12 European cities, Am J Respir Crit Care Med, https://doi.org/10.1164/rccm.200802-217OC
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- Vaghefi, A.S., Bucher, I., Senni, C.C., Muccione, V., Ragettli, M.S., Mirmashhouri, A., Huggel, C. & Leippold, M., 2026, Quantifying the financial burden of heat-related hospital admissions in Switzerland under a changing climate: A scalable analytical framework, https://link.springer.com/article/10.1186/s44263-026-00275-w.
- 15. VRT NWS, 25 juni 2026, Niet-dringende operaties in AZ Sint-Lucas Gent en UZA Edegem blijven nog hele dag geschrapt door oververhitte servers
- World Health Organization, 2023, Operational framework for building climate resilient and low carbon health systems, https://www.who.int/publications/i/item/9789240081888
- World Weather Attribution, 2026, Fossil fuel emissions have rapidly worsened European heatwaves in just a few decades, https://www.worldweatherattribution.org/fossil-fuel-emissions-have-rapidly-worsened-european-heatwaves-in-just-a-few-decades/
