Adapting Paris: Climate Resilience Strategies in the Face of Rising Temperatures

• Rising temperatures and frequency of heatwaves prompt the urgent need for robust climate adaptation policies and resilience measures in Paris.
• Ongoing adaptation efforts are necessary to continually upgrade cooling systems and infrastructure to mitigate the impacts of increasingly severe heatwaves.
• Real estate companies must recognise the evolving risks associated with rising temperatures, with properties in high-risk areas facing potential declines in value and insurability.

A recent study published by the Journal of Hospital Management and Health Policy encompassing 2,184,193 residents across 20 districts (arrondissements) in Paris shows that temperatures reached unprecedented levels in 2019.

The highest average temperature was recorded at 33.06 °C and the all-time high hit 42.6 °C, marking the latter part of July as the period most impacted by this heat increase. Summer temperatures caused 1500 fatalities in the country that year.

Since then, climate change has led to a rise in the occurrence, severity, and length of heatwaves in France, with record-breaking temperatures around 40°C every year between 2020 and 2023.  

From the year 2022 onward, Paris, one of the hottest cities in Europe, has experienced increasingly severe heatwaves, impacting significantly urban infrastructures and public health.

Many older buildings, not designed to withstand such extreme temperatures, suffered from thermal stress, leading eventually to accelerated deterioration of building materials.

Such occurrence in cities is usually understood as “urban heat island effect”.

For example, older haussmannian buildings built with grey rooftops are made of zinc, a metal known to absorb and retain heat. From another angle, heatwaves in 2019 already indicated a risk of rising energy consumption. In Paris and across other French cities, the demand for electricity surged to around 59.5 gigawatts (GW) in the summer that year, a rise compared to the records set two years prior according to the French grid operator RTE.

This increase was in part due to heatwaves across France and western Europe, which heightened the need for cooling.

Although France secured over 63 GW of power from wind, hydropower, solar and nuclear sources that year, rising temperatures and more intense heatwaves could strain the electrical grid and building infrastructure. As demand for air conditioning increases, this may lead to occasional blackouts and added pressure on public services, particularly in cities like Paris, which are prone to the heat island effect.

Heatwaves can have a significant impact on businesses, with research indicating that a one-degree Celsius rise above 25°C can result in an annual sales decline of approximately 0.63% and a reduction in profit margins by around 0.16%.

For example, during the 2019 European heatwave, numerous factories in France and Germany were forced to shut down temporarily due to overheating equipment and hazardous working conditions, leading to millions of euros in lost production. Moreover, outdoor workers, such as those in construction, faced serious health risks, which reduced productivity and increased medical expenses for employers.

Given these challenges, it is essential for businesses to comprehend these complex impacts and adapt by implementing robust risk management strategies. This includes investing in cooling technologies, modifying work hours, and reassessing insurance coverage to mitigate potential losses.

This also broadly means that addressing the impacts of heatwaves on urban infrastructures and public health requires a multifaceted and long-term approach that encompasses both physical infrastructure upgrades and community resilience measures.

In response, Public Health France emphasised in 2023 the necessity to improve urban areas to cope with high temperature conditions.

This includes the implementation of the "green towns" concept, which involves mainly revegetation, the use of building materials that minimise heat absorption, and the establishment of water fountains and water bodies.

Among other initiatives, the French government introduced in 2022 new building regulations (RT 2022) aimed at enhancing thermal efficiency and promoting the use of heat-resistant materials in construction.

In line with the French Climate Plan, the environmental regulations RE 2020 (which substitute the former thermic regulations RT 2012) establish new guidelines for the energy efficiency, environmental sustainability, and health standards of new building projects, with the explicit goal of ensuring that future structures in France are equipped to tackle the issues posed by climate change.

To assess portfolio adaptations capacities, Climate X designed Adapt, a unique platform for asset managers and real estate professionals to optimise adaptation measures in seconds.

At the local level, the City of Paris implemented several heat mitigation strategies, including the installation of cooling stations and green roofs to reduce ambient temperatures, in alignment with its Climate Action Plan.

These include long-standing projects (since 2019), including the creation of 800 "Cool Island" spaces throughout the city.

These spaces encompass parks, water fountains, and public facilities such as swimming pools and museums. The “cool islands” can be 2 °C to 4 °C cooler than the adjacent streets. This project is important because it provides an effective solution to the infrastructure and health risks posed by more frequent and severe heatwaves, particularly for vulnerable groups like the elderly and those with health issues.

Moreover, these actions aid in cutting down energy usage, as less heat translates to reduced reliance on air conditioning, thereby aligning with the city's wider objectives of energy conservation and sustainability.

The effectiveness of these approaches highlights the significance of forward-thinking and all-encompassing urban planning in the context of climate change. It stands as a benchmark for other global cities that are facing similar predicaments due to escalating worldwide temperatures.

The city of Paris plans to plant 170,000 trees in Paris by the year 2026, leveraging on its natural capacity – as Paris is known to be one of the “most wooded capitals” in Europe – to maintain the city cool in response to heatwaves and climate change as a whole.

Trees contribute to cooling urban zones, offering shade and humidity while also reflecting the sun's heat.

In a similar perspective, Anne Hidalgo, Mayor of Paris, stressed: “We also must adjust Paris to climate change by cooling the city, reducing impervious surfaces, planting trees and protecting our buildings from heat waves”, showing the critical role of urban adaptation strategies in creating a resilient and sustainable future in the face of climate change.

Undoubtedly, real estate companies operating in Paris, along with their financiers, wield significant influence in realising the city’s resilience ambitions and must accordingly prepare.

In this sense, there are two crucial considerations:

• Property Value: Locations with "Cool Island" spaces may see a surge in property values, due to enhanced liveability and resilience against heatwaves.
  
  This trend could attract more buyers, leading to increased demand and possibly higher prices. However, the attractiveness of properties located in high-risk areas in Paris as well as their values and insurability are poised to decline over time, if adaptation measures cease to evolve as climate change advances.
  
  In 2023, Thibault Gallot-Lavallée, a notary in Neuilly, noted that "Paris is no longer holding out. [...] The market for older homes in the Paris region, once the most dynamic since the pandemic, saw a 25% drop". Overall, sales of existing homes in the Paris region declined by 22% year-on-year, driven primarily by socio-economic issues and exacerbated by the effects of climate change.
  
  
• Risk Assessment: Participating in heat-prone scenario exercises like the 2023 Paris Heat Dome exercise, looking at a Paris-under-50°C scenario, allows stakeholders to assess the vulnerability of different urban areas to extreme heat events, identifying high-risk zones and potential adaptation strategies.
  
  For example, knowing that properties in the 13th and 19th arrondissements may face failing generators during peak temperatures of 50°C in summer 2024, they might strategically invest in advanced cooling technologies or choose properties in cooler, less vulnerable areas.
  
  This approach can help reduce long-term financial risks related to climate change impacts on property values and insurability.

To address rising temperatures and the increasing frequency of heatwaves impacts, Paris needs robust climate adaptation policies and resilience measures.

Ongoing efforts to upgrade cooling systems and infrastructure are crucial to mitigate the impacts of severe heatwaves. In assessing specific physical risks, measuring financial losses, and deciding adaptation measures, businesses must first recognise the evolving risks associated with rising temperatures.

The journey toward resilience begins with Climate X reliable data, empowering communities to adapt and thrive in a changing world.

And yet, as Édith Piaf once sang in Sous le ciel de Paris, 'Tout peut s'arranger, Quelques rayons du ciel d'été (...) L’espoir fleurit, Au ciel de Paris'.

"Even in the face of challenges, Paris will find a way to endure—its spirit unbroken, its hope ever-blooming under the summer sky."