How heatwave resistant are Brussels and other cities?

Europe is experiencing temperatures rising twice as fast as the global average, and heat-related mortality has increased by about 30% over the past 20 years. Sweco's new report examines 24 European cities using the climate risk dashboard of the European research project PROVIDE. The findings reveal a significant flaw in cities' climate plans when it comes to heat-related concerns.

More than 70% of Europeans currently live in cities, a figure that is expected to rise to 84% by 2050 due to ongoing urbanization. Urban areas are now experiencing increasingly higher temperatures compared to rural areas due to climate change and the "Urban Heat Island (UHI) effect". Sweco's report shows that some European cities are taking steps in the right direction to combat heat, but there are still major gaps to be addressed.

Séverine Hermand, Climate resilience planning expert at Sweco, and one of the main authors behind the report: “European cities’ climate plans need to focus more on protecting vulnerable groups, by improving the cooling of facilities such as preschools, assisted living facilities and care homes. EUR 680 billion of the EU’s budget is allocated for climate-relevant measures during the 2021–2027 period, so there is funding available. It is now time for European cities to level up by implementing new methods that help cool cities. It can be done, and there is an array of solutions for this.”

Brussels: a critical situation

One of the analyzed cities is Brussels, where Sweco is already working on projects to combat heat. Due to the urban heat island effect (UHI), Brussels sees city temperatures that are up to 8°C higher than surrounding rural areas. The number of days with moderate heat stress is expected to increase by 150% from 2020 to 2100, which means nine additional days per year. Historical data shows a significant increase in the frequency and duration of heatwaves, posing serious threats to public health, infrastructure, and resources.

In response, Brussels has developed a major climate resilience policy, focusing on nature-based solutions, infrastructure adaptation and urban planning. Nature-based solutions include the creation and improvement of green spaces and biodiversity through projects such as 'Reseau Nature' and the Neder-Over-Heembeek Urban Forest, together with diversification of tree planting in the 'Air-Climate-Energy Plan'. We apply infrastructure adaptation by promoting the Sustainable Building Guide and the Materials tool, as well as retrofitting.

Sweco’s key recommendations in the report:

• Invest in granular data: Increase vulnerability mapping across cities, with better monitoring and evaluation. This can be done by creating “digital twins” making use of GIS spatial mapping, and other digital solutions, for better heat assessment and management.

• Enable innovation and co-creation: Design solutions at the building and neighbourhood scale to adapt urban spaces. More nature-based solutions, more green-blue infrastructure and updates of regulations for new and existing buildings.

• Pursue transparent and collaborative governance: Cities must work together more to address heatwaves effectively. This requires investments in knowledge, data-driven heat management and joint planning for the organisation of dedicated team structures in a heatwave crisis.

• Decide on a long-term vision: Authorities and policy makers must establish more efficient, modern strategies to protect vulnerable populations from extreme heat, to safeguard overall public health in general and to increase climate equality between groups in particular.

Examples of figures from the report:

Sweco’s analysis of 24 European cities* and their resilience policies and heatwave data includes in-depth case studies of six cities, and is showing how temperatures are expected to rise for each city from 2020–2100:

• Copenhagen +160% estimated increase in heatwave days

• Stockholm +150%

• Oslo +140%

• Rotterdam +130%

• Brussels +130%

• Helsinki +100%

*Sweco has studied 24 cities: Brussels, Copenhagen, Helsinki, Oslo, Rotterdam, Stockholm, Amsterdam, Edinburgh, Madrid, Glasgow, Seville, London, Rome, Lisbon, Paris, Vienna, Barcelona, Geneva, Prague, Istanbul, Toulouse, Gdansk, Warsaw and Athens.

Sources: ERA5, European State of the Climate 2023/Copernicus, the Lancet Planetary Health, Provide Climate Risk Dashboard, Sweco. Please see report for full list of references.

About Urban Insight by Sweco

Urban Insight is a series of insight reports written by Sweco experts on various aspects of urban development from a citizen perspective. The latest report is found here: https://www.swecogroup.com/urban-insight/resilient-societies/heatwave-resilience

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Interviews with our experts are available upon request