Managing heatwaves in European cities: Strategies and solutions

Published on: September 19, 2024

As cities across Europe grapple with the intensifying impacts of climate change, managing heatwaves has become a crucial concern. Urban areas are facing severe heat effects, including the Urban Heat Island (UHI) effect, which significantly raises temperatures compared to surrounding areas.

Drawing from a recent Sweco study, this article explores how various cities are adopting multi-level strategies to address heat impacts, enhance green infrastructure and adapt urban planning. Efforts include improving building and infrastructure resilience, expanding green spaces and integrating nature-based solutions. By examining these strategies, the article highlights how cities are developing and implementing resilience plans to cope with the growing challenge of heatwaves and protect their environments and residents.

Heatwaves days per day

Brussels

Image of Brussel

Current heatwave impact:

Brussels is particularly vulnerable to heatwaves compared with other Belgian municipalities, with the UHI effect making air temperatures in the city up to 7-8°C greater than surrounding rural areas.

The city is experiencing an increased frequency and intensity of heatwaves, with at least one heatwave occurring every year between 2015-2019.  Additionally, the duration of heatwaves doubled in the period 1988-2016 compared with 1901-1930.

Climate resilience plans and key heat policies:

Brussels’ key heat resilience policies span three key areas.

The city’s climate plan identifies nature-based solutions as the first step in combatting increased heat. Policy measures include creating and enhancing local greenspaces, a “Reseau Nature” programme to increase urban biodiversity and the continued development of the Neder-Over-Hembeek Urban Forest project. This is consolidated in the region’s Air-Climate-Energy Plan, which asserts the need for diversified tree-planting to increase the climate resilience of local forests.

Infrastructure adaptation and retrofitting to improve comfort in the summer is another key part of the climate change plan. These are complemented by the promotion of the Sustainable Building Guide and Materials tool for architects and construction professionals.

Finally, the city recognises that “urban planning and urbanisation are essential levers” for ambitious climate adaptation measures. Municipal authorities are looking to increase access to urban green space through a programme of “verdurisation,” in collaboration with the environmental division of the city authority Environnement.Bruxelles and Be.Sustainable, a network of Brussels transition actors who work towards developing a resilient city. The city is also “committed to carrying out three pilot projects to reduce the UHI,” though no further detail is provided.

“In Belgium we have chosen to combine the management of high temperatures with the issue of ozone peaks, which are often associated with them. The implementation of the Heatwaves and Ozone Peaks plan adopted in 2015 was the subject of a coordination protocol between the three regions and CELINE (Interregional Environment Cell). The various authorities in Belgium have an ozone and heat plan,” says Pascale van der Plancke, climate policy advisor at the City of Brussels.

Copenhagen

Image of Copenhagen

Current heatwave impact:

The Copenhagen Climate Adaptation Plan (2011) identifies UHI and high surface temperatures as a key issue for the city. Copenhagen experienced its hottest average summer in 2018, with heatwaves in consecutive years from 2020-2022, and record July temperatures in 2022.

Climate resilience plans and key heat policies:

To reduce probability, scale and vulnerability to heat, the plan promotes targeted multilevel actions at the municipal, district, street and property levels. These include integration of nature-based solutions in local plans and legislation, establishment of continuous green structures and the Municipal District Cooling Act.

“In Copenhagen’s Municipality’s climate adaptation plan, we have identified rising temperatures as a challenge that will grow in line with climate change. We have prepared a study of the extent of the problem and possible measures that can reduce UHI. Handling of UHI is included in the municipal plan’s general guidelines as a possible parameter that can be incorporated into local plans. Political decisions on prioritising the work with UHI and financing measures are needed to reduce UHI,” says Jan Rasmussen, project director, Center for Climate Adaptation at the City of Copenhagen.

Helsinki

Image of Helsinki

Current heatwave impact:

The UHI effect and summer heatwaves are some of the key climatic and adaptation challenges Helsinki faces. A 2018 summer heatwave is estimated to have caused 380 premature deaths in the city.

Climate resilience plans and key heat policies:

The 2017 Climate-Smart Helsinki city plan calls for the implementation of a green roof policy and expanded district cooling to help the city adapt to the UHI effect.

Climate adaptation strategies have been developed to combat increased heat, focusing on urban greening and embedding climate adaptation measures into city administration.

The City of Helsinki is a project partner in the Green Handbook, a model for the digital, participatory urban planning of multifunctional green infrastructure.

However, in its 2019-25 Climate Adaptation strategy, the city recognised that actions for mitigating the UHI effect remain insufficient due to resource constraints and that there is a need to integrate adaptation into city management through staff training and in-depth scenario planning.

“The city has planned to launch policies regarding heatwaves this year (2024). However, since this is completely new, there is no city body that is ready and organised to take this as their responsibility. It requires cooperation and responsible parties throughout the city’s different organisations. Regarding rain and flooding, these processes have existed for a long time, but for heatwaves everything needs to be built from scratch now,” says Susanna Kankaanpää, project manager, adaptation to climate change at City of Helsinki.

Oslo

Oslo

Current heatwave impact:

The unique topography of Oslo, with its basin shape and compact city centre, increases the risk of UHI. Over the past century the climate in Oslo has become 1.5 degrees warmer and — with temperature rise projected to be highest in polar regions — this rise will be felt acutely in Norway’s capital.

Despite its status as being considered one of the cities with lower exposure to climate risks compared to other parts of the world, ranking 575th globally, Oslo experienced consistently high temperatures and drought in 2016-2018. This acutely increased the risk of wildfires owing to drought-stressed fir trees in Oslomarka, the forest surrounding the city.

Climate resilience plans and key heat policies:

In 2015, Oslo became the first Norwegian city to adopt a climate change adaptation strategy. This strategy was revised and integrated in the Climate Strategy of Oslo adopted in 2020, with goals for both adaptation and mitigation. The strategy has one focus area on managing and protecting the forest surrounding the city, and another focus area on building resilience in the built environment. Both focus areas include action points that will enhance resilience to heat, such as further developing green spaces, planting trees, promoting sustainable forestry and reopening streams. Other initiatives being implemented:

  • A clear focus on nature-based solutions through preservation and enhancement of blue-green infrastructure, including a flagship tree-planting project, green roofs and rain gardens.
  • Integration of climate change adaptation into urban planning. For instance, the Agency for Planning and Building Services has developed standards for mandatory blue-green infrastructure and climate change criteria in new housing projects, as well as in other transportation and construction works.

“The city might in the future implement various measures to help residents cope  with the heat, especially for vulnerable populations like the elderly and those with pre-existing health conditions,” says Guro Sørnes Kjerschow, special advisor for climate change adaptation at the City of Oslo.

Rotterdam

Rotterdam

Current heatwave impact:

Rotterdam is experiencing longer periods of drought and more frequent and intense heatwaves, with heatwaves labelled one of the “key shocks and stresses” impacting the city.

Additionally, these heatwaves are exacerbated by the UHI effect, which causes the city to be up to eight degrees warmer than the surrounding countryside.

Climate resilience plans and key heat policies:

Rotterdam has more than a decade of experience in implementing heat resilience measures. Today, the city identifies heat as a key risk factor influencing climate, biodiversity and health crises. It aims to adapt to extreme heat through policy implementation in four key areas: public spaces, existing properties, new properties and “residents in motion.”

Incorporating nature-based solutions in public spaces was a key focus area in its 2013 Climate Change Adaptation strategy. It included the expansion and creation of new blue-green networks, incorporating more flora and less paving into urban spaces, and increasing the number of green roofs and facades throughout the city.

Infrastructure policies include encouraging heatproofing measures as standard at the design phase for all new construction projects and retrofitting existing buildings with heatproofing measures such as white and green roofs, sun blinds and easy-to-open windows.

The adaptation strategy also states an intention to “keep the people of Rotterdam well-informed about heat stress” to encourage behaviour change, though it is unclear exactly how this was operationalised. City planners state they will be working on a Rotterdam heat plan for 2028.

“Since 2019, we have been mapping and using all kinds of data in WeerWoord Rotterdam. There is also a national programme for measuring heatwaves to reduce heat stress. Inclusive Climate Action Rotterdam (ICAR), a part of Weer-Woord, is putting a lot of effort into inclusive climate action, and making sure that the policies and projects we develop reach as many Rotterdammers as possible,” says Johan Verlinde, programme manager, Rotterdams WeerWoord.

Stockholm

Stockholm

Current heatwave impact:

Climate change is faster in Sweden than the global average, with temperatures already nearly 2°C higher than the pre-industrial average and rising even higher in Stockholm.

Heatwaves are rare in Sweden compared with southern Europe, yet the last decade has brought the three hottest years since 1945 with record-breaking 2018 heatwaves directly attributable to anthropogenic climate change. These resulted in drought and wildfires across the country.

Climate resilience plans and key heat policies:

One-third of Swedish municipalities have developed routines, checklists and action plans to counter extreme heat, although Stockholm has not.

The Stockholm Environment Programme for 2020-2023 does, however, identify the need to create an action plan for heatwaves.

Example mitigation measures identified by the city include:

  • A risk and vulnerability analysis for city operations
  • Nature-based solutions
  • Temperature-lowering measures on buildings
  • Cool rooms in homes
  • Rainwater collection

“It is important to realise that climate adaptation is about managing risks in many ways. If you link up with others who also do this, you can benefit greatly,” says Karin Dhakal, strategist at the City of Stockholm administration.

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