Strategies to combat heatwaves in European cities
In our recent Urban Insight report, Sweco identifies the approaches that European cities have adopted to enhance the resilience of their local communities in response to the increasing frequency and severity of extreme heatwaves.
Sweco conducted a study of 24 European cities to assess their preparedness for heatwaves. The study analysed climate resilience policies and heatwave data, focusing on six primary case study cities: Brussels, Copenhagen, Helsinki, Rotterdam, Oslo and Stockholm. Despite projections showing a doubling of heatwave days by 2100, few cities have dedicated heatwave adaptation teams, especially in Northern Europe where heatwaves are relatively new.
While cities recognise the health risks of heatwaves, they often fail to incorporate equitable resource distribution and protection for marginalised communities into urban resilience planning. This is compounded by a lack of detailed data and vulnerability mapping across cities, hindering monitoring and evaluation of existing adaptation policies.
To effectively tackle heatwaves, clear governance, innovation and co-creation are crucial, along with long-term visions and adaptable strategies. Collaborative governance, public awareness and community empowerment are key for effective adaptation. Action on blue-green infrastructure is also vital, ensuring solutions meet community needs and have positive impacts.
How did we get here?
The impacts of heatwaves are already being felt worldwide. Between 2013 and 2022, the number of heatwave days increased by 94 per cent globally compared to the period from 1986 to 2005.
The European State of the Global Climate 2023 report shows that Europe is in fact the continent where warming is occurring most rapidly, with temperatures rising approximately twice as fast as the global average.
The Urban Heat Island (UHI) effect exacerbates this situation, leading to significantly faster surface warming in cities compared to rural areas. This temperature difference occurs when cities’ unshaded roads and buildings absorb heat during the day and radiate that heat into the surrounding air.
This temperature difference is mainly caused by the extensive use of concrete and asphalt, which absorb and retain heat more efficiently than natural landscapes, as well as by heat generated from vehicles, industrial processes, energy systems and waste heat. The lack of vegetation in cities also contributes to this effect, as plants and trees can cool the air. The UHI effect can exacerbate the discomfort of hot weather, increase energy consumption for cooling and can contribute to poorer air quality.
Increasing temperatures
European cities are projected to witness a rise in both the number of heatwave days per year and the maximum heatwave temperature. High-impact scenarios suggest that 72 per cent of European cities will experience a temperature increase of at least 10 degrees during heatwaves.
These extreme heat events pose significant risks to public health, energy infrastructure and economic productivity in urban areas. During the summer of 2022, more than 61,000 people died because of Europe’s record-shattering heat wave, according to scientists.
A study published in the scientific journal Nature shows that heatwaves caused somewhere between 0.3-0.5 per cent of Europe’s GDP in damages between 1981 and 2010. Future projections suggest that by 2060, impacts could increase by a factor of almost five in Europe if no further mitigation or adaptation actions are taken.
Despite these risks, heat-related health concerns are often overlooked in climate mitigation and adaptation plans. Moreover, there is a significant heat disparity within urban centres that disproportionately impacts vulnerable and marginalised communities.
The rapid urbanisation trend is undeniable, with more than two-thirds of the world’s population predicted to reside in urban areas by 2050. In Europe, this figure is even more staggering, reaching 84 per cent.
This demographic shift brings about a heightened focus on urban climate resilience, with heat management being a critical issue for cities to address.
Europe needs to improve its adaptation
Europe needs to improve its adaptation to the effects of climate change, according to the European Environment Agency (EEA), which recently warned that extreme heat, drought, wildfires and floods will worsen and negatively impact living conditions.
In this report, the EEA has examined how European cities are being equipped to withstand more frequent and intense extreme weather in the future. It turns out that almost all are increasingly using nature-based solutions to enhance resilience. Of the 19,000 local climate action plans analysed, 91 per cent included nature-based methods such as the construction and maintenance of parks, urban forests and green roofs. Vegetation can help cool cities and manage water – but it also brings other benefits, such as providing recreational spaces or reducing air pollution, as emphasised by the EEA.
However, the EEA warns that relying solely on nature-based tools is not enough. The climate effects are expected to grow to a magnitude that requires a combination of various measures, including changes in physical infrastructure.
Countries that fail to address climate change and its effects might face dire consequences. In the spring of 2024, Switzerland faced judgement from the European Court of Justice in Strasbourg for inadequately protecting vulnerable older women from the impacts of climate change, particularly heatwaves. This case, known as Klimaseniorinnen, marked the European Court’s first climate-related conviction.
