Leuven is cool, mapping urban heat through public participation

 

By Michael Van Hout and Hannes De Praitere

 

Imagine this: when walking in a city on a hot summer day, where would you like to spend your afternoon. Most likely, your answer would be a cooler area near a park or a pond. However, on days like these it can be quite busy in these areas so perhaps you decide to go outside the urban center instead. What can be done to alleviate the worst effects of heat waves inside an urban center?

 

To tackle that question, we need to first introduce the concept of ‘urban heat islands’, a scientific term to describe areas within the city where temperatures are much higher than in the surrounding countryside. In the context of global warming this is a very real issue city councils have to urgently address. Hence there has been a lot of scientific investigation into the main causes of urban heat islands. Some of its main contributors include high rise buildings, which block wind and reflect additional sunlight to the surface, and road infrastructure, where asphalt and concrete absorb much sunlight and release it in the form of additional heat, thus acting like a glowing furnace. By now it has been widely established that such conditions form a dangerous situation for the residents, especially children, the elderly and pregnant women. There is also good news in that several relatively small adaptations can already greatly reduce the worst effects. As you might have guessed this includes more plants and trees (the so-called green infrastructure) and waterways and ponds (the blue infrastructure). However, they also stress the importance of private gardens in mitigating extreme heat, which is why they recently started collaborating with Klimaattuiniers, another KU Leuven initiative focusing on the climate benefits of gardens.

 

Leuven.cool map showing the temperature on May 1st 2023 at 2:30 pm 

Source: https://www.leuven.cool/

 

For the city council it is obviously very important to know where the heat islands are located. This is where Leuven.cool comes in, an initiative founded in collaboration between the city council, Leuven 2030 (a non profit organization aiming to green the city), the KMI (Belgium’s meteorological institute) and KU Leuven. For its initial phase, residents were asked to install small weather stations to calculate temperature for a few years, so based on that data the city can identify the most problematic heat islands. In a more recent phase, the participants were also asked some questions about how heat waves affect their way of living. The organization has recently also included measurements from outside the Leuven area, such as Tervuren, and hopes to develop new insights based on results from similar projects in other cities as well (e.g. Ghent and Amsterdam), though also taking into account the unique characteristics of each city.

 

The city of Leuven challenges people, together with Hack Belgium, to find solutions to measure and reduce the local heat island effect. The most promising solution will be offered the opportunity to develop the project with support of the city of Leuven, through the city of Leuven award. The mayor of Leuven, Mohamed Ridouani supports Leuven 2030 and their motto “to innovate for the better and for all”. Ridouani stated Leuven 2030 is creating “a new narrative”.

 

 

Measuring station at Pieter De Somer Aula, Leuven. Source: Google Maps

 

Since the project is still in its piloting phase of collecting and analyzing the data, the project has thus far not led to greening initiatives of the city in the most affected areas. While the Leuven.cool project will be crucial in mitigating the urban heat island effect, enhancing urban attractiveness, and providing multiple ecosystem services, it could drastically change the character of certain neighborhoods and lead to green gentrification and other negative social effects. However, this does not mean that the project is undesirable or disadvantageous. Thus far, little concern has been raised by any of the stakeholders about possible negative effects, or at the very least stressing that the projects would overall still be beneficial to the city and the residents. Moreover, the study hopes to show that small changes like softening the pavement or increasing plant diversity in the private gardens. It should also be noted that Leuven is already among the most expensive cities in Belgium, thus additional gentrification effects may be small.

 

Arenberg castle and the Dijle river, pictures taken by Hannes De Praitere

In conclusion, we are convinced of Leuven.cool’s important role in urban climate mitigation and improving health and other benefits. The project is still young so most greening initiatives resulting from the study are not for the immediate future. Still, some caution may be required in context of the threat of green gentrification and the possible disruption of the social connections within the city.

 

References

 

Garcia-Lamarca, M., Anguelovski, I., Cole, H., Connolly, J. J., Argüelles, L., Baró, F., ... & Shokry, G. (2021). Urban green boosterism and city affordability: For whom is the ‘branded’ green city?. Urban Studies, 58(1), 90- 112. <https://journals.sagepub.com/doi/10.1177/0042098019885330>. 

Leuven.be (n.d.). Ontharden en vergroenen via natuur-gebaseerde oplossingen, accessed 1 May 2023, <https://leuven.be/ontharden-en-vergroenen-natuur-gebaseerde-oplossingen>.

Leuven.cool (n.d.). Leuven 2030, accessed 1 May 2023, <https://www.leuven.cool/>. 

Leuven 2030 (z.d.). accessed 1 May 2023, <https://www.leuven2030.be>.

Vlaamse Milieumaatschappij (2021). Hitte-eilanden in steden (2012-2020), Vlaamse overheid, accessed 1 May 2023, <https://www.vmm.be/klimaat/hitte-eilanden-in-steden>. 

Pierreux, S. (2019). Hack Belgium: Leuven City challenges you to reduce local heat stress, accessed 1 May 2023, < https://hackbelgium.be/blog/leuven-challenges-you/>

Waymouth, L. (2022) Leuven’s journey to becoming carbon neutral, accessed 1 May 2023, <https://citymonitor.ai/environment/leuven-journey-to-becoming-carbon-neutral>

Wouters, E. (2022). Leuven.cool zoekt vrijwilligers die de impact van hitte in kaart willen brengen. From Het Laatste Nieuws: https://www.hln.be/leuven/leuven-cool-zoekt-vrijwilligers-die-de-impact-van-hitte-in-kaart-willen-brengen~aba38997/