Trees vs. heat waves: How cities can use green infrastructure against climate change
On Strossmayer Square in Prague 7, the Technical Road Administration (TSK) has started planting 17 Julian alder trees, selected for their resilience to man-made climate change. I spoke with Katarína Svitková, Associate Research Fellow at the EUROPEUM Institute, about this project as a case study for what Czechia can do differently to combat extreme weather conditions in its cities
Heat waves have become increasingly common in recent years, negatively impacting people’s lives. Urban areas face particular challenges during heat waves due to the effects of buildings and infrastructure. Materials like concrete absorb heat during the day and fail to cool sufficiently at night, exacerbating high temperatures for city residents.
Given these challenges, Svitková argues that Czech municipalities are underprepared when it comes to the increasing number of extreme weather conditions, including heatwaves.
“Generally, [we are unprepared] because of the frequency of heatwaves that Czechia or Czech cities have experienced. This is not as frequent, of course, compared to cities in Southern Europe or elsewhere in the world. Czechia is only beginning to wake up to the challenge of heatwaves, and many cities and municipalities are already starting to address them.
“It’s a step-by-step process, but it’s definitely not on the level of preparedness seen in Southern European cities, which is why those cities are more equipped to handle such conditions.”
As Svitková explains, the most obvious solution to this would be to create more green and blue spaces. Indeed, a 2023 study examining 93 European cities found that increasing tree coverage to 30% could reduce urban temperatures by an average of 0.4°C. Svitková touches on some other possible solutions:
“There are many things on many levels that work. First of all, you have the mitigation efforts, which means you're trying to reduce the carbon footprint of cities as a whole. So, you're looking at how much and where your city is producing carbon emissions, and you try to cut down wherever possible. For example, when it comes to buildings or transport, etc., there are many ways to go about this.
“The second part, which is very important, is the adaptation effort. When we already accept a certain level of climate change, we know there's no way around it; it's already happening, and it's already having all these impacts on cities, such as extreme weather events, floods, heat waves, etc. So, what we have to do is adapt.
“Adaptation efforts can take many forms—for example, greenery and water elements in cities, which you can develop and adapt to handle heat waves or at least provide some kind of shelter during the worst extreme days of summer heat waves.
“What you can do, for example, is maintain and further develop all the green areas, such as parks, lines of trees, green facades, green roofs, etc.—any kind of greenery or green infrastructure in the city. That's what we're trying to do. The goal is to move the city forward and make sure it's maintained well, irrigated, and capable of handling the heat. At the same time, it provides the necessary shade and humidity during extreme heat days in cities.”
When it comes to the project in Holešovice, Prague, Svitková was receptive because apart from the two parks Letná and Stromovka, there are not many cooling areas.
“It's a step in the right direction because you have to work with the layout of the city—with the planning, the buildings, and the streets and roads that you already have in place. Of course, Prague 7 is a bit specific. We do have two large park areas, which naturally create a cooling environment. However, the rest of the area is much more exposed to heat because there's less greenery.
“So, any effort to plant trees and project and plan more greenery there is challenging, but it's definitely worth doing.”
In addition to green solutions, blue infrastructure is essential for effective water management in cities, Svitková explains. Rainwater should be retained, not lost to drainage systems, and used for purposes like irrigating green areas. Similarly, cities can also replace impermeable surfaces with permeable materials and install retention barriers to conserve water.
