From Heat Islands to Green Islands: Transforming Modern Cities in the Face of Climate Change

Due to increasing extreme temperature events and growing urbanization, Europe’s cities have become vulnerable to environmental hazards, such as excess heat and increased pollution, causing concerns for the health and well-being of local populations. While heatwaves and urbanization are both expected to increase in the future, changing the city infrastructure can mitigate their adverse effects. Urban greening, in particular, is seen as a major strategy to keep modern cities cool and comfortable. We invited Pipelife’s Irrigation Specialist Konstantinos Akritanakis to share his expertise in greenspace solutions and adapting them to the city conditions in a sustainable way.

_{Europe’s Cities Are Warming Up}

Currently, more than 70% of all Europeans live in cities, and urbanization keeps increasing due to economic and social causes. However, as Europe’s metropolises are growing, so do the temperatures inside them. Covering vast land areas with pavement and buildings has increased heat absorption and retention. Such an infrastructure, together with the extra heat generated by human activities, has caused many cities to become significantly warmer than the rural areas surrounding them.

The phenomenon is known as the urban heat island effect, and the difference between a busy metropolitan area and its surroundings can reach 3-5 °C or more. With global temperatures expected to rise further, heating cities have become an issue requiring an urgent solution.

_{A Green Array Keeps the Heat Away}

Urban greening is one of the key strategies for increasing heat resilience in cities. Apart from creating shade over areas that typically draw and retain heat, plants also evaporate water and produce oxygen, keeping the air fresh. Furthermore, green spaces have been shown to improve the emotional well-being of city dwellers.

While new districts nowadays are typically planned envisioning sufficient green zones, bringing vegetation back to the areas that have been covered in concrete and mortar for decades can be difficult.

“When we talk about the engineering of urban greeneries, the most important challenge is space. In most cities, space is limited, and it is not easy to create large green areas. The second challenge is maintenance — how to care for such areas long term and how to make them sustainable regarding water and energy consumption,” comments Konstantinos Akritanakis, R&D Project Manager for irrigation solutions at Pipelife.

_{Green Facades: Giving City Premises a New Face}

Also known as vertical gardens or eco-walls, green walls have been enjoying growing popularity in urban greenspaces. Among other benefits, plant-covered facades efficiently reduce surface temperatures, improve air quality and help increase biodiversity in the area. Besides, unlike other urban greening solutions, green facades require minimal ground space.

However, from structural damage caused by plant roots to high irrigation costs and complex maintenance, improperly planned green walls can also pose problems to buildings and their owners. Plants used on green walls require regular water supply and fertigation, which, depending on the setup of the wall, may require professional care.

“There are two main ways of creating green walls. One is planting climbing plants at the ground level, and the other is hanging pots or installing panels on the wall,” explains Akritanakis, “Walls with climbing plants are the easiest to care for. For example, it is possible to collect rainwater from the roof in underground retention crates and pump it to the irrigation pipe in the root area — such a system is largely self-sufficient and requires hardly any maintenance.”