‘Marry’ nature and concrete against global warming

Open the window and touch the vegetation on your apartment’s external walls. Smell the leaves’ grassy scent and feel its cooling effect around you. With plants and trees an integral part of rooftops, balconies and walls, nature is back in the city. It hugs and adorns concrete to bring down temperatures and counter the effects of climate change.  

Welcome to the future of urban architecture in Europe. This summer’s sweltering days are the latest tangible sign that the planet is overheating before our eyes faster than we think.

In recent years, extreme weather episodes have intensified, worsening air pollution and making cities impossible to live in. Adjusting to the new conditions will mean reimagining urban buildings, turning them into an antidote and a shelter against hot weather’s whirlwind fury. 

A much-needed comeback

This architectural overhaul will head in the opposite direction of the building spree that in the 20th century saw construction expand uncontrollably in cities at the expense of nature.

Fuelled by demographic needs, the concrete jungle that resulted from this urban overdevelopment is now responsible for much of today’s misery. Like a highly infectious disease, it goes by its own name: ‘urban heat island.’  

Green vegetation on building
Photo by Steven Pecoraro

The term describes how buildings, asphalted roads and concrete pavements trap warmth on hot days and ratchet up temperatures by 1-3 degrees Celsius compared to nearby rural areas.  

Think of it as a hellish circle: heatwaves warm up hard surfaces, which, in turn, stow and release that heat for hours on end. Without respite from high temperatures, dwellings become torrid and unlivable even at night.

By comparison, nearby rural zones remain cooler thanks to nature’s heat mitigation effect. Trees and vegetation provide shelter and shade from the sun; they also capture water through their roots and release it through their leaves, cooling the air around them by up to 5°C. In addition, natural areas decrease air, noise pollution and greenhouse emissions, helping to retain rainwater and improving overall wellbeing.

Although the heat island effect is a complex problem, helping to tackle it can rest on an easy solution – to welcome back what cement stamped on for decades: nature.  

In Europe, several cities are spearheading an urban transformation that combines buildings and vegetation. In Milan, Malmo and Barcelona, for example, nature-based solutions are proving a viable and effective tool to build climate resilience, bringing added economic, social and air quality benefits.  

Milan's 'Bosco Verticale' (vertical forest) - a residential building with green vegetation all over its walls
Milan’s ‘Bosco Verticale’ (Vertical Forest). Photo by Victor

Forest and the city

Climate adaptation strategies aim to improve people’s life quality as global warming ramps up temperatures across the planet. With its 3.26 million residents, Milan has recently implemented solutions that other densely populated areas can follow. 

The city’s most visible and renowned symbol of the urban integration of nature is the iconic ‘Vertical Forest’ (‘Bosco Verticale’) building. With its luxuriant vegetation placed all around the structure’s external walls, the ‘Vertical Forest’ exploits nature’s mitigation effect by bringing back biodiversity to the city’s heart.  

Likewise, the vertical green wall at the ‘Il Fiordaliso’ shopping centre is another example from Milan’s largest metropolitan area: with its 44,000 plants and 200 different species, ‘Il Fiordaliso’ extends over a 1,250-square-metre surface and is one of the largest green vertical walls in the world.

The vegetation enhances the building’s thermal performance, shields it from the heat, helps reduce energy consumption, lowering CO2 emissions and noise pollution. Located in the municipality of Rozzano, ‘Il Fiordaliso’ entered the Guinness World Record in 2012.  

Green rooftops are an alternative tool to mitigate climate change. The idea is to replace inert concrete with living plants and place them on top of urban structures, like Milan’s ‘Garden among the courtyards’ (‘Orto tra I cortili’) 

This roof vegetable yard on the upper layer of an architectural firm’s complex produces flowers and vegetables. It protects the building against the urban heat island’s effect while providing a charming co-working and social space.  

Glass and vegetation on a building
Photo by Nosiul

Rooftops can also turn into agricultural spaces devoted to the farming of vegetables and fruit. The greenery helps to cool down temperatures during hot weather spells. At the same time, growing seasonal produce boosts social inclusion, increases biodiversity and provides economic benefits to those involved in their farming and sale.  

In recent years, urban rooftop farms have become part of the city landscape in European cities like Brussels and Paris.  

Parking cars near a garden  

In Sweden, Malmo offers a twist to Milan’s vertical green walls and sustainable urbanism effort.  

The Anna and Godsmagasinet parking garages boast an external 600-metre wall with vegetation spreading over concrete. The structure increases biodiversity and stores rainwater which is then recycled to irrigate the wall’s plants.  

The initiative is part of the ‘Blue Green City Lab’, a project conceived to expand green areas and waterways in Malmo and mitigate the effects of extreme weather conditions.  

Vegetation on building
Photo by Lily Banse

The Blue Green City Lab matches property owners and builders with experts on urban sustainability.  The project is part of the city’s effort to stay ahead of the curve, seeking protection from rising temperatures and eventually meeting UN, national and local sustainable development goals.  

Cool it with a playground  

Barcelona’s hot and humid summers make it imperative to protect its 1.6 million residents. A recent initiative turning local schools into climate shelters is providing answers to this Mediterranean city.

Barcelona

Launched in 2019, the scheme transforms Barcelona’s playgrounds and yards into a cooling haven when schools are closed for the summer recess. The conversion exploits nature’s ability to lower temperatures by adding plants and water facilities to the existing infrastructure.   

Enhanced by vegetation, waterways and plants, these spaces are made available to all residents wishing to escape scorching weather conditions. They can be a particularly saving grace for vulnerable individuals such as the elderly and those suffering from heat-sensitive illnesses.  

Once schools reopen, students can also reap the benefits of these transformed playgrounds by playing in a  healthier, sustainable environment instead of around hard concrete structures.  

Barcelona’s first ten pilot schools were completed in August 2021 after being turned into climate shelters. In the long run, the project is set to transform a total of 3,000-square-metres and be replicated in schools all over the city. 

A helping hand

Portrait of Eugenia Masutti
Eugenia Mansutti, Policy Advisor on Energy, Eurocities

Initiatives such as the EU Adaptation Strategy and the Covenant of Mayors provide a crucial framework to cities engaged in sustainable urbanism, says Eugenia Mansutti, Eurocities’ Projects Coordinator and Policy Advisor for the Environment.  

The EU Adaptation Strategy focuses on promoting nature-based solutions for climate adaptation. In an urban context, this often means that remedies will be applied to a densely built environment,” explains Mansutti.

“For signatories of the Covenant of Mayors, integrating nature in the built environment can be a way to achieving climate targets in a holistic way.”

“This means, for example, improving buildings’ thermal insulation and making space for nature in the city. The newly-launched Policy Support Facility for Climate Adaptation will also aid cities to develop new projects by offering technical assistance and peer-learning exchanges.”

Author: