5 “green cities” lead the way
- Cities consume 75% of global resources and produce 50-60% of global greenhouse-gas emissions.
- Sustainable ideas include introducing flora and fauna, building with wood and adopting the concepts of a circular economy.
1. Barcelona: creating an urban forest
With its high population density, Barcelona’s old town can experience temperatures that are 7°C higher than in the greener suburbs. Climate change will only make the ‘”urban heat island” hotter. Projections suggest that, if nothing is done, average temperatures across the city could rise up to 3°C by 2100.
In response, city planners have rolled out an innovative “Green Corridor” programme, which doubles the number of trees and creates a seamless habitat for fauna, like Iberian wall lizards and Mediterranean tree frogs, from the city limits to its centre. The plan will deliver 44 hectares of new green space by the end of 2019 and more than 160 hectares by 2030.
Stephan Pauleit of the Technical University of Munich explains how such projects differ from typical planning efforts. “We associate urban green space planning with parks and gardens, but green infrastructure planning considers the need to connect many types of green space within a network,” he explains. Ten large interior courtyards in the Eixample district will be planted with trees, while 10 city squares will get parking restrictions that create more space for flora like roses, pomegranate bushes and boxwood.
2. Copenhagen: putting users at the heart of research
The Smart Cities Accelerator is a Danish-Swedish collaboration aiming to increase consumption of renewable energy in five municipalities of the Greater Copenhagen area. From better storage to intelligent optimisation, the accelerator highlights how sustainable municipal energy systems could be implemented. While digital tools play an important role, the focus is also on people. “You can’t solve every problem with a screen and smart data management,” says Anne Marie Damgaard, leader of the project. “A user-centred approach is so important.”
In one project focused on a Danish school, anthropologists used ethnographic methods to observe a wide array of social obstacles that new technologies face. By measuring indoor conditions, data engineers from the Technical University of Denmark assumed the devices would create a heightened awareness of the often-poor indoor climate, which would encourage students and teachers to make adjustments.
A Swedish architect has developed a masterplan for a sustainable district: 31 skyscrapers built of wood, containing 3,000 homes.
3. Amsterdam: bringing a DIY spirit to planning
The neighbourhood of Buiksloterham, just north of Amsterdam’s historic core, may seem unassuming, but the district is a radical experiment in bottom-up planning as a form of climate action.
Cities consume 75% of global resources and produce 50-60% of global greenhouse gas emissions. Effective climate action will require them to transition from global resource drains to circular, bio-based, productive, ecologically- and socially-integrated hubs.
The 76-hectare reclaimed brownfield site was left undeveloped after the global financial crisis in 2008. In stepped an informal group of planners, urbanists and tech specialists who pitched a new direction for the site’s development. Their aim: to give residents and engaged citizens the power to participate in a sustainable design-build process using social media tools.
In 2014, Buiksloterham became a living laboratory for circular-economy concepts – in which resources such as energy, water, building materials and peer-to-peer knowledge sharing are considered. The district has become a long-term experiment, prototyping the potential of bottom-up sustainable planning with public-private partnerships.
Handling growth is part of the experiment. Buiksloterham will ultimately accommodate around 550 residences and at least 4,000 m2 of work units and hospitality locations.
4. Stockholm: wooden skyscrapers on the waterfront
In 2018, Stockholm’s Centre Party commissioned Anders Berensson Architects to masterplan a sustainable district. The company proposed 31 skyscrapers built of wood, which would rise above the development as self-contained city blocks containing 3,000 homes and 30 restaurants.
At street level, the development would comprise 19 blocks of between six and 10 floors, with homes as well as 60,000 m² of office space and 90 shops and restaurants. The sheer ambition of the concept could raise awareness about cross-laminated timber’s (CLT) potential as a high-rise material. Part of the proposal was to cover the roofs of all lower blocks with public parks and connect them with bridges.
The key to the development’s sustainability is the use of CLT. Its overwhelming advantage lies in carbon sequestration. Taking into account materials, transport, site work and end-of-life, a steel-framed CLT building generates almost half the CO2 emissions per square metre as one built with reinforced concrete.
5. Helsinki: man-made caves for hot-water storage
Beginning in 2021, caves under Helsinki’s bedrock will store hot water that will be used for district heating. Such heating is popular in Scandinavia: the simultaneous production of heat and electricity in combined heat and power generation plants makes it energy efficient and reduces carbon emissions.
The man-made caves – formerly used for fuel-oil storage – are located on the Mustikkamaa recreational island of Helsinki. They will be filled with 260,000 m3 of domestic water, kept at a maximum of 90 °C.
The heat stored in the water will be released into the district heating network with heat exchangers. Ten percent of Helsinki’s district heat is now produced with heat pumps, a move in the right direction for a city that aims to cut carbon dioxide emissions fully by 2050.