Climate change resources – nature in the city

CLIMATE EMERGENCY BRIEFING By Claire Thirlwall

As part of a regular series, Claire Thirlwall explores tools and guidance available to help professional understanding of this issue’s theme

Superilles, (Superblocks) Barcelona

Like many cities Barcelona has a street layout that has become dominated by cars, with the associated high level of pollution and background noise. The city centre has a scarcity of open space, low pedestrian usage and few opportunities for residents to access nature.

Aerial view of Barcelona Eixample residencial district, Sagrada familia, typical urban squares.

© Shutterstock

In 2017, using the concepts already being used in other Spanish cities, a series of superilles or superblocks were created. Typically, 4 x 440m in size and encompassing nine city blocks, each superblock uses a system of one-way streets and a 10km per hour speed limit to deter through traffic and to give priority to cyclists and pedestrians. Each block is bounded by through routes for public transport and cars, with only local residents allowed to use the roads within the block.

The freed-up space is used to create dedicated cycle lanes, seating areas and play space. With the busy intersections removed the area at the centre of each junction becomes an open space, demarcated by large tree and shrub planters.

The redesign has reduced traffic by 83%, increased pedestrian use by 28% and reduced noise levels, as well as reducing traffic accidents and reducing the urban heat island effect.

It will be interesting to see if similar ideas are adopted in the UK, given the changes mentioned in the article on page 15.

Black routes allow public transport and cars at 50km/h, while green routes only allow private vehicles at 10km/h to prioritise pedestrians and cycling.

© BCNecologia 1

Some of the streets of Barcelona have been closed to the traffic and transformed in social places where people can meet, that are called “Superilles”.

© Shutterstock

UN Habitat report – Urban patterns for a green economy – working with nature

Written in 2012 this UN Habitat report provides a useful reminder of the potential positive benefits of cities, and how they can be an effective way to manage resources.

“The city is one of the highest pinnacles of human creation. Concentrating so many people in dense, interactive, shared spaces has historically provided distinct advantages, that is, agglomeration advantages. Through agglomeration, cities have the power to innovate, generate wealth, enhance quality of life and accommodate more people within a smaller footprint at lower per capita resource use and emissions than any other settlement pattern.”

The report includes case studies from different countries and cultures, including South Africa, Croatia, the Philippines and Tanzania. Topics covered include urban agriculture, watershed management and the ecological benefits of parks.

Urban farm – growing vegetables on the roof of urban buildings.

© Shutterstock

The report makes important points about the potential value of cities for nature:

“Cities are often located in biodiversity hotspots, for example estuaries, coastlines, ecotones and fertile plains. If they are well managed, cities can support biodiversity in the following ways:

– Cities act as refuges for species whose habitats have been destroyed by intensive agriculture and forestry

– Cities are socio-ecological systems where new habitats and species communities can develop; and

– Urban green areas provide cities with ecosystem services that cannot be imported, for example noise reduction, absorption of air and water pollutants”

Lyon Lieux at Parcours frais (Fresh Places and Routes) – using green spaces to provide public health resilience

Mapping from the city of Lyon showing open spaces, showing green spaces.

With the predicted changes in our climate, cities can expect to experience more frequent heatwaves. As part of the city of Lyon’s Energy Climate Plan public green spaces have been mapped, allowing residents to find their nearest shady open space.

As well as green spaces the city’s interactive website shows water points and free-to-access public buildings, providing a network of 600 city wide sites that can be used as a refuge in a heatwave. The scheme is a useful reminder of the practical public health value of open space.

Derbyshire Street Pocket Park, London

Derbyshire Street Pocket in Bethnal Green is a great example of how small, incidental and overlooked spaces can be used to provide climate change resilience and bring nature into the city. This dead-end space for 12 cars next to Oxford House community and arts centre was transformed into a pocket park and outdoor café space. The site was also opened up to adjacent streets to become an important thoroughfare for cyclists and pedestrians. Using permeable paving and attenuation planters the pocket park diverts rainwater away from the sewer system, reducing the need for irrigation. New green-roofed cycle racks and seating were included in the design around a central rain garden channel. The bike shelters and bin stores include habitat panels that provide nesting sites for bees, insects and birds and the planting schemes include nectar rich native planting. To reduce the environmental impact, materials including granite setts and crushed concrete were reused.

The scheme was a collaboration between Greysmith Associates, Tower Hamlets Council, Thames Water Utilities and Oxford House, and won the Design for a Small- Scale Development Landscape Institute Award in 2015.

Claire Thirlwall is a director of Oxfordshire-based landscape practice Thirlwall Associates. Her book “From Idea to Site: a project guide to creating better landscapes” for RIBA Books was published in January 2020.