Cities present a dilemma. They provide a necessary social, cultural and economic focus. At the same time, the concentration of population and activities exerts environmental stresses that need to be addressed.

In all regions of the world, response to changing economic circumstances is causing some urban areas to retrench while other grow. CAR offers consultancy at the urban scale to manage these impacts in fast-changing circumstances. Our special concern is with minimising the climate-change impact of emissions from urban areas, and that means minimising the use of energy from the combustion of fossil fuel. Two sectors are important here: the role of energy use in buildings and in transport.

Within a given situation, differences in urban built form can have a considerable impact on energy use. For example, in transportation, a mix of uses – including commercial, retail and leisure alongside houses – could help to keep travel distances short and encourage pedestrian and cycle trips.

Minimising CO2 emissions can be achieved by energy efficient building and transport design, and the use of renewable energy sources. Ultimately, the goal is to achieve high quality design that addresses both local and global environmental problems.

Pollution reduction in Chongqing
Chongqing is a municipality in central China that has autonomous status comparable to that of a province – not surprising, since it has 33m inhabitants. The city is growing at breakneck speed, leading to serious air quality problems in the urban area. CAR partnered with Chinese practice CH&W to deliver a strategy document to the municipal government that proposed a congestion charging system similar to the one in London. This improves use of public transport, pedestrian and cycle options; with attendant benefits in reducing fuel use and airborne pollution from vehicles.

Reviving shrinking cities – innovative paths towards livability
Cities that are losing population and facing economic retrenchment present challenges to environmental sustainability – but also new opportunities to address the issues. It may be difficult to maintain viable public transport networks and build new low-carbon housing, for example. On the other hand, a reduction in the density of city fabric makes renewable energy installations easier to site, and offers the chance to create urban green space. These trade-offs were explored by CAR in RE-CITY, an international collaboration funded by the EC to study promising responses to shrinkage.

Starting in October 2018, interdisciplinary research teams from Europe, the USA, Mexico and Japan investigated how the quality of life in shrinking cities can be improved, by comparing how different cities deal with these problems. The project was designed to promote young scientists: the project formed an international network of 13 PhD students – one of whom is based at CAR. The project partners offered intensive joint training courses, and each student pursued an individual research topic within the theme of the project. The aim was to train the participants so that they can then approach the topic innovatively as managers in public authorities, research institutions or the private sector.

See the RE-CITY project website: https://www.uni-kl.de/re-city/about-re-city-itn/