Environ. Res. Lett. http://doi.org/c6xc (2019).
As the world rapidly urbanises, city design can play an important role in climate mitigation. However, city design also needs to consider adapting to avoid extreme temperatures caused by urban heat islands (UHIs). This can be achieved by designing low density, or non-compact, cities; but these come with greater greenhouse gas emissions from transport and the building sector, compared to compact cities.
To determine the optimal city design in light of these contrasting outcomes, Carl Pierer and Felix Creutzig, of Technical University Berlin, and Mercator Research Institute on Global Commons and Climate Change, Berlin, develop a geometrical optimization framework and model which design is best for both mitigation and adaptation. They report that star-shaped cities, with linear transit axes, allow low-carbon public transport, as well as reducing urban heat stress and emissions.
A greater number of axes increases UHIs, whereas emissions decrease. The optimal design needs to consider transport costs; medium to high fuel taxes correspond to low emissions and acceptible UHI effects, if the number of axes is small. These findings can inform rapidly developing regions on how to create liveable and sustainable cities.
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Wake, B. Optimal city design. Nat. Clim. Chang. 9, 499 (2019). https://doi.org/10.1038/s41558-019-0523-8