EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Global climatic controls on the hydrological and thermal trade-offs of urban greening

Mark Cuthbert1,2, Gabriel Rau3, Marie Ekstrom1, Denis O'Carroll2, and Adam Bates4
Mark Cuthbert et al.
  • 1Cardiff University, School of Earth & Environmental Sciences, Cardiff, UK (
  • 2School of Civil and Environmental Engineering, The University of New South Wales, Sydney, Australia
  • 3Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 4School of Animal, Rural & Environmental Sciences, Nottingham Trent University, Nottingham, UK.

Heat-related mortality and flooding are pressing challenges for the >4 billion urban population worldwide, exacerbated by increasing urbanization and climate change. Urban greening, such as green roofs and parks, can potentially help address both problems, but the geographical variation of the relative hydrological and thermal performance benefits of such interventions are unknown. Here we quantify globally how climate driven trade-offs exist between modelled hydrological retention and cooling potential of urban greening. Water retention generally increases with aridity in water limited environments, while cooling potential favors lower aridity, energy limited, climates. Urban greening cannot yield high performance simultaneously for addressing both urban heat-island and urban flooding problems in most cities globally. However, in more arid locations, where sustainable, irrigation might be used to improve potential cooling benefits while maintaining retention performance. We demonstrate that as precipitation becomes increasingly variable with climate change, the hydrological and thermal performance of thinner substrates would both diminish more quickly compared to thicker and more deeply vegetated systems, presenting challenges for urban greening strategies. Our results provide a conceptual framework and geographically targeted quantitative guide for urban development, renewal and policymaking.

(See further details in the forthcoming paper Cuthbert et al. (In Press) in the journal Nature Communications, which is a more developed version of the pre-print available here:

How to cite: Cuthbert, M., Rau, G., Ekstrom, M., O'Carroll, D., and Bates, A.: Global climatic controls on the hydrological and thermal trade-offs of urban greening, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7789,, 2022.