IntroductionCities are globally warmer
IntroductionThe importance of cities
The researchAn engineer’s point of view
ResultsA complex mechanism
ResultsGreen cover a good foundation for action
The model shows that in dry areas (e.g. Southern Europe) where annual precipitation is limited (< 700 mm. yr-1), 20-40% green cover could be enough to offset the UHI effect.
However, cities located in a hot and wet climate (e.g. South-East Asia) would require a far higher amount of green cover (up to 80% or more) to offset the urban heat island effect.
ResultsA portfolio of mitigation strategies will be required
Vegetation strategies will need to be combined with other solutions such as increasing albedo (i.e. reflecting light away from surfaces) or convection efficiency (i.e. creating better air circulation). Nevertheless, the importance of green spaces in cities must not be underestimated, as other benefits can be drawn from them such as improving biodiversity, air quality and water filtration.
ConclusionFirst global modelisation
This work was done at the Chair of Hydrology and Water Resources Management (ETH Zurich) in collaboration with the Crowther Lab (ETH Zurich), ETH-FCL, Duke university, Princeton university and funded by the Branco Weiss Foundation.