UCL News


Opinion: ‘If we free up space in cities, we can plant trees’

14 August 2020

As city centres are expect to become ‘heat islands’ due to rising temperatures, Professor Izaskun Chinchilla (Bartlett School of Architecture at UCL) asserts that by redesigning cities, more green spaces can be made to help urban residents survive the effects of climate change.

Dr Izaskun Chinchilla

Lockdown has given us a taste of how good it is to live in a more local way: walking to shops, working from home, spending less time commuting. Emissions have decreased, and the air we breathe has felt cleaner. But if we change the way we design our cities, in particular, we can hold on to this climate-friendly way of living.

The “15-minute city” is a vision of urban living where everything you need – house, job, supermarket, school, park, health centre, post office – is a quarter of an hour away, by foot or bike. Paris, Barcelona, Bogotá and many other cities are exploring this. It means making cities more pedestrian- and cyclist-friendly, and prioritising refurbishment over new construction, retrofitting buildings to include a greater mix of uses, such as retail, office space, education, small makers and housing.

If cities reduce the number of cars on the road, and with them the need for parking, we could free up 10% extra space in cities. That’s a lot – and the best thing we can do with it is plant trees, creating green, low-emission urban areas. If we do that, natural species will follow, and biodiversity will increase.

But size matters: if these green spaces are small and scattered, they won’t be as effective. Only 13% of urban trees in the UK are in areas bigger than 0.25 hectares; they need to be 10 to 35 hectares to support wildlife. We have to fight against the building of “hard squares” – the large, concrete public spaces seen in cities the world over. All public spaces need varied greenery and water-permeable paving. We can further green up our cities with green roofs, balconies and small gardens. We can promote urban laws, like in San Francisco, forcing green roofs in new constructions, or when significant refurbishment happens in existing buildings.

As temperatures rise, city centres are predicted to become “heat islands” – around 3C hotter than surrounding areas. Trees and greenery will combat this. What is beautiful about this plan is that it can reap financial benefits, too, by making cities more attractive to residents, businesses and tourists.

If our cities are designed in this way, we will be better able to weather climate change, but also future pandemics.

This article was first published in the Guardian on 14 August.



‘Central park new York nyc manhattan’ Credit: Image by Free-Photos from Pixabay CC by 2.0