Botanical gardens aren’t just beautiful — they can cool city air by up to 5°C during heatwaves, according to the most comprehensive review of its kind led by the University of Surrey.

The study analyzed how green spaces and waterways cool cities and towns.

Professor Prashant Kumar, Director of the Global Center for Clean Air Research (GCARE) in Surrey said:

“We’ve known for some time that green spaces and water can cool cities. However, this study gives us the most comprehensive picture yet. What’s more — we can explain why. Shade provides From trees that cool the air to water that cools the air.”

They found that success depended heavily on local factors — there were some general patterns. Among the key findings, the following green spaces and waterways significantly cooled the air:

  • Botanical gardens: -5°C average (variation: -2.2°C to -10°C)

  • Wetlands: -4.7°C average (range: -1.2°C to -12°C)

  • Rain garden: -4.5°C average (variation: -1.3°C to -7°C)

  • Green walls: -4.1°C average (variation: -0.1°C to -18°C)

  • Street trees: -3.8°C average (range: -0.5°C to -12°C)

  • City Farm: -3.5°C Average (Variation -3°C to -3.9°C)

  • Parks: -3.2°C average (variation -0.8°C to -10°C)

  • Reservoir -2.9°C average (variation -1.8°C to 5°C)

  • Playground: -2.9°C average (variation: -2.8°C to -3°C)

Up to a point, the bigger the park — the bigger the cooling effect. Cities can reap maximum benefits by connecting green spaces with ‘green corridors’.

Greening projects can also offset carbon emissions and help prevent flooding.

Professor Kumar said:

“This will help town planners around the world meet the challenges of global warming. By implementing just a few of the steps we’ve outlined, cities can become more resilient, and their citizens healthier and happier.” are.”

However – the team also found areas of the world that were suffering from heat – but had not researched the best way to use green spaces for cooling.

Professor Maria de Fatima Andrade of the Department of Environment at the University of São Paulo in Brazil said:

“Our paper confirms how many ways to stay cool. But it also shows how much work remains to be done. Institutions around the world need to invest in the right research — because our study What’s very clear is that no solution is one-size-fits-all. It depends on what works for your community.”

The research is published in the journal, The Innovation.

This study demonstrates the University of Surrey’s contribution to the United Nations Sustainable Development Goals, specifically Goal 11 (Sustainable Cities and Communities) and Goal 13 (Climate Action).