Scientists call for a tree planting drive to help tackle heatwaves

After a year of monitoring temperatures in four distinct areas* of Guildford, England, researchers found that nature-based locations—woodlands, grasslands, and lakes—were up to 3°C cooler on average than built-up areas. 

Researchers from the GCARE are now urging town and city planners to focus on adding 'green' and 'blue' areas to help combat increasingly frequent annual heatwaves. 

Professor Prashant Kumar, co-author of the study and Founding Director of GCARE, is endorsing a national tree-planting and nature-based solutions initiative: 

"With global temperatures soaring and the UK recording its hottest-ever temperature in July 2022, our research adds to the growing body of evidence that confirms that nature is the key to keeping our urban areas cool. 

"We recommend planting trees in as many public spaces as possible, especially around our schools, as a great starting point to help communities tackle the urban heat island effect. Water bodies, such as lakes and ponds, can also help cool areas, and could be useful for managing excess stormwater." 

Researchers monitored temperatures continuously from June 2021 until the end of August 2022, with temperature sensors placed two to three metres above ground level. The sensors captured data every minute, taking 633,780 readings in total. 

Researchers found that during the summer of 2022, there was an increased likelihood of more intense and longer-lasting heatwaves compared to 2021. The built-up area frequently exceeded the heatwave threshold of 28°C. On 19 July 2022, which was the most extreme day of the year and the hottest day ever recorded in the UK, the temperature soared to 40.7°C. 

Professor Kumar added: 

"We want our data to help build city-scale environmental models and assist planners and ordinary citizens in incorporating natural elements into built-up areas. This work aligns with Sustainable Development Goals 11 (sustainable cities and communities) and 13 (climate action)." 

The study is supported by the H2020-OPERANDUM, UKRI-RECLAIM Network Plus and NERC-GreenCities. The research has been published in Environment International.  

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Notes to Editors 

Reference: 

Sahani, J., Kumar, P. and Debele, S.E., 2023. Efficacy assessment of green-blue nature-based solutions against environmental heat mitigation. Environment International, 179,108187. Online link: https://doi.org/10.1016/j.envint.2023.108187 

• *The four locations monitored were: Stringer's Common (representing woodland); a nature reserve (representing waterbody); Stoke park (representing grassland); and a junction of Guildford Park Road and Farnham Road (representing built-up area). 
• Professor Prashant Kumar is available for interview upon request. 
• For more information, please contact the University of Surrey's press office at mediarelations@surrey.ac.uk.