Renaturing a microclimate: The impact of greening a neighbourhood on indoor thermal comfort during a heatwave in Manchester, UK

Abstract

Higher air temperatures in large cities like Manchester, UK, reduce human thermal comfort. In this paper, the impact of land cover on microclimate, and consequently on indoor thermal comfort is studied. Through different stages, field measurements and computer modelling were carried out for a heat wave episode in summer 2017 in Manchester: First, the urban heat island (UHI) was measured between the city centre of Manchester and the campus of the University of Salford (between May to October 2017). Maximum detected UHI was 2.3 °C at 4:00, during the hottest day of the year. Parallel measurements within the university campus showed that the park was 0.9 °C cooler than the paved areas (maximum cooling effect was 3.6 °C at 14:45).Finally, the impact of the current land cover of the campus, and a greener land cover (as a renaturing scenario) with more planted trees on indoor thermal comfort of a house within the campus were studied. It was found that by adding 17% more trees to the campus, indoor thermal comfort was improved by 20.8% during the hottest day of 2017 in Manchester. These showed that renaturing cities could be a solution for future warmer climates.