Future air temperature projection in high-density tropical cities based on global climate change and urbanization – a study in Singapore

Abstract

Urban air temperature projection is essential to prepare cities for future heat risks. This study aims to anticipate future air temperature increment contributed by climate change and urbanization. First, we identified the rural area in Singapore by historical data, and downscaled global/regional modelling results to investigate climate change at the identified rural area. Representative concentration pathway 8.5 was chosen at the downscaling study for the worst case scenario. Results indicate air temperature at the rural area will increase by 0.4–0.6 °C in 2030s, 1.2–1.6 °C in 2050s, and 2.2–3.8 °C in 2080s. Secondly, we estimated future urbanization based on master planning by planning department, and associated urbanization with air temperature using linear regression. Based on planned plot ratio for future, we calculated sky view factor and site coverage ratio as urban morphology and planning index respectively. Linear regression analysis indicates that air temperature at urban areas could increase 0.05 °C - 0.79 °C in 2030s due to various urbanization in Singapore. This study conducted projections, which are based on global/regional modelling results and associated closely with urban planning. Projection results indicate that pre-emptive urban planning and design strategies are needed at the districts with potential heat risk and enables urban planners to make evidence-based decisions.