Urban Heat Vulnerability Analysis for Singapore: D 2.4 – Vulnerability Map

Abstract

In the past decades, the increasing temperatures and the impairment of health conditions related to heat have repeatedly been pointed out. This report describes the urban heat vulnerability analysis conducted for Singapore, a city in the tropics. Tropical regions in general are exposed to high temperatures and high humidity levels throughout the year, which makes them extremely vulnerable to heat stress. Additionally, the overall global increase in temperature and precipitation (due to climate change) can severe the cities’ environmental conditions and even cause serious health problems to their citizens. Another threatening phenomenon is the rapid urbanization that tropical cities are facing in the recent decades. This phenomenon generates additional heat which intensives not only the Urban Heat Island (UHI) effect, but also causes health, social and economic challenges, which are closely linked to Urban Heat Vulnerability (UHV). The UHV assessment described in this technical report follows the latest IPCC definitions of vulnerability found in the literature. Indicators were identified, then normalised and given equal weight to form additive index of physical exposure, sensitivity and adaptive capacity. The spatial distribution of vulnerability in Singapore was examined for the hottest period of the day (2 pm to 4 pm local time, LT), as well as for the coldest hour of the day (7 am local time, LT). Warmer days further increase people’s vulnerability, as buildings don’t cool down sufficiently overnight. The areas with the highest UHV are defined as risk areas or hotspots. As a result of the vulnerability analysis, a vulnerability map was created that summarizes the planning areas into three hotspots (Geylang, Jurong East, and Marine Parade) in the coolest hour of the day (at 7 am), and five hotspots (Geylang, Punggol, Sengkang, and Serangoon, and Woodlands) in the hottest hours of the day (from 2 pm to 4 pm). These findings help to identify areas where heat mitigation measures are needed most, in order to ensure the protection of the population. Also, the vulnerability map can support planners to strategically plan wind corridors, location of green areas and urban density across the city. This analysis provides information that can be useful for emergency management, hazard reduction, public policy and community education. The vulnerability map maps both the known and likely impacts of hazard events and the socio-economic characteristics of the population.