Spatially explicit assessment of heat health risk by using multi-sensor remote sensing images and socioeconomic data in Yangtze River Delta, China

Qian Chen,Kejia Hu,Jiaguo Qi,Xuchao Yang,Mingjun Ding

doi:10.1186/s12942-018-0135-y

Abstract

BackgroundThe increase in the frequency and intensity of extreme heat events, which are potentially associated with climate change in the near future, highlights the importance of heat health risk assessment, a significant reference for heat-related death reduction and intervention. However, a spatiotemporal mismatch exists between gridded heat hazard and human exposure in risk assessment, which hinders the identification of high-risk areas at finer scales.MethodsA human settlement index integrated by nighttime light images, enhanced vegetation index, and digital elevation model data was utilized to assess the human exposure at high spatial resolution. Heat hazard and vulnerability index were generated by land surface temperature and demographic and socioeconomic census data, respectively. Spatially explicit assessment of heat health risk and its driving factors was conducted in the Yangtze River Delta (YRD), east China at 250 m pixel level.ResultsHigh-risk areas were mainly distributed in the urbanized areas of YRD, which were mostly driven by high human exposure and heat hazard index. In some less-urbanized cities and suburban and rural areas of mega-cities, the heat health risks are in second priority. The risks in some less-developed areas were high despite the low human exposure index because of high heat hazard and vulnerability index.ConclusionsThis study illustrated a methodology for identifying high-risk areas by combining freely available multi-source data. Highly urbanized areas were considered hotspots of high heat health risks, which were largely driven by the increasing urban heat island effects and population density in urban areas. Repercussions of overheating were weakened due to the low social vulnerability in some central areas benefitting from the low proportion of sensitive population or the high level of socioeconomic development. By contrast, high social vulnerability intensifies heat health risks in some less-urbanized cities and suburban areas of mega-cities.

Highlights

The increase in the frequency and intensity of extreme heat events, which are potentially associated with climate change in the near future, highlights the importance of heat health risk assessment, a significant reference for heat-related death reduction and intervention
Low daytime temperatures were observed in northern Yangtze River Delta (YRD) and areas covered by forest and water bodies
Nighttime warming centers concentrated in highly urbanized areas (≥ 30 °C) and expanded to neighboring area, demonstrating a considerable urban heat island (UHI) effect at night

Summary

Introduction

The increase in the frequency and intensity of extreme heat events, which are potentially associated with climate change in the near future, highlights the importance of heat health risk assessment, a significant reference for heat-related death reduction and intervention. A spatiotemporal mismatch exists between gridded heat hazard and human exposure in risk assessment, which hinders the identification of high-risk areas at finer scales. With global warming as the main feature, has become the biggest challenge for human health [1, 2]. Extreme heat events (EHEs), as one of the most serious meteorological disasters, are projected to increase in frequency, intensity, and duration in the background of future climate warming [3]. The health implications of extreme heat events highlight the significance of studies on risk assessment and identification of high-risk population. Climate change adaptation is increasingly linked to natural hazard risk management [7, 8]

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Conclusion