Exposure to Floods, Climate Change, and Poverty in Vietnam

Mook Bangalore,Ted Veldkamp,Andrew Smith

doi:10.1007/s41885-018-0035-4

Abstract

With 70% of its population living in coastal areas and low-lying deltas, Vietnam is highly exposed to riverine and coastal flooding. This paper conducts a “stress-test” and examines the exposure of the population and poor people in particular to current and future flooding in Vietnam and specifically in Ho Chi Minh City. We develop new high-resolution flood hazard maps at 90 m horizontal resolution, and combine this with spatially-explicit socioeconomic data on poverty at the country and city level, two datasets often kept separate. The national-level analysis finds that a third of today’s population is already exposed to a flood, which occurs once every 25 years, assuming no protection. For the same return period flood under current socioeconomic conditions, climate change may increase the number exposed to 38 to 46% of the population (an increase of 13–27% above current exposure), depending on the severity of sea level rise. While poor districts are not found to be more exposed to floods at the national level, the city-level analysis of Ho Chi Minh City provides evidence that slum areas are more exposed than other urban areas. The results of this paper provide an estimate of the potential exposure under climate change, including for poor people, and can provide input on where to locate future investments in flood risk management.

Highlights

Vietnam is a rapidly developing country highly exposed to natural hazards
Comparing exposure of poor people to average exposure, poor households are 71% more exposed to flooding in the Mithi River Basin in Mumbai, India (Hallegatte et al 2016). We examine these dynamics in Ho Chi Minh City (HCMC), using high-resolution local-scale flood maps designed for HCMC (Lasage et al 2014) and a proxy for poverty using the spatial location of potential slums from the Platform for Urban Management and Analysis (PUMA) data set (World Bank 2015)
This paper conducts a stress-test and presents some initial findings on what exposure to floods looks like in Vietnam, how it may change under a changing climate, and whether poor people are relatively more exposed

Summary

Introduction

Vietnam is a rapidly developing country highly exposed to natural hazards. One of the major natural hazards the country faces is riverine and coastal flooding, due to its topography and socioeconomic concentration: Vietnam’s coastline is 3200 km long and 70% of its population lives in coastal areas and low-lying deltas (GFDRR 2015). Climate change is expected to increase sea level and the frequency and intensity of floods, globally and in Southeast Asia (IPCC 2014; World Bank 2014). Given the country’s concentration of population and economic assets in exposed areas, Vietnam has been ranked among the five countries most affected by climate change: a 1 m rise in sea level would partially inundate 11% of the population and 7% of agricultural land (World Bank and GFDRR 2011; GFDRR 2015). Evidence suggests poor people are more vulnerable than the rest of the population to natural disasters such as floods, as their incomes are more dependent on weather, their housing and assets are less protected, and they are more prone to health impacts (Hallegatte et al 2016, Chapter 3). Poor people have a lower capacity to cope with and adapt to shocks due to lower access to savings, borrowing, or social protection; and climate change is likely to worsen these trends (Hallegatte et al 2016, Chapter 5)

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Results

Conclusion