Building Coastal City Resilience and Extreme Heat Action in Zanzibar, Tanzania through Multi-Hazard Risk Assessment (MHRA)

Abstract

The Coastal City Resilience and Extreme Heat Action Project (CoCHAP) is an ongoing initiative of the Red Cross Red Crescent Climate Center that aims to build climate resilience in urban areas, particularly addressing extreme heat and coastal threats in Southeast Asia, Latin America, and East Africa. This project is conducted in collaboration with the International Federation of Red Cross and Red Crescent Societies (IFRC), American Red Cross (Am. RC), Global Disaster Preparedness Center, and the National Red Cross Societies. As part of CoCHAP, this thesis investigates the spatial vulnerabilities of compound risks related to heatwaves and flooding in Zanzibar, East Africa, in partnership with the Tanzania Red Cross Society (TRCS). Recent increase in temperature and precipitation have heightened Zanzibar's vulnerability. With one of the highest population densities in Africa, the region's economy heavily relies on climate-sensitive activities such as agriculture, tourism, and fishing, making it the most climate-vulnerable small island region. To understand the region's dichotomous predicament, I analyze the location-dependent climatic, socio-economic, physiological, and environmental parameters using a Multi-Hazard Risk Assessment (MHRA). The assessment evaluates three latent variables — exposure, vulnerability, and hazard — derived from remote sensing and household census survey (HCS) data. Principal component analysis and spatial analysis techniques were employed to assess the weighted vulnerability of over 100 wards (the smallest administrative zones) to both heat and flood risk. I find that while the hazard factor itself, does not pose a major risk in Zanzibar, the socio-economic conditions, coupled with inflexible planning under neoliberal frameworks, exacerbate risks, particularly in urban wards. This is evident in the distribution of flood and heat risk, which is random throughout the island city, although high land surface temperatures and precipitation are concentrated around existing built-up coastal areas. 20 wards were identified as highly vulnerable to heatwaves and coastal flooding, revealing nuanced variations in multi-risk distribution across urban, suburban, and agrarian areas, influenced by gradients from coastal low-elevation to high-elevation inland zones. Notably, tourism-dependent wards emerge as potential areas for synergistic ecological and economic gains. These findings offer crucial insights for the TRCS, informing tailored adaptation plans as part of the Zanzibar Climate Change Alliance: City Wide Risk Assessment (CWRA).