The Economics of Climate Change in Zanzibar: Vulnerability, Impacts and Adaptation

Abstract

The study has undertaken a review and initial climate change assessment of vulnerability, impacts and adaptation on Zanzibar. These findings were discussed with stakeholders at workshops on Unguja and Pemba. The findings are summarised below, presented by sector. A full report on impacts and adaptation work is included in a technical report, available on the project web-site at http://www.economics-of-cc-inzanzibar. org/. Coastal Zones The coastal zones of Zanzibar contain high populations and significant economic activity. These areas are at risk from future sea-level rise and storm surge, as well as from coastal erosion.  The coastal areas of Zanzibar are already vulnerable to coastal erosion and there are reports of enhanced flooding on the islands, as well as salt water intrusion in water supplies. While changing weather patterns on the islands may have a role, these effects need to be seen against a background of socio-economic development, population growth, land pressures, resource use, and natural processes, i.e. they are not due only (or indeed mostly) to climate change. Nonetheless, addressing these existing impacts is an early priority, to reduce existing impacts and help build resilience for the future.  As an island, Zanzibar will be vulnerable to future sea level rise from climate change. The potential impacts of sea-level rise include flooding and loss of low-lying areas, shoreline (coastal) erosion, saltwater intrusion and increased salinity in aquifers and water supplies. The inundation and erosion (flooding and eventually loss of land) may affect human settlements, agricultural land, infrastructure, transport, and water resources within the coastal zone, as well as tourism and provisioning services (fishing, aquaculture and agriculture).  The study has progressed a rapid analysis of the vulnerability of the islands to sea level rise. Contour mapping show the areas at potential risk on both islands (shown in the figures below). This reveals significant low lying areas, on both islands, though it is stressed that these are the areas at risk of flooding (not of disappearing under water). The results show a high proportion of the land – and an even higher proportion of the population – is located in these low lying coastal zones. Based on these results, further work on more dis-aggregated contour mapping and hazard analysis is recommended – as this would allow more accurate identification of the potential areas at risk.  It is highlighted that this information also needs to feed through to spatial planning/land-use policy and infrastructure siting decisions, to avoid building and development in areas of current or future high risks. There is also a need for enhanced capacity building including awareness raising, institutional strengthening, and monitoring and assessments to provide the evidence base for future decisions, including coastal and marine data (e.g. sea surface temperatures, wind speeds, shoreline erosion)  The study has also reviewed potential adaptation options and costs, drawing on the previous Zanzibar Adaptation Programme of Action (ZAPA) and other literature. While hard coastal protection may have a role for some key areas (Stone Town), the most promising and cost-beneficial options are likely to be ecosystem-based adaptation, because of multiple benefits that these options offer (so called ‘no regret’ options). These include shoreline vegetation and forest planting, mangrove restoration and replanting (i.e. coastal forest buffer zones) and seagrass replanting. There is also a need for strengthening of the on-going plans for integrated coastal zone management.