Influence of Nairobi’s Biophysical Characteristics on its Vulnerability to a Changing Climate

Urban areas experience exacerbated impacts of the regional climate variability because of their form characteristics such as imperviousness of surfaces, building density and distribution of open spaces. These are further confounded by geographical aspects such as topography, soil types, and vegetation types. Nairobi city is increasingly exposed to flood and heat risk as an aggregation of its urban form and the changing global climate. The paper sought to establish the influence of Nairobi’s biophysical characteristics on its vulnerability to both flooding and heat risks. The paper used a descriptive research design augmented with Geographic Information Systems to spatially model the landcover, soil drainage, topography, green space networks, and population density characteristics at the sub-location level. Vulnerability indices were developed using the expert ranking system and used to determine the vulnerability of the different sub-locations. The findings revealed a vulnerability pattern close to the historically segregated planning of the city. The central and eastern parts of the city exhibit high vulnerability while the western, northwestern, and southern parts of the city display moderate to low vulnerability. The paper recommends that adapting existing neighbourhoods and proactive planning of new neighbourhoods uses the ecosystem-based approach. This to entail decentralization of smaller green spaces, redesign of road medians for water management, re-specification of street vegetation species to incorporate a mix of deciduous and evergreen trees and incorporating eco-roofs and walls in high-density developments like the Central Business District.