Navigating the Threat of Rising Ocean Levels in Coastal Africa: A Climatological Analysis of Hazardous Influences and Mitigation Strategies

The frequency, intensity, and spatial distribution of climate-related hazards in Africa's coastal metropolises are influenced by several climatological factors. These factors interact in a complex system that involves regional climate systems, oceanic circulations, and atmospheric circulation patterns (Klutse, N.A.B, et al., 2016). The first key factor is the increase in global temperature. This leads to the melting of polar ice caps and subsequent rise of sea levels, thereby exerting pressure on coastal regions (Church, J.A. et al., 2013). This rise is variably distributed, with regions experiencing warmer ocean temperatures witnessing higher relative increases (Church, J.A. et al., 2013). Regional climatic systems, including the seasonality of rainfall, the direction and speed of trade winds, and interannual climate oscillations (e.g., El Nino Southern Oscillation, ENSO) also significantly impact the risks coastal communities face(Nicholls, R.J., et al., 2007). For instance, periods of ENSO bring unusually warm ocean temperatures in the eastern Pacific (McGregor, S. et al., 2014), which can intensify storm activities and cause increased rainfall, hence coastal flooding in Africa (Klutse, N.A.B, et al., 2016). Oceanic currents, specifically the warm Agulhas Current and cold Benguela Current flowing along Southern Africa's east and west coasts respectively, also play a role (Ndebele-Murisa, M.R. et al., 2019). The Agulhas Current's increasing intensity influences coastal storm frequency and can increase sea surface temperatures, leading to potential storm surge increases (Rouault M. et al., 2010) Finally, atmospheric circulation patterns also play crucial roles. Changes in air pressure patterns cause shifts in wind patterns, storm tracks and the distribution of precipitation, altering the vulnerabilities of coastal zones (Ndebele-Murisa, M.R. et al., 2019). Extreme weather events such as cyclones, largely influenced by such shifts, can result in hazardous storm surges (Meyer, I. et al., 2019). References: Church, J.A., et al. (2013). Sea Level Change. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., et. al.] Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Klutse, N.A.B, et al. (2016). Climate variability over Ghana (1980–2014). International Journal of Climatology. 36, 74-784. McGregor, S. et al. (2014). Recent Walker circulation strengthening and Pacific cooling amplified by Atlantic warming. Nature Climate Change, 4(10), 888-892. Meyer, I. et al. (2019). Changes in tropical cyclones under stabilized 1.5 and 2.0 °C global warming scenarios as simulated by the Community Atmospheric Model under the HAPPI protocols. Environmental Research Letters, 13 (6), 064024. Nicholls, R.J., et al. (2007). Coastal systems and low-lying areas. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Cambridge University Press, Cambridge, United Kingdom. Ndebele-Murisa, M.R. et al. (2019). Climate change in Zimbabwe: a review of statistical trends and environmental impacts. Weather and Climate Extremes, 24, 100211. Rouault M. et al. (2010). Ocean–atmosphere interactions in the Agulhas Current region and their impacts on climate in the southern African region. African Journal of Marine Science, 32(1), 1-8.