A significant number of households (~40 %) depend on groundwater especially in the north , . In particular after mid-century, climate change will reduce the recharge into groundwater reservoirs (aquifers), while increased requirements for agricultural water use under dry periods can lead to water scarcity. This risk is significant for closed basins such as Lake Bosomtwi, which has a small catchment . In the south, sea level rise and storm surges will also increase the risk of salt water intrusion in freshwater especially in aquifers. Model results from the literature for the impacts of climate change on the Volta river basin in Ghana indicate that extreme flows will be more frequent , . This means there is a likely increase of periods with either relatively higher or lower mean annual discharge than in the past, sometimes in consecutive years, affecting availability of fresh water for agriculture, sanitation, generation of hydropower and other economic activities.
Per capita water availability
Current projections for water availability in Ghana display high uncertainty under both GHG emissions scenarios. Assuming a onstant population level, multi-model median projections suggest a slight decline in per capita water availability over Ghana by the end of the century under both RCP2.6 and RCP6.0 (Figure 9). Yet, when accounting for population growth according to SSP2 projections², per capita water availability for Ghana is projected to decline by about 70 % by 2080 relative to year 2000 (Figure 9, B). While this decline is not primarily driven by climate change but population growth, it highlights the urgency to invest in water saving measures and technologies for future water consumption.
Spatial distribution of water availability
Looking at the spatial distribution of future water availability projections within Ghana, it becomes evident that water saving measures will become especially important after 2050 in the north of the country (Figure 10). For all other parts of Ghana, water availability projections are too uncertain to make any such statement.
² Shared Socio-economic Pathways (SSPs) outline a narrative of potential global futures, including estimates of broad characteristics such as country-level population, GDP, or rate of urbanisation. Five different SSPs outline future realities according to a combination of high and low future socio-economic challenges for mitigation and adaptation. SSP2 represents the “middle of the road”-pathway.
 P. Gyau-Boakye and S. Dapaah-Siakwan, “Groundwater as source of rural water supply in Ghana,” J. Appl. Sci. Technol., vol. 5, no. 1, pp. 77–86, 2000.
 E. Obubie and B. Barry, “Ghana,” in Groundwater availability and use in Sub-Saharan Africa: a review of 15 countries, P. Pavelic, M. Giordano, B. Keraita, T. Rao, and V. Ramesh, Eds. Colombo, Sri Lanka: International Water Management Institute (IWMI), 2012, p. Ch. 4, pp.43–64.
 B. F. Turner, L. R. Gardner, and W. E. Sharp, “The hydrology of Lake Bosumtwi, a climate-sensitive lake in Ghana, West Africa,” J. Hydrol., vol. 183, no. 3–4, pp. 243–261, Sep. 1996.
 K. Owusu, P. Waylen, and Y. Qiu, “Changing rainfall inputs in the Volta basin: implications for water sharing in Ghana,” GeoJournal, vol. 71, no. 4, pp. 201–210, Apr. 2008.
 L. Murken et al., “Climate Risk Analysis for Identifying and Weighing Adaptation Strategies in Ghana’s Agricultural Sector,” 2019.