Getting water security right across Africa: recognising major dataset biases and space-time change divergence

How water changes interplay with climate change around the global land area is essential for societal water security and major water-related sustainability challenges, but still largely unknown over the global land area, particularly across the African continent that still largely lacks relevant monitoring data. Based on several comparative global datasets and with focus on the terrestrial water system over Africa, we have deciphered the change relationships in space and time between the landscape water fluxes and storages and the associated temperature and precipitation conditions during 1980-2010 in numerous non-overlapping hydrological catchments. We find that widely used climate reanalysis data imply distinctly unrealistic 30-year drying over Africa and the whole southern hemisphere, with physically unreasonable water flux and storage changes and sensitivities to warming. Robustly across the datasets, the landscape water sensitivities to the climatic changes also emerge as differing between space and time, questioning the use of space-for-time substitution for water changes on land. The complexities of terrestrial water system change are essential to recognize for getting water security planning and strategies right, in particular across the relatively data-poor African continent.