Adaptation to climate change in international river basins in Africa

Even though the paper "Adaptation to climate change in internationalriver basins in Africa: a review" from 2009 by Marisa Goulden et al. mostly addresses to the issue of climate change in relation with water management she points out some interesting facts regarding climate change and freshwater resources.

About 90% of African river basins form borders of several countries. Varying river discharges can therefore lead to further conflicts if the precipitation variability and geographical distribution lowers further. Freshwater is indispensable to life of people providing them with work, food, energy and industrial supplies. Accompanied with a population growth and urbanization the already high demand of water rises even higher.  

The African continent is separated into 3 climate regimes: wet (>1000mm/year), intermediate (400-1000mm/year) and dry (<400mm/year) - greatly illustrated in Maarten de Wit´s paper - including seasonal-arid tropical, sub-tropical Mediterranean and humid climate near the equator. Central Africa receives almost 40% of the annual precipitation even though it contains only 20% of the total continental area whereas northern Africa with about the same area receives less than 3% precipitation. 

The intermediate regime spreads around 25% of the country area including some of the densest populated regions like the South Africa Orange river basin, the east African upper Nile basin and the east-west-belt from Sudan to Senegal including Lake Chad, Niger etc. This regime is feared for the most due to already highly varying seasonal rainfall.

Green water (stored as soil moisture) is also an important contribution to the water circle. It evaporates from plants, at a certain threshold contributes to groundwater recharge and is essential for any kind of agricultural use of soil.  

Local climate is influenced by the Atlantic and Indian Ocean dynamics. Changes within those patterns will lead to changes in Climate in the African continent as well as floods and droughts in coastal areas. Globally thinking a sea level rise could have a major impact on Africa.

Therefore, it is reasonable to say that some of the densest populated areas are located in the intermediate regime and local river basins and lakes suffer from a severe water stress caused by the demand of millions of people connected with a lowering river discharge.

Data supporting theories of scarcity only refer to "blue water" from lakes and rivers not taking account of local aquifers or green water due to bad monitoring. Climate Models predict temperature rises of 3-4°C within the next 60 years, drier climate in southern Africa and Sahara, wetter climates in West and East Africa.