Planning of Africa’s land/water future: Hard or soft landing?

Abstract

In the 1970s and 1980s, widespread African poverty, famines and rapid population growth generated an urgent need for solution-oriented water research in order to get a basic idea of the water availability and degree of water scarcity of the vast semiarid drylands (Falkenmark 2018), and possible implications for African social-economic development research was focusing on the absence of water in the semi-arid soils, rather than on the water that had in fact infiltrated (Falkenmark and Rockström 2015). My paper in Ambio (1989) study revealed that water scarcity was threatening two thirds of the African population , with large regional differences. The paper identified increasing problems both in terms of the water required to secure self-sufficient crop production, and in terms of the growing number of people competing for each unit of available water, i.e. as supplied to the country from the water cycle. This meant that from a medium-term perspective , water would not be readily available to support improved quality of life for the growing sub-Saharan population (Falkenmark 2018). Increased awareness among African leaders of water cycle realities stood out as crucial for social-economic development under severe water scarcity. UNPACKING THE PROBLEM: AFRICAN BLUE WATER SCARCITY BY YEAR 2050 During following years, the water crowding scale from the Ambio 1989 paper was made two-dimensional by adding a scale of water stress, expressed as the amount of water already in use (% of water availability) (Falkenmark 2018). The resulting two-dimensional diagram (Fig. 1) would demonstrate two simultaneous pressures on the blue water availability in a country: in terms of how many people are competing for the locally accessible water, and how much is already in use. In this diagram, actual water use would appear as a point, and its development over time as a line. An historical overview of a large number of such country lines (so called archetypes of water scarcity), were recently identified by Kummu et al. (2016), showing how water withdrawal had continuously been increasing since 1900 AD. The future blue water shortage expected in African countries by 2050 is shown in Fig. 2, in terms of water availability projections (m3 per person per year after attention paid to both population growth and climate change effects). Brown colours show countries with high water stress (less than 1000 m3 per person per year), showing chronic shortage for much of the vast semi-arid region in sub-Saharan Africa. Dark brown colour shows those with extreme stress (less than 500 m3per per person per year) and more than 40% of the availability already in use. The particularly exposed sub-Saharan African regions includes several large urban water hubs. In the east the Nile River has its sources, in the south are the sources of a quartet of transnational rivers, supplying a multitude of downstream countries with the water on which their socioeconomic future largely depends.