The Water-Energy-Food Security Nexus

 The Water-Energy-Food security nexus is an approach that highlights the interdependencies between achieving water, energy and food security for the benefit of human well-being, poverty reduction and sustainable development. The constraints of isolated water and energy policies has been demonstrated in countries like Zambia, who relies on the Kariba hydropower project for half its electricity needs. Over-using its waters for food production through crop irrigation has resultantly reduced its hydropower potential.

The potential of the nexus approach to support the transition to a Green Economy has also been recognised. It encourages multiple-use systems where waste and by productions can be used as resources for other products and services, including wastewater energy-integration. Moreover, it advocates for sustainable system efficiency and investment in 'natural capital' which can help to avoid 'sunk costs' - investments that lock countries into trajectories of unsustainable development. 

In sub-Saharan Africa, the nexus approach has great potential to reduce trade-offs and build synergies across the water, food and energy sectors in countries that are experiencing deteriorating economic growth, population increases (and consequently sky-rocketing resource demands) and risks from climate change, principally reduced annual precipitation levels, soil moisture and runoff. 

The application of nexus-thinking to create integrated energy and agricultural policies that mitigate the negative trade-offs involved in biofuel expansion on food security will be essential for the region's future.  The expansion of the highly water-intensive biofuel sector in SSA has garnered worldwide attention for the environmental and socioeconomic risks it presents including deforestation and GHG emissions (Gasparatos et al., 2015). Critically, land and water resources are being diverted away from agriculture for biofuel production which will have serious implications for food supply and prices. 

Bringing the nexus to fruition in southern Africa 

Some countries in the southern African region including Tanzania have already used the nexus to develop integrated policies where physical and socioeconomic exposure to climate is high in energy, water and food sectors for rain-fed agriculture. However, there is no one-size-fits-all approach and localising and contextualising the WEF nexus must be a key priority in its application. Across southern Africa there is a highly variable distribution of water which impacts the allocation of water to food production and energy industries like hydro-power. For example, almost 100% of electricity production in the DRC, Lesotho, Malawi, and Zambia is from hydropower-projects on river whereas other low-access countries like Angola and Nigeria are dependent on fossil fuels like petroleum production (Avila et al., 2017). 

There are also other socioeconomic challenges that mean that nexus interventions might be very different across the region. One key factor is unequal infrastructure provisioning. Malawi, for example, lacks basic infrastructures which is at the core of its poor energy and services delivery which has also limited its irrigation potential. So suitable policy interventions could involve agroforestry techniques like agri-silviculture, where agriculture and woody plants are cultivated on the same land to increase agricultural productivity whilst conserving water and energy resources. The planting of shelter belts and intercropping of maize with nitrogen-fixing trees like the 'Faidherbia albida' has doubled maize yields in Southern Malawi, as it has increase the production natural fertilisers from the decomposition of leaves, fruits and biomass and significantly increased soil nutrient availability (Nielson et al., 2015; Akinnifesi et al. 2007). Surface-level erosion is also decreased as trees around fields reduce runoff through higher rates of soil infiltration, and act as "biotic pumps" by drawing moisture from oceans' which increases precipitation and evapotranspiration  (Ellison, Futter, and Bishop, 2012).  It can also increase energy security as trees can provide firewood.

Other countries like South Africa have fairly developed water and energy infrastructural networks to support well-established industrial sectors that support food production. However, the development of coal mines is actually reducing the area of high potential arable soils, i.e. soils best suited for cash crop production, which is already limited to 1.5% of it's land area (BFAP, 2012). Its pursuit of fossil-fuel based energy dependency is therefore threatening food security and water quality and WEF nexus-based assessments have indicated that it needs to shift to low-carbon, renewable energy generation to reduce these risks (Simpson & Jewitt, 2019). 

Integrated River Basin Management (IRBM): A future solution?

IRBM is a multi-disciplinary and multi-sectoral approach to water conservation, development and management that aims to balance the conflicting economic and social demands on freshwater resources. It has gained recognition in SSA where 70% of surface water resources are in 15 transboundary river basins as shown below.

Southern Africa and its transboundary river basins (Nhamo et al., 2018)

It is complementary to WEF-nexus thinking as it also integrates ecological requirements and the needs of multiple water users into water management, thus promoting institutional capacity building throughout the river basin. The Southern African Development Community (SADC) already has a number of shared river basin agreements in place to ensure there is sustainable and coordinated management of shared watercourses (Nhamo et al., 2018). Along with this, individual river basin committees have been formed of subsistence and commercial farmers and potential agricultural water users across the region, including the Inkomati Water Management committee in South Africa which have successfully allocated water sources for a range of diverse needs. Ultimately, WEF-nexus thinking can encourage stakeholder participation across the energy, water and food sectors which is vital to resolve conflict and strengthen institution-building practices.