SDG 6 – Water scarcity in agriculture, an accessibility issue?

In 2022, 7 years after the initiation of SDG 6, the SDG Progress Report states that unless progress accelerates, billions of people will still lack these essential services in 2030. In 2021, 2.3 billion people lived in water-stressed countries and roughly half of the world’s population currently experiences severe water scarcity for at least some part of the year. Water scarcity refers to a situation where freshwater demand exceeds availability, when the demand exceeds over 25 percent of the available resources it is referred to as water stress. Water scarcity is an increasing problem on every continent, with poorer communities most badly affected.

Furthermore, the water demand is expected to rise due to rapid population growth, urbanization and increasing pressure from agriculture, industry, and the energy sector. Besides, climate change is exacerbating the situation, intensifying erratic rainfall, floods, and droughts. This shows the complex relation between water and various other SDGs, like SDG 2, 3, 12, 13 and 15.

Especially the link with SDG 2 (zero hunger) is evident, in part due to the widespread statement that in most regions of the world, over 70 percent of freshwater is used for agriculture. However, lack of water security is at times not due to lack of water but lack of its mobilization, specifically in the African context.

Primarily a distinction between blue and green water scarcity can be made. Green water is root-zone soil moisture that is available for uptake by crops whereas blue water is fresh water in surface and groundwater bodies. In the case of agriculture, green water scarcity (GWS) corresponds to a situation in which the precipitation is unable to meet the crop water requirements. 76% of global croplands face GWS for at least 1 month a year. Hence, in a situation of GWS, irrigation is needed to prevent limited crop growth or crop failure. Blue water scarcity (BWS) occurs in croplands facing GWS if the available renewable blue water resources are not sufficient to meet the irrigation requirements. In case of BWS, farmers can either practice sustainable irrigation without completely meeting the crop water requirements, increase the efficiency of their system, or practice unsustainable irrigation. Blue water has been at the centre of SDG 6 as it underlies the emerging competition between water uses for societal and environmental needs. Target 6.4 of SDG 6 explicitly addresses BWS with the goal of ensuring adequate blue water resources for humans and ecosystems. In contrast, GWS has received much less attention and a management plan for green water is still missing in the SDG agenda. Much observed in the African context is, however, the concept of agricultural “economic water scarcity” (EWS). Agricultural EWS is the condition whereby croplands exposed to GWS are not irrigated although enough renewable blue water resources for irrigation is locally available. These conditions occur due to a variety of socio economic and political factors that impede irrigation.

Besides increased access to blue water, promoting and improving water-use efficiency can prevent water scarcity. Water-use efficiency improved by 12 percent from 2015 to 2019 – from $17.4 to $19.4 per cubic metre. However, in agriculture, it was only $0.63 per cubic metre in 2019. Improving water-use efficiency is therefore relevant to increase the productivity of agricultural water, particularly in regions of BWS.

The global program Sun4Water, part of the international initiative Water and Energy for Food, focusses on expansion and sustainable use of solar powered irrigation systems for smallholder farmers in East and West Africa. In regions of agricultural economic water scarcity, Sun4Water implements capacity development measures on all levels to foster affordable access of small-scale solar powered irrigation systems and therewith enhanced agricultural productivity within sustainable limits. Efficiency improvements are being promoted through efficient irrigation systems like drip irrigation. However, efficiency should not be overemphasized at the expanse of increasing affordable access and combatting rainfall risk in areas with agricultural EWS. Increasing access within sustainable limits will feed more people than making current access more efficient.

The article is based on data collected from following sources:
The Sustainable Development Goals Report 2022
Monitoring Water and Sanitation in the 2030 Agenda for Sustainable Development - An executive briefing, 2016
Synthesis Report of the IPCC Sixth Assessment Report (AR6)
UN SDG Water & Sanitation, UN Water
Rosa, L., Chiarelli, D. D., Rulli, M. C., Dell’Angelo, J., & D’Odorico, P. (2020). Global agricultural economic water scarcity. Science Advances, 6(18). DOI:10.1126/sciadv.aaz6031.