Everybody depends on it; there is no substitute for it if we run out; in some places, it’s more valuable than oil. Freshwater is at the very core of human development: it is inextricably linked to food security, economic growth, and poverty reduction.
At face value, water use for food production today largely occurs at the expense of ecosystems, which is the number one reason for their rapid degradation. Already, a quarter of the world’s major rivers no longer reach the ocean.
According to a new study published by Nature Communications, and violates life-supporting environmental flows of rivers. To achieve the UN’s Sustainable Development Goal (SDG) 6, these water volumes need to be re-allocated to the ecosystem, which puts a heavy strain on current agricultural water use: food production would drop by at least 10% on half of all irrigated land, with losses of 20-30% at the country level, especially in Central and South Asia.
At the same time, SDG 2 is dedicated to food security, and aims at doubling agricultural productivity. This twin challenge of reconciling water and food targets is at the heart of the 2030 Agenda for Sustainable Development. It was brought to the highest political level earlier this month through the Hamburg G20 Leaders´ Declaration: “Towards Food Security [and] Water Sustainability […]: we are committed to increase agricultural productivity and resilience in a sustainable manner, while aiming to protect, manage, and use efficiently water and water-related ecosystems”.
. On average, about 50% of irrigation water is lost in transfer and application. The new study also demonstrates that the transition to more efficient systems can substantially reduce water consumption per unit of crop growth, especially in countries with large-scale surface irrigation systems and unlined canals, like Pakistan, Uzbekistan, or Bangladesh. In Tajikistan, environmental flow constraints imply a 15% loss of food production, but a change from surface to sprinkler systems could compensate for such losses.
While irrigation can be improved, rainwater management is the largest untapped opportunity to tackle the water-food security challenge. Smallholder farmers still produce more than half of the world’s food; often it is not the total volume, but the unreliable and erratic rainfall that poses the greatest problems. Water harvesting, for instance, is an effective traditional, yet widely underexplored measure to collect and store excess rainwater for supplemental irrigation during dry spells. Conservation tillage and mulching – crop residues or plastic films covering the soil surface – are additional rainwater management techniques that help alleviate soil evaporation.
In semi-arid farming systems, such simple interventions can prevent crop failure, sustainably double crop yields, and strengthen climate resilience, directly improving livelihoods of the poor. While these traditional and affordable farming practices are sporadically applied – for instance in the African Sahel – they can be scaled up, particularly in regions where both population and food demand is growing fast.
In summary, the paper presents data showing that better irrigation systems can compensate for food production losses. Combined with optimizing the use of rainwater, food production can even see a 10% global net gain -- with regional gains often over 20% -- suggesting that the potential of farm water management interventions is well beyond what we expected.
In the context of the SDG discussion, however, these strategies remain largely unexplored and certainly merit higher political attention. In fact, farm water management turns out to be a pivotal target in supporting the implementation of the ambitious yet conflicting SDG agenda.
After all, water management alone will not suffice to attain both SDG 2 and 6. But , and the 2030 Agenda could start to fall into place without relying on future technology fixes.
Article: Jägermeyr, J., Pastor, A., Biemans, H. and Gerten, D. (2017): Reconciling irrigated food production with environmental flows for Sustainable Development Goals implementation. Nature Communications.
The views expressed in this blog are those of the author alone. Publication does not imply endorsement of views by the World Bank.