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Managing water better is central to attaining our development goals

Jonas Jägermeyr's picture
Rainwater harvesting for drip irrigation, Lake Victoria, Tanzania.
Photo credit: Wisions.net

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, about 40% of global irrigation water is used unsustainably 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”.

Irrigation is central to feeding the world but often is plagued by excessive and leaky water use. 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.
Drip irrigation lines being installed for lettuce in the
Salinas Valley, California, US.
Photo credit: Tim Hartz, UC Cooperative Extension

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 mainstreaming simple water management measures can have sizeable effects, 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.

Comments

Submitted by John Turner on

We have been marketing a sub-irrigation system that saves on average 50% of irrigation water, saves on fertilizers as it is contained, plant performance and yield is improved as roots are able to take what they need,not what we give them, when irrigating from the top. Containment of the fertilizers etc, also means less contamination, creating of algae blooms in localized rivers streams and ground water aquifers.You also get better soil management and less erosion. It might be seen to be expensive, but, just look around the corner, and tell me the "true cost of not" taking action or being a bit more innovative. JT

Submitted by M kumar on

In India lots of people using water harvesting method for collecting water for their personal uses. At the present time water harvesting revolve into extremely popular in India.Groundwater Consultancy India specialize in the sustainable growth, protection and management of groundwater resources . They support clients with project supervision services, technical studies, ground supervision and regulatory.

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