Irrigation might worsen water scarcity

Raising irrigation efficiency through irrigation technologies alone is failing to reduce water consumption and, paradoxically, may even be making water scarcity worse, the International Food Policy Research Institute stated in late August 2018.
   
According to the study The Paradox of Irrigation Efficiency published in Science, increases in irrigation efficiency may result in greater on-farm water consumption, groundwater extractions and even water consumption per hectare. Hence the paradox - greater irrigation efficiency may make water scarcity worse, not better.
   
This paradox results from increased water use by existing crops, a switch to more water-intensive crops, or an expansion of irrigated areas, all due to improved field application under advanced irrigation technologies.
   
Irrigation accounts for 70 per cent of global water extractions, more than 80 per cent of water consumption and provides about 40 per cent of the world’s food calories. Thus, understanding how increases in irrigation efficiency change water availability is critical to solving the world’s water problems.
  
The study shows that for advanced irrigation technology to reduce water scarcity, investments need to be accompanied by hydrologic assessment and monitoring of water flows, a limit on water off-take for irrigation; an assessment of risks and uncertainties; the valuation of trade-offs; and a better understanding of the incentives and behaviour of irrigators.
   
The authors of the study strongly warn against carrying on with the practices applied today. They criticise that policymakers and investors focus on single-minded technology solutions—supporting food security over water security and ecosystem health.  In their opinion, current irrigation policies must be reformed to achieve the Sustainable Development Goals and to avoid a global water crisis.
  
(IFPRI/ile)

Read the paper The Paradox of Irrigation Efficiencyscience.sciencemag.org/content/361/6404/748