Sustainable irrigation expansion to feed 800 million more people

A study about irrigation over economic water scarce croplands


A team of Italian scientists from Politecnico di Milano, the University of California of Berkeley and the University of Amsterdam published in the prestigious journal Science Advances a study on the global geography of agricultural water scarcity.

The study finds that there is enough locally available water to expand irrigation over 140 million hectares of agricultural lands, currently not irrigated due to socio-economic reasons. The study shows that 800 million more people could be fed by sustainably expanding irrigation over economic water scarce croplands.

Using data intensive global hydrological models developed at Politecnico di Milano, the researchers were able to quantify the water currently provided to crops, the optimal amount of water that crops need to grow under unstressful conditions, the type of water scarcity affecting the croplands and the regions of the world where additional water is available to expand irrigation sustainably.

Two thirds of lands suitable for irrigation expansion are in Sub-Saharan Africa, East Europe, and Central Asia. In addition to increasing the production of food to feed 800 million people, the expansion of irrigation on lands where there is economic water scarcity, could at the same time be an important strategy of adaptation to climate change, contributing to more reliable and resilient agricultural production.

Lorenzo Rosa, Alumnus of Politecnico di Milano, now PhD Candidate at UC Berkeley, tells us:

In this study we assessed, for the first time, physical and economic water scarcity over global agricultural lands. While physical water scarcity refers to conditions associated with insufficient freshwater availability to meet human needs, economic water scarcity has been defined as the condition in which renewable water resources are physically available, but lack of economic and institutional capacity limits societal ability to use that water.

Maria Cristina Rulli, who coordinates Politecnico di Milano's team that have taken part in the study, explains:

This study determines the agricultural regions where investments in the water sector are needed to sustainably increase food production. The analysis quantifies the untapped potential of rainfed croplands and provides insights that could help to achieve future food security and environmental goals together.

The paper is online:
Global agricultural economic water scarcity
Lorenzo Rosa, Davide Danilo Chiarelli, Maria Cristina Rulli, Jampel Dell’Angelo, Paolo D’Odorico
Science Advances  29 Apr 2020: Vol. 6, no. 18, eaaz6031
https://advances.sciencemag.org/content/6/18/eaaz6031