With the world's population set to increase by 65% (3.7 billion) by approximately 2050, the additional food required to feed future generations will put further enormous pressure on freshwater resources. This is because agriculture is the largest single user of fresh water, accounting for approximately 75% of current human water use. At present approximately 7% of the world's population live in areas where water is scarce. This is predicted to rise to a staggering 67% of the world's population by 2050. Because of this water scarcity and because new arable land is also limited, future increases in production will have to come mainly by growing more food on existing land and water. This paper looks at how this might be achieved by examining the efficiency with which water is used in agriculture. Globally, in both irrigated and rain fed agriculture only about 10-30% of the available water (as rainfall, surface or groundwater) is used by plants as transpiration. In arid and semi-arid areas, where water is scarce and population growth is high, this figure is nearer 5% in rain fed crops. There is, therefore, great potential for improving water use efficiency in agriculture, particularly, in those areas where the need is greatest. The technical basis for improving agricultural water use efficiency is illustrated. This may be achieved by increasing the total amount of the water resource that is made available to plants for transpiration and/or by increasing the efficiency with which transpired water produces biomass. It is concluded that there is much scope for improvement, particularly, in the former and that future global change research should shift its emphasis to addressing this real and immediate challenge.

PR | IFPRI4; CRP2 | EPTD; PIM | CGIAR Research Program on Policies, Institutions, and Markets (PIM)

This study explores the potential effects of electricity pricing on crop cultivation in Saudi Arabia. The country recently started implementing a domestic energy price reform strategy to make energy consumption more sustainable and increase government revenues as highlighted in the Fiscal Balance Program one of the key realization programs of Vision 2030. Two modeling schemes were developed to complete this analysis. First, a model that applies physical equations to estimate water and energy requirements for 21 crops across 13 provinces. Second, an optimization model that runs iteratively to determine short-run electricity costs, import costs and export revenues. The main finding from the model simulations is that increasing electricity prices will shrink the domestic cultivation and exports of the crops while increasing their imports. For example, as an extreme case, if the agriculture electricity price is raised from $0.048 per kWh to the US industrial electricity price level of $0.692 per kWh, the model optimizes that this will reduce electricity consumption from 33.65 gWh to 7.84 gWh, domestic crop cultivation from 15.1 million tons to 6.3 million tons, and crops' export from 0.062 million tons to 0.057 million tons while will increase crops’ import from 9.5 million tons to 18.3 million tons.