By R. Quentin Grafton, John Williams, Qiang Jiang
8 March 2015
(Food Security) – This graph shows a set of projections of surplus or deficit in food production (billions kcalories) for eight scenarios for dryland and irrigated cropping based on 19 countries. In all scenarios we adopted an irrigation regime of 200 mm of water. In Scenarios 1 to 5, 50 kg/ha of N were examined under five annual rates of crop yield improvement of 0.5%, 1.0 %, 1.25%, 1.50% and 2.0% respectively. In Scenario 6, 150 kg/ha N was examined at a rate of annual crop improvement of 1.25 % while in Scenarios 7 and 8, 0 kg/ha of N was examined at rates of crop yield improvement of 1.25% and 0.5% respectively. Graphic: R. Quentin Grafton, John Williams, Qiang Jiang, 2015
ABSTRACT: We review the pressures, threats and risks to national food and water availability based on projected global population growth to 2050 using the Global Food and Water System (GFWS) platform. This platform is used to explore food availability deficits for scenarios of crop production under various fertiliser, water use, crop improvement and land use options. The GFWS platform can be used to assess the effects of annual crop productivity improvements on food production and incorporates data from 19 major food-producing nations to generate projections of food and water gaps in irrigated agriculture. Preliminary results indicate that crop-based food supply is able to meet food requirements by 2050, but this is only possible with ‘input intensification’ that includes increased rates of water in irrigated agriculture and fertiliser use per hectare and continued annual growth of crop yield productivity improvement of at least 0.5 % per year over the period. Increased water withdrawals for agriculture with input intensification would, without any increases in withdrawals in the manufacturing, mining or household uses, place the world above the safe operating space in terms of overall water use by 2050. Even with input intensification, large and increasing crop-based food availability deficits to 2050 can be anticipated in some countries and regions within the group of 19 countries, especially in South Asia.