Estimating virtual land use under future conditions: Application of a food balance approach using the UK

Abstract

Virtual land use refers to the area of land used to produce a unit food commodity that is traded. The role of virtual land use in future food security under conditions of land scarcity has received little policy and research attention, partly due to the constraints of complex modeling and data requirements. This study demonstrates a simple food balance approach to estimate virtual land use under projected population, climate, and land use change using the United Kingdom (UK) and feed barley in the 2050s. In this approach, future supply (production based on climate and land use change scenarios) was distributed over utilization components based on proportions derived from baseline food balance sheet. Subsequently, future surplus or deficit was estimated as the difference between supply and projected demand (a product of per capita demand and population). Based on the commodity balance (surplus or deficit), virtual land use was estimated for different combinations of population, climate change and land use scenarios. The results showed that, even at 90th percentile yield, the minimum and maximum area of land required in addition to the current area of land under barley cultivation to meet projected demand in the UK, for all combinations of population, climate and land use change, were 306 and 840 thousand ha. However, due to reductions in projected area of land, virtual land use imports ranged from 315 to 1450 thousand ha for all combinations of population, climate, and land use change. The UK’s contribution to global land losses due to productivity differences between the UK and partner countries were between 9–577 thousand ha. It is concluded that the food balance approach applied in this paper is simple and replicable in data-poor contexts to provide comparable estimates of future virtual land use transfers, bearing in mind the limitation imposed by the assumption of time invariance of the proportionate distribution of utilization components. Further, the UK example highlights the need to examine the impacts of national policies of countries that currently have high productivity for some globally important crops on future virtual land use and efficient use of dwindling global land resources.