Trading Land: A Review of Approaches to Accounting for Upstream Land Requirements of Traded Products.

Land use is recognized as a pervasive driver of environmental impacts, including climate change and biodiversity loss. Global trade leads to "telecoupling" between the land use of production and the consumption of biomass-based goods and services. Telecoupling is captured by accounts of the upstream land requirements associated with traded products, also commonly referred to as land footprints. These accounts face challenges in two main areas: (1) the allocation of land to products traded and consumed and (2) the metrics to account for differences in land quality and land-use intensity. For two main families of accounting approaches (biophysical, factor-based and environmentally extended input-output analysis), this review discusses conceptual differences and compares results for land footprints. Biophysical approaches are able to capture a large number of products and different land uses, but suffer from a truncation problem. Economic approaches solve the truncation problem, but are hampered by the limited disaggregation of sectors and products. In light of the conceptual differences, the overall similarity of results generated by both types of approaches is remarkable. Diametrically opposed results for some of the world's largest producers and consumers of biomass-based products, however, make interpretation difficult. This review aims to provide clarity on some of the underlying conceptual issues of accounting for land footprints.