An inventory of land use in the United States based on publicly available data will be created that will assign the land used to produce commodities in the U.S. economy. These data will then be incorporated into a hybrid process - economic input-output life cycle assessment framework to evaluate the importance of land use across the supply chain of production. Unique challenges associated with the inclusion of land use in life cycle analysis will be considered, most importantly allocation issues. Completion of a land use inventory and development methods to accurately include land use in life cycle assessment will permit an in-depth analysis of land use for many sustainability research questions. The inventory and resulting data will be made available on the Internet so that it is accessible to other land use and sustainability researchers. A number of case studies using the newly created data set will be conducted to quantify the implications of land use change within the U.S. as well as globally. For these, the focus areas will be on increased use of biofuels production (to assess food versus fuel debates) and on the effects of urbanization by considering the total land footprint of metropolitan areas. This project will serve the environmental sustainability community by adding a relevant and significant category (land use) to the existing focus areas of energy, air and water emissions, and toxic releases. The project will develop course modules on land use sustainability that will be disseminated via the Internet.
As populations and demands increase for land-intensive products, e.g., cattle and biofuels, the need to understand the relationship between land use and consumption grows. This research developed a production-based inventory of land use (i.e., the land used to produce goods) in the U.S. With this inventory an input-output analysis is used to create a consumption-based inventory of land use. This allows for exploration of links between land used in production to the consumption of particular goods. For example, it is possible to estimate the amount of cropland embodied in processed foods or healthcare services. As would be expected, agricultural and forestry industries, in the form of cropland, animal land, and timberland, are the largest users of land in the production-based inventory. Final demand from personal expenditures drives the majority of land used for the production of goods and services, accounting for 65% of total land use. Similarly, we found that processed foods and forest products are the largest users of land in a consumption-based inventory. Somewhat less expectedly this work finds that the majority of manufacturing and service industries, not typically associated with land use, require substantial amounts of land to produce output due to the purchase of food and other agricultural and wood-based products in the supply chain. Through export of US-created products, we virtually export use of about 165 million hectares of our own land (20% of our total economically used land) to trading partners. Since U.S. crop and animal yields are among the highest in the world, if the U.S. were to decrease exports to meet domestic demand then global cultivated land would need to increase, either through increased yields or expansion of land in use. We further created a model that considered trade of goods and services to and from the US and updated the estimates of consumption-based land use across imports, domestic use, and exports. 182 Mha of land are virtually imported to meet U.S. consumption. Finally, we considered potential ways to reduce or shift land use through dietary change and consumption lifestyle scenario analysis. Our work to date has found that eliminating beef consumption entirely would not make enough cropland available to meet corn ethanol and soy biodiesel goals. Further, in order to maintain the current caloric consumption in the U.S. demand for other foods must increase. Likewise, replacing dairy products with grain products increased land use across all categories, dairy cows consumed grain in order to produce output and thus there are no gains in cropland. This result demonstrates that animal food products as currently produced still require a large amount of grain. With vegan diets, cropland is freed up, however by substituting grain or fruit and vegetables for meat products cropland is consumed nearly equivalently. Note however, that very large amounts of pasture and grasslands are freed up in these scenarios, which may be useful for cellulosic ethanol feedstock production. This analysis also demonstrates that cattle are the primary cause for pasture and grassland use. Again this result may seem obvious, but if the U.S. is interested in making these lands available for cellulosic feedstocks without sacrificing meat as a major food source, poultry and swine products may be helpful. The overall conclusion here is that dietary shifts are unlikely to make enough cropland available to meet biofuel production goals. However, dietary shifts may improve the outlook for cellulosic feedstock production. Cropland associated with imported food products is estimated at 4.9 Mha, therefore, even if import of food products was ceased there would not be enough land made available for ethanol. In addition to the results discussed above, we developed a web-enabled model of the embodied land use in all goods and services in the United States and made it available on the Internet (available at www.eiolca.net/). We also worked with the Koshland Museum at the National Academy of Science on a periodic display they are producing regarding multi-attribute decisions on the environment. Our contribution was related to land use. The exhibit opened in 2012.
