Abstract  Although the United States has pursued rapid development of corn ethanol as a matter of national biofuel policy, relatively little is known about this policy's widespread impacts on agricultural land conversion surrounding ethanol refineries. This knowledge gap impedes policy makers' ability to identify and mitigate potentially negative environmental impacts of ethanol production. We assessed changes to the landscape during initial implementation of the Renewable Fuel Standard v2 (RFS2) from 2008 to 2012 and found nearly 4.2 million acres of arable non-cropland converted to crops within 100 miles of refinery locations, including 3.6 million acres of converted grassland. Aggregated across all ethanol refineries, the rate of grassland conversion to cropland increased linearly with proximity to a refinery location. Despite this widespread conversion of the landscape, recent cropland expansion could have made only modest contributions to mandated increases in conventional biofuel capacity required by RFS2. Collectively, these findings demonstrate a shortcoming in the existing 'aggregate compliance' method for enforcing land protections in the RFS2 and suggest an alternative monitoring mechanism would be needed to appropriately capture the scale of observed land use changes.

Abstract  Expansion of ethanol production in the United States has raised concerns regarding its land- use change effects. However, little is known about the extent to which observed land use change in the United States can be attributed to ethanol plant proximity or is caused by changes in crop prices that may be partly induced by expansion in ethanol production. This study aims to examine the determinants of changes in corn acreage and aggregate crop acreage by simultaneously identifying the effects of establishment of ethanol plants serving as terminal markets for corn and the effects of changes in crop prices in the United States between 2003 and 2014. Our results show that corn acreage and total acreage are fairly inelastic with respect to both changes in ethanol capacity in the vicinity, as well as changes in crop prices. Our estimates of acreage elasticity with respect to corn ethanol production are smaller than those obtained by previous studies that disregard the price effect on crop acreage. We find that, ceteris paribus, the increase in ethanol capacity alone led to a modest 3% increase in corn acreage and less than a 1% increase in total crop acreage by 2012 when compared to 2008. The effect of corn price and aggregate crop price on acreage change from 2008 to 2012 was more than twice larger than that of effective ethanol production capacity over this period; but this price effect was largely reversed by the downturn in crop prices after 2012. This study shows that land- use change is not a static phenomenon and that it is important to examine how it evolves in response to various factors that may change over time.

Abstract  Meeting future biofuel targets set by the 2007 Energy Independence and Security Act (EISA) will require a substantial increase in production of corn. The Midwest, which has the highest overall crop production capacity, is likely to bear the brunt of the biofuel-driven changes. In this paper, we set forth a method for developing a possible future landscape and evaluate changes in practices and production between base year (BY) 2001 and biofuel target (BT) 2020. In our BT 2020 Midwest landscape, a total of 25 million acres (1 acre = 0.40 ha) of farmland was converted from rotational cropping to continuous corn. Several states across the Midwest had watersheds where continuous corn planting increased by more than 50%. The output from the Center for Agriculture and Rural Development (CARD) econometric model predicted that corn grain production would double. In our study we were able to get within 2% of this expected corn production. The greatest increases in corn production were in the Corn Belt as a result of conversion to continuous corn planting. In addition to changes to cropping practices as a result of biofuel initiatives we also found that urban growth would result in a loss of over 7 million acres of productive farmland by 2020. We demonstrate a method which successfully combines economic model output with gridded land cover data to create a spatially explicit detailed classification of the landscape across the Midwest. Understanding where changes are likely to take place on the landscape will enable the evaluation of trade-offs between economic benefits and ecosystem services allowing proactive conservation and sustainable production for human well-being into the future.

Abstract  Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products.

Abstract  Carbon intensities are calculated under the LCFS on a full life cycle basis. This means that the carbon intensity value assigned to each fuel reflects the GHG emissions associated with that fuel’s production, transport, storage, and use. Traditionally, only these steps, termed direct effects, have been included in the life cycle assessment of transportation fuels. In addition to these direct effects, some fuel production processes generate GHGs indirectly, via intermediate market mechanisms. Stakeholders participating in the LCFS process have suggested that most or all transportation fuels generate varying levels of indirect GHG emissions. To date, however, ARB staff has only identified one indirect effect that has a measurable impact on GHG emissions: land use change effects. A land use change effect is initially triggered when an increase in the demand for a crop-based biofuel begins to drive up prices for the necessary feedstock crop. This price increase causes farmers to devote a larger proportion of their cultivated acreage to that feedstock crop. Supplies of the displaced food and feed commodities subsequently decline, leading to higher prices for those commodities. Some of the options for many farmers to take advantage of these higher commodity prices are to take measures to increase yields, switch to growing crops with higher returns, and to bring non-agricultural lands into production. When new land is converted, such conversions release the carbon sequestered in soils and vegetation. The resulting carbon emissions constitute the “indirect” land use change (iLUC) impact of increased biofuel production. Based on research and published work, most of the land use change impacts result from the diversion of food crops to producing biofuels. During the regulatory process (i.e., workshops and meetings with stakeholders) leading up to the 2009 LCFS Board Hearing, the magnitude of this impact was discussed and also questioned by renewable fuel advocates. Land use change is driven by multiple factors, some of them not related to the production of biofuels. Because the tools for estimating land use change were few and relatively new when the regulation was originally adopted in 2009, biofuel producers argued that land use change impacts should be excluded from carbon intensity values, pending the development of better estimation techniques. Based on its work with land use change academics and researchers, however, ARB staff concluded that the land use impacts of crop-based biofuels were significant, and must be included in LCFS fuel carbon intensities. To exclude them would assume that there is zero impact resulting from the production of biofuels and would allow fuels with carbon intensities that are similar to gasoline and diesel fuel to function as low-carbon fuels under the LCFS. This would delay the development of truly low-carbon fuels, and by not accounting for the GHG emissions from land use change, would jeopardize the achievement of a ten percent reduction in fuel carbon intensity by 2020. Details of ARB’s estimated land use change impacts of biofuel crop production for the 2009 regulation is provided in the ISOR from 20091. Since 2009, there have been numerous peer-reviewed publications, dissertations, and other scientific literature, that have focused on various aspects of indirect land use changes related to biofuels. Staff has reviewed published articles, contracted with academics, and consulted with experts, all of which have led to significant improvements to the GHG modeling methodologies and analysis completed in 2009. Complete details of the updates and results from the current analysis are presented in this section.

Abstract  U.S. ethanol production capacity increased more than threefold between 2002 and 2008. We study the effect of this growth on corn acreage. Connecting annual changes in county-level corn acreage to changes in ethanol plant capacities, we find a positive effect on planted corn. The building of a typical plant is estimated to increase corn in the county by over 500 acres and to increase acreage in surrounding counties up to almost 300 miles away. All ethanol plants are estimated to increase corn production by less than their annual requirements.

Abstract  Over 22 million hectares (ha) of U.S. croplands are irrigated. Irrigation is an intensified agricultural land use that increases crop yields and the practice affects water and energy cycles at, above, and below the land surface. Until recently, there has been a scarcity of geospatially detailed information about irrigation that is comprehensive, consistent, and timely to support studies tying agricultural land use change to aquifer water use and other factors. This study shows evidence for a recent overall net expansion of 522 thousand ha across the U.S. (2.33%) and 519 thousand ha (8.7%) in irrigated cropped area across the High Plains Aquifer (HPA) from 2002 to 2007. In fact, over 97% of the net national expansion in irrigated agriculture overlays the HPA. We employed a modeling approach implemented at two time intervals (2002 and 2007) for mapping irrigated agriculture across the conterminous U.S. (CONUS). We utilized U.S. Department of Agriculture (USDA) county statistics, satellite imagery, and a national land cover map in the model. The model output, called the Moderate Resolution Imaging Spectroradiometer (MODIS) Irrigated Agriculture Dataset for the U.S. (MIrAD-US), was then used to reveal relatively detailed spatial patterns of irrigation change across the nation and the HPA. Causes for the irrigation increase in the HPA are complex, but factors include crop commodity price increases, the corn ethanol industry, and government policies related to water use. Impacts of more irrigation may include shifts in local and regional climate, further groundwater depletion, and increasing crop yields and farm income.

Abstract  Releases of greenhouse gases (GHG) from indirect land-use change triggered by crop-based biofuels hate taken center stage in the debate over the role of biofuels in climate policy and energy security. This article analyzes these releases for maize ethanol produced in the United States. Factoring market-mediated responses and by-product use into our analysis reduces cropland conversion by 72% from the land used for the ethanol feedstock. Consequently; the associated GHG release estimated in our framework is 800 grants of carbon dioxide per megajoule (MJ); 27 grants per MJ per year, over 30 years of ethanol production, or roughly a quarter of the only other published estimate of releases attributable to changes in indirect land use. Nonetheless, 800 grants are enough to cancel out the benefits that corn ethanol has on global warming, thereby limiting its potential contribution in the context of California's Low, Carbon Fuel Standard.

Abstract  A socioeconomic model is used to estimate the land-use implications on the U.S. Conservation Reserve Program from potential increases in second-generation biofuel production. A baseline scenario with no second-generation biofuel production is compared to a scenario where the Renewable Fuels Standard (RFS2) volumes are met by 2022. We allow for the possibility of converting expiring CRP lands to alternative uses such as conventional crops, dedicated second-generation biofuel crops, or harvesting existing CRP grasses for biomass. Results indicate that RFS2 volumes (RFS2-v) can be met primarily with crop residues (78% of feedstock demand) and woody residues (19% of feedstock demand) compared with dedicated biomass (3% of feedstock demand), with only minimal conversion of cropland (0.27 million hectares, <1% of total cropland), pastureland (0.28 million hectares of pastureland, <1% of total pastureland), and CRP lands (0.29 million hectares of CRP lands, 3% of existing CRP lands) to biomass production. Meeting RFS2 volumes would reduce CRP re-enrollment by 0.19 million hectares, or 4%, below the baseline scenario where RFS2 is not met. Yet under RFS2-v scenario, expiring CRP lands are more likely to be converted to or maintain perennial cover, with 1.78 million hectares of CRP lands converting to hay production, and 0.29 million hectares being harvested for existing grasses. A small amount of CRP is harvested for existing biomass, but no conversion of CRP to dedicated biomass crops, such as switchgrass, are projected to occur. Although less land is enrolled in CRP under RFS2-v scenario, total land in perennial cover increases by 0.15 million hectares, or 2%, under RFS2-v. Sensitivity to yield, payment and residue retention assumptions are evaluated.

Abstract  Lifecycle analysis (LCA) metrics of greenhouse gas emissions are increasingly being used to select technologies supported by climate policy. However, LCAs typically evaluate the emissions associated with a technology or product, not the impacts of policies. Here, we show that policies supporting the same technology can 1 lead to dramatically different emissions impacts per unit of technology added, due to multimarket responses to the policy. Using a policy-based consequential LCA, we find that the lifecycle emissions impacts of four US biofuel policies range from a reduction of 16.1 gCO(2)e to an increase of 24.0 gCO(2)e per MJ corn ethanol added by the policy. The differences between these results and representative technology-based LCA measures, which do not account for the policy instrument driving the expansion in the technology, illustrate the need for policy-based LCA measures when informing policy decision making.

Abstract  BACKGROUND: The GTAP model has been used to estimate biofuel policy induced land use changes and consequent GHG emissions for more than a decade. This paper reviews the history of the model and database modifications and improvements that have occurred over that period. In particular, the paper covers in greater detail the move from the 2004 to the 2011 database, and the inclusion of cropland intensification in the modeling structure.

RESULTS: The results show that all the changes in the global economy and agricultural sectors cause biofuels induced land use changes and associated emissions can be quite different using the 2011 database versus 2004. The results also demonstrate the importance of including land intensification in the analysis. The previous versions of GTAP and other similar models assumed that changes in harvested area equal changes in cropland area. However, FAO data demonstrate that it is not correct for several important world regions. The model now includes land intensification, and the resulting land use changes and emission values are lower as would be expected.

CONCLUSIONS: Dedicated energy crops are not similar to the first generation feedstocks in the sense that they do not generate the level of market-mediated responses which we have seen in the first-generation feedstocks. The major market-mediated responses are reduced consumption, crop switching, changes in trade, changes in intensification, and forest or pasture conversion. These largely do not apply to dedicated energy corps. The land use emissions for cellulosic feedstocks depend on what we assume in the emissions factor model regarding soil carbon gained or lost in converting land to these feedstocks. We examined this important point for producing bio-gasoline from miscanthus. Much of the literature suggests miscanthus actually sequesters carbon, if grown on the existing active cropland or degraded land. We provide some illustrative estimates for possible assumptions. Finally, it is important to note the importance of the new results for the regulatory process. The current California Air Resources Board carbon scores for corn ethanol and soy biodiesel are 19.8 and 29.1, respectively (done with a model version that includes irrigation). The new model and database carbon scores are 12 and 18, respectively, for corn ethanol and soy biodiesel. Thus, the current estimates values are substantially less than the values currently being used for regulatory purposes.

Abstract  BACKGROUND: Although the system for producing yellow corn grain is well established in the US, its role among other biofeedstock alternatives to petroleum-based energy sources has to be balanced with its predominant purpose for food and feed as well as economics, land use, and environmental stewardship. We model land usage attributed to corn ethanol production in the US to evaluate the effects of anticipated technological change in corn grain production, ethanol processing, and livestock feeding through a multi-disciplinary approach. Seven scenarios are evaluated: four considering the impact of technological advances on corn grain production, two focused on improved efficiencies in ethanol processing, and one reflecting greater use of ethanol co-products (that is, distillers dried grains with solubles) in diets for dairy cattle, pigs, and poultry. For each scenario, land area attributed to corn ethanol production is estimated for three time horizons: 2011 (current), the time period at which the 15 billion gallon cap for corn ethanol as per the Renewable Fuel Standard is achieved, and 2026 (15 years out).

RESULTS: Although 40.5% of corn grain was channeled to ethanol processing in 2011, only 25% of US corn acreage was attributable to ethanol when accounting for feed co-product utilization. By 2026, land area attributed to corn ethanol production is reduced to 11% to 19% depending on the corn grain yield level associated with the four corn production scenarios, considering oil replacement associated with the soybean meal substituted in livestock diets with distillers dried grains with solubles. Efficiencies in ethanol processing, although producing more ethanol per bushel of processed corn, result in less co-products and therefore less offset of corn acreage. Shifting the use of distillers dried grains with solubles in feed to dairy cattle, pigs, and poultry substantially reduces land area attributed to corn ethanol production. However, because distillers dried grains with solubles substitutes at a higher rate for soybean meal, oil replacement requirements intensify and positively feedback to elevate estimates of land usage.

CONCLUSIONS: Accounting for anticipated technological changes in the corn ethanol system is important for understanding the associated land base ascribed, and may aid in calibrating parameters for land use models in biofuel life-cycle analyses.

Abstract  This paper integrates economic and physical models to assess: a) how increases in agricultural commodity prices, driven by ethanol production and other factors, affect land use and cropping systems in the US Midwest, and b) how the changes in land use and cropping systems in turn affect environmental quality in the region. The empirical framework includes a set of econometric models that predict land conversion, crop choices, and crop rotations at the parcel level based on commodity prices, land quality, climate conditions, and other physical characteristics at the sites. The predictions are then combined with site-specific environmental production functions to determine the effect of rising commodity prices on nitrate runoff and leaching, soil water and wind erosion, and carbon sequestration. Results suggest that increasing commodity prices will result in widespread conversions of non-cropland to cropland. Fifty percent of the region’s pasture and range land will be converted to cropland with $6 corn. Rising commodity prices will also result in dramatic changes in crop mix and rotation systems in the Midwest. With $6 corn, the total acreage of corn will increase by 23% and 40% in the Corn Belt and Lake States, respectively; the acreage of continuous corn will increase considerably in both regions as well. These changes in land use and crop mix will have a large impact on agricultural pollution. Approaches to mitigating the environmental impacts are discussed.

Abstract  We investigate effects of corn-based ethanol plants on local land uses using county-level panel data for Iowa for 1997 through 2009 and an Arellano-Bond difference-generalized method-of-moments estimator. Our results show that ethanol plants have statistically significant effects on the proportion of acres planted to corn in the plants’ host counties. Furthermore, ceteris paribus, the land-use-change effect of locally owned plants (owned by local farmers or cooperatives) is about twice as large as the effect of plants with nonlocal owners. We also explore implications for the environment of ethanol plants and the changes in land use that they induce.