## 2 Experimental Section  
### Evolution in Agricultural Land Use and Major Land Allocation Patterns in 1990-2010  
This section uses two FAO data sets to examine global land use changes by region to reveal regional common land allocation patterns in response to changes in markets for agricultural commodities. The first set represents expansion and/or contraction in agricultural land (representing changes in cropland cover). In FAO data, pasture is included in cropland, so an expansion in cropland cover indicates deforestation and a reduction in cropland cover could represent reforestation and or conversion of agricultural land to other uses (e.g., expansion in urban areas). The second data set characterizes changes in harvested areas. An expansion in total harvested areas could be due to many factors. The harvested areas of a region may increase due to deforestation (expansion in crop cover), returning idled croplands to crop production, increases in double cropping, or reduction in crop failures. On the other hand total harvested areas may decrease in a region due to reduction in demand  
Figure 1: New and old land supply trees in GTAP-BIO model. for crops, drought or other catastrophic events. In general, over a long time period total harvested area and land cover move together. However in the short run they may diverge. In this section we also use harvested areas to analyze changes in supply of land to alternative crops. During the time period of 1990-2000 commodity markets were relatively stable, and in many countries agricultural activities were under governmental support programs. The agricultural markets experienced major changes in the next decade. Several countries (in particular, USA and EU members) reduced or modified their agricultural support programs during this decade. Biofuel production began to grow much faster around 2004 in many countries, especially USA, Brazil, and EU. Many counties, especially China and India, observed significant food demand expansion due to rapid economic growth. In addition, the crude oil price reached to its historical high with significant impacts on the production costs of agricultural products. In response to these changes, crop prices went up significantly and agricultural markets experienced major turbulences especially during the years 2008-2011. The higher commodity prices led to increases in cropland cover globally. The study of regional land use changes during these time periods, in particular after 2004, is the key to tuning the land transformation elasticities used in G TAP-BIO model. The global area of agricultural land has increased by about 37.5 million hectares (MH) during the past two decades. During this time period the area of global forest has decreased by about 135 MH. These figures confirm land conversion along the land cover frontier at the global scale. On the other hand, the global harvested area followed a relatively flat trend in the 1990s, and then it sharply increased by about 71 MH during the next decades (from 1353 million hectares (MH) in 2000 to about 1424 MH in 2010 (Figure 2). This rapid growth in the global harvested area reflects major expansion in the demand for agricultural products during the time period 2000-2010. The allocation of cropland among alternative crops has changed significantly during the past two decades. Figure 3 summarizes changes in global harvested areas by crop for the past two decades (for the list of crop categories and their member see Table A1 in Appendix A). This figure indicates positive and large changes in the harvested areas of maize and oilseeds and negative and large changes in the harvested areas of crop categories of wheat, other coarse grains, and animal feed. From these observations we can conclude that global harvested area has increased significantly during 2000-2010. However, the rate of land conversion from forest to agricultural land has decreased in this time period compared to the time period of 1990-2000. Reduction in the area of global id  
Figure 2: Global harvested area 1990–2010.