Table 1.

Independent Global Predictor Variables and Their Theoretical Justification for Cropland Expansion

Variable	Theoretical Justification
Bioclimatic Suitability29	Ricardian land rent theory30
Steepness29	Ricardian land rent theory30
Access (distance to markets)31	von Thünen's location theory32
Bioclimatic Suitability ∗ Access OR Steepness ∗ Access	interactions between land rent theory and location theory (i.e., steep land is more valuable near markets)
Population Density (1990)33	induced intensification34
GDP (1992)35	market demands for agriculture20
Population Density ∗ Bioclimatic Suitability OR Steepness OR Access OR GDP	interactions between induced intensification, land rent theory and between induced intensification and location theory or market versus subsistence demands for agriculture
GDP ∗ Access OR Steepness OR Biophysical constraints	interactions between subsistence and market demands on agriculture20

These predictor variables were used to explain cropland extent in 1992 and expansion between 1992 and 2015 (Model 1), and construct the Null Model of current cropland extent. The ∗ represents interaction terms between variables. Full details of the justification for these variables are in the Experimental Procedures.