Quantification of Regional and Global Sustainability Based on Combined Resource Criticality of Land and Water

The overall global food sustainability is limited by the simultaneous availability of primary resources at regional scales, although the international trade network can redistribute available (surplus) food. Assessments based on isolated resource (like water) or demand (like food) cannot provide correct estimates of sustainability. We define a novel criticality index on the basis of simultaneous regional availability of arable land and water to quantify sustainability. Analyses at regional and global scale show that while a relatively small fraction of world population is subcritical in terms of food availability, much larger fractions are becoming subcritical in terms of food production. The combined resource criticality implies stronger constraints for sustainability.