Effects of phosphorus fertiliser use redistribution on crop calorie production and equal availability

Abstract There are large regional differences in the use of phosphorus (P) in global food production. Likewise, the access of people to food calories and exposure to water pollution differ largely among world regions. Redistribution of P use is needed to meet the planetary boundary (PB) and to improve P-related inequalities. We present a global redistribution of P according to four principles: responsibility, capability, equality and food security, and under strict and loose PB targets. These principles yield contrasting results for the geographical distribution of P fertiliser use, crop calorie production and equal availability. Redistributing P fertiliser use under PB without improvement of P management may pose a threat to global food security: 3–43% of the current global crop calorie production may be threatened. The impact is smaller under the loose PB targets and equality redistribution principle. There is a tradeoff between low crop calorie losses and equal availability for people to crop calories. Overall, the negative impacts on food security could remain limited but would likely be achieved at the cost of increased inequality in per capita food calorie distributions, which implies an increasing need for free international trading of agricultural products.