Disparate history of transgressing planetary boundaries for nutrients

The activation of nitrogen and phosphorus for food production has caused the transgression of the safe operating space of the Earth system. However, countries differ in the use of their fair share of global nutrient activation, causing a disparity that has severe implications for the environment, land degradation and food security. Both the impact on Earth system processes as well as productivity gains and losses and the consequent socio-economic impacts depend on past use. Therefore, in this study, we examined how the activation of nitrogen and phosphorus for food production in relation to countries’ fair shares has evolved globally. The first transgressions of the planetary boundaries occurred in 1970 and 1964 for nitrogen and phosphorus, respectively. Since then, activation has increased 160% and 200%, respectively. Further, notable differences were observed between countries, in which high-income regions such as western Europe and North America had the highest cumulative transgression and sub-Saharan Africa and Oceania had the greatest deficit relative to their fair shares. The main driver for transgression was economic growth rather than population growth or the relatively recent fertiliser subsidies. Although the use of fertilisers has decreased in areas with previous high use, past usage will slow down the effects of fertiliser reductions on ecosystem recovery and maintain a legacy of inequality. Consequently, in addition to reductions in nitrogen and phosphorus activation, recycling accumulated nutrients to regions operating below their fair shares should be explored and economically enabled in order to secure Earth system functioning while eradicating hunger.

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