Identifying the safe operating space for food systems

Abstract

Global environmental pressures from food systems threaten biodiversity and the stability of the Earth system, yet the safe operating space for food systems is unknown. Here we calculate food system boundaries as shares of planetary boundaries, proposing budgets for the food system across nine boundaries. Our results indicate that food systems are a critical driver of planetary boundary transgressions, dominating at least four transgressed boundaries (that is, biosphere integrity, land system change, freshwater change and biogeochemical flows) while strongly contributing to the transgression of two more (that is, climate change and novel entities). Moreover, global food systems are currently beyond all nine food system boundaries; moving to the safe operating space requires reducing related greenhouse gas emissions substantially, halting the conversion of intact nature to agriculture, redistributing fertilizer inputs, limiting pesticide and antibiotic use, and preserving critical freshwater flows without negatively affecting yields.

Fig. 1. Definition of the food system and inclusion of food system elements and non-food agricultural production.

a, Elements (columns) of the food system that are included in our estimate of the contribution of the food system to the PBs (rows). A further breakdown of elements is given in Supplementary Table 12. Elements within ‘Agriculture’ (orange) are equal to IPCC AFOLU accounting. Light shaded boxes represent elements that are partly included. Box numbers: 1, excludes surface area of ponds (only covers 0.055 Mkm² (ref. ); 2, includes crop feed but excludes wild fish feed; 3, includes pasture lands but excludes seminatural extensive grazing land; 4, excludes livestock drinking water (only 2% of livestock water use); 5, evaporation from ponds is excluded (no data); 6, higher end of range includes biomass burning; 7, includes biomass burning from vegetation clearance in forest and peatlands. b, Estimated percentage share of non-food agricultural production (that is, crop and animal production for fibre, fuel or other industrial uses) included in our presented food system contribution estimates in Table 1. See Supplementary Table 1 and the data repository for Fig. 1 for details.

Fig. 2. Status of the food system across PBs and the FSBs.

FSBs (pink line) are represented in a stylized and uniform radius within the safe operating space (green sphere). The radar plot is adapted from ref. (data) and ref. (visualization). The contribution of the food system (in percentages, see Table 1 and Supplementary Table 11, indicated by the black dotted pattern) is projected based on the length of each wedge starting from the PB (for all transgressed boundaries) and the FSB (for the other three boundaries). The components representing novel entities (pesticides and antimicrobial use) are shown as pie charts within the largest set of all (up to now unquantified) novel entities. Note that CO₂ concentration is provided here in terms of CO₂, in contrast to the CO₂e in Table 1. Credit: Azote.

Fig. 3. Exceedance of intact nature by cropland.

Intactness data (blue) represents the land where natural processes predominate^,. Cropland (brown) data are based on HYDE3.2 for 2017. In 10% of the ecoregions, cropland alone is already covering >40% of the land area. Including grazing land increases the number of ecoregions that are in the zone of increasing risk from 10% to 43% (Supplementary Fig. 2).

Fig. 4. Agricultural nitrogen surplus.

a–d, Global nitrogen input and critical input levels (where current input exceeds local thresholds) (a) and associated nitrogen uptake and surplus (b) that lead to exceedance of critical surplus value based on surface water loading, groundwater leaching and deposition in terrestrial ecosystems (c), and the spatial distribution of the critical nitrogen surplus exceedance (d). Agricultural inputs in a are provided for fertilizer application, biological nitrogen fixation, manure, and deposition from NH₃. Numbers on top of the bars in a represent current inputs; the solid parts of the bars represent the required input reductions considering critical input values, assuming other nitrogen inputs will not change. Of the total inputs (233 TgN yr⁻¹), 114 TgN yr⁻¹ is taken up by plants while 119 TgN yr⁻¹ is surplus. Data from refs. ^,. See Supplementary Table 8 for details.