Ten billion people can be fed within planetary boundaries
A newly published study shows that it may be viable to feed ten billion people without crossing the planetary boundaries for nitrogen flows, biodiversity loss, land system change, and freshwater use. Planetary boundaries are a concept established by a group of researchers that refer to the safe operating space for nine processes in the Earth system. Human activities must be kept within these boundaries to avoid irreversible changes in the Earth system that put the welfare of future generations at risk.
The study quantifies the extent to which the current food system is dependent on crossing the four planetary boundaries above, and found that almost half of the food produced today relies on exceeding these boundaries. If food production were adjusted using the measures needed to keep within all these four boundaries, the potential food supply would only provide a balanced diet for 3.4 billion people. However, when other measures are included, such as improved water and nutrient management, change of diets and a reduction in food waste, the amount of calories available increased to a level sufficient to supply around 10.2 billion people, while strictly respecting the planetary boundaries for nitrogen flows, biodiversity loss, land system change and freshwater use.
Respecting the safe operating space for nitrogen flow alone would decrease the global production in kilocalories by 25.1 percent, which is mainly due to a necessary reduction in heavy fertilizer use in Europe, India, China and the eastern United States. The study suggests that some regions in the world cannot be self-sufficient in food within the planetary boundaries, even when all measures are applied. These regions (e.g. the Middle East, the Indus Basin, Indonesia and parts of Europe) will probably have to rely on international trade or future innovations to feed their inhabitants a balanced diet.
The planetary boundaries for climate change are not fully integrated in the study, but it is indirectly assumed that climate change is primarily mitigated through decarbonization and by reducing emissions connected with decreased land use change simulated in the study.
Source: Gerten, D., Heck, V., Jägermeyr, J. et al. (2020) Feeding ten billion people is possible within four terrestrial planetary boundaries. Nature Sustainability. https://doi.org/10.1038/s41893-019-0465-1