Supplying a sufficient and healthy diet for every person whilst keeping our biosphere largely intact will require no less than a technological and socio-cultural U-turn. It includes adopting radically different ways of farming, reduction of food waste, and dietary changes. These are the main findings of a study led by researchers of the Potsdam Institute for Climate Impact Research (PIK) in Potsdam/Germany, published in the scientific journal Nature in mid-January 2020. The study's publication coincides with the World Economic Forum in Davos and the International Green Week in Berlin, the world's biggest food and agriculture fair.
“When looking at the status of planet Earth and the influence of current global agriculture practices upon it, there’s a lot of reason to worry, but also reason for hope – if we see decisive actions very soon,” says Dieter Gerten, lead author from PIK and a professor at Humboldt University Berlin. “Currently, almost half of global food production relies on crossing Earth’s environmental boundaries. We appropriate too much land for crops and livestock, fertilise too heavily and irrigate too extensively. We collectively need to rethink how to produce food. PIK’s research shows that such transformations will make it possible to provide enough food for up to ten billion people.”
The researchers are asking themselves how many people could be fed while keeping a strict standard of environmental sustainability world-wide. These environmental capacities are defined in terms of a set of planetary boundaries – scientifically defined targets of maximum allowed human interference with processes that regulate the state of the planet. The present study accounts for four of nine boundaries most relevant for agriculture: biosphere integrity (keeping biodiversity and ecosystems intact), land-system change, freshwater use and nitrogen flows.
Based on a simulation model, the spatial and process impacts of food on these boundaries are scrutinised and aggregated to the entire planet. This analysis demonstrates where and how many boundaries are being violated by current food production and in which ways this development could be reverted through adopting more sustainable forms of agriculture.
The encouraging result is that, in theory, ten billion people can be fed without compromising the Earth system. This leads to very interesting conclusions, as Johan Rockström, director of PIK points, out. “We find that currently, agriculture in many regions is using too much water, land, or fertiliser,” Rockström explains. “Production in these regions thus needs to be brought into line with environmental sustainability. Yet, there are huge opportunities to sustainably increase agricultural production in these and other regions. This goes for large parts of Sub-Saharan Africa, for example, where more efficient water and nutrient management could strongly improve yields.”
As a positive side effect, sustainable agriculture can increase overall climate resilience while also limiting global warming. In other places, however, farming is so far off local and Earth boundaries that even more sustainable systems could not completely balance the pressure on the environment, such as in parts of the Middle East, Indonesia, and, to some extent, in Central Europe.
Importantly, there is the consumers’ end, too. Large-scale dietary shifts seem to be inevitable if the tide is to be turned to a sustainable food system. For example, regarding China’s currently rising meat consumption, parts of animal proteins would need to be substituted by more legumes and other vegetables. “Changes like this might seem hard to chew at first. But in the long run, dietary changes towards a more sustainable mix on your plate will benefit not only the planet, but also people’s health,” adds Vera Heck of PIK.
Perhaps the most sensitive and challenging implication of the study relates to land. “Anything involving land tends to be complex and contested in practice because people’s livelihoods and outlook depend on it,” Heck notes. “Transitioning to more sustainable land use and management is therefore a demanding challenge in policy-making. Key to success is that the regions affected need to see clear benefits for their development.”
Dieter Gerten, Vera Heck, Jonas Jägermeyr, Benjamin Leon Bodirsky, Ingo Fetzer, Mika Jalava, Matti Kummu, Wolfgang Lucht, Johan Rockström, Sibyll Schaphoff, Hans Joachim Schellnhuber (2020): Feeding ten billion people is possible within four terrestrial planetary boundaries. Nature Sustainability [DOI 10.1038/s41893-019-0465-1]:
Further related research by PIK researchers:
Walter Willett, Johan Rockström, Brent Loken et al. (2019): Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. The Lancet. DOI: [10.1016/S0140-6736(18)31788-4]: