UChicago Postdoc Co-Authors Study on Feeding 10 Billion Without Wrecking the Planet

January 20, 2020

Global population that can be provided with a global average net food supply of 2,355 calories when respecting the different planetary boundaries given unchanged current practices (left side) and when making use of opportunities of agricultural land expansion, management and sociocultural changes within the safe operating space (SOS) (right side).

Almost half of current food production is harmful to our planet – causing biodiversity loss, ecosystem degradation and water stress. But as world population continues to grow, can that last? A study in Nature Sustainability led by researchers from the Potsdam Institute for Climate Impact Research (PIK) — and co-authored by UChicago CS postdoctoral researcher Jonas Jägermeyr — now suggests a comprehensive solution package for feeding 10 billion people within our planet’s environmental boundaries. 

Supplying a sufficient and healthy diet for every person while keeping our biosphere largely intact will require no less than a technological and socio-cultural U-turn, the authors write. It includes adopting radically different ways of farming, reduction of food waste, and dietary changes.

“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,” said Dieter Gerten, lead author from PIK and professor at Humboldt University of Berlin. “Currently, almost half of global food production relies on crossing Earth’s environmental boundaries. We appropriate too much land for crops and livestock, fertilize too heavily and irrigate too extensively. To solve this issue in the face of a still growing world population, we collectively need to rethink how to produce food. Excitingly, our research shows that such transformations will make it possible to provide enough food for up to 10 billion people.”

The researchers ask the question of how many people could be fed while keeping a strict standard of environmental sustainability worldwide. These environmental capacities are defined in terms of a set of planetary boundaries – advisable limits to 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, land-system change, freshwater use, and nitrogen flows. 

Jägermeyr, a researcher working with UChicago CS Professor Ian Foster and Cynthia Rosenzweig, Senior Research Scientist at the NASA Goddard Institute for Space Studies, contributed simulations of Earth’s biosphere and agriculture to the study. Through these models, the planetary boundaries could be scrutinized globally at a new level of spatial and process detail. 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. 

“We have to acknowledge environmental limits, but at the same time eradicate poverty and food insecurity. To achieve these Sustainable Development Goals we need to sustainably increase agricultural production, and that’s a pretty tricky dilemma,” Jägermeyr said. “By implementing better farm water management and using irrigation in a better way, by redistributing current fertilizer applications and cropland patterns, we can substantially boost agricultural production.”

But even those massive changes on the production side of agriculture won’t be enough to feed the estimated Earth population of 10 billion in the coming decades. And the study points out that a food system “U-turn” would be necessary, including consumer change, to fully maximize sustainable intensification while minimizing environmental damage. 

“The critical point is there needs to be societal demand change as well, and that requires reductions in food losses and dietary changes,” Jägermeyr said. “We have to rethink global agriculture  and our current behavior and then start over, in order to see a fundamental transformation of global agriculture. It’s not just a progression forward, but it’s a redesign of traditional measures.” In concert, synergies in sustainably intensifying the global food system are tremendous.

Globally differentiated picture: In some regions, less would be more

The encouraging result is that, in theory, 10.2 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 fertilizer. 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 side effect, such more sustainable agriculture can increase overall climate resilience and adaptability while also limiting global warming. In other places, however, farming is so far off local and Earth’s limits 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. Even after recalibrating agricultural production, international trade will remain a key element of a sustainably fed world. 

Importantly, there is the consumers’ end, too. Large-scale dietary changes seem to be inevitable for turning the tide to a sustainable food supply. 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 not only benefit the planet, but also people’s health,” adds Vera Heck from PIK. 

Another crucial factor is reducing food loss. In line with scenarios adopted in the present study, the most recent IPCC Special Report on land use found that currently, up to 30 percent of all food produced is lost to waste. “This situation clearly calls for resolute policy measures to set incentives right on both the producers’ and consumers’ ends,” Heck further lays out.

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. Transitioning to more sustainable land use and management is therefore a demanding challenge to policy-making. Key to success is that the regions affected need to see clear benefits for their development. Then there is a real chance that support for new directions will grow fast enough for stabilising the Earth system,” said Wolfgang Lucht, co-chair for Earth System Analysis at PIK and co-author of the study. 

Article: 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]

[Adapted from a news release by the Potsdam Institute for Climate Impact Research (PIK)]