Feeding 10 billion people on Earth is possible—and sustainable, scientists say

Study co-author: ‘We have to rethink global agriculture and our current behavior’

People have worried about overpopulation on Earth for centuries, and climate change has only recently accelerated that fear. But a new study found that feeding 10 billion people on Earth is not only possible—but it could be done sustainably as well.

Researchers from the University of Chicago and the Potsdam Institute for Climate Impact Research suggest a comprehensive outline for feeding 10 billion people within our planet’s environmental boundaries in a recent study in Nature Sustainability. 

“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.

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

“We have to rethink global agriculture and our current behavior and then start over, in order to see a fundamental transformation of global agriculture,” said Jonas Jägermeyr, a UChicago postdoctoral researcher and co-author on the study.

Recalibrating methods—and behavior

Jägermeyr, a researcher working with UChicago Prof. Ian Foster and the NASA Goddard Institute for Space Studies’ Cynthia Rosenzweig, contributed simulations of Earth’s biosphere and agriculture to the study. This allowed the planetary boundaries to be scrutinized globally at a new level of spatial and process detail.

“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.”

The encouraging result is that, in theory, 10.2 billion people can be fed without compromising the Earth system.

“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,” said Johan Rockström, director of PIK. “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 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, the study found.

Even after recalibrating agricultural production, international trade will remain a key element of a sustainably fed world. 

Importantly, there is the consumer end, too. For example, some portion of animal proteins would need to be substituted with more legumes and other vegetables.

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% of all food produced is lost to waste.

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,” said Wolfgang Lucht, co-chair for Earth System Analysis at PIK and co-author of the study. “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 stabilizing the Earth.”

Citation: “Feeding ten billion people is possible within four terrestrial planetary boundaries.” Gerten et al, Nature Sustainability, 2020. DOI 10.1038/s41893-019-0465-1

Funding: Emil Aaltonen Foundation, Open Philanthropy Project, University of Chicago, European Union Horizon 2020, Swedish Foundation for Strategic Environmental Research, Academy of Finland, European Regional Development Fund, Land Brandenburg, Maa-ja vesitekniikan tuki ry.

— Adapted from a news release by the Potsdam Institute for Climate Impact Research.

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