Reaching the maximum feeding capacity from current agricultural land would require a global shift to plant-based diets and vast amounts of industrial fertiliser, a study has found.
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| Farmers planting rice in China STR/AFP via Getty Images |
Almost 20 billion people could be fed on the world’s current agricultural land, according to new research, but doing so would push the planet’s “feeding capacity” to its limit and create huge biodiversity and climate change risks.
The global population hit 8 billion in 2022 and is predicted to reach 11 billion by the end of the century, according to the United Nations, meaning the question of how many people Earth could possibly feed will be crucial in the coming decades.
Feeding 20 billion people from existing agricultural land would require the liberal use of industrial nitrogen fertiliser, says Petros Chatzimpiros at Paris Diderot University.
“Nitrogen is the key limiting nutrient in agricultural production,” he says. “If you have enough nitrogen, you can reach the upper limits of land productivity.”
It would also necessitate a sharp reduction in meat and dairy consumption, from 35 per cent of global diets today to 15 per cent.
However, maximising food production in this way would come with a severe environmental cost, warns Chatzimpiros, blowing past any safe thresholds for nitrogen pollution.
Nitrogen is a vital fertiliser, but its production and overuse causes serious pollution. Excess nitrogen in aquatic systems feeds the growth of toxic algae, creating dead zones in rivers and coastal areas. Meanwhile, nitrogen fertiliser can react to form nitrous oxide, a powerful greenhouse gas that has a warming ability over 300 times more potent than carbon dioxide.
The world passed its “planetary boundary” for nitrogen use in the 1960s, says Chatzimpiros. He warns that doubling down and using even greater amounts of nitrogen in the future would be a risky strategy.
“We don’t have good enough knowledge on the potential negative feedbacks from global pollution on human systems, including agriculture,” he says. “The Earth’s system may produce delayed feedbacks that could impact agricultural productivity, the quality of the soil, so that capacity of humanity to perform agriculture as efficiently as we do today.”
A safer way to feed the world’s growing global population might be to switch to organic farming, the paper concludes. Organic food production could feed between 3 and 14 billion people using current agricultural land, depending on how much meat and dairy was consumed and how carefully the farming systems were managed to prevent nitrogen leaching.
This would include ensuring nitrogen-rich manure is used to feed soils and rotating crops to include nitrogen-fixing plant varieties, such as legumes.
“The organic feeding capacity is the most sustainable, according to our results,” says Chatzimpiros. “The upper limit of the people to feed is lower than in the industrial-based simulations, but still global organic agriculture is able to meet the population challenges of the 21st century.”
Under all scenarios, how much meat and dairy people consume is crucial. If everyone in the world consumed a Western diet, which consists of roughly 55 per cent animal protein, feeding 9 billion people would be impossible – even if plenty of fertiliser was used and additional grassland covering an area equivalent to Russia was converted to agricultural land.
Journal reference