Huge reductions in meat-eating are essential to avoid dangerous climate change, according to the most comprehensive analysis yet of the food system’s impact on the environment. In western countries, beef consumption needs to fall by 90% and be replaced by five times more beans and pulses.

The research also finds that enormous changes to farming are needed to avoid destroying the planet’s ability to feed the 10 billion people expected to be on the planet in a few decades.

Food production already causes great damage to the environment, via greenhouse gases from livestock, deforestation and water shortages from farming, and vast ocean dead zones from agricultural pollution. But without action, its impact will get far worse as the world population rises by 2.3 billion people by 2050 and global income triples, enabling more people to eat meat-rich western diets.

This trajectory would smash critical environmental limits beyond which humanity will struggle to live, the new research indicates. “It is pretty shocking,” said Marco Springmann at the University of Oxford, who led the research team. “We are really risking the sustainability of the whole system. If we are interested in people being able to farm and eat, then we better not do that.”

“Feeding a world population of 10 billion is possible, but only if we change the way we eat and the way we produce food,” said Prof Johan Rockström at the Potsdam Institute for Climate Impact Research in Germany, who was part of the research team. “Greening the food sector or eating up our planet: this is what is on the menu today.”

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The new study follows the publication of a landmark UN report on Monday in which the world’s leading scientists warned there are just a dozen years in which to keep global warming under 1.5C, beyond which even half a degree will significantly worsen the risks of drought, floods and extreme heat. The report said eating less meat and dairy was important but said current trends were in the opposite direction.

The new research, published in the journal Nature, is the most thorough to date and combined data from every country to assess the impact of food production on the global environment. It then looked at what could be done to stop the looming food crisis.

“There is no magic bullet,” said Springmann. “But dietary and technological change [on farms] are the two essential things, and hopefully they can be complemented by reduction in food loss and waste.” About a third of food produced today never reaches the table.

The researchers found a global shift to a “flexitarian” diet was needed to keep climate change even under 2C, let alone 1.5C. This flexitarian diet means the average world citizen needs to eat 75% less beef, 90% less pork and half the number of eggs, while tripling consumption of beans and pulses and quadrupling nuts and seeds. This would halve emissions from livestock and better management of manure would enable further cuts.

In rich nations, the dietary changes required are ever more stark. UK and US citizens need to cut beef by 90% and milk by 60% while increasing beans and pulses between four and six times. However, the millions of people in poor nations who are undernourished need to eat a little more meat and dairy.

Reducing meat consumption might be achieved by a mix of education, taxes, subsidies for plant-based foods and changes to school and workplace menus, the scientists said.

To halt deforestation, water shortages and pollution from overuse of fertiliser, profound changes in farming practices are needed. These include increasing crop yields in poorer nations, more universal water storage and far more careful use of fertilisers.

“I was surprised by the fact we need a combination of very ambitious options,” Springmann said. “We really need to push it to the edge of what is possible.”

All the diet and farming options are already being implemented in somewhere in the world, said Springmann. In the Netherlands and Israel, fertilisers and water are being better used, while big cuts in meat consumption are being seen among young people in some cities.

But a global change is needed, he said: “I think we can do it, but we really need much more proactive governments to provide the right framework. People can make a personal difference by changing their diet, but also by knocking on the doors of their politicians and saying we need better environmental regulations – that is also very important. Do not let politicians off the hook.”

Prof Tim Benton at the University of Leeds, who was not part of the research team, said: “Ultimately, we live on a finite planet, with finite resources. It is a fiction to imagine there is a technological solution allowing us to produce as much food as we might ever want, allowing us to overeat and throw food away.” He said the environmental burden of the current food system “undermines the ability of future generations to live on a stable and ecologically rich planet”.