If one in five people in richer countries went near-vegan, and threw away a third less food than they currently do, while poor countries were assisted to preserve their forests and restore degraded land, the world’s agricultural systems could be absorbing carbon dioxide by 2050 instead of adding massively to global heating as they do at present.
Tree-planting and improving the fertility of soil through better farming practices would also be needed, according to a study of global forests, farming and food systems published in the journal Nature Climate Change.
Managing agricultural and other land in a more environmentally sound manner could take the world nearly a third of the way towards meeting the Paris agreement goals. “These [measures] are feasible now and deliver many other benefits,” said Stephanie Roe, environmental scientist at the University of Virginia and lead author of the paper.
“Recent reports on the state of our forests and food systems show a worrying lack of progress in the land sector, and our window of opportunity to deliver on the Paris agreement is getting smaller. However, I remain optimistic because we have all the tools we need, as well as increasing public pressure and political will to turn things around.”
The changes would also allow for healthier diets globally, improve livelihoods in poor areas, preserve wildlife and flora, and make for higher water and air quality. Many of the measures suggested, such as cutting food waste and shifting from excessive meat consumption, would also save money. For example, improving soil management through organic farming practices would cost about $57bn (£43.9bn) but save nearly $2tn over the period, according to one estimate used in the study.
Land accounts for about 25% of global greenhouse gas emissions, or 11 gigatons of carbon dioxide a year. With the right measures, according to the study, it would act instead as a carbon sink absorbing 3 gigatons from the atmosphere a year by 2050. That could give some scope for other sectors such as aviation to continue to use limited amounts of fossil fuels while staying within the global carbon budget needed to avoid a temperature rise of more than 1.5C (a rise of 2.7F) above pre-industrial levels.
The authors set out a roadmap for the six large-scale measures they propose, including: reducing deforestation, peatland burning and mangrove destruction by 70%; restoring forests, peatlands and coastal mangroves to generate enough carbon dioxide saving to cancel out China’s annual emissions; planting trees to save as much carbon dioxide as that emitted by the EU.
Improving farming practices, including moving to more organic practices, would mean better soil management that could cut carbon dioxide equal to India’s annual emissions. Consumer food waste in rich countries and big developing countries could be cut by a third, while the losses from food production in poor regions such as sub-Saharan Africa and south-east Asia could be cut drastically through simple measures such as more refrigeration and better transport. Moving a fifth of people to plant-based diets in developed and emerging countries, particularly the US, the EU, China, Brazil, Argentina and Russia, is seen as possible by 2030. These near-vegan diets would involve consuming less than 2,500 calories a day and no more than 60g of animal protein.