As people’s incomes increase, they tend to switch from “starchy staples” such as grains, potatoes and roots to meat and dairy.“You would expect that there would be huge cultural differences between populations in these patterns,” said Thomas Tomich, a food systems economist at the University of California, Davis, who was not involved in the new paper. Some, But what’s surprising is how nearly universal this shift is: how rising incomes, especially from the poor to the middle class, actually affect people’s consumption of livestock products. “
However, cattle and dairy products are especially important to the climate conversation because they are huge sources of methane emissions. Ivanovich’s modeling shows that ruminant meat alone could be responsible for one-third of the warming associated with food consumption by 2030. Dairy products will account for another 19%, and rice will account for another 23%. Together, these three groups are responsible for three-quarters of the warming of the global food system.
There is a silver lining, though: The team argues that we can avoid half of the warming by improving food systems and diets. Start by eating less cows and other ruminants – the less fermenting stomachs the better. New food technologies can certainly help, such as plant-based meat imitations like the Impossible Burger, or meat grown from lab-grown cells, also known as cellular agriculture. Researchers are also experimenting with feed additives for cows to reduce methane in burps.
In the field, rice growers can significantly reduce methane emissions by switching between wet and dry rice fields, rather than letting the plants be flooded. Researchers are also developing crops that fix nitrogen themselves to reduce nitrous oxide emissions. (Legumes do this automatically, thanks to symbiotic bacteria that live in their roots.) One team has bred rice plants that grow biofilms that serve as homes for nitrogen-fixing microbes, reducing the need for synthetic fertilizers. Making such fertilizers is energy-intensive, so reducing reliance on them would further reduce emissions.
But Ivanovic stresses that wealthy countries certainly cannot force developing countries to adopt methane-conscious diets. In some parts of the world, cattle are just food and milk, but for subsistence farmers it can be a working animal or currency. “It is very important that diets are not altered without being culturally appropriate and supporting local production practices and their contribution to economic livelihoods,” she said.
Ivanovich’s 1 degree number is an estimate, not a prediction. For one thing, she couldn’t complexly model how new food and agricultural technologies might reduce emissions over the next few decades. Adrian Leip, an environmental scientist and lead author of last year’s IPCC report on climate mitigation, noted that while these technologies are promising, it’s unclear when or how quickly people will adopt them. “At some point, one of these technologies—I don’t know if it’s cellular agriculture or a plant-based analogue—is going to be so cheap. It’s going to be so tasty and nutritious that people start thinking: Why did I ever eat animals?said Leip, who was not involved in the new paper. “I’m sure it’s going to happen because I don’t really see a good reason no It’s about to happen. So if social norms start to shift, it will be very fast. “
Complicating matters is an additional feedback loop: As the food system raises global temperatures, crops will have to endure more heat stress and more severe drought. “It’s really a dynamic interplay of changes in both directions,” Ivanovich said. “The agriculture we produce affects our changing climate, and our changing climate does affect our ability to produce crops and support the global population.”
But she does offer hope: Once people stop producing methane, methane declines rapidly. It disappears from the atmosphere after ten years, while CO2 lasted for centuries. “If we reduce emissions now, we will experience a reduction in future warming very quickly,” she said.