The global food system, and the agriculture industry that supports it, could cause as much global warming as all human activity has caused since the Industrial Revolution, new research finds.
The planet has already warmed by about 1.1 degrees Celsius since preindustrial times. That might not seem like much, but it’s the primary driver of more extreme weather and a cascade of other dangerous effects from climate change. Under the current status quo, greenhouse gas emissions from our food system alone could warm the planet by an additional degree. That’s enough to blow past global climate goals set under the Paris agreement and significantly intensify climate disasters.
Fortunately, there are ways to prevent that grim scenario, according to the research published today in the journal Nature Climate Change. But we’ll have to rethink the way we farm, eat, and handle our food waste.
We’ll have to rethink the way we farm, eat, and handle our food waste
“Everybody eats,” says Catherine Ivanovich, lead author of the new research and a PhD candidate at Columbia University. Considering the environmental impact of our food is “important as we look into the future in terms of supporting a global population, while also maintaining a secure climate future,” she says.
Ivanovich and her colleagues poured through assessments of how much pollution different food items produce and then modeled how much they each contribute to global warming through 2100. All in all, if the world continues to produce and consume food in the way that it does today, the food sector alone could cause the planet to heat up an additional 0.9 degrees Celsius.
A few food groups in particular are responsible for a whopping 75 percent of that global warming. They’re foods that are high sources of methane, a powerful greenhouse gas that is 80 times more potent than carbon dioxide in the first couple of decades after it’s released.
Beef and other ruminant meat, a category that includes hoofed mammals with four stomach compartments like goats and sheep, are at the top of the list when it comes to causing climate change. Rice and dairy are next, the other two food groups responsible for a whole lot of methane emissions.
This is how cows became notorious for their gas. When they burp, they let out methane. Their manure also releases methane and another potent greenhouse gas, nitrous oxide. But people are still at fault; global meat consumption rose by 500 percent between 1992 and 2016 along with growth in population, incomes, and the adoption of more Western diets across the world.
After ruminant meat, rice is the food item responsible for the most global warming. Flooded rice paddies are a breeding ground for methane-producing microbes. And rice is a staple food for much of the world, which is also why it has such a big environmental footprint. But on a per-calorie basis, rice and other plant foods are much less greenhouse gas intensive than animal foods.
The authors of the new research highlighted three big steps to take to limit greenhouse gas pollution from food, strategies that could cut their global warming potential by more than half.
The trickiest of those tactics is for humans to adapt to the climate risks we face by altering our diets. In this case, the researchers aren’t asking for anything extreme or even for people to eat vegetarian. Their modeling, which found a 55 percent reduction in the food sector’s contribution to future global warming, is based on people following healthy diet recommendations from Harvard Medical School. Those recommendations include a protein-rich diet that cuts down on saturated fat and cholesterol. That might entail residents of more affluent countries reducing their meat consumption, while people experiencing poverty might increase how much meat they eat. And Ivanovich is quick to say that any changes in diet need to respect cultural traditions.
“There’s never going to be one silver bullet”
Changing systems for how we produce food and treat waste is just as important. About a third of the world’s food production is lost or wasted, which then goes on to generate methane emissions in landfills. Throwing less food out will be crucial for efforts to tackle climate change, and that can be achieved through relatively simple fixes like retailers offering products in smaller packages.
There are more complex efforts to genetically engineer rice or produce cattle feed that reduces methane emissions. And while those technologies could play a role in limiting climate change, they need to be balanced with other strategies that get us away from the “business as usual” that got us into a climate mess in the first place.
“There’s a valid concern that if we get too hung up on a technological fix, then we might ignore the other behavioral and policy interventions that we need,” says Brent Kim, a research program manager at Johns Hopkins Center for a Livable Future and who was not involved in the new research. “There is absolutely a role for technology, but I think that has to be considered holistically. Climate change is such a severe and urgent problem, there’s never going to be one silver bullet.”