The global food system and the agricultural industry it supports may be causing as much global warming as all human activity has caused since the industrial revolution, new research finds.
Since pre-industrial times, the planet has already warmed by about 1.1 degrees Celsius. That may not seem like much, but it is the leading driver of more extreme weather and a cascade of other dangerous effects of climate change. Under the current status quo, greenhouse gas emissions from our food system alone could warm the planet another degree. That’s enough to circumvent the global climate targets of the Paris Agreement and significantly intensify climate catastrophes.
Fortunately, there are ways to avoid that grim scenario, according to the research published today in the journal Nature climate change. But we will have to rethink the way we farm, eat and deal with food waste.
We will have to rethink the way we farm, eat and deal with food waste
“Everyone is eating,” said Catherine Ivanovich, lead author of the new study and a doctoral student at Columbia University. Considering the environmental impact of our food is “important as we look to the future in terms of supporting a global population while also maintaining a secure climate future,” she says.
Ivanovich and her colleagues went through assessments of how much pollution different foods 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 the way it does today, only the food sector could warm the planet by an additional 0.9 degrees Celsius.
A few food groups in particular are responsible for as much as 75 percent of that global warming. They are foods high in methane, a potent greenhouse gas 80 times more potent than carbon dioxide in the first few decades after it is released.
Beef and other ruminant meats, a category that also includes ungulates with four stomach compartments such as goats and sheep, top the list when it comes to causing climate change. This is followed by rice and dairy, the other two food groups responsible for a lot of methane emissions.
This is how cows became notorious for their gas. When they burp, they release methane. Their manure also releases methane and another potent greenhouse gas, nitrous oxide. But people are still to blame; global meat consumption increased by 500 percent between 1992 and 2016, along with growth in population, incomes and the adoption of more Western diets around the world.
After meat from ruminants, rice is the food responsible for the greatest 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 why it has such a large environmental footprint. But per calorie, rice and other plant foods are much less greenhouse gas intensive than animal foods.
The authors of the new study highlighted three major 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 changing our diets. In this case, the researchers are not 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 Harvard Medical School’s healthy diet recommendations. Those recommendations include a high-protein diet that is lower in saturated fat and cholesterol. This may lead residents of more affluent countries to reduce their meat consumption, while people living in poverty may eat more meat. And Ivanovich is quick to say that any change in diet should respect cultural traditions.
“There will never be one silver bullet”
It is equally important to change systems for how we produce food and treat waste. About a third of the world’s food production is lost or wasted, which then leads to methane emissions from landfills. Throwing less food away will be crucial to efforts to tackle climate change, and that can be achieved through relatively simple solutions, such as retailers offering products in smaller packages.
There are more complex efforts to genetically engineer rice or produce animal feed that reduces methane emissions. And while those technologies could play a role in mitigating climate change, they need to be weighed against other strategies that move 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 technology solution, we’re ignoring the other behavioral and policy interventions we need,” said Brent Kim, a research program manager at the Johns Hopkins Center for a Livable Future and who was not involved in the new investigation. “There is definitely a role for technology, but I think that needs to be viewed holistically. Climate change is such a serious and urgent problem that there will never be one panacea.”