GHG emissions from food production are headed up

Most of the debate about what’s driving climate change--and the best ways to minimize the damage--focuses on transportation, power plants, and buildings. But a study published recently in the journal Science found that rising emissions from worldwide food production will make it extremely difficult to limit global warming to the Paris targets, even if emissions from fossil-fuel burning were halted immediately.

Food production results in emissions of carbon dioxide, methane, and other planet-warming gases in many ways, The New York Times’ Henry Fountain noted. They include land clearing and deforestation for agriculture and grazing, digestion by cattle and other livestock, production and use of fertilizers, and the cultivation of rice in flooded paddies. 

Overall emissions from 2012 to 2017 were equivalent to about 16 billion metric tons of carbon dioxide a year, or about 30 percent of total global emissions. Those figures are headed higher, the researchers found, as world population grows and diets and consumption patterns change as some countries become more affluent.

Brent Loken, the World Wildlife Fund’s global lead scientist, who was not involved in the research, told Fountain, “It’s really less about where the food system is today, and more about where it’s heading.” The study determined that, if left unchanged, future greenhouse gas emissions from food production would alone lead to the world warming by 1.5°C by 2050 and by 2°C by the end of the century compared to pre-industrial levels.

What’s the solution? Michael Clark, the lead author, said the study showed clearly that all of the world’s increasing population could be fed a healthy diet while meeting the Paris goals, as long as concerted action was taken to reform the global food production system. He is a researcher in the Nuffield Department of Population Health at the University of Oxford in England.

He and others are trying to determine what policies and behavioral changes it may be possible to implement. “Maybe it’s a combination of nudges at grocery stores, and top-down policies from governments,” he told The Times. “It could be very bureaucratic or individualistic. Every person has a role to play; every corporation as well. Through collective action and political will, we can actually do this pretty rapidly.”

“There are at least five different changes that would allow us to prevent this agriculturally-driven climate change,” said University of Minnesota Professor David Tilman, who helped produce the study. “These are farming more efficiently, helping farmers in low-income countries increase their yields, eating healthier foods, avoiding overeating and wasting less food. Even partially adopting several of these five changes would solve this problem as long as we start right now.”

The paper cited research showing that all five strategies are readily achievable and have many benefits beyond controlling climate change, such as improving human health, reducing water pollution, improving air quality, preventing species extinctions and improving farm profitability.

Clark told The Guardian that diets in wealthy countries should change if we are to have a shot at reducing emissions from food production to safe levels. “These countries are primarily those that are middle or high income where dietary intake and consumption of meat, dairy and eggs is on average well above [health] recommendations,” said Clark, citing the UK, the U.S., Australia, Europe, Brazil and Argentina, and countries such as China where meat consumption is high and increasing.

If you think you’re going to be asked to adopt a vegan diet, relax. Clark does not believe that is necessary. 

Changing cows’ diets appears to be one promising approach. Mixing seaweed into their feed has cut methane emissions in half in a California study. Improving soil management is another worthy idea. For example, covering the soil with a protective blanket of crops during the winter can keep the earth from washing away.

Like all other sectors that are causing the planet to heat up, food production could move more rapidly toward lower emissions if there were an honest price on carbon dioxide emissions. The next Congress should make carbon pricing a high priority.