A recent study published in the journal Nature Food found that global greenhouse gas emissions from animal-based foods are double the amount of emissions associated with plant-based foods. Taking farmland, livestock, and land use changes into consideration, global food production is responsible for 17,318 billion metric tons of greenhouse gas emissions annually – accounting for 35 percent of all human-caused greenhouse emissions.
A computer modeling study led by Professor Atul K. Jain at the University of Illinois Urbana-Champagne is the first to analyze carbon dioxide, methane, and nitrous oxide emissions from all sub-sectors related to food production and consumption. These sub-sectors include land use changes, farmland management activities, raising livestock, and all of the operations that take place after the food leaves the farm.
“Although CO2 is the most important and most frequently discussed GHG (greenhouse gas), methane generated by rice cultivation and animals, and nitrous oxide from fertilizers are 34 and 298 times more powerful than CO2, respectively, when it comes to trapping heat in the atmosphere,” explained study lead author Xiaoming Xu.
The researchers discovered that animal-based food emissions contributed 57 percent of food-based emissions, while plant-based emissions amounted to only 29 percent. Out of all meat and dairy products, beef was by far responsible for the most emissions (four billion metric tons), followed by cow milk, pork, and chicken meat. Among vegetables, rice production appeared to be the most damaging, contributing two billion metric tons of annual greenhouse gas emissions.
In terms of location, the scientists found that South and Southeast Asia, as well as South America are the largest emitters of greenhouse gases related to food production and consumption, with China leading both animal- and plant-based emissions.
According to Professor Jain, developing climate mitigation strategies must rely on accurate estimates of GHG emissions from all sources, including those from the production and consumption of total and individual plant- and animal-based foods.
This comprehensive study is an important step forward towards encouraging policymakers to develop strategies to mitigate greenhouse gas emissions before climate change will become irreversible.