U.S. Ag Emissions Far Less Than World's
Published: Friday, January 14, 2022
Critics often point out that significant greenhouse gas (GHG) emissions come from farming. But, as one air quality specialist pointed out in a Zoom webinar last week, most of the data is based on global emissions. When you look at emissions in developed countries, it's a very different story.
Frank Mitloehner, professor of animal science and an air quality Extension specialist at the University of California-Davis, was the keynote speaker during Purdue University's annual Top Farmer Crop Workshop last Friday.
Roughly 18 percent of global GHG emissions are from the agriculture sector, Mitloehner said. But looking at emissions in the United States, only 10 percent of GHG emissions are from livestock and crop production.
He compared it to the emissions from a single car. There are many variables, such as the type of car, who is driving it and where it is being driven.
"All these things matter," Mitloehner said. "You can't just ask, 'What are the emissions of a car?' But that is exactly what people who produce graphs like this one here (showing global GHG emissions) do. They say, 'What are the emissions of beef globally, on average, versus tomatoes, versus bananas?' No wonder people are confused."
The public's perception about agriculture suffers when journalists take this distorted information and write news stories about it.
"It's not to say livestock doesn't have an impact on climate," he said. "It does, but it's important that we understand the nuance around it."
Globally, greenhouse gas emissions are largely driven by the use of fossil fuels—oil, coal and gas—and related sectors such as transportation and power production. The energy sector makes up 73 percent of all GHG emissions.
Agriculture and forestry make significant contributions to global GHGs, Mitloehner said. But developing countries produce 80 percent of livestock-related GHGs, while developed nations like the U.S. contribute only 20 percent.
"In the U.S., the picture is very different," he said.
Only 10 percent of U.S. GHG emissions come from agriculture. That's because the U.S. livestock sector is more efficient and more productive—with fewer animals. New technologies and feed additives can reduce cows' methane emissions and capture harmful gases from manure lagoons and convert them into energy.
Contrast that to GHG emissions in places like India and Africa.
India has 300 million dairy cows, while the U.S. has only 9 million.
"In India, when a cow stops producing milk after a few years, that cow is just released," Mitloehner said. "The farmer lets her go. That cow will not be slaughtered. She will just be let go and she walks around for years being an idle animal. She will not produce milk and nobody will ever eat her. That is an idle animal."
In Africa, livestock often are kept as a retirement mechanism, like social security.
"Beef cattle in Africa live for 10, 15, 20 years and then they are eaten once they fall over from old age," Mitloehner said. "Well, that is the worst thing you can do from an environmental perspective. We have to change the way people deal with social security and retirement. We have to help them install monetary systems and replace livestock systems, and have livestock for the intended purpose of eating them and not just for other reasons."
Mitloehner said progress is being made with respect to reducing agriculture's environmental footprint, but the industry faces headwinds from critics who tend to be more vocal. He said agriculture needs people who are willing to speak up.
"The critics of agriculture are on social media," he said. "They are out there, and the people in agriculture are not. And that is a critical problem that our sector has. I think we have made huge progress, but there is a lot of room to grow."
Regarding crop production, Mitloehner said no-till and low-till systems are important to keeping carbon in the soil. He expects these to be promoted and incentivized.
"Soils have the capacity to capture carbon," he said. "If you have a crop like soybean, corn or others, they suck the CO2 out of the air in photosynthesis. The carbon goes into the above ground, and then into the below-ground vegetation (roots), and from the roots into the soil. That's a process called soil carbon sequestration.
"Soil carbon sequestration captures one-third of all human-caused carbon to stay in the ground. The question, however, is, will it stay in the ground or not? The answer to that is, it will only stay in the ground if we use minimized tillage."
Fertilizer will always be part of the equation but in a different form.
"Anhydrous ammonia, for example, has a way larger carbon footprint than pelleted nitrogen," Mitloehner said. "There are huge differences in the energy intensity of producing fertilizers. In the future, there will be a focus on that."
Return to Top of Page