Dairy is under scrutiny for contributing to climate change, but farmers argue that their cows aren’t the problem and are making changes to prove it.
The production, processing, and transportation of milk caused an estimated 2.7% of all human-caused greenhouse gas emissions in 2007, reported an assessment from the Food and Agriculture Organization of the United Nations. Most of these emissions occur at the farm. A portion stem from deforestation for land use and fossil-fuel burning for farming activities, but most of the emissions come from cow manure.
Consumers concerned about the environment have taken the issue into their own hands by adopting veganism and creating an explosion in the plant-based milk market. Kayleah Aldrich, an eco-friendly college student in New York, went vegan when she realized that what she ate had an impact on the environment. Now that she knows, she’s disappointed in the dairy industry for being unsustainable. Aside from methane emissions, environmentalists often critique dairy’s high water and land use. While cows often don’t take up much space in their closed barns, a large swath of farmland is dedicated to growing feed for cows. The land is a resource, vegans argue, that could be put to better use if the crops went directly to people.
“Animals need way more land, they need way more water, way more energy, way more upkeep than a person does,” said Aldrich.
Meanwhile, dairy farmers have been hurt and shocked by the claims.
“You talk about being good environmental stewards… Now we take that real serious.” said Eric Zuber, a dairy farmer in New York. The dairy industry points to numerous efforts that have been made to mitigate dairy’s environmental impact. Cows are now able to produce more milk than ever before, so it takes significantly fewer cows to meet consumer demand. Cow manure in its raw state and after being processed is being used more frequently as fertilizer. Alternative foods like bakery feed, which is prepared for livestock from bakery waste, are widely adopted, reducing the amount of land needed for farming. The industry also points out that not all milk has the same emission footprint: What dairy cows are fed and how far the milk travels has an impact that’s often overlooked.
But these changes aren’t enough, Aldrich said. Although the environmental impact of alternative milks, like the use of herbicides or shift towards monocultures, are still widely contested, Kayleah believes that if her diet change helps the planet even a little then it’s worth it.
Despite the shift in consumer eating habits, dairy products are still present around the world. In June 2020 the U.S. alone produced 610 million pounds of milk every day, a slight increase from the same month in 2019, as recorded by the United States Department of Agriculture.
With the intense pressure that environmental activism puts on dairy to reduce greenhouse gas emissions and the continued demand for milk, many farmers are finding ways to change their operations to keep up. Anaerobic digesters, an emerging technology in renewable energy, are becoming an increasingly common way to fight climate change on dairy farms.
At Zuber Farms in Byron, NY Eric Zuber milks 2,600 cows. Every one of those cows poop, and in 2009 he decided to put all that manure to work. His anaerobic digester has been a part of the farm ever since, reducing his environmental footprint and giving him multiple products to use in all areas of his operations.
“The concept seems pretty simple,” Zuber said, “You build this big vat, you put a heat rack in it, you put a top on it so the gas can’t escape and you heat it to 100 degrees. And you seed it with the right bugs of bacteria and, you know, it breaks the manure down and you make gas.”
Anaerobic digesters are a method of creating renewable natural gas by fermenting organic material. In the case of dairy farmers, the organic material is cow manure. They fill their digesters, which are huge tanks partially buried in the ground, with the waste their cows naturally produce. There, bacteria and mechanical agitators break down the solids into a poop soup. During this breaking-down process greenhouse gasses like methane are released and captured by the digester. The gas is pumped into a scrubber that cleans it of impurities, transforming it into a versatile commodity, commonly referred to as biogas, that can be burned on stove tops or generated into electricity.
There are multiple benefits to creating biogas. The most obvious is the renewable source of energy it provides. Many dairy farmers, including Zuber, generate their biogas into electricity. Many people don’t consider how much power it takes to milk cows; Zuber says that his generator was putting out about 300 kilowatts a day, which was just enough to power his entire operation. This reduces reliance on fossil fuels, which is the largest greenhouse gas source.
Capturing the methane from the manure also keeps it out of the atmosphere, directly reducing the amount of gas contributing to climate change.
But there are other benefits, too. Zuber originally became interested in digesting because of the solid by-product that can be used as cow bedding in the barns. He said the switch has cut his bedding costs by more than half. This organic material is pumped out of the digester, separated, and dried. And even though it was once poo, it doesn’t smell or resemble its past life at all. In fact, it’s more reminiscent of the grains that the cows ate in the first place.
The other by-product of anaerobic digestion is less pleasant but equally as important. This nutrient-dense liquid is a type of biofertilizer, and can be used as a completely organic fertilizer on crops of all kinds. Synthetic fertilizers often have negative impacts on the environment, and create a lot of emissions when they’re manufactured.
These biogas benefits have been recognized across the world, but anaerobic digestion hasn’t boomed yet. Companies like Brightmark Energy, who was contacted but did not respond, are looking to change that. Last year Brightmark reached out to Zuber and four other farms in Western New York to participate in the Yellowjacket Project, one of their many renewable natural gas initiatives. Beginning last August this project has assisted renovations of digesters already on the farms. In exchange, the farmers lease their digesters to Brightmark.
“Our job was to get the manure into the digester and get it out. Their job is all gas,” explains Zuber. For the duration of the contract the farmers will supply the digesters with manure and receive any solid or liquid by-products. Brightmark will take control of the natural gas, transporting and processing it to be supplied to the Empire Gas Line, a pipe that runs 300 feet behind Zuber’s cow barn.
This new process means that Zuber will no longer be generating his gas into electricity, thus retiring his old engine. But the money he’ll be getting from Brightmark will cover the return of his $12,000 electricity bill. Besides, Zuber says, the engine was a pain in his and his mechanic’s behinds anyways.
Despite his use of anaerobic digestion for the past decade and his contract to continue doing so, Zuber isn’t convinced that renewable natural gas is the energy source of the future. “Something’s worth what it’s worth, but sooner or later economics will prevail… Beware of business that are made and lost with the stroke of a pen. And that’s exactly what this is.”
Anaerobic digestion may not be the solution to all of dairy’s environmental problems, but it’s making the impact that it can. In 2013 anaerobic digesters on farms prevented the emission of greenhouse gasses equivalent to 1.73 million metric tons of carbon dioxide, as reported by the U.S. Environmental Protection Agency. 255 digesting farms are currently registered in the U.S. with the number rising each year thanks to increasing support from government grant programs and interested companies, as well as the disbursement of research on the topic.
In the larger picture of greenhouse gas emissions dairy fills only a small space. Transportation, electricity production, and industry activities are still the largest emitters. But environmental activists seek to reduce their negative impact in all areas of their lives, and that includes dairy. The dairy industry has heard the cry for sustainable milk, and farms are changing in response to it.
