Dairy farming has undergone a sea change in the last several decades.
While 97% of U.S. dairy farms are still family-owned, tools and technologies available to modern farmers are significantly more sophisticated than before.
Advances in genetics and feed efficiency allows today's 9 million dairy cows to produce 60% more milk than 25 million cows did in the 1950s, according to UC Davis professor Frank Mitloehner Ph.D.
That equates to a two-third reduction in carbon emissions, Mitloehner testified to the Senate Committee on Agriculture, Nutrition and Forestry.
We also have a better understanding of our environmental impact.
For example, ruminant animals emit methane, a greenhouse gas that is around 28 times more effective than CO2 at trapping heat on Earth.
But it doesn't hang around as long CO2 (which can last for up to a century after emitted).
"In about a decade's time, it's converted to water vapor and carbon dioxide," Mitloehner writes on his UC Davis blog, "which is part of the cycle whereby plants take CO2 out of the atmosphere and convert it into feed via photosynthesis."
So, what does this mean for the planet?
If herd sizes stay relatively stable, dairy cows do not add new carbon to the atmosphere.
But, if we can deploy various strategies to limit enteric emissions, then we can quickly reduce methane concentrations and promote global cooling.
The Food and Agricultural Organization of the United Nations (FAO) estimates that global dairy production in 2015 contributed 1.7 million tons of greenhouse gases to the atmosphere.
In the U.S., according to the Environmental Protection Agency (EPA), dairies contribute around 1.3% of total emissions.
Yet there are "many ways in which the dairy carbon footprint can be reduced," Rattan Lal, Ph.D. and the 2020 winner of the World Food Prize for his work in climate-resilient agriculture, told the Daily Churn, Darigold's blog charting innovation in global dairy.
Part of the way dairies offset their carbon footprint, he adds, is by employing a variety of methods to sequester carbon. Here are at least five.
1. Cover crops for forage and pasture
Most dairy farmers plant extra crops, or cover crops, during the off-season. The U.S. Department of Agriculture's (USDA) Sustainable Agriculture Research and Education Center notes these crops comprise an "important soil carbon sequestration strategy" because they leave roots in the ground, feeding soil microorganisms that capture carbon.
2. Conservation tillage
Tillage — the process of churning up the soil in preparation for planting —destroys soil structure and releases carbon from the soil, according to the Natural Resources and Conservation Service (NRCS).
Abstaining from tilling, or cultivating narrow pathways into previous crops for new seeds, was shown in a review of soil carbon literature published in the Environmental Evidence Journal to promote higher soil organic carbon in topsoil.
3. Managed grazing
Some dairy farmers frequently shift their cattle through paddocks, allowing cows to have just "one bite" before moving to a new pasture.
Also called "regenerative grazing," cows eat and trample grass before moving to the next field. The feces they leave behind feeds microorganisms in the soil, boosting its ability to sequester more atmospheric carbon.
4. Riparian buffers improve watersheds and sequester carbon
The NRCS calls riparian buffers a "livestock best management practice."
So, when dairy farmers plant riparian buffers — a strip of land planted with trees and shrubs between pasturelands and sensitive watersheds — it's not only to promote water quality, but also to sequester carbon.
Planting an acre of forest draws down twice the amount of CO2 produced via an average car's mileage, according to the Pennsylvania-based Keystone 10 Million Trees Partnership.
5. Innovative manure management
Manure application is an important tool in sequestering carbon in drylands, according to the FAO, helping to promote organic matter in the soil.
Studies show that over five years, soil applied with manure had 1.18 tons per hectare more carbon than soil that received plant residue alone.
While these are basic strategies many dairies already employ, we are seeing an explosion of innovations like worm-powered water treatment and seaweed that can further mitigate dairy's carbon contribution.
And that's a win for everyone.