Drawing Carbon Out of Air Into Soil, Part 2 – Raising Livestock

The carbon farming techniques of Part 1 touch on crops, but not on the role of livestock in carbon sequestration. Here we have dissonance. We’ve heard for decades about the massive GHG impacts of industrial livestock agriculture, and that from an environmental impact standpoint, you’re better off raising a variety of grains and beans and feeding humans directly, rather than using animals as a protein middleman (as food crops are typically what’s fed to livestock, rather than grasses that people don’t eat). BUT there is newer thinking that holds out livestock as a solution, indicating that livestock help capture carbon in soil by invigorating the growth of grasses through grazing as well as generating manure at amounts that can be assimilated by local soils.

To get benefits, as noted by Savory Institute and its Holistic Management, grazing livestock should be managed to mimic wild grazing, rather than concentrated in feedlots where those environmental impacts escalate. It’s important to consider the type of livestock. Critics note that cattle can still be damaging to soils. And with cattle and sheep, additional greenhouse gas concerns arise, beyond impact on soil carbon, as relatively large amounts of methane are inherently generated in the animal (enteric). (The question of which ruminants/grazers have much lower methane emissions (goats, deer, etc.) remains as a research topic.)

Research suggests seaweed as a feed additive can reduce that methane. More recent field tests suggest the reduction is in the 30%-40% reduction range, rather than the 99% lab test reduction highlighted by Project Drawdown. There is evidence that composting manure fixes carbon more effectively than direct soil application of manure – and though that requires manure collection, which then means animals are likely more concentrated than wandering the landscape like natural grazers – it can certainly be part of the solution where we still have feedlots. In addition, direct soil application of manure can generate a third and particularly potent greenhouse gas — nitrous oxide (N2O). Even if nature has applied manure directly to soils for millennia, in an age where GHG emissions have become a critical issue, we would do well to look at the most effective ways to minimize emissions.

Natural processes which were acceptable a century ago now invite scrutiny. We had tens of millions of buffalo on this continent, which had a crucial role in shaping and integrating with the landscape, and which also generated significant methane, like modern cattle. Their methane emissions were not an issue for us to consider, as at that time, there was not also the rampant and large-scale burning of fossil fuels that has brought GHG into focus . In trading buffalo for cattle and hundreds of millions of high-emission humans, hoofed mammal methane now becomes a consideration, as does integration of much lower GHG emission lifestyles into our lives.

Beyond soil carbon considerations, protein can be raised holistically and in a low-carbon way in farms where nutrients cascade between plants and animals:

  • Aquaponics systems that raise both fish and greens, using fish manure as a plant nutrient
  • Garden-wandering chickens that provide meat and eggs from plants and bugs that people don’t eat, and leave nutrients for crops that people do eat; and
  • A return to eating insects like crickets and mealworms that grow with near-zero inputs.

But, back to soil carbon.

Displacing carbon from deep beneath the earth and putting it back into the air has put much of life into jeopardy. Fossil fuel use has taken carbon equivalent to that which was drawn out of the air over the last 15 million years, and is injecting it back in less than 100 years. It’s a rapid shock to the system, compromising the ability of much of life to survive (and surely creating evolutionary pressures toward species able to navigate the new climate).

Yes, this carbon was once in the biosphere. Fossil fuels are merely congealed plant/animal carbon that became buried and removed from the biosphere. Ultimately, the fact is that the life that is currently on the planet evolved in a lower carbon era. We now make the moral choice to not jeopardize the livelihood of the vast majority of life on the planet, and make major investments in concerted climate action. Those investments must include carbon farming and low-GHG methods to raise our food.

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