Wednesday, September 4, 2013
Can cows help save the planet?
In this VEC guest blog, the journalist and author Judith Schwartz, gives us a taster from her new book: Cows Save the Planet, in which soil is examined as a crucible for our many overlapping environmental, economic, and social crises. Schwartz reveals that for many of these problems—climate change, desertification, biodiversity loss, droughts, floods, wildfires, rural poverty, malnutrition, and obesity—our ability to turn these crises into opportunities may depend on how we treat the soil more than you think…
I’ve devoted the last few years to thinking and writing about soil, that fine earthy layer that hugs our planet—the stuff we dismiss as “dirt”, yet, it appears, is central to how we grapple with climate change.
How central? Few people realize that there is more carbon in the world’s soil than in the atmosphere and all plant life put together and that cultivated soils are estimated to have lost 50 to 70 percent of their carbon. Or that some scientists say regenerative agricultural practices that return carbon to the soil could bring atmospheric carbon concentrations back to 350 ppm.
A soil’s-eye view of the world allows us to see that climate change is not just a matter of counting molecules; climate is a complex, multi-faceted phenomenon that in many ways we’re still learning about. And soil, which rarely if ever comes up in discussions of climate, is part of the picture. Several ecological cycles that hinge on soil—the energy, water and nutrient cycles in addition to the carbon cycle—have an impact on temperature, humidity, and vulnerability to weather events like floods and droughts. In other words, the constellation of factors that we call climate involves not just physics, but also biology; not just the sky, but also the ground. When a parched landscape devoid of plants gets really hot, the culprit isn’t simply CO2: it’s also the way solar radiation hits the area, unmediated by natural cover or the moisture that moves through plants. Here’s what we don’t talk about when we talk about climate: we can suck all the carbon out of the atmosphere that we want, and still have the problems we now associate with CO2-driven climate change. To truly address climate change, we need to think holistically.
the land needs the animals in the same way that the animals need the land
Enter Holistic Management, developed over several decades by Zimbabwean wildlife biologist Allan Savory. I encountered Savory’s model when I was looking at ways carbon can be brought back to the soil; I was struck by how HM engages natural processes on the level of soil, the elegant dynamics of energy, nutrients, water and carbon. The core of HM is Holistic Planned Grazing, in which livestock are used as a tool for large-scale land restoration. Savory’s insight was that grasslands and grazing animals evolved together—that the land needs the animals in the same way that the animals need the land. Specifically, the land needs animal impact: herbivores act so as to kickstart biological processes that would otherwise stall. Just as land might suffer from being overgrazed, it can also be undergrazed.
A quick snapshot of how it works: animals nibble grasses in a way that stimulates plant growth; their waste adds fertility to the soil; and as herds in the wild bunch up and flee en masse to avoid predators, their trampling breaks capped earth, pushes down dead plant matter so it’s in contact with microorganisms and other soil-dwellers that will break it down, and presses in seeds so that a diversity of species can germinate. The perennial grasses, plant residues and animal waste build carbon, which makes soil less prone to dry out and the rain that falls is more effective. In practice, the rancher takes on the role that the predator does in nature, keeping animals on the move so that land is neither under- nor overgrazed.
Grasslands—which, depending on where you live, might be called savanna, steppes, pampas or prairie—represent about 40 percent of the world’s land mass apart from Greenland and Antarctica. Much of this is desertifying, which is when once-productive land loses the capacity to sustain life, a process driven by the loss of carbon and water.
A few examples of how Savory’s approach has reversed desertification:
–At the Dimbangombe Ranch in Zimbabwe, where Holistic Planned Grazing has been applied since the early 1990s, the Dimbangombe River is again flowing year-round. This has meant that women who used to walk as much as five kilometers for water now have it in their communities, and elephant herds can water on the river rather than traveling to pools.
–Flooding on the Musselshell River in 2011 devastated areas of Central Montana, but the Twodot Ranch, which has been under Holistic Management since the 1980s, was unscathed. While neighboring farms lost livestock, barns, and tens of thousands of dollars in equipment, rancher Zachary Jones says the carbon-rich soil allowed the water to soak in: “We didn’t have much water running off our pastures. Where it did run, it was clear—no runoff of soil.”
–At Rancho Las Pilas in the Chihuahuan Desert, rainwater used to stream off bare soil and collect in dirt dams. In 1978, they shifted to Holistic Management. Owner Guillermo Osuna now says that with full plant cover, streams run through the dry season, there’s no standing water after heavy rains, and he’s doubled the animal stocking rate. These photos were taken at the same location in 1963 (left) and 2003 (right).
A reader might think: Sure the land looks better, but what about climate? The point is that Holistic Planned Grazing has reinvigorated the land, and functioning land is potentially storing a lot of carbon (bolstering soil fertility), moderating against temperature extremes (thanks to plant cover and transpiration), holding water (enhancing resilience to floods and droughts) and supporting life (above and below ground).
Reviving land ecosystems, in which the hydrological, carbon and nitrogen cycles are restored, belong in our discussions of climate. The upside here is that we can make this happen. And by working holistically, the benefits, which include the potential to sustainably draw down a significant amount of atmospheric CO2, could greatly exceed the sum of all the parts.
By Judith Schwartz, images courtesy of the Savory Institute.
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