Around 95% of food comes from the soil. Generating three centimeters of top soil may take up to 1,000 years. Healthy soils are not only the foundation for food, fuel, fiber and medical products, but they are also essential to ecosystems. Soils play a key role in absorbing carbon and in the carbon cycle.
Soils also store and filter water, and improve resilience to floods and droughts. Overgrazing is a significant driver of climate change by reducing the global photosynthetic CO2 sink, altering retention of surface waters, and by increasing the albedo of the earth's surface.
About 33% of the world's soil has already been degraded, due to erosion, compaction, soil sealing, salinization, soil organic matter and nutrient depletion, acidification, pollution and other processes caused by unsustainable land management practices. Top soil is being lost at the rate of 30 soccer fields of soil every minute, mostly due to intensive farming.i
Livestock grazing is the main cause of land degradation on grasslands and soil erosion. The impact of run-off from areas used for cattle grazing is even affecting the Great Barrier Reef in Australia.ii
If current rates of degradation continue, all of the world's top soil could be gone within 60 years. Unless new approaches are adopted, the global amount of arable and productive land per person in 2050 will be only 25% of the level in 1960 due to growing populations and soil degradation.
Many skeptics of animal-based agribusiness emissions cite Allan Savory's claim that livestock can be controlled through “holistic management and planned grazing.” This process allows domesticated herds to act as “a proxy for former herds and predators”, in trampling dry grass and leaving “dung, urine and litter or mulch.”
This supposedly enables the soil to “absorb and hold rain, to store carbon, and to break down methane.”iii So, to reverse desertification and climate change, and return the atmosphere to preindustrial levels, Savory argues for a massive increase in livestock production, rather than a reduction. Science suggest that this claim is simply not reasonable. The massive, ongoing additions of carbon to the atmosphere from human activity far exceed the carbon storage capacity of global grasslands.iv
Savory’s methods have found little support from mainstream science, and there are many studies critical of his unscientific methods.v For example, one accuses him of piecing together false assumptions to produce ineffective but popular recommendations on climate change.vi Another point to his inconsistencies and changing methods.vii
A review of studies from 13 North American sites and additional data from Africa found little evidence for any of the environmental benefits which Savory claimed for his methods.viii Others point out that intensive (cell) grazing is only viable where water points are close and labor is cheap. Temporary or permanent fencing is labor intensive, and moving herds daily requires far more labor than most operations can afford.
Emma Archer's study of 14 years of satellite imaging data in South Africa found Savory's intensive grazing practices resulted in lower levels of vegetation than more traditional approaches, when rainfall is included.ix And, rather that the desertification caused by Savory's methods, there is massive potential for reforestation in Africa if livestock were removed and the related savanna burning was stopped.x
Animal-based agribusiness emission skeptics also refer to preliminary research by a Sidney team that showed some managed soil can sequester more that 8,760 kilograms per hectare per year. However, their calculations were off by a factor of 1,000. The corrected figure suggest these soils can oxidize only 8.76 kg per hectare per year.xi
Worldwide, the practice of overgrazing are substantially reducing many grasslands' performance as carbon sinks.xii Overgrazing occurs on 33% of all rangeland.xiii And, marginal rangelands are used intensively when historically productive adjacent range has become overgrazed and unproductive.
The demand for animal flesh has led to overstocking of fragile lands and massive soil erosion and desertification. Overgrazing, from the downlands of southern England to the uplands of Ethiopia and mountains of Nepal, causes great loss of fertility, as well as flooding.
i FAO. 2014. "Nothing dirty here: FAO kicks off International Year of Soils 2015" Rome: Food and Agricultural Organization of the United Nations. 4 December.
ii J. Brodie, C. Christie, M. Devlin, D. Haynes, S. Morris, M. Ramsay, J. Waterhouse and H. Yorkston, “Catchment management and the Great Barrier Reef”, pp. 203 & 205, Water Science and Technology Vol 43 No 9 pp 203–211.
iii Mahony, Paul. 2013c. "Livestock and climate: Why Allan Savory is not a saviour." Terrastendo.net March 26.
iv Jason West and David Briske. 2013. "Cows, Carbon and the Anthropocene: Commentary on Savory TED Video." Real Climate. November 4th
v Goodland, Robert. 2013. “Meat, Lies & Videotape (a Deeply Flawed TED Talk).” Planetsave, 26th March; McWilliams, James. 2013. “All Sizzle and No Steak: Why Allan Savory’s TED talk about how cattle can reverse global warming is dead wrong.“ Slate, 22nd April.
vi Maughan, Ralph. 2013. "Alan Savory gives a popular and very misleading TED talk." The Wildlife News. March 18
vii Adam Merberg. 2013. "Cows Against Climate Change: The Dodgy Science Behind the TED Talk." Inexact Change. March 11
viii Jerry L. Holechek, Hilton Gomes, Francisco Molinar, Dee Galt, and Raul Valdez. 2000. "Short-Duration Grazing: The Facts in 1999." Rangelands 22(1) 18-22.
ix Archer, Emma R.M. 2004. “Beyond the ‘climate versus grazing’ impasse: using remote sensing to investigate the effects of grazing system choice on vegetation cover in the eastern Karoo.“ Journal of Arid Environments, Volume 57, Issue 3, May. Pages 381–408.
x Mahesh Sankaran et al. 2005. “Determinants of woody cover in African savannas”, Nature 438, 846-849. December 8th
xi Cawood, M, 2010. “Error in Snowy Soils Carbon Report”, The Land, 16 July.
xii C. Michael Hogan. 2009. “Overgrazing. Encyclopedia of Earth,”
Sidney Draggan, topic ed.; Cutler J. Cleveland, ed., National Council for Science and the Environment, Washington DC