'Eat more meat and save the world': the latest implausible farming miracle

Cattle walk an arid landscape in Texas. ‘Holistic management’ claims to halt desertification while allowing the continued consumption of meat. Photograph: D.J. PETERS/AP

Allan Savory tells us that increasing livestock can reduce desertification and reverse climate change – but where is the scientific evidence?

By  - TG - @GeorgeMonbiot 

It doesn’t matter how often miracles are disproved; our willingness to believe in them remains undiminished. Miracle cures, miracle crops, miracle fuels, miracle financial instruments, miracle profits: the continued enthusiasm for these claims reflects the triumph of hope over experience.

Here’s another one: a miracle technique that allows us to reconcile our insatiable demand for meat with the need to protect the living planet. Better still, it proposes, eating meat could actually save the biosphere. A TED talk which makes this claim has been viewed 2.6m times.

Over the weekend in London, the author of this talk, Allan Savory, convened an international conference, in which a long list of speakers lined up to insist that his methods have been vindicated.

I was intrigued by his TED talk, in which he screened astonishing before-and-after pictures purporting to show the transformative impacts of his technique. Savory maintained that without grazing by livestock, grasslands turn to desert. He claimed that he had reversed desertification by raising the number of cattle and goats by 400%, grazing them intensively for short bursts in small paddocks and then moving them on.

By this means, he said, the hooves of the animals break up what he calls the “cancer of desertification”: the crust of algae that forms on bare soil in dry areas. Breaking it up, he claimed, encourages the growth of grass. By trampling vegetation and coating it with manure, the livestock produce a mulch that ensures the soil absorbs and retains more water.

As a result of this transformation, we can do something astonishing:

We can take enough carbon out of the atmosphere and safely store it in the grassland soils for thousands of years, and if we just do that on about half the world’s grasslands that I’ve shown you, we can take us back to pre-industrial levels while feeding people. I can think of almost nothing that offers more hope for our planet, for your children, for their children and all of humanity.

Savory’s grazing technique, which he calls “holistic management”, could, in other words, reverse not only desertification but also climate change – while permitting us to keep consuming vast quantities of meat. No wonder it has been received with such enthusiasm.

I would love to believe him. But I’ve been in this game too long to take anything on trust – especially simple solutions to complex problems. So I went to the library and started reading. A large number of academic papers have been published in response to his claims, testing them by means of experimental and comparative studies. The conclusion, overwhelmingly, is that his statements are not supported by empirical evidence and experimental work, and that in crucial respects his techniques do more harm than good.

A new review of experimental results, in the journal Agricultural Systems, has this to say about Savory’s claims that his intensive rotational grazing (IRG) can regenerate grassland:

The vast majority of experimental evidence does not support claims of enhanced ecological benefits in IRG compared to other grazing strategies, including the capacity to increase storage of soil organic carbon ... IRG has been rigorously evaluated, primarily in the US, by numerous investigators at multiple locations and in a wide range of precipitation zones over a period of several decades. Collectively, these experimental results clearly indicate that IRG does not increase plant or animal production, or improve plant community composition, or benefit soil surface hydrology compared to other grazing strategies

Another review article, in the International Journal of Biodiversity, found that grazing by livestock in arid places is more likely to destroy grass and other vegetation than to protect it:

Published comparisons of grazed and ungrazed lands in the western US have found that rested sites have larger and more dense grasses, fewer weedy forbs and shrubs, higher biodiversity, higher productivity, less bare ground, and better water infiltration than nearby grazed sites.

Among these sites was a ranch in Arizona whose vegetation, Savory had claimed, had become “moribund” and increasingly sparse since grazing there had ceased. In reality, there has been a massive increase in both plant cover and plant diversity on this site since the livestock were removed.

As for the claim that the algal crust is the “cancer of desertification”, it appears to be just the opposite: a rich, diverse and ancient ecosystem in its own right, that stabilises the soil, increases organic matter and absorbs water. These crusts are “fragile, highly susceptible to trampling, and are slow to recover from trampling impacts. Loss of these crusts results in increased erosion and reduced soil fertility”.

Overall, it concluded: “Ecologically, the application of holistic management principles of trampling and intensive foraging are as detrimental to plants, soils, water storage, and plant productivity as are conventional grazing systems.”

So what exactly do Savory’s dramatic pictures of transformation show? As they are uncaptioned and not linked in his presentations to scientific studies, it’s hard to tell. Many factors affect the way vegetation changes in arid places. Do these shifts really depict the results of the application of his techniques, or something else entirely?

As for the claim that holistic management can reverse the build-up of carbon dioxide in the atmosphere, according to RealClimate.org, he’s wrong by orders of magnitude. Just to balance current carbon emissions, the uptake of carbon by all the world’s vegetation (not only grasslands) would have to triple. But Savory says he can go beyond that, and his technique can bring atmospheric carbon “back to pre-industrial levels”. As RealClimate puts it: “science tells us that this claim is simply not reasonable.”

Far from grazing helping to store carbon, holistic management seems to have the opposite effect: the evidence strongly suggests that livestock reduce carbon storage rather than raising it. In terms of total greenhouse gas emissions, the intensive grazing of cattle on grasslands can be even worse than producing them in feedlots.

While Savory was in London, I managed to secure a telephone interview with him, to ask him about these challenges. It did not go well. He began by comparing himself to Galileo, which is never a good sign, and it went downhill from there. I have learnt to be suspicious of people who give long, distracting, irrelevant answers to simple questions. Apart from Ian Plimer, I have never come across anyone who does it to greater effect.

I asked him about that ranch in Arizona, and the claim that he was diametrically wrong about what had happened to the vegetation once grazing had ceased. He launched into a long disquisition about a court case in Namibia. After several attempts I at last managed to break in, to remind him I’d asked about a ranch in Arizona. It was as if he registered the name of the state and nothing else: he started talking about the quality of the state’s scientists, its rifle ranges and its tortoises.

I asked him about his carbon claims. He told me it wasn’t him who had made such claims, but other people who knew far more about it than he did. Could he gave me the names of those people?

He gave me a long, rambling answer about the different impacts of land management around the world, climate change, fire, poverty, violence, red meat and veganism. I tried and tried again. At last I managed to bring him round to the question, and extracted some names from him. So where had they published their calculations? They hadn’t.

His staff later sent me an article on the issue published on the Savory Institute’s website, but - as far as I can tell - nowhere else. There are no named authors. If you intend to make a massive and extraordinary scientific claim, and build your position around it, you had better ensure that it has been properly tested, which is why the peer review process exists.

Broadly, however, his theme was that what scientists were studying was not the entirety of holistic management, but only one aspect of it:

It’s like having a plane that flies that lands on three wheels, and we’ve only had wheelbarrows or tricycles for centuries and so people are studying the tricycle and saying well it’s got three wheels, and we cannot make it fly; it can’t fly. How come the plane can fly when it’s also got three wheels?

Savory referred me to a paper he’d written, which he said, explains the science and methodology of holistic grazing. This paper (again apparently unpublished except on his website) explained the lack of scientific support for his claims as follows:

Holistic management does not permit replication. Because of this fact we can only validate the ‘science’ used and monitor or document ‘results achieved’. Note: This point is critical to understanding the great difficulty reductionist scientists are experiencing trying to comprehend holistic planned grazing – because no two plans are ever the same even on the same property two years running, planned grazing cannot be replicated which reductionist scientists do to try to understand the ‘science.’

It then contended that:

The only independent assessment of all available critics and their citations was done by Chris Gill. Gill, involved in management and with a liberal arts education, studied every citation he could locate and who in turn those authors cited. As he reports not a single paper discrediting Holistic Management actually studied, or even attempted to study, holistic planned grazing.

Unfortunately Savory gives no reference for this assessment. In the academic literature, I’ve been unable to find a paper on the subject by anyone called Gill. Elsewhere, all I have been able to locate is a three-page magazine article by Gill, reproduced on Savory’s websites. It contains no references, no data and no links to any experimental or empirical research. If this is “the only independent assessment of all available critics and their citations” that Savory will accept as valid, I think it might tell you something about the substance of his claims.

It all reminds me, I’m afraid, of the way in which certain evangelists for alternative medicine operate.

For example:

- Savory maintains that it’s not the claims that are wrong but the scientific process by which they are assessed. (In one interview he says: “you’ll find the scientific method never discovers anything.”)

- He claims that “reductionist science” doesn’t understand what holistic management involves, which is why it fails to measure the outcomes properly. But, as Adam Merberg points out, his account of what holistic management means appears inconsistent and poorly defined, which “allows Savory to blame any failures on a misunderstanding of the method.”

- As scientific studies don’t produce the results he wants, he relies instead on testimonials.

- He diagnoses normal conditions as deadly pathologies (“the cancer of desertification”) then claims to have found a cure for them.

- He makes claims about his techniques which are not only implausible but appear to be scientifically impossible.

It seems to me that there’s a fairly solid rule, that applies to almost any question: what you want to believe is almost always wrong. If something sounds too good to be true, that’s because, in nearly all cases, it is.

 

UPDATE:

Allan Savory's 5 Big Lies - Debunked

 

 

Allan Savory's 5 Big Lies - Debunked - PART 2

 

 

COWSPIRACY - Official Trailer - HD

 

 

COWSPIRACY - The Sustainability Secret in about 15 minutes (Short Version)

 

 

COWSPIRACY: The Sustainability Secret - EN

 

 

Cowspiracy is it Bull?

 

 

New basic rebuttal to the Savory myth 'Holistic Management can reverse Climate Change'

By Seb V - 18 March 2019

The Myth:

Holistic Management can reverse Climate Change 
“Holistic management as a planned grazing strategy is able to reverse desertification and sequester atmospheric carbon dioxide into soil, reducing atmospheric carbon dioxide levels to pre-industrial levels in a period of forty years.” (Allan Savory, 2014)

The Rebuttal:

Holistic Management is a form of grazing management that has become popularised in recent years by Allan Savory, founder of the Savory Institute. The management technique has been subject of international attention, mainly due to the infamous TED talk that Savory gave in 2014. Savory preaches that Holistic Management, applied to most of the world’s grassland, can increase productivity of farms and reverse climate change. His explanation is that livestock, grouped in large herds, will ‘mimic nature’ and increase plant growth because of this. The increased plant growth will then, according the Savory, be able to store a great deal of carbon into soil by taking the carbon out of the atmosphere, thus reducing the level of carbon dioxide contributing to the greenhouse effect. He claims all of this can be achieved in 40 years.

Quite simply, it is not possible to increase productivity, increase numbers of cattle and store carbon using any grazing strategy, never-mind Holistic Management. There are several factors which are important in controlling the ability of soils to store carbon dioxide from the atmosphere. A list of these factors, and their importance and relevance to Holistic Management, is listed here:

The Carbon Cycle

Processes such as photosynthesis, plant respiration and bacterial respiration are all part of the cycle of carbon in and out of the atmosphere. Levels of each process determine if the carbon is stored in soil, used or is released. Plants, for example, depend on carbon for growth. In photosynthesis, energy from the sun allows plants to extract carbon dioxide in the atmosphere for its own growth, producing oxygen as a waste product. The additional carbon not used for growth is stored in soil as something called humus, which gives soil its volcanic colour. The darker the colour of the deep soil, the increased level of soil organic carbon (SOC). SOC will be increased if the level of photosynthesis is high but is also dependent on the presence of soil microbes and nutrients. The level of SOC determines soil quality and potential to store even more carbon (Ontl & Schulte 2012, Figure 1).

https://static.skepticalscience.com/pics/1_Fig1.jpg

Figure 1: A simple version of the carbon cycle, related to how plants cycle carbon for growth, release, and storage. Source: https://ecosciencewire.com/2016/06/09/the-hurdles-to-carbon-farming/

However, stored carbon can also be lost from soils. Damage to soils, like erosion and increased decomposition, leads to an overall loss of carbon, where their potential of the soil to store carbon is outweighed by carbon losses. This carbon seeps from the soil back into the atmosphere, further increasing the greenhouse effect.

Carbon losses over time

Applying a new grazing technique on grasslands which have been mismanaged may indeed have positive results in terms of soil carbon storage during the first few years. But the main problem is that storage slows after the initial change, and over a long period of time (such as 50 years), the storage potential of the soil is maximised as it approaches an equilibrium (Nordborg, 2016). This effect is more observable in dry regions of the planet. This is because dry regions have lost much of their soil content, therefore having low carbon storage potential. They are at risk of completely drying out because of increasing temperatures and more at risk to the detrimental effect of mismanaged grazing (Lal, 2004).This makes it unreasonable to apply Holistic Management to such dry areas, where the intense grazing would no doubt leave soils further damaged. In fact, one of the principals of Holistic Management - focusing on using the intense hoof action of cattle – has been claimed by the Savory Institute to increase the absorption of water by soils. However, several studies in fact stated that the opposite effect was seen. When comparing land that was not grazed with land that had been managed using a short rotational grazing system (which is very similar to Holistic Management in its ideas), water infiltration was significantly reduced, and the hoof action did not improve incorporation of litter into soil (Dormaar et al. 1989, Holechek et al. 2000). 

Long term studies on the effect of grazing on soil carbon storage have been done before, and the results are not promising. Two studies – by Bellamy (2005) and Schrumpf (2011) – studied soil carbon data and soil organic carbon, respectively, over periods of 25 years and a range of 10-50 years in European grasslands. Bellamy’s study came to the conclusion that there was no significant change in soil organic carbon stocks over this long period of time, and Schrumpf’s study showed that as an overall, there was no clear pattern in carbon storage. Increases and decreases were observed, as well as times of stability. There was no overall pattern to suggest that grazing had any sort of positive effect on carbon storage.  

Increasing temperature 

Allan Savoury wants to expand Holistic Management to cover land across the globe, that he believes can be saved from complete desertification by using his grazing technique. Simply, this is not possible due to the variety of climates that exist around the world, and in many cases, land which he has highlighted as targets to save by his technique cannot support livestock. This is clear in Figure 2:

https://static.skepticalscience.com/pics/1_Fig2.jpg

 

Figure 2: 

Top: A view of the world’s land and their vulnerability to desertification by climate change. Points to note are the land in grey – which is already dry – and the red / orange areas which at a high risk. Source: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/nedc/training/soil/?cid=nrcs142p2_054003

Bottom: The land that Savory highlights at land that is desertifying, taken from his TED talk. Note the difference between the correct figure (above) and Savory’s “estimate”. Source: https://www.youtube.com/watch?v=vpTHi7O66pI&t=255s

To expand on this, land which is already desert, such as the Sahara, cannot be revived by any management technique. The climate is too harsh, cannot support plant growth, and therefore cannot support livestock. This is the same case for land which is at high risk of desertification, in countries such as Iran and Iraq (Figure 2). This leaves semi-arid and humid land as the only potential land able to support livestock. Climate change is likely to further damage these soils further. The explanation is that, as temperature increases, soil becomes drier. The soil becomes vulnerable to erosion, less likely to retain water, and levels of soil organic content will go down as the soil gets drier (Dalias et al. 2001). The carbon will seep out from soil back into the atmosphere. The soil changes from a carbon “sink” to a carbon “source”. In turn, this affects livestock. As the plant productivity gets worse, the livestock have less to feed on, and overall productivity of the farm goes down.

Methane

Methane, CH4, is a potent greenhouse gas. It is capable of trapping heat in the atmosphere, like carbon dioxide, and is a significant factor in global warming. Melting permafrost, methane clathrates in ocean and mostly importantly emissions from livestock are responsible for a large proportion of methane that has been released into the atmosphere. When cows burp or excrete gas, they release methane (Figure 3). This methane then accumulates in the atmosphere for a period of around 12 years before it is broken down into water vapour and carbon dioxide, which are both greenhouse gases themselves (Ripple et al. 2014). As methane has a shorter atmospheric lifetime than carbon dioxide, its global warming potential is 28 times higher (Shindell et al. 2009). Part of the problem is that as the human population grows, the demand for meat grows too.  At the time of writing, the population of livestock (ruminants) is increasing by 25 million per year (FAO). This has the knock-on effect of increased methane emissions, and further global warming.

Allan Savory has refused to put a limit on the number of livestock that a farm can accommodate using the Holistic Management practice, claiming that bacteria capable of breaking down methane will solve this problem. He also has claimed that the number of wild ruminants in the past is equal to the current number of domesticated ruminants. This is inaccurate. The level of methane in the atmosphere today is 2.5 times higher than the level recorded before the industrial revolution (IPCC, 2001). This number has certainly increased as result of the expansion of the meat industry, in addition to other reasons listed. The methane-eating bacteria are common in both oxygen rich and oxygen depleted environments but are certainly not capable of breaking down the huge pool of methane that is present in the atmosphere today. 

https://static.skepticalscience.com/pics/1_Fig3.png

 

Figure 3: The Methane Emissions which are attributable to cattle. Note the increased warming effect of methane over a 100-year time scale, compared to carbon dioxide. Source: https://www.ccacoalition.org/en/activity/enteric-fermentation

Overall, methane emissions have continued to rise at an unprecedented rate over the past 250 years. Reducing livestock-based methane emissions will have a positive effect on global warming. For Holistic Management to work, there must be a balance between the amount of methane produced by livestock and the amount of carbon stored, which is known to be small. 

Conclusions 

Because of the complex nature of carbon storage in soils, increasing global temperature, risk of desertification and methane emissions from livestock, it is unlikely that Holistic Management, or any management technique, can reverse climate change. Studies of several grazing techniques and carbon storage have produced no ground-breaking results to suggest that Savory’s idea is doable. With increasing temperature, the ability of soil to store carbon will decrease, and grazing will likely speed up the process of desertification. Finally, methane emissions from cattle are currently too high, and their effect on global warming cannot be ignored. Adding more livestock to the planet will not help this.

References 

Bellamy, P.H. et al., 2005. Carbon losses from all soils across England and Wales 1978-2003. Nature, 437(7056), pp.245–248.


Dalias, P. et al., 2001. Long-term effects of temperature on carbon mineralisation processes. Soil biology & biochemistry, 33(7), pp.1049–1057.

Holechek, J.L. et al., 2000. Short-duration grazing: the facts in 1999. Rangelands Archives, 22(1), pp.18–22.

Johan F. Dormaar, Smoliak, S. & Walter D. Willms, 1989. Vegetation and Soil Responses to Short-Duration Grazing on Fescue Grasslands. Journal of Range Management, 42(3), pp.252–256.

Lal, R., 2004. Soil carbon sequestration to mitigate climate change. Geoderma, 123(1), pp.1–22.

Monica Petri, Caterina Batello, Ricardo Villani and Freddy Nachtergaele, 2009. Carbon status and carbon sequestration potential in the world’s grasslands. FAO. Available at: https://www.fao.org/3/a-i1880e.pdf.

Nordborg, M., 2016. A critical review of Allan Savory’s grazing method. SLU/EPOK – Centre for Organic Food & Farming & Chalmers. Available at: https://publications.lib.chalmers.se/records/fulltext/244566/local_244566.pdf.

Ontl, T.A. & Schulte, L.A., 2012. Soil carbon storage. Nature Education Knowledge, 3, p.3(10):35.

Schrumpf, M. et al., 2011. How accurately can soil organic carbon stocks and stock changes be quantified by soil inventories? Biogeosciences , 8(5), pp.1193–1212.

Shindell, D.T. et al., 2009. Improved attribution of climate forcing to emissions. Science, 326(5953), pp.716–718.

Thornes, J.E., 2002. IPCC, 2001: Climate change 2001: impacts, adaptation and vulnerability, Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, edited by J. J. McCarthy, O. F. Canziani, N. A. Leary, D. J. Dokken a: BOOK REVIEW. International Journal of Climatology, 22(10), pp.1285–1286.

 

'Holistic Management' - can it reverse Climate Change?

What the science says...

Multiple scientific studies from climate scientists and agricultural specialists show little or no significant gain in carbon sequestration on soils managed holistically to those with other grazing techniques. Even under the most favourable conditions, Holistic Management (HM) alone can only slow climate change by a small percentage, over a limited period, and certainly cannot reverse climate change.

Climate Myth...

Holistic Management can reverse Climate Change

“Holistic management as a planned grazing strategy is able to reverse desertification and sequester atmospheric carbon dioxide into soil, reducing atmospheric carbon dioxide levels to pre-industrial levels in a period of forty years.” (Allan Savory, 2014)

When Allan Savory gave his TED talk in March 2013, his philosophy of Holistic Management as a tool to reverse climate change was presented to a global audience. His bold claims of reviving deserts by simply using cattle to “mimic nature”, greening arid land and boosting productivity of farms globally, seemed a miraculous solution to the growing problem of desertification. Many people, especially farmers, have invested in his idea and firmly believe in it. However, carbon scientists and climate experts were sceptical.   

What is Holistic Management? 

Holistic Management (HM) was coined by ecologist Allan Savory and is termed as a “planning system that helps farmers, ranchers and land stewards better manage agricultural resources in order to reap sustainable environmental, economic, and social benefits”. It aims to strategically ‘mimic nature’ through planning, monitoring, and calculating factors which influence the grazing plan. Whilst these appear to be a good approach to cattle farming, there is little evidence or accurate description about how exactly HM works (Figure 1); and can work well enough to yield high productivity and carbon sequestration rates compared to other grazing techniques. 

https://static.skepticalscience.com/pics/1_HolisticGrazingAccurate.png

Figure 1: A basic summary of how Holistic Management (HM) works. A set stock group graze on land continuously for a period between 1-5 days (lightly coloured grass) and are then shuttled to a section of land which has been allowed to rest for around 2 months since grazing last occurred (Darkest coloured grass). The cattle are shuttled quickly between systems to ensure trampling of soil and supposed increase of water filtration. This system ensures that grass has long recovery time before it is grazed, and cattle are less selective in the grass they eat compared with continuous grazing. HM has several similarities to short duration grazing and intensive rotational grazing (Undersander DJ et al, 2002). Source: Vaughan S, 2019. 

It has been proven that excessive continuous grazing with high stocking rates is a form of mismanagement, accelerating carbon depletion in previously carbon-rich soils and increasing the risk of desertification (Nordborg, 2016). The Savory Institute has claimed that grazing under Holistic Management is superior to continuous grazing. Savory has claimed over two-thirds of the world’s ice-free land is at risk of desertification, and only the use of HM can stop this process. He claims that 500 billion tonnes of carbon can be stored on roughly 5 billion hectares of land managed holistically over a period of 40 years, assuming soil can sequester carbon at a rate of 2.5 tonnes of carbon per hectare per year (Nordborg, 2016). Coincidently, 550 billion tonnes of carbon have been released since the start of the industrial revolution. Therefore, Savory has branded Holistic Management as a solution for climate change. To fully assess these claims made, it is important to consider how exactly atmospheric carbon can be converted into soil organic carbon. This involves looking at the carbon cycle, previous studies of Short Duration Grazing (SDG) and Intensive Rotational Grazing (IRG), and carbon sequestration data from managed soils. 

Soil Carbon and the Carbon Cycle

https://static.skepticalscience.com/pics/2_carbon_cycle.jpg

Figure 2: The fast carbon cycle, showing the interchange of carbon between the atmosphere, land and the ocean. White numbers indicate stored carbon, yellow numbers indicate natural fluxes and red numbers are human contributions. Carbon is measured in gigatons per year (Source: NASA – The Carbon Cycle).

Soil is a major contributor to carbon storage in both the fast and slow carbon cycle (Figure 2). Whilst the slow carbon cycle takes 100-200 million years to move carbon between rocks, soil, oceans and the atmosphere, the fast carbon cycle takes approximately a lifetime(NASA). Plants and phytoplankton are the main drivers of the fast cycle, and oxygen is combined with sugar to release water, carbon dioxide and energy. The atmospheric CO2 is then fixed via photosynthesis into plant biomass. Soil carbon materialises because of direct growth and death cycles of plant roots and symbiotic relationships with mycorrhizae fungi, where proportions of carbon dioxide are lost through microbial respiration, and some of the original carbon is stored as humus (Ontl, T. A. & Schulte, L. A., 2012). If carbon input from photosynthesis exceeds carbon loss, the level of soil organic carbon increases over time. An average of 81% of carbon in the earth’s biosphere is estimated to be present in soil, with the remaining 19% stored in plants (IPCC, 2000).

The ratio of Soil Organic Carbon (SOC) and Soil Inorganic Carbon (SIC) is important in soil globally and particularly relevant to arid regions. SOC content plays a key role in preventing erosion of soils, temperature balance, increasing water retention and acting as a source of essential plant nutrients (Lal, 2004). Because of the low SOC content in arid regions, this plays a part in the increased risks of desertification. Lal (2004) coincidingly states that loss of SOC content is increased by accelerated soil erosion and mineralisation, on sloped soils and flat soils respectively, and that “global hotspots” of soil degradation are South Asia, the Andean Region, Central America, sub-Saharan Africa and the Caribbean. Not only this, but severely eroded soils are said to have lost between a third to two thirds of their original carbon pool, something which is commonly observed in tropical regions. In this case, improved management techniques are required to try and slow this SOC decline, but grazing may not be the answer. In addition, focus should be put onto slowing this existing decline, opposed to attempting to rescue soils with very little of their original SOC left.

Studies of similar grazing systems show little or no benefit to soil

As described in Figure 1, HM is synonymous with SDG and IRG.  Several reviews of both SDG and IRG have provided evidence that intensive, short duration systems have damaging effects on soil, rather than beneficial effects. A review on the effects of SDG in 1999 (Holechek et al, 2000) found water infiltration was significantly reduced following hoof action of ruminants, and a detailed 5-year study in Canada (Dormaar et al. 1989) stated that hoof action did not significantly increase incorporation of litter into soil. This directly contradicts the apparent importance of hoof action in the HM technique. Further evidence comes in the form of nine out of ten studies in North America, which found SDG had no benefit in terms of livestock productivity. In addition, a similar report of over 50 grazing studies in Africa found little differences in productivity between continuous and SDG systems (Holechek et al. 2000).

What is interesting about these studies is that most of the research on SDG was published from 1980-2000 and found no credible results to support SDG and its supposed benefits over other management techniques. Considering the negative findings of these studies, it is no surprise that several forms of current “evidence” listed on the Savory website come in the form of anecdotal quotes from ranchers. Their testimony is most likely due to a productive year with high precipitation and therefore higher productivity (Holecheck, 1996); rather than a direct result of implementing HM. Furthermore, the HM technique has no set limits on stocking rates. Naturally, higher stocking rates – combined with favourable environmental conditions – will lead to increased profits for the ranchers directly, so if a good year happens to coincide with implementing HM, then it reflects well on HM as a grazing technique. However, it is important to focus on what the science tells us, and that is that SDG itself is not beneficial for Soil Organic Content (SOC) or soil productivity. It is dependent on factors out of direct control. 

Carbon sequestration is dependent on several factors

Carbon Sequestration is defined as the uptake of atmospheric carbon dioxide via photosynthesis, which is stored in the form of carbon and dead organic matter in soil (Lal, 2004), and its rate is dependent on the type, usage and treatment of the land. From the carbon cycle, there is certain evidence that soil carbon can act as a substantial carbon sink. In relation to HM, the supposed increased carbon sequestration achieved using Holistic Management allows a huge proportional of atmospheric carbon dioxide to be locked away in soil (Nordborg, 2016).

There are several reasons why HM cannot achieve his high sequestration rate. The primary reason is that carbon sequestration is not a simple concept. It is dependent on climate, temperature changes, history of grazing and soil nutrient content, among other factors.

Temperature has a large influence on carbon sequestration. With increasing temperature, the likelihood is that carbon loss from soil will outweigh carbon storage. There is a higher tendency for slower plant growth over a longer growing season, and drier, warmer soil that will likely release CO2 and methane into the atmosphere. This will create a net release creating a positive feedback loop for carbon loss (Johnston, C. et al. 2004).

Extending this viewpoint, one could argue that increasing CO2 will lead to increased photosynthesis and in turn, increased plant productivity and eventually higher rates of retention and sequestration of carbon in soils which currently lie in colder climates. This argument is supported by White et al (1999), where he states increased temperature and rainfall decrease may benefit boreal forest regions, and by various sources which agree that longer growing seasons in Northern Europe and America will improve harvests and may introduce new beneficial species (Sohlenius and Bostrom, 1999; Kleemona et al 1995). On the contrary, increased temperature will most likely prove detrimental to SOC content. Increased mineralization and susceptibility to soil erosion (Dalias et al, 2001) will be a common occurrence in less temperate regions. The soil will crust, have increased water runoff on the surface, and become less likely to store water, carbon, and other important nutrients. Moreover, and perhaps the most significant, is that peat and organic soils will add to growing carbon dioxide emissions with increasing temperature, switching from a carbon sink to a source.

Another problem with studies claiming large sequestration rates in soils is that soil is a sensitive, living environment. It is combined of fungi, macro and microfauna, animal matrix products, dead and living plant matter, all held within a matrix of several states (Johnston et al, 2004). Thus, measuring carbon sequestration in a living environment, which typically requires disturbing the soil, will likely give several false positives. Compared to this, simulations of carbon loss and gain in soils are not a much better solution to this problem.   

Carbon is lost over time

As reported by Smith (2004), soils globally have lost somewhere between 40 and 90 billion tonnes of carbon historically, with the IPCC estimating around 30 billion tonnes have been lost from terrestrial ecosystems since the start of the industrial revolution. Even should these soils, under better management techniques, be able to re-sequester 90 billion tonnes, it accounts for only 16% of carbon emissions since the beginning of the industrial revolution(Nordborg, 2016). Soils also have varying degrees of carbon sequestration potentials. Global studies of potential of grassland soils to re-sequester carbon ranged from 0.5-1.9 billion tonnes of carbon per year (Lal, 2001 & 2004, Petri et al. 2010), with the upper limit equal to 20% of current emissions.

Several long-term studies of carbon sequestration and soil organic carbon content have also been conducted on grasslands. Two examples were studies of Soil Organic Content (SOC) in European grasslands over 10-50 years (Schrumpf et al. 2011) and a review of experimental soil carbon data from grasslands in the UK over a period of 25 years (Bellamy et al. 2005). Considering that European grasslands are not one of the areas that Savory has targeted for implementing large scale HM – as it is not at risk of desertification – it seems likely that positive sequestration rates would be expected, and thus giving HM a better chance of success compared to a harsher climate. However, no such results were apparent. The studies concluded that there was no significant change in SOC stocks (Bellamy et al. 2005) or that there was no clear trend in sequestration; decreases, increases, and periods of relative stability were observed (Schrumpf et al. 2011).

Realistic estimates of HM’s potential are 18 times less than Savory’s estimate

An extremely generous estimate for carbon sequestration on soils managed holistically was proposed by Nordborg. She uses the most optimistic assumptions such as:

  1. HM applied to 1 billion hectares worldwide;
  2. Plant growth measured as Net Primary Productivity (NPP) above and below ground is 3.8 tonnes of C per ha and year before introduction of HM;
  3. NPP doubles following implementation of HM;
  4. 10% of NPP is sequestered in the soil in the first year;
  5. Soil carbon sequestration declines from 10% to 2% to 0% after 50 years and then 100 years respectively.

Factors such as NPP rate at 3.8 tonnes of carbon per ha and year are based on the most optimistic rates, as the likelihood of this rate observable in grasslands worldwide is likely to be around 1.7 tonnes, and plant productivity is limited by temperature and precipitation in climates around the world (del Grosso et al. 2008). Another factor to consider is increasing anthropogenic carbon emissions and climate (see below). However, using the assumptions, a calculation of 26.5 billion tonnes of carbon was produced, which is approximately 4.8% of the total emissions of carbon since the industrial revolution. What is more staggering, is that this is 18-fold times less than the estimate proposed by Savory.

https://static.skepticalscience.com/pics/2_Figure3.jpg

Figure 3: Graph displaying the billions of tonnes of carbon potentially gained on soils using Holistic Management on either 5 billion hectares of land over a period of 40 years (Savory Estimate) or 1 billion hectares of land over a period of 100 years using generous estimates (Nordborg Estimate). This is compared to the 90 billion tonnes maximum that is predicted to have been lost from soils (Smith, 2004) since the Industrial Revolution.

For a more appropriate assessment, this data could be compared to one of the Savory Institute’s ‘scientific studies’ that back up his claims. One explanation offered on the Savory Institute website is that of Itzkan (2014), where the upper limit of 2.4 tonnes of C per ha and year, over 3.5 billion ha, is based on before and after photograph inspection of the soils by the author. One of many “methods” which Savory has stated as reliable in backing up HM’s capability have included before and after photographs, anecdotal reports, and non-peer reviewed reports. These make up 26 papers of the 40 published on the website. (Savory Institute, Nordborg, 2016).   

Methane emissions from livestock is overlooked 

Methane (CH4) is an extremely potent greenhouse gas. It has an atmospheric lifetime of around 12 years and offers the largest potential for reduction in radiative forcing when compared to CO2. The ability of CH4 to absorb infrared radiation is 20-30% greater than CO2. Ruminants are the largest contributor of anthropogenic methane emissions and livestock production occupies the most land globally than any other land use (Ripple et al. 2014). The number of ruminants on earth, as of 2011, was estimated to be around 3.6 billion domestic ruminants, and an unknown, far lower number of wild ruminants. The number of ruminants is on average increasing by 25 million per year (FAO). Demand is also on the rise, with a projected increase of 69% consumption of beef on global scale (FAO). However, Holistic Management believes the idea of increasing ruminant population will not have an overall impact on climate change. Continually, an article on the Savory Institute website states several reasons to explain this, such as:

  • Oxidation of methane by soils represents 10% of the total methane sink.
  • Large pre-agricultural populations of ruminants had methane levels cycling consistently between 350-750ppb.
  • Methanotrophic bacteria break down roughly 1 billion tonnes of methane each year on well managed soils. 
https://static.skepticalscience.com/pics/1_figure4.jpg

 

Figure 4: Figures a-d show the link between methane emissions and livestock, taken from Ripple et al (2014).  a, Estimates of direct radiative forcing in 2008 for CO2 and non-CO2 greenhouse gases from anthropogenic sources. b, Projections of radiative forcing in four different scenarios: constant future emissions at 2008 levels (red); 80% reduction in only non-CO2 emissions (orange), 80% reduction in only CO2 emissions (blue), and 80% reductions in both non-CO2 and CO2 emissions (green). c, Estimated annual anthropogenic emissions from major sources of methane in recent years. Error bars represent 1 standard deviation. d, Global ruminant numbers from 1961 to 2011.

Atmospheric methane levels have more than doubled from 1750 to 1999. Its concentration has increased from 700ppbv to 1745ppbv and is steadily increasing at a rate of 7ppbv/year (IPCC, 2001). This is directly correlated with a steading increase of ruminants worldwide (FAO), natural gases, landfill, coal and the rice industry (Figure 4, Heilig, 1994), and increasing climate change is also likely to have played a part in releasing pools of methanetrapped in the oceans and under thawing permafrost (NASA). The Savory Institute’s point of methane cycling between 350-750ppb is true, and while the populations of wild ruminants is unknown and likely to be large, it is not as large as current farmed ruminant populations. A study by Hristov (2015) in the United States concluded that enteric CH4 emissions by presettlement ruminants, such as elk, deer and bison (estimated at 50 million) is 86% of the current emissions by farmed ruminants. As the level is similar, it seems likely that the shift occurring today in methane emissions is due to increase of ruminants combined with change in land use – especially in tropical regions, where native forests are cleared to make way for animal feed crop and grazing land – helped with the increase in climate change, which accelerates the loss of carbon from mismanaged soils.

Alternative non-grazing solutions offer more scientific promise 

There are numerous scientific studies which agree that better management techniques can aid carbon sequestration in grasslands, improve soil organic content (SOC) and slow desertification (Follett, Kimble and Lal, 2001, IPCC, 2007, Jones, 2010). There are a few studies which showed that different management techniques, other than grazing, could influence the carbon sequestration rate of soil. In a study by Conant et al (2001), some of the 115 studies worldwide produced results of high carbon sequestration rates for some management practices, such as a conversion of cultivation to pasture, improved grass species and earthworm introduction. However, there are problems in stating this data as reliable. Grass species was the subject of one study (Fisher, 1994). The cultivated to pasture switch is likely to have a high rate due to restoring carbon lost in the previous conversion, and introduction of earthworms was the subject of two studies and is dependent on soil type. These studies are subject of very specific conditions and the results are not repeatable. In addition, the most important fact is that sequestration rates will be high in the first few years, in line with Nordborg’s estimate (Figure 3), but over an extended period carbon release is likely to increase with carbon storage. Therefore, it is not applicable to include “reliable” data on this matter if the study has lasted less than 40 years. For this reason, data from studies such as Schrumpf et al. 2011 is more reliable. Despite this, a more promising solution would be to conduct long term studies on grassland over long periods, using management practises listed in Conant’s paper and perhaps more techniques appropriate for the specific nature of the soils studied. For this reason, HM should be assessed long term alongside these studies.

Conclusions 

From the wide range of scientific studies conducted into carbon sequestration in soils, contribution of ruminant methane emissions to the greenhouse effect, and the effect better grazing management has on productivity, there is little to suggest that HM has any significant contribution – positive or negative – on increasing carbon sequestration in soils both at risk or not at risk of desertification, or that it is any better than other similar grazing techniques implored on soils. From the research conducted into this topic, several conclusions are presented:

  1. Holistic Management, or any other grazing method, alone cannot reverse climate change – and at most, can slow the current rate of emissions over a limited period by less than 5% over a 100-year time-frame.
  2. The potential of soils to sequester atmospheric carbon is primarily dependent on climate and nutrient balance, and not grazing.
  3. Long term studies of carbon sequestration in grasslands show no overall loss or gainof carbon under favourable climate conditions.
  4. Methane release by domesticated ruminants is extortionate and has a significant effect on increasing the greenhouse effect.
  5. Allan Savory’s claims and statistics about the potential of HM on desertifying grassland are based on assumptions and anecdotes are therefore not scientifically reliable, repeatable or valid.

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