At the time of writing, a recent TED presentation by Allan Savory with the title How to green the desert and reverse climate changehad been viewed more than 700,000 times. At the end of the presentation, Savory received a standing ovation, and  host Chris Anderson said, “I’m sure everyone here (a) has 100 questions and (b) wants to hug you”.

The comment about a hug may have partially reflected some relief on the part of those present, based on a new belief that they could eat meat without contributing to massive climate change impacts and other environmental problems.

Perhaps Anderson’s more pertinent comment was the one relating to 100 questions, because the audience and viewers would be well advised to consider the validity of Savory’s claims.

In case you haven’t seen the presentation and would like to, here it is (22 minutes duration including brief questions):

Video filmed Feb 2013 • Posted Mar 2013 • TED2013

What was Savory’s main point?

Savory’s key claim is that livestock can be controlled through a planning process he called in the presentation “holistic management and planned grazing”, so as to be “a proxy for former herds and predators”, in trampling dry grass and leaving “dung, urine and litter or mulch”, enabling the soil to “absorb and hold rain, to store carbon, and to break down methane”.

In this way, he says that we can “mimic nature”. In the final 8 minutes of the 20 minute (plus questions) presentation , Savory used the term “mimic nature” (or “mimicking nature”) 9 times. He used it again when answering the first question. (The notion of mimicking nature is very relevant to animal population figures referred to below.)

Savory also refers to his process as “Holistic Resource Management” or HRM, and has previously referred to it as “short duration grazing”.

How valid are Savory’s claims?

Savory’s approach has been considered by two Australian researchers, Geoff Russell and Gerard Wedderburn-Bisshop.

Geoff Russell

  • Geoff Russell is a mathematician, researcher and writer, and the author of CSIRO Perfidy“. His work has been published in (amongst others) Australasian Science, The Monthly, Dissent, The Age, Punch, The Advertiser and Climate Spectator. He is also a regular contributor to Brave New Climate, the website of Professor Barry Brook, head of climate science at the University of Adelaide.
  • Russell points to a study by Emma R.M. Archer of the University of Capetown, published in a 2004 edition of the Journal of Arid Environments, investigating the effect of commercial stock grazing practices on vegetation cover in an eastern Karoo study site in South Africa. Based on 14 years of satellite imaging data and objective assessment methods, the researchers reported that HRM strategies resulted in lower levels of vegetation than more traditional approaches.
  • Russell has also reported extensively on the impact of livestock grazing in Africa, including within his “Boverty Blues” (Parts 1 and 2) series on Brave New Climate. He has cited a study reported in the journal Nature in 2005, indicating the massive potential for reforestation (as opposed to desertification) if livestock were removed and the related burning of savanna ceased. (Refer to MODIS satellite maps and additional comments below.)
  • Russell coined the term “boverty blues” to mean “the human impact of too many bovines overwhelming the local biosphere’s ability to feed them”.
  • Very relevant to Savory’s focus on mimicking nature, Russell has pointed out that current livestock populations dwarf natural populations that preceded them. He states: “Wildlife rates of conception, growth, and the like don’t match what can be achieved by artificial selection, artificial insemination, good fences, irrigated feed production, predator extermination and all the other paraphernalia of modern agriculture. These have produced a totally unnatural and unprecedented explosion in numbers of those animals which people have designated as livestock.” His table comparing numbers from the year 1500 with those from 2004 can be seen below. Today’s animals have also been bred to be much larger than they would be in nature, adding further to their total biomass and the related resource requirements.

rsubak-500-333

Gerard Wedderburn-Bisshop

  • Gerard Wedderburn-Bisshop is a former Principal Scientist with the Queensland Government Department of Environment and Resources Management Remote Sensing Centre. He was responsible for assessing and monitoring vegetation cover, structure and trend across the state. This involved leading a team of remote sensing scientists to develop satellite monitoring methods to cover an area of 1.7 million square kilometres each year.  He is currently a Director and Lead Scientist with the World Preservation Foundation and a researcher on Beyond Zero Emission’s Land Use Plan as part of its ZCA2020 project.
  • The points that follow in italics are from his comments on the TED website in response to Savory’s presentation.
  • What Savory does not mention is that intensive (cell) grazing is only viable where water points are close and labour is cheap. Temporary or permanent fencing is labour intensive, moving herds daily requires far more labour input than most operations can afford.
  • Also absent is mention of the failure of traditional intensive grazing in Russia, Siberia, Mongolia, Kazakhstan, China and eastern Africa where large herds are constantly moved by traditional herders (as the Savory method does) – but sheer weight of livestock numbers has ravaged these landscapes in drought years, leading to more degradation.
  • China has gone to great efforts to reverse desertification, including the Great Green Wall, and is discovering that in marginal areas the most effective method is re-planting native perennial grasses, and removing all livestock – see http://www.chinadialogue.net/books/4772-Books-simple-ecology-complex-issues/en
  • Long-time Australian pasture agronomist and climate scientist Greg McKeon has coined the term “hydro-illogical cycle”, which is:
    - it rains, grass grows, graziers stock up
    - drought comes, graziers hold on to stock due to lower prices
    - drought continues, pastures are flogged, devoid of edible grass
    - government steps in with drought aid and permits to cut down trees that stock will eat such as acacias
    - rain comes, washes away the (unprotected) soil
    - cycle continues
  • This has led to a dramatic long term deterioration of soils and native vegetation – see http://www.longpaddock.qld.gov.au/about/publications/pdf/preventingdegradation.pdf .
  • Climate change – hotter, drier droughts, more flooding rains – will only accelerate the degradation of grazed rangelands.
  • The best aspect of Savory’s method is that burning is stopped. Burning is a very effective tool to stop forests re-growing, and half of Africa is high rainfall savannah, which will revert to forest if the burning were stopped – see http://www.nature.com/nature/journal/v478/n7369/full/nature10452.html. After a few years when herders see their grazing lands overtaken with trees, they will turn back to fire.
  • ‘Conservation grazing’ – http://theconversation.edu.au/can-livestock-grazing-benefit-biodiversity-10789 does work in the more temperate regions where rainfall and feed production can support the cost of fencing, but is not a cure-all as is proposed.
  • There is enormous potential in above ground and below ground carbon sequestration, but this will only happen when we stop burning the daylights out of grasslands for pasture management and to stop ‘woody weeds’; and when we remove grazing pressure.
  • You can hear an interview with Wedderburn-Bisshop on these issues here. It’s from radio station 3CR’s “Freedom of Species” program, and was broadcast on 7th October, 2012. The podcast can be downloaded from this page. The interview was also referred to in my blog post “Omissions of Emissions: a critical climate change issue“.
  • Here is an extract from that blog post: “The northern and southern Guinea Savannas in Africa have also been adversely affected by livestock grazing. As an example of an alternative approach to livestock in Africa, Gerard Wedderburn-Bisshop discussed the Kenya Hunger Halt program, administered by the World Food Program. Under the program, people have been taught to grow alternatives such as root crops.  The Maasai, traditional herders, have been converting to the program, growing nutritious crops and thriving.”
Sheep grazing in the Little Karoo region of South Africa near Oudtshoorn

Sheep grazing in the Little Karoo region of South Africa near Oudtshoorn

What do others say?

Blogger Adam Merberg has said (with direct quotes in italics):

  • Savory’s methods have found little support from mainstream science. The [February 2000 issue of Rangelands] included an article by Jerry L. Holechek and others, which attempted to review the evidence for a number of Savory’s claims. Their 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. Moreover, the research consistently indicated that “hoof action from having a large number of animals on a small area for short time periods reduced rather than increased infiltration,” seemingly contradicting a key assumption of Savory’s methods.
  • Regarding an experiment undertaken with Savory’s involvement in Zimbabwe during the 1960′s (“the “Charter Grazing Trials”), Savory said in 1983:  “The only trial ever conducted proved what I have always advocated and continue to advocate when livestock are run on any land.” In general, it is unlikely that a single study on a few plots of land will definitively prove a statement about “any land.” Moreover, while I haven’t seen the original papers (which were published in the Zimbabwe Agricultural Journal), Holechek summarized the published work in a later issue of Rangelands, finding relatively weak support for Savory’s methods. [Note: Merberg refers to a letter to the editor of Rangelands, published in June 2000, in which Savory claimed, "we could double the stocking rate on any land under conventional management, improve the land and make more profit".]
  • Holechek’s 2000 article also claims that Savory had “expressed doubt that holistic resource management could be validated experimentally.” While I was not able to find a precise reference for this claim, Savory did not deny it in his response, and elsewhere he has expressed some reservations about scientific testing.
  • That is problematic because the scientific method is what will tell us whether Holistic Management works. Savory would like us to graze more cattle to fight desertification and climate change, even as scientific evidence indicates that his “solution” will actually exacerbate these problems.
  • As Chad Kruger writes, “Being ‘unconventional’ is not, in itself, a problem, but when what you are arguing for is unconventional, you’d better ‘bring data.’”
  • In a review of Savory’s 1988 book Holistic Resource Management, M.T. Hoffman wrote “The apparent inconsistencies and lack of definitions (eg. for concepts such as complexity, stability, resilience, diversity and production which have a number of different meanings in the ecological literature), render it frustratingly difficult to compare his [Holistic Resource Management] approach with the broader literature.” Imprecise language doesn’t just make it hard to compare Savory’s methods with the existing literature. It also makes it nearly impossible to evaluate his approach scientifically because it allows Savory to blame any failures on a misunderstanding of the method.

[Please see the postscript below regarding additional articles commenting on Allan Savory's work.]

Something they all agree on

All those referred to in this blog who have touched on the issue agree that the biosphere provides enormous potential for drawing down atmospheric carbon, and that the burning that occurs for pasture management needs to stop.

Here are  images from NASA depicting the extent of burning in Africa during two ten-day periods from 29th July to 7th August, 2012 (right) and 1st to 10th January 2013 (left):

firemap-Africa-combined

Extracts of MODIS Fire Maps from NASA Earth Data

Some background from NASA on the MODIS fire maps:

“Each of these fire maps accumulates the locations of the fires detected by MODIS on board the Terra and Aqua satellites over a 10-day period. Each colored dot indicates a location where MODIS detected at least one fire during the compositing period. Color ranges from red where the fire count is low to yellow where number of fires is large. The compositing periods are referenced by their start and end dates (julian day). The duration of each compositing period was set to 10 days.”

Something they do not agree on

To a large extent, the fire regions shown above cover areas within the northern and southern Guinea savanna. Geoff Russell (refer above) has said that a roughly corresponding area shown by the vertical lines in this image “has an average rainfall over 780mm and would, according to Sankaran and the large number of other authors [of the cited Nature article], revert to some kind of forest if given half a chance. Its status as savanna is anthropogenic and not a product of natural attributes like soil type and climate.”

Gerard Wedderburn-Bisshop (refer above) has made a similar point, citing another Nature article by Jonathan Foley and colleagues.

On the other hand, Savory says: “Now, looking at this grassland of ours that has gone dry, what could we do to keep that healthy? And bear in mind, I’m talking of most of the world’s land now. Okay? We cannot reduce animal numbers to rest it more without causing desertification and climate change. We cannot burn it without causing desertification and climate change. What are we going to do? There is only one option, I’ll repeat to you, only one option left to climatologists and scientists, and that is to do the unthinkable, and to use livestock, bunched and moving, as a proxy for former herds and predators, and mimic nature. There is no other alternative left to mankind.”

A key difference between the alternative views is that Russell and Wedderburn-Bisshop have based theirs on peer-reviewed scientific literature, which is widely supported by other scientific sources. On the other hand (as indicated above), the scientific support for Savory’s approach appears scant.

Potential next steps

Adam Merberg (refer above) has suggested that TED apply some of its own criteria for “identifying bad science” in assessing the worth of Savory’s presentation. Those criteria include:

  • It has failed to convince many mainstream scientists of its truth.
  • Much of it is not based on experiments that can be reproduced by others.
  • It comes from an overconfident fringe expert.
  • It uses imprecise vocabulary to form untested theories.

Let’s hope that TED heeds Merberg’s call.

Postscript 19th September, 2013: Two additional articles commenting on Allan Savory’s work have come from Robert Goodland (referred to above) and James McWilliams. Goodland’s article is Meat, Lies & Videotape (a Deeply Flawed TED Talk) from Planetsave, 26th March, 2013, while McWilliams has written All Sizzle and No Steak: Why Allan Savory’s TED talk about how cattle can reverse global warming is dead wrong, published on Slate, 22nd April, 2013. Included in the McWilliams article are these comments about algal growth and desertification, a key aspect of Savory’s TED presentation: “Further weakening Savory’s argument for the wholesale application of holistic management to the world’s deserts is his distorted view of desert ecology. There are two basic kinds of deserts: genuinely degraded landscapes in need of revival and ecologically thriving ones best left alone. Proof that Savory fails to grasp this basic distinction comes when, during his talk, he calls desert algae crust (aka “cryptobiotic crust”) a “cancer of desertification” that represses grasses and precipitate runoff.  The thing is desert algae crust, as desert ecologists will attest, is no cancer. Instead, it’s the lush hallmark of what Ralph Maughan, director of the Western Watersheds Project, calls ‘a complete and ancient ecosystem‘. According to the U.S. Geological Survey, ‘Crusts generally cover all soil spaces not occupied by green plants. In many areas, they comprise over 70 percent of the living ground cover and are key in reducing erosion, increasing water retention, and increasing soil fertility’. Savory, whose idea of a healthy ecosystem is one with plenty of grass to feed cattle, neglects the less obvious flora – such as, in addition to algae crust, blackbrush, agaves, and creosote – that cattle tend to trample, thereby reducing the desert’s natural ability to sequester carbon on its own terms. ‘It is very important,’ Maughan writes, ‘that this carbon storage not be squandered trying to produce livestock.’”

Postscript 26th December, 2013: Another article criticising Allan Savory’s TED presentation was published on the Real Climate website on 4th November, 2013. Real Climate “is a commentary site on climate science by working climate scientists for the interested public and journalists.” The article, from ecosystem scientists  Jason West and David Briske and titled Cows, Carbon and the Anthropocene: Commentary on Savory TED Video“, stated: “It is important to recognize that Mr. Savory’s grazing method, broadly known as holistic management, has been controversial for decades. . . . We focus here on the most dramatic claim that Mr. Savory made regarding the reversal of climate change through holistic management of grasslands. . . . While it is understandable to want to believe that such a dramatic outcome is possible, science tells us 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.”

Blog Author: Paul Mahony (also on on Twitter, Slideshare and Sribd)

Livestock biomass chart:

Russel, G. Forget the quality, it’s the 700 million tonnes which counts, 17 Nov 2009, http://bravenewclimate.com/2009/11/17/700-million-from-livestock/, citing Subak, S., GEC-1994-06 : Methane from the House of Tudor and the Ming Dynasty, CSERGE Working Paper, http://www.cserge.ac.uk/sites/default/files/gec_1994_06.pdf and Thorpe, A. Enteric fermentation and ruminant eructation: the role (and control?) of methane in the climate change debate, Climatic Change, April 2009, Volume 93, Issue 3-4, pp 407-431, http://link.springer.com/article/10.1007%2Fs10584-008-9506-x

Images:

Sheep grazing in late afternoon sun near Oudtshoorn © Peter Marble | Dreamstime.com

MODIS satellite maps from NASA Earth Data, http://rapidfire.sci.gsfc.nasa.gov/firemaps/

References:

Archer, E.R.M., Journal of Arid Environments, Volume 57, Issue 3, May 2004, Pages 381–408, Beyond the ‘climate versus grazing’ impasse: using remote sensing to investigate the effects of grazing system choice on vegetation cover in the eastern Karoo“, http://www.sciencedirect.com/science/article/pii/S0140196303001071

Sankaran, M; Hanan, N.P.; Scholes, R.J.; Ratnam, J; Augustine, D.J.; Cade, B.S.; Gignoux, J; Higgins, S.I.; Le Roux, X; Ludwig, F; Ardo, J.; Banyikwa, F; Bronn, A; Bucini, G; Caylor, K.K.; Coughenour, M.B.; Diouf, A; Ekaya, W; Feral, C.J.; February, E.C.; Frost, P.G.H.; Hiernaux, P; Hrabar, H; Metzger, K.L.; Prins, H.H.T.; Ringrose, S; Sea, W; Tews, J; Worden, J; & Zambatis, N., Determinants of woody cover in African savannas, Nature 438, 846-849 (8 December 2005), cited in Russell, G. Burning the biosphere, boverty blues (Part 2)”, 4 Feb, 2010

Additional reference material will be inserted for the links contained in this article.

About these ads