This article first appeared on the author’s Terrastendo blogging site on 26th March, 2013.
At the time of writing, a recent TED presentation by Allan Savory with the title “How to green the desert and reverse climate change” had 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 is a link (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.
What do others say?
Blogger Adam Merberg has said (with direct quotes in italics):
[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):
Image: 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:
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.”
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
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/
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.
Paul Mahony is an environmental and animal rights campaigner who is trying to remove what he considers to be blinkers and blindspots in the community, resulting from social, cultural and commercial conditioning. You can find Paul on Twitter, Slideshare, Sribd and his own blogging site, Terrastendo.