Guest post by Jason West and David Briske
Allan Savory delivered a highly publicized talk at a “Technology, Entertainment, Design (TED)” conference in February of this year (2013) entitled “How to fight desertification and reverse climate change.” Here we address one of the most dramatic claims made – that a specialized grazing method alone can reverse the current trajectory of increasing atmospheric CO2 and climate change.
The talk was attended by many conferees and has since been viewed on the TED website over 1.6 million times. It has received substantial acclaim in social media, some of which is available at the Savory Institute website, but it has also received considerable criticism (of particular note is a blog post from Adam Merberg and an article in Slate magazine. Although these criticism quickly followed Mr. Savory’s presentation and are broadly supported by the available science, his sweeping claims have continued to resonate with lay audiences. An apparent example is his invitation to deliver a speech to Swiss Re during their 150 year anniversary celebration in London in September, in which he is quoted as saying “…only now due largely to my TED talk on the desertification aspect of the global problem, was the public becoming aware of such hope in a world so short on solutions…”.
As a result of the continuing discussion regarding this presentation, we felt compelled to interpret these claims within the context of Earth System science to facilitate broader discussions and evaluation. It is important to recognize that Mr. Savory’s grazing method, broadly known as holistic management, has been controversial for decades. A portion of this controversy and the lack of scientific support for the claims made for his method on livestock productivity and grassland ecosystem function may be found in peer-reviewed papers (e.g. Briske et al. 2008). This presentation, however, argued for an additional application to climate change.
We focus here on the most dramatic claim that Mr. Savory made regarding the reversal of climate change through holistic management of grasslands. The relevant quote (transcript by author from video provided on TED website) is as follows:
“…people who understand far more about carbon than I do calculate that for illustrative purposes, if we do what I’m showing you here, 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…”
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.
Approximately 8 Petagrams (Pg; trillion kilograms) of carbon are added to the atmosphere every year from fossil fuel burning and cement production alone. This will increase in the future at a rate that depends largely on global use of fossil fuels. To put these emissions in perspective, the amount of carbon taken up by vegetation is about 2.6 Pg per year. To a very rough approximation then, the net carbon uptake by all of the planet’s vegetation would need to triple (assuming similar transfers to stable C pools like soil organic matter) just to offset current carbon emissions every year. However, the claim was not that holistic management would maintain current atmospheric CO2 levels, but that it would return the atmosphere to pre-industrial levels. Based on IPCC estimates, there are now approximately 240 more Petagrams (Pg) of carbon in the atmosphere than in pre-industrial times. To put this value in perspective, the amount of carbon in vegetation is currently estimated at around 450 Pg, most of that in the wood of trees. The amount of carbon that would need to be removed from the atmosphere and stabilized in soils, in addition to the amount required to compensate for ongoing emissions, to attain pre-industrial levels is equivalent to approximately one-half of the total carbon in all of Earth’s vegetation. Recall that annual uptake of carbon is about two orders of magnitude smaller than the total carbon amount stored in vegetation.
At a global scale, grasslands are generally distributed in regions of low precipitation across a wide range of temperatures, with precipitation particularly limiting grassland productivity. Within a zone, grassland carbon cycles respond significantly and sometimes dramatically to fluctuations in inter-annual precipitation. This is because soil water is essential for vegetation to remove carbon from the atmosphere in the process of photosynthesis and it also drives variation in microbial processes that affect the loss of carbon from soils. Consequently, soil water availability represents a much greater limitation to maximum carbon storage in global grasslands than does grazing management. Grasslands represent approximately 30-40% of the planet’s land surface and only a fraction of annual global productivity and carbon sequestration (~20% of global carbon stocks). It is simply unreasonable to expect that any management strategy, even if implemented on all of the planet’s grasslands, would yield such a tremendous increase in carbon sequestration.
Humanity faces many challenging problems in this period of human domination of planet known at the Anthropocene. These problems, including that of climate change, require efforts to find solutions in all sectors of society and that we engage in diverse and dynamic dialogue about potential solutions, including those that may lie far outside the current mainstream. However, potential solutions must be assessed with a dispassionate and rigorous treatment of risks, benefits, and costs. We should pursue solutions that are most likely to succeed on the basis of scientific validity and societal acceptance . Extravagant claims like those in Mr. Savory’s TED video must be weighed against known physical realities to credibly serve society.
Rangeland management strategies appropriately emphasize conservation of previously stored soil carbon, rather than sequestration of additional carbon, based in part on the limitations previously described. Emphasis should be placed on climate change adaptation, rather than mitigation as advocated by Mr. Savory, to support the well-being of millions of human inhabitants. Mr. Savory argues that we adopt his grazing method as a simple solution to resolve a key Anthropocene contributor – the ongoing perturbation of Earth’s carbon cycle. The appeal of this claim to casual observers is enhanced in that it does not require humans to face any tradeoffs. The implication is that we can continue to use fossil fuels and emit carbon into the atmosphere because application of holisitic management on the Earth’s grasslands provides a ‘silver bullet’ that will sustainably solve the climate change problem and provide abundant livestock products as well. We would be thrilled if a simple solution such as this existed. However, it clearly does not, and it is counter-productive to believe that it does. Humanity must look beyond hope and simple solutions if it is to successfully navigate its way through the Anthropocene.
No doubt Bjorn Lomborg and the Freakonomics gentlemen will be running Mr. Savory’s strategies up the flagpole shortly…
If I’m understanding this right, grasslands currently store 0.2*450 Pg of carbon. That is 90 Pg of carbon. To absorb the outstanding 240 Pg of carbon, they would need to increase their carbon content 2.67 times – thus containing 330 Pg of carbon. That does certainly seem to be in miracle working territory.
Look, guys, can’t you just leave the facts out of it for a change? You’re ruining everything.
Thanks for this much needed correction. I have seen many otherwise fairly intelligent people be swayed by this talk on various blogs.
People are too easily wowed by such claims and miss the orders of magnitude that he is off in his claims of how much C could be sequestered versus how much is both being produced and how much excess needs to be removed from the atmosphere. I do think that grasslands can and must play some role in sequestering carbon. But, as you point out, there is no one solution to this predicament (if ‘solution’ is even the right term for anything that is possible at this point.)
Another way of comparing the potential carbon-sequestration contribution of grasslands to the expanding scope of the problem is to consider just one source that threatens to add itself to the equation: thawing permafrost.
There is more carbon in permafrost than in all life forms, twice as much as is currently in the atmosphere, and it accounts for about half of all organic matter in all soils, iirc. So to hope that grasslands by themselves could offset even some of this one looming source for atmospheric carbon is clearly (and unfortunately) not realistic.
What should be obvious to all by now (but obviously isn’t) is that we have to stop making the increasingly impossible problem even worse.
That is we have to end all mining of any more coal, all pumping of any more oil, and all fracking (or otherwise extracting) of any more NG, and we have to stop all this massive UN-sequestration of otherwise-safely-buried carbon as quickly as possible if not much, much sooner.
But I see scant indication of movement in that direction.
I particularly liked your closing line:
“Humanity must look beyond hope and simple solutions if it is to successfully navigate its way through the Anthropocene.”
Mere hope won’t cut it. I actually would like to see people embrace what I would call “post-hope environmentalism.” Not meaning that we embrace despair.
But that we recognize that hoping for silver bullets to save us or even to avoid major negative consequences of our continued and increasingly idiotic and destructive behavior is not a useful or realistic strategy.
Doing what’s right is doing what’s right, whether we can have a reasonable hope that everything will be ‘alright’ in the end or not.
The ability to remain grimly determined even in the face of overwhelming odds and with little or no hope of success is a deeply rooted ethos in Anglo-Saxon (and many other) culture(s) that needs to be tapped again.
It was perhaps best expressed in the Old English poem, “The Battle at Maldon” by words set in the mouth of a member of a small retinue of warriors whose chief had been slain and who were in the process losing a battle against Vikings who were about to overwhelm them. He said:
hige sceal the heardra heorte the cenre
mod sceal the mare the ure maegen lytlath
(Here’s the manuscript version: http://penelope.uchicago.edu/~grout/encyclopaedia_romana/britannia/anglo-saxon/maldon/maldontrans.html)
Which is something like: “Our minds must be that much firmer, our hearts that much keener, our spirit must be that much greater, as our strength diminishes.”
(Probably a good motto for facing old age, generally, come to think of it.)
Thanks again, and sorry for the digression.
It would actually be an even larger challenge than just to remove “now approximately 240 more Petagrams (Pg) of carbon in the atmosphere than in pre-industrial times.”
If we really do succeed in drawing down atmospheric CO2 concentrations, a maddening knock-on effect will be a reversal of the net flow of CO2 into the oceans. I.e. the ocean will become a net supplier of CO2 to the atmosphere… Sigh…
But yet another reason that grassland restoration, etc. is an insufficient (but necessary!) tool in the box…
Perhaps someone should buy him a subscription to ESD -oh, it’s open access – where we can read, for example, Becker et al., Lindeskog et al, or, in ESDD, Bowring et al., all of which might help illuminate the darkness…
Why is the whole article in italics? I kept wanting to get past the preface and into the body. [fixed the glitch -mike]
I always thought that plants absorbed carbon dioxide faster than we emitted it. I was convinced of this because the annual cycles in the Keeling curve are much larger than the smoothed growth is. Even though the ocean may absorb half of the carbon dioxide, I still find it hard to believe. (Not that this would the extravagant claims being made any more believable.)
> increase
Easy. Restore, for example, some English
Ah, the return of Allan Savory. What an unsavory development. I work for an agency that manages lands in the western US. Allan Savory first appeared in the 1980s with his “holistic management” which promised similar magic for western rangelands. Being a geologist this wasn’t my concern, but I’ve always been interested in larger land management issues so I paid attention.
Miracle, not so much: http://en.wikipedia.org/wiki/Allan_Savory#Criticism
I’m not surprised that he’s reappeared since I and other observers felt what Allan Savory was most interested in was, Allan Savory.
Forgive me if these are stupid questions. I am not a climate scientist, or any other sort of scientist, but I am a mathematician with a scientific mind. I read this website to become more acquainted with the science of climate change (I’m also attending Prof. Archer’s Coursera class on climate change right now), and because this website seems trustworthy to me as someone who doesn’t know enough about climate science to decide for myself who’s right or wrong about this subject.
As I was reading this article, my questions struck me when I read “the amount of carbon in vegetation is currently estimated at around 450 Pg, most of that in the wood of trees.”
My questions are:
Would any amount of reforestation of deforested areas be capable of absorbing the excess 240 Pg since pre-industrial times? If so, approximately how many acres would need to be reforested? What level of annual carbon release by fossil fuel use would be low enough to reasonably “offset” it’s use with reforestation on an annual basis? Is there enough forest land surface on the planet to significantly reverse previous carbon release and leave some room for annual offsets? Are offsets even realistic solutions at all, or does the carbon just release back into the atmosphere when the trees die and decay?
Many of the things I read about climate change seem quite dire. The idea of reforestation, combined with the minor potential of Allan Savory’s methods, combined with who-knows-what-other carbon sequestration techniques, and finally combined with reduced emissions seems like a possible solution to me, (albeit one with little hope of implementation since it seems humans cannot get our s**t together), but I’m not smart enough to know if it is at all realistic scientifically, or just false hope.
Thanks to anyone who has any thoughts for me, on any or all of the answers. I know there’s probably a dissertation that could be written answering those questions, so I don’t expect much. (Unless of course there is already a dissertation that’s been written… then please refer me!)
Kyle, asking about what amount of forest would remove all the excess carbon, is rather like asking what amount of grassland management would remove all the excess carbon.
The answer is going to be that it isn’t that simple, you aren’t going to manage everything that’s changed due to excess CO2 by doing one thing differently from now on.
Tree farms aren’t forests, for just one example; most of the carbon captured by a forest is moving through a complex ecosystem, not just standing there.
In the grief continuum I guess this leaves us at “bargaining?”
Kyle,
That kind of question was once asked on another forum. This is the answer provided by Mark Cochrane, a climate scientist:
While Savory’s obviously over optimistic, grasslands, depending on how they’re farmed, can be either a net carbon sink or emitter, ditto for forests.
The carbon isn’t being stored in the living plant matter, but in the soil, and the amount of carbon in 4″ of top soil (which is black because of that carbon) is going to be far greater than that in the plants growing in it.
Good posting, although to make the demonstration even more clear, it might have been great to summarize, at the end, by providing an estimated range of how much carbon sequestration can be realistically expected, assuming a hypothetical method that would allow for similar increases in carbon storage as is expected in Savory’s method (well, if he provides any numbers…)
I’m just puzzled by this: “Emphasis should be placed on climate change adaptation, rather than mitigation”
?? Is this really what you think?? Not only it seems misleading, but also it runs counter you call for “solutions in all sectors of society”.
[Response: We suggest an emphasis on adaptation over mitigation for grasslands in particular, especially where precipitation is relatively low, because they fluctuate annually between weak sources and sinks and the extensive management strategies applied have minimal effects on carbon balance. -Jason & David]
Thanks for posting this analysis. While there may be aspects of the Savory TED talk that have merit, I was puzzled by the claim that any grazing management system could somehow offset many decades of shuttling subterranean carbon into the atmosphere. It seems that the most we could hope to accomplish with grazing management is to return grasslands to their equilibrium state, with carbon levels at preindustrial levels in both the vegetation and the soil organic matter. I don’t see a agronomic technology in his talk that would exceed the carbon capture of preindustrial grasslands. So that still leaves 240 Pg of additional carbon to soak up somehow.
Grassland management may contribute to mitigation, but unfortunately, nowhere near the scale he suggests in his talk.
Savoury has been active in Australian agriculture for some time, although his influence has waned over recent years as many of his followers went broke. Most of his claims have been tested in rigourous independent trial work and found not to be true for temperate and subtropical pasture systems. These findings may not apply to the arid rangelands, but a long term trial in Queensland found it didn’t work in semi-arid rangelands. In short, he’s charismatic, but short on facts.
The criticism of rotational grazing is not so much that it doesn’t work but that it is not the only strategy for maintaining viable grasslands.
A later article by Briske among others notes:
“The scientific evidence refuting the ecological benefits of rotational grazing is robust, but also narrowly focused, because it derives from experiments that intentionally excluded these human variables. Consequently, the profession has attempted to answer a broad, complex question—whether or not managers should adopt rotational grazing—with necessarily narrow experimental research focused exclusively on ecological processes. The rotational grazing debate persists because the rangeland profession has not yet developed a management and research framework capable of incorporating both the social and biophysical components of complex adaptive systems.”
Origin, Persistence, and Resolution of the Rotational Grazing Debate: Integrating Human Dimensions Into Rangeland Research
The fact is that the maintenance and/or restoration of grasslands is a complex problem with a sociocultural components. In that sense, it is much like the problem of climate change itself.
Savory’s numbers may be wildly off but that doesn’t mean that restoration of grasslands in many areas of world would be of no benefit. It would certainly be of direct benefit to people living in those areas and would make perhaps a modest contribution to overall carbon problem. The same could also be said for reforestation efforts.
Since it does not seem likely that there will be ever a significant and deliberate effort to cut carbon emissions, it might be best to look for alternative solutions even if they solve only a part of the problem. Both grassland restoration and reforestation have good arguments in their favor besides whatever effect they might have on carbon sequestration.
Science! (per comment # 3)
http://smbc.myshopify.com/collections/frontpage/products/science-shirt
Cattle that grazed according to Savory’s method needed expensive supplemental feed, became stressed and fatigued, and lost enough weight to compromise the profitability of their meat. And even though Savory’s Grazing Trials took place during a period of freakishly high rainfall, with rates exceeding the average by 24 percent overall, the authors contend that Savory’s method “failed to produce the marked improvement in grass cover claimed from its application.” The authors of the overview concluded exactly what mainstream ecologists have been concluding for 40 years: “No grazing system has yet shown the capacity to overcome the long-term effects of overstocking and/or drought on vegetation productivity.”
http://www.slate.com/articles/life/food/2013/04/allan_savory_s_ted_talk_is_wrong_and_the_benefits_of_holistic_grazing_have.html
http://freethoughtblogs.com/pharyngula/2013/03/17/adam-merberg-on-grazing-and-allan-savory-and-ted/
Kyle,
Deforestation would definitely help. Much of the reason that atmospheric CO2 levels have not risen faster is the uptake by plant life. Different species of trees have different rates of CO2 uptake, but generally faster growth requires greater quantities of CO2. This also varies throughout their life cycle. In theory, this is possible. In practice, it may not be that easy. Any reforestation would help, and the higher levels cause trees to grow faster, using more CO2.
I agree that Savory is part of the problem, not part of the solution. The accumulation of CO2 is clearly a consequence of widespread earnest confusion and self-delusion on these matters.
People need to be able to think quantitatively at the planetary level. The skill is not especially difficult or sophisticated but most people lack it, and some of them, like Savory, make prominent claims that others believe. People ought to be able to calculate at the “spherical cow” level.
But I’d appreciate some help lifting some confusion of my own on two points. The first is basically that mentioned by Greg Simpson in point 7; the seasonal flux in biomass seems to exceed the background rate of change of CO2 in the atmosphere by a large enough factor that it probably exceeds the total emissions. This doesn’t prove anything about the capacity of the biosphere to hold that carbon indefinitely, but doesn’t it at least prove, as SImpson says, that is is possible for the biosphere to absorb carbon at a more rapid instantaneous rate than we are currently emitting it?
The second is related. How much carbon can be stored in the biosphere? Growing woody trees will not be fast enough, but there is also the soil reservoir. How much carbon can be maintained in soil? How deep can the soil layer get? How quickly can we reverse the depletion of surface soils and how carbon-rich can we make them?
There’s a fellow by the name of Rattan Lal at Ohio State that comes up with optimistic answers to these questions. He is widely celebrated by the biochar community, but he seems to be practically alone in academia making these claims.
I haven’t encountered a serious response from the earth science community. If we set about manufacturing soil, rather than just encouraging cattle to do their thing, would we have a sequestration strategy that might have positive side effects? Or is this just another case of getting the numbers wrong at scale?
Some journals are beginning to put older work online in searchable form, e.g. this.
Belowground cycling of carbon in forests and pastures of eastern Amazonia
Global Biogeochemical Cycles
Volume 9, Issue 4, pages 515–528, December 1995
first made available online 21 SEP 2012
DOI: 10.1029/95GB02148
Short answer from that, apparently a study from the early years of converting the Amazon to beef cattle: deforestation converting forest to unmanaged, unfertilized grassland loses carbon storage; conversion to managed, fertilized grassland increases carbon storage — compared to the original forest on the site.
No mention of biodiversity or longterm stability; one can hope they revisited the sites 20 years later and will publish a followup.
Couldn’t he have simply been refering to “pre-industrial [temperature] levels”, instead of carbon levels? (implying a simple misidentification of what ‘levels’ we’re talking about)
After all, considering the math presented, if the soil/foliage carbon capture is tripled such that it eliminates the net carbon emission into the atmosphere, the natural component alone will eventually take us back to the pre-industrial range.
@Kyle & others. No genuine question like yours is a stupid question. It shows you can think for yourself. Adding to other responses as a non-scientist myself, circa 1992 the planet was destroying (clear felling alone) 3,000 acres of forests per hour (?) if my memory is accurate. Every hour every day every year. Since then it’s not got any slower, probably increased +/- year to year. So imagine the shift required to simply replace what “natural forests” have gone in the last 20 years alone @ 3,000 acres per hour, before one even begins to absorb an extra Kg of CO2 from the atmosphere. Luckily the Oceans are absorbing (is it) 90% of CO2 emissions already. Um, hang on, that’s another problem. The sheer scale of this “issue” is very hard, nay impossible, to get one’s head around. Mine hurts! :) [corrections welcomed]
So how does one get to be invited to do a TED talk then? I thought having a clue and making some significant contribution were requirements, not optimistically punting non-solutions to distract the masses from inevitable disaster if we do nothing.
Here’a another critique.
As always, if it sounds to good to be true, the chances are it is.
As someone who has been vaguely a “fan” of Savory’s, I appreciate the reality check. (Me: not a scientist nor a cattle rancher, just one of those curious people out and about.) My comments only nibble at the edges, but anywho…
The first issue addressed in this post is that plausible carbon uptake could hardly keep pace with ongoing anthropogenic emissions. I don’t recall whether Savory said it in that particular TED talk, but I do recall him saying–either in writing or on a publicly posted video presentation–that addressing climate change requires a halt to the burning of fossil fuels. To treat his claims fairly, I think you need to use that as his starting point for what grassland sequestration could accomplish.
The post also points out soil moisture as a key factor affecting carbon uptake in grasslands. In Savory’s defense, much of his argument for his grazing method is specifically that it promotes retention of seasonal moisture in soils in arid grasslands. If he’s right (and yes, I noticed the link to research that he isn’t, but this is for sake of argument), then his method should, or at least plausible could, absent other mitigating factors, lead to increases in carbon storage in those grasslands–not necessarily at the scale he claimed on TED, but conceivably pointed in the right direction.
Finally, as I have understood the claims for holistic management, carbon sequestration occurs (to the extent that it in fact occurs) primarily in soils rather than in the biomass of the grasses themselves. Says http://www.nature.com/scitable/knowledge/library/soil-carbon-storage-84223790, soils hold 80 percent of the carbon in terrestrial ecosystems, and hold 3.1 times the quantity in the atmosphere. Granted, this doesn’t differentiate between forest soils and grassland soils (and any other categories). But it does suggest that the scales aren’t quite so off–framed this way, the question is whether it is plausible to convert that 3.1:1 ratio to something more like 3.5:1 (not calculated, merely a gut guestimation). Maybe still implausible… am I even right to think that this is a reasonable framing of the debate?
Well, for change, it’s good to see someone too excited about some solution that does take up some carbon (even if a lot less than he says). Usually we see no will at all…
As a farmer, my observations are that:
Converting organic forest soils to pasture releases substantial carbon, the ground is dried in the process and the organic matter that had been pickled in the wet acidic subsurface environment starts to rot.
Well managed pastures on mineral soils will grow the amount of topsoil.
Well managed means:
fertilizer: promotes pasture growth, the more you grow, the more available fort soil sequestration, in appropriate temperate climates pastures will grow over a kg dry matter per m^2 a year, most of that dry matter is carbon.
rotational grazing: this promotes pasture growth, when grass grows from low initial cover it draws on root reserves to promote leaf, set stocking will result in cattle preferentially grazing this fresher leaf rather than the older, lower quality, leaf, this will slow pasture recovery and lower leaf production.
Avoiding compacting of the soil: water is stored in the voids between soil particles, compact the soil with trampling and the rain will increasingly runoff.
Your stocking rate has to be matched to the available feed supply, otherwise disaster awaits.
So to me a lot of what Savory’s saying is nonsense.
Kyle, when you see a fact claim from Dan H. without a citation to a supporting source, it’s always rewarding to paste what he writes into the search box for Google Scholar.
Here’s an example:
http://scholar.google.com/scholar?as_ylo=2013&q=tree+growth+rate+CO2
Seconding Hank Robert’s point at 30: “numerous studies have concluded that the replacement of older forests with younger forests results in a net release of C to the atmosphere…” Nunery, Jared S., and William S. Keeton. “Forest carbon storage in the northeastern United States: Net effects of harvesting frequency, post-harvest retention, and wood products.” Forest Ecology and Management 259.8 (2010): 1363-1375. Also look for work by Olga Krankina and Mark Harmon (both at Oregon State).
I am another non-scientist follower of RC, but I’m a long-time forest management policy analysis, and I immediately picked up that comment 21 is not based on any science I’m aware of. The only way to make clearing and “reforestation” of forests work to significantly sequester CO2 over time is to harvest without using fossil fuels (no chain saws! no mechanical yarding or hauling!), and then stack the logs without processing it at all. About as likely as the only real “solution” to global warming–stop burning carbon (fossil fuels).
Peal Oil can’t come soon enough, painful as it’s going to be.
Did The Music Man ever play in Australia ? At least one of it Pacific neighbors seems bent on giving Savory’s agrarian Theory Of Everything some stiff competition in the credulity sweepstakes:
That de-linquent bug ate the URL behind your “some stiff competition” link there.
Sean,
The oceans take up about 90% of the excess heat that is the earth’s energy imbalance. They take up very roughly 50% of the CO2, not 90%. Of course, even with that proportion, the oceans are acidifying frighteningly quickly.
Whoops, I realised that my last post included an error. I said that the oceans took up, “very roughly 50%” of our CO2 emmissions. That is incorrect. The oceans take up the largest component but there are other CO2 sinks that, including the oceans, makes up the roughly 50% figure (actually a bit less, but it’s variable). I understand that oceans, themselves, take up about a third of our CO2 emmissions.
I agree with James Cross above (#18) that Mr. Savory’s ideas are constructive. He does not defend those ideas with data, but rather with demonstrated results which should be studied. Here, though, is an excellent argument for restoring grasslands, replete with data, given by Tony Lovell in 2009:
http://permaculturenews.org/2012/11/10/tony-lovell-on-soil-carbon-putting-carbon-back-where-it-belongs-in-the-earth-tedx-video/
The comments on the permaculture hosting site are also helpful.
#26 – Actually that critique is already linked to in the second paragraph of this post. It is a Slate article written by a professor of history.
Regarding various posts regarding converting forests into pasture, that has nothing to do with what Savory is proposing. Savory is about restoring plants and organic matter to soils that are depleted due to previous mismanagement- either over grazing or insufficient grazing.
I am not sure what Dan H meant. I thought he meant “reforestation” not “deforestation”. If he meant cutting down forest to create pasture, of course, that is a ridiculous proposal.
Savory is about management of relatively low rainfall areas that can support grasses but not forests or agriculture without irrigation.
Savory’s response to some criticism is that the comparisons between rotational grazing and continuous grazing that the study linked above does not actually study his holistic management method. The short duration rotational methods studied in experimental trials are, in fact, ones that Savory himself said would fail and are not his methods.
An article from a businessman and rancher who uses Savory’s methods explains this:
http://www.savoryinstitute.com/media/40675/Doing_what_works.pdf
Unfortunately, the rangeland solution falls into the category of the single silver bullet theory which is a shame. There are a variety of agricultural and land management strategies that could play a small but useful role. But it is magical thinking to believe that any one strategy can save us from fossil fuels and the damage they are doing.
Jonathan Teller-Elsberg:
http://www.nature.com/scitable/knowledge/library/soil-carbon-storage-84223790
Thank you very much for that most excellent link! I wasn’t aware of the nature.com Education site. What I’ve seen during my brief visit is exciting.
It’s easy after listening to Savory’s TED talk to agree, feel hopeful, and support the idea. It’s also easy to read RC, Slate, Briske, et al, and call Savory’s conclusions nonsense. Weigh each argument, check the notecards in your brain, find a few references,…. It may still be easy to draw a conclusion if Google leads you down one path or the other, or if you are predisposed…. I have ended up on the Savory path. Here’s why.
The math of soil carbon is that increasing soil organic matter by 1% means 0.58% carbon, but let’s consider 0.5% SOM. Determine bulk density or use a chart , e.g., http://www.sciencedirect.com/science/article/pii/S0016706111003247. Let’s use 80 lb/cuft. How deep is the soil measurement? Let’s use 6″. One acre = 43560 sqft, so 21780 x 80 x 0.29/100/2000 = 2.5 tons C/acre or X 3.67 = over 9 tons CO2/acre. Add subsoil increase and subtract CO2e for methane, and we have about 10 tons CO2 per acre in the soil. Topsoils can grow rapidly with good grazing, and there is a carbon subsoil profile as well. My five acre experiment with sheep doubled SOM from 1.5% to 3% in three years from seeding what used to be an Ohio soy field to pasture grazed two years, the second using a holistic grazing plan. The cost was about that of a down payment on a hybrid car, but had a much greater climate impact.
Consider that about a third of emissions are cycled into biomass and soil. ~12 GT CO2/yr are handled already. That leaves 24 GT. How many acres would it take at 10 tons CO2 per acre to have a positive impact. What percentage of the 12 bn non-forest arable land?
My first conclusion is that grass and grazing can be a rapid and massive mitigation tool.
There are many examples of restored landscapes. Water harvesting is one key. Sepp Holzer’s remarkable landscape restoration in Tamera, Extremadura, and elsewhere, creating waterscapes that maintain broadacre hydration, demonstrate this.
Grasses and animal impact can be another. Hooves break crusty soil allowing seasonal rains to penetrate, or they can create imprints that plant seeds, hold water, bend dead grasses and mulch them, allowing grasses to germinate and grow. This site has several examples of successes — http://www.ecoresults.org. Savory’s Africa Centre in Zimbabwe is another. Ian Mitchell-Inness is a highly successful HM rancher in South Africa. Greg Judy and Cody Holmes (who gets astounding soil carbon numbers btw) get great results in Missouri.
Pasture cropper Colin Seis plants annual grain in his sheep pastures, and gets the same yield as conventional at a fraction of the cost. The last report I heard was that his best numbers on his 2000 acres were above 30 tonnes CO2 sequestered per hectare per year. It’s a successful method. There are now 5000 pasture croppers in Australia.
My second conclusion is there are many successes that demonstrate the viability and potential of the method.
The third thing I look at is how it fits with respect to climate and planetary destabilization factors. CO2 emissions are only part of the issue. Carbon is part of a cycle, and good grazing management is part of that. There are two other facets. One is geophysics. Measure bare earth temperature on a sunny day, compared to grass or tree leaves. Higher temperatures mean more IR re-radiation, proportional to the absolute temperature to the fourth power. Yes, fourth power. Subtract albedo first, but this is still significant. More water is held in covered soil than bare. Trees transpire water and provide cloud and droplet nucleating compounds and microbes. The 540 cal/gram of evaporated water removed is released in the upper troposphere, where some of the heat released can be radiated into space = net cooling effect. More green can affect all of these factors which contribute to warming.
The other facet is that our earth problem is more than climate change. Extinction and desertification are majorly decreasing the livability of our planet. We need much more life to reverse this trend. Annual agriculture is destructive and consumptive. Perennial systems have many advantages here.
Conclusion — grasslands and forests are an important part of planetary stability. More is good.
Holistic management is a decision making framework. The tools, guidelines, and procedures used are up to the manager. Feedback may say that a method isn’t working. A water harvesting technique or grazing style may be damaging. Then work through the planning process again. Circumstances change, so adaptive management is key.
There are a number of defenses of HM and rebuttals to Briske and others. See, for example, http://planet-tech.com/allblogs.
If there are successes and failures, and the successes are potentially positively earth changing, we need to look at why successes and why the failures, and work to increase the success rate, not dismiss the method out of hand. That hurts rather than helps. Visit some of the successes. Try your own experiments. This is a potential earth-changer.
The survival or human, and maybe all, life may depend on how well we manage. Let’s learn from this and apply it as broadly as possible. The ultimate success will depend on our willingness to earnestly pursue a path of regeneration of life and systems that sustain it.
Thanks Tony Weddle and everyone else for your responses. You’re helping my pea-brain wrap around the immensity of all of this. I know there is no silver bullet, but I’m wondering if a barrage of (metaphorical) lead ones (trees, grassland management, whatever other geoengineering project there is) all aimed at carbon emissions, might offer some hope. If only, right?
#40
Great post.
Links at planet tech are good.
I am still struggling with the numbers:
Savory writes this:
“If we were to capture 1 ton of carbon per acre per year on the roughly 5 billion hectares of grasslands worldwide, we would remove 12 Gt of C from the atmosphere per year, that is, 6 ppm annually. If gross soil sequestration were approximately 6 ppm/year, after subtracting current annual carbon emissions of 2.5 ppm/year net sequestration would be 3.5 ppm per year.”
I am trying to reconcile the 8 and 2.6 petagrams in the post with Savory’s numbers and with your 12 and 24 GT numbers.
Can you clarify?
Toby,
I think you misunderstood Kyle’s original question (#10) and my following response (21). We are talking about harvesting forests as a means to increase carbon uptake. The question centered around the possibility of atmospheric CO2 removal by planting more trees. Check data on the Keeling curve. The seasonal CO2 decrease exceeds the annual increase. Image the change, if the numbers of trees doubled.
The existing anthropogenic excess of atmospheric CO2 is self-evidently already causing dangerous warming so we do need to draw it down to preindustrial levels as quickly as possible.
Savory’s proposal seems dubious but I have seen other studies which show that organic agriculture and reforestation can sequester large amounts of carbon in soils and biomass — and of course they have other benefits as well, for biodiversity and human health. So I think we should pursue those approaches as aggressively as possible.
However, carbon sequestration, by whatever means, should ABSOLUTELY NOT be regarded as a way to “offset” or “reduce” ongoing GHG emissions, or as an alternative to phasing out fossil fuels.
We still need to end ALL anthropogenic GHG emissions as soon as possible — AND we need to beging drawing down the excess CO2 that we have already put into the atmosphere.
Savory also ignores cattle methane. Consider Australia. We have more cattle than people and even more sheep. About 30 million cattle and 80 million sheep. They produce about 3 million tonnes of methane annually.
Using Shindell’s figure of the GWP of methane over a 20 year period of 105:
https://www.sciencemag.org/content/326/5953/716
This makes 3mt of CH4 equal to 315 tonnes of CO2 over a 20 year period. In addition, the practicalities all over the planet are that its cheaper and easier to just knock down more trees when you want more pasture rather than muck around with labor intensive new methods. So in Australia our cattle producers have averaged about 69 million tonnes of CO2 from converting forests to grass every year since 1990 (National Inventory 2010, Vol 2, table 7.2). Taken together this is rather more than double the 169 million tonnes of CO2 coming from our coal fired power stations.
Kyle, in mid to upper latitudes where snow is a factor, trees can actually have a fairly significant local warming effect.
Relevant: http://www.yaleclimatemediaforum.org/2013/10/strange-bedfellows-climate-change-denial-and-support-for-geoengineering/
My money* is on converting from corn and soy to woody crops: see Woody Agriculture: Badgersett’s 2013 MIT Climate CoLab Presentation
___________
*I’ve been supporting Phil Rutter’s work for decades; he’s an old friend.
#45
Geoff, I think your example may be misleading. Given the short life of methane, current emissions are at least partly replacing emissions from the previous decade that were subsequently reduced. As a result, a stable population of ruminants need not increase the stock of atmospheric methane over time (or the associating forcing). In contrast, the CO2 emissions emitted by a coal plant represents a cumulative contribution to the atmospheric stock of carbon.
Comment by Dan H. — 6 Nov 2013 @ 4:00 PM
Harvesting trees releases all their carbon fairly quickly which will not be sequestered by new growth for many years.
Steve
Re- Comment by Geoff Russell — 6 Nov 2013 @ 4:46 PM
Where do you think that the methane from cows or sheep comes from? It comes from grass that removed the CO2 from the atmosphere for growth (I am not talking about CO2 from the use of fertilizer derived from fossil fuels). Methane only lasts a short time in the atmosphere (relative to CO2), and that from sheep burbs and cow pies are a wash because you have to subtract the carbon that was first removed from the atmosphere.
Steve