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RedBaron at 15:07 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
OK great. Now for an even bigger factor, pore space in the soil. This is the habitat the actual methanotrophs colonize. As that surface area increases it both increases the habitat for the methanotrophs and increases the flow of methane from the atmosphere to them by increasing the aeration of the soil. The entire soil food web including all the animals, worms, plants, fungi, other soil biota etc can either positively effect that pore space or negatively effect it. As a general rule the more living biomass, the more improvement in soil pore space. Every bit of that living biomass has it's role to play from the predator to the herbivore to the plant to the soil biota. The role of the ruminant is to rapidly start the break down of plant material that is resistant to decay. By rapidly starting that process, which is finished by other trophic levels, it increases that cycle rate, increasing the growth rate of all. A ruminant can do in a day what would take at least a month or more to happen without the cellulolytic microbes found in a rumen, and they leave plenty of food available for everything else. This is why they are superior at soil building to other types of herbivores. The emergent property is that even though the emissions increases, so does sequestration, compared to the biome without a ruminant to start that process of decay. Now it doesn't actually need to be a ruminant, but the advantage a ruminant that makes them even better is that they actually extract comparatively little from that forage. When they start the process, there is an abundance of energy still available for the other trophic levels by compareson. That filters all the way down through the entire soil food web, including those parts responsible creating pore space.
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scaddenp at 13:40 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Okay, I agree that you get more methane oxidation from soils closer to the animal. That still doesnt deal with issue that amount of oxidation/absorption is small compared to emissions. Assuming no methane capture at all in feedlots, that would increase net methane by 1% cf to same animal in grasslands. (Actually more complex than that because feed is different).
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RedBaron at 12:53 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
OK I will walk you through it. From the previous review I gave you: ROLE OF MICROORGANISMS AS CONTROLLERS OF TRACE GAS FLUXES.
"In most upland soils, CH4 production is usually absent or marginal and the CH4 flux is dominated by CH4 oxidation."
Then a discussion about why and exceptions. Then:
"The subsurface location of methanotrophs means that energy
requirements for maintenance and growth are obtained from
CH4 concentrations that are lower than atmospheric."By Fick's laws of diffusion methane from a higher concentration will move to the lower concentration. There it will be used by the methanotrophs for energy requirements, keeping the concentration low. So there is a steady flow unless blocked in some way. Upland soils are generally well aerated. Of course management can effect this, but generally where there is a healthy population of earthworms, arthropods, insects etc.... the soil will be well aerated. So in those healthy soils you have a flow from higher methane concentration to lower methane concentration. As long as the other environmental factors don't restrict it, the methanotroph population will grow rapidly as the flow of methane increases, increasing biotic oxidation proportionately.
But as wideEyedPupil observed, spacial relationships do matter. You can get a flow from the cow to the soil if the cow is right there. Even easier to get a flow from the manure since it is even closer. But you cant get much of a flow from many miles down the road at the feedlot. Also locally at the feedlot, the large concentration of animals constantly there overwhelms the ability for those soils to keep up.
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scaddenp at 11:53 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Hmm, well firstly, the soil doesnt actually remove much of the airborne methane anyway according del Grosso. Secondly, methane becomes very quickly well mixed gas so soil around the feedlot would do it's bit. I am not convinced that grasslands with ruminants were ever net sinks for methane. CO2 equivalents, yes, thanks to increase in SOC from plant material, but not for just methane.
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RedBaron at 11:20 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@wideEyedPupil
Absolutely I agree with you observation that spacial relationships matter. Now go from 8" to 8' to 80 miles and you see the problem with the feedlot production model and why what was a methane sink turned into a methane source. One can understand the enteric methane emissions mixing with the atmosphere near the soil surface, but remove those animals from close contact with the soil and you break the link. For the grazer/grassland biome as a whole to be viewed as a sink, those grazers absolutely must be in direct contact with the grassland. What does escape due to being lighter than many other gasses in the atmosphere and diffusing upwards, subject to abiotic oxidation. But in a feedlot the majority of emissions do count as a source. So I am not disputing the IPCCs view currently, only adding the refinement that shows how this can be changed.
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wideEyedPupil at 10:54 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@redbaron
8" —> 8 feet
you are climaing that in this study you refer to and I'm yet to read that all enteric fermentation dervived methane never enters the atmosphere because it is locked up in soil biota (given a particular pasture managmanet system). Methane being a gas that is lighter than many other gases in the atmosphere it's going to rise, to suggest that 100% is trapped in the soil when it's being breathed out ~1 meter above the soil is counter-intutative to me. I use that phrase because I'm sure it's music to *your* ears :-) -
scaddenp at 10:53 AM on 9 December 2015There is no consensus
What you should be looking for is "stratospheric cooling". It is not an easily understood concept, but there are several attempts around the internet to explain it. At basic level, It falls out of the equations for radiative transfer if you increase a greenhouse gas. Other forcings that change the surface temperature like changing albedo, solar influx, or aerosols do not produce this effect.
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scaddenp at 10:43 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Redbaron, this still avoids the main points.
1/ microbial soil activity in changing CH4 is insignificant compared to enteric emissions. The very highest rates of CH4 soil oxidation measured by Del Grosso are still an order of magnitude less than ruminant emissions. 2 orders of magnitude for grassland. Are you disputing that measurment? Your reference appears to be hopelessly dated compared to modern sources (eg see the methane cycle in the IPCC from 3rd report onward and the references from which this table is based).
2/ If you want to argue for soils being significant in sinks, then SOC must be demonstrated to be increasing. No matter how complex the interactions going in soil/atmosphere, if SOC is decreasing, then soil is not a sink. Furthermore soil oxidization only accounts 5% of methane destruction so hardly a "controlling" influence.
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wideEyedPupil at 10:42 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@redbaron
thanks for the responce. I'm quite aware of emergent behaviors in complex systems (and the modeling of such phenomena in theoretical computational simulations), and the general complicatedness in addition to the complextiy of soil biota and any biological systems above the ground that might be active on it and therefore interacting with biota.
as someone challanging the dedicated work of the Land Use Plan that puts land use sector at 55% of emissions (and I've never heard that number challenged in the literature) i think the onus is on you to demonstrate any complexity that undermines 55% of total emissions with data and evidence — the rallying of phrases like emergence, complexity and reductionist science is no doubt music to my ears but data and specifics it is not.
you seem to find a way to build condencension into every second para but what I want to see is evidence, not defensive assessments of whether or not I 'get' your riddles. I understand the importance of soil biota and not destroying the surface vegetation in protecting the soil biota. I understand that your exmaple of ten fat cows and five skinny cows is designed to impress on one the problem of overgrazing (even though intensive over-grazing and recovery is exactly what Savory advocates so you gloss that detail too) but you forgot to I've read a tiny bit of everything from Masanobu Fukuoka's "The One-Straw Revolution" to Permiculture One to sitting in some of Dr Eliane Inghams (USA/Australian biota and fungi expert) online lectures and watched "One-Cow One-Planet".
I've visited many properties where overgrazing is a conceeded fact and others where the reverse is happening e.g. a biodynamic berry farm where the green manure crop of barley was reaching 8" high and still growing. It's clear increasing soil health increases 'carrying' capacity of the land when bio-diversity is encouraged in principle at a sytems thinking level rather than reductive Green Revolution type ag-disaster industrial farming.
But all that is not a substantive proof that methane is neutralised nor is it evidence that intensive grassing on rotational basis is vastly more productive, or indeed that animal intensive agriculture is a prefered responce to climate change. I'm reading a lot of commentary and philospohising in your posts and not much science. Thanks for the references I'l attempt to comprehend the work and get back to you on the science. -
RedBaron at 10:19 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
I guess maybe where you are struggling is the concept of soil microorganisms as a controller of atmospheric trace gasses. Without that foundational understanding, any new studies lack the contextual relationship for you to understand. So to help you understand, I found an old review from 1996 that explains what we knew and didn't know about how soil biology controlls atmospheric trace gasses at that time. This maybe will give you the context needed to understand how new discoveries are unlocking the mechanisms by which the grazer/grassland biome taken as a whole functions as a methane sink and not an emissions source....managed properly of course.
Soil Microorganisms as Controllers of Atmospheric Trace Gases
(H2, CO, CH4, OCS, N2O, and NO) -
wideEyedPupil at 10:11 AM on 9 December 2015There is no consensus
Thanks for Responce @Rob P and for the link to Climate Cluedo. I get that carbon isotopes are critical in determining CO2 sources and ways of determining concentrations but my question speicifically was what is it about a cooling upper atmosphere in conjunction with a warming lower atmosphere that is unique. Another way to ask this might be, why is the upper atmosphere cooling with increased GHG levels while the lower atmosphere continues to rise at a sharp rate compared to background seasonal oscilations? And how do we know that in the past when the lower atmosphere warmed, so to did the upper atmospthere, or did it just stay the same. (I only found three hits on the Cluedo page when searching "upper atmos" and they were all in comments. no hits for "lower atmos")
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scaddenp at 09:43 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Michael, I suspect the amount of time that you have available for animal management might be the overriding factor. Sheep need shearing (which is plus if you can get more for wool than cost of shearing), but fattening a few lambs might be good option. Goats climb and like eating things other than grass...
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scaddenp at 09:36 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
RedBaron, I am not disputing the reference. The release of methane to the atmosphere from agricultural use is mostly a/ paddy fields (where there is no oxidizing layer) b/ Enteric emissions from ruminants (nothing to do with soil microbial activity) plus some from manure.
I am just failing to understand how you are linking this idea to position that increasing ruminent intensity even on MIRG isnt putting more methane into the atmosphere. If microbial activity is binding more carbon into soil, then it should show up in SOC measurements. Mostly, we see the reverse - intensity = less SOC, or that enteric emissions overwhelm increased SOC.
And dont forget that areas with increased SOC are counted in GHG inventories. It's not like GHG emission strategists have missed something.
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RedBaron at 08:46 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
You are definately missing the boat on methane. The reference says even though there was a "dramatic" increase in methane produced, "none" was released to the atmosphere. So other studies that simply measured emissions failed to account for this emergent property. Also I am well aware that current methods of agriculture most commonly used do release methane to the atmosphere. The reason I showed that the natural ecosystem functions as a sink, is because ecoagriculture uses biomimicry to mimic that ecosystem function already evolved in a natural ecosystem (grazer/grassland biome) in order to change what is currently an emissions source into a sink as well. A sink that self regulates. ie when when production of methane increases, none releases to the atmosphere because the biotic reduction of methane also increases. Go back and read that a little closer please. "Nevertheless, no CH4 was released". This is the perfect example of an unexpected emergent property of the system. And do keep in mind we are talking about aerobic soils managed in a certain way. They exchange gasses with the lower levels of the atmosphere ie they "breathe". The CH4 goes into the soil, but none is released. That's why it can be viewed as a sink under those conditions.
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michael sweet at 08:42 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Scaddenp and Fool on the Hill,
Thank you for your interesting comments and references. I will have to think about methane and see what I can do to minimize my emissions. I have about one hectare of land that would support one or two cattle without suplimentary feed (or a comparable number of smaller animals). Currently there is a sizable population of rabbits that the local coyotes eat.
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scaddenp at 07:10 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
RedBaron, firstly we talking about effect of farming. The effect of grassland expansion on climate in Cenozoic is not that relevant compared to even pre-industrial farming.
If I understand you correctly, you are now saying that CH4 production from increased ruminant density is offset not only by SOC increase (yet to be demonstrated) but also by changes to CH4 sources/sinks in microbial soil activity? My first reaction is to be highly skeptical since biogenic methane budgets are estimated both top down and bottom up. While there is imperfect closure which might be accounted for from microbial changes, this cant be very significant.
Assuming I have understood your argument correctly, I do not really see support for this in your papers. "Methane fluxes from differentially managed grassland study plots: the important role of CH4 oxidation in grassland with a high potential for CH4 production" looked at changes with different fertilizer and water but as you stated, it found no increase in flux due to oxidation in top layer. How does this support your thesis of "large enough to completely offset the CH4 produced"?
The fluxes measured in the experiment are tiny compared to enteric emissions (0.0017g CH4/day cf 140-160 dry cattle).
Methane uptake in upland soils is acknowledged as a sink but the paper suggests to me that this capacity would damaged by agriculture. Indeed, it references del Grosso which surveyed methane oxidation across upland soils and concluded: "The soils used for model testing showed a clear division in CH4 uptake rates among biomes. Grassland and agricultural soils had the lowest annual CH 4 uptake (<1.5 kg C ha-1 yr-1), coniferous and tropical forests showed intermediate CH 4 consumption (1.2-3.5 kg C ha -1 yr-1), and deciduous forest soils had the highest CH4 oxidation rates (4.5-10 kg C ha-1 "
Note also that enteric methane production is at least an order a magnitude greater than highest oxidation rate.
I dont want to be critical of MIRG, especially compared to grain feedlots, but certainly dont see this as answer to CH4 emissions.
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scaddenp at 06:22 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Michael Sweet, I looked at this quite a while ago and thought that for same amount of forage, production of methane per hectare was pretty similar between sheep and cattle. However, a review paper here suggest greater differentiation than this, with 10 sheep = 1 cow (and less CH4 from manure). This paper based on identical feed gives cattle lower, (8 sheep = 1 cow). I dont have figures for goats easily to hand but I remember them as being very similar to sheep. That said, there are very considerable differences in management of the 3 species for a small lot! Of course you could also look at rabbits or guinea pigs which are much better than ruminants ( but with completely different management and harvest issues).
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RedBaron at 01:57 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@wideEyedPupil several posts
Your posts while thoughtful and well referenced do hilite the limitations of applying reductionist science to complex self regulating biological systems. Some of the things you talk about do partly take into account some of the unexpected emergent properties of the system, and some view it quite linearly. You really do need to be careful how you build back the reductionist science into a systems view.
Also you answered the riddle wrong, which means you haven't thought that out correctly either. So lets start with that. Overgrazed land produces less forage, less forage means it supports less animals, thus the correct answer is the overgrazed land is the one with 5 skinny cows. Properly managed land produces more forage. Much more. in the field we see 3X more forage, maybe 5X more forage, maybe more, it really depends how badly the land was overgrazed to begin with. The worse it was, the more improvement to be gained by proper management. So more forage means it supports more animals. The 10 fat cows are on the properly managed land in the riddle. I know it is counterintuitive, but once you think it through, hopefully you will understand.
Next, you said, "It's a while since I read it but because I was working with the principle authors I'm aware that they found sufficent evidence for them to reject the hypothesis often possed ... that oxidation of methane by water vapour above grass neutralises the effects enteric fermentation"
That's not the hypothesis, so rejecting that hypothesis doesn't really get you anywhere. That is describing abiotic oxidation. The hypothesis is the soil biota increases, including but not limited to methanotrophs. Increases in methane, in the right environmental conditions causes an explosion of methanotroph populations, and that is what biotically reduces the methane. Those environmental conditions that lead to the explosion of soil biota populations, including but not limited to methanotrophs, being enhanced in a properly managed grazing system. It's biotic, not abiotic.
Next you said, "Nobody has replicated the Savory assertions in a commercial livestock operation any place in the world in a study that can varify the claims around sequestration."
That isn't true. Maybe the ZCA Land Use Report couldn't find anything, but that doesn't mean it doesn't exist. I even posted one here that included several commercial scale ranches. At least I think I did. Just in case, here you go: [1] There are more even larger, but I don't think they have been published yet.
Next you said, "You make this assertion liberally but I can't find your citation 'up above', yet."
No problem. I repeated that citation and added some new in post #84, since people were having problems finding and/or understanding.
Next you said, "the technology to reduce the enteric fermentation in your cattle does exist, fed them some grain. various studies have looked at this and other inteventions. of course the grain also has emissions associated with it and if synthetic fertlizers have been used destruction of the soil biota and therefore short term carbon cycle is part and parcel their use."
This indicates to me you almost kinda understand. Just use that type of thinking, but expanded to include a wider array of emergent properties and interactions. More variables change than just the ones you mentioned and they all have interlocking interdependencies.
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Zambrall at 01:12 AM on 9 December 2015Analysis: the key announcements from Day 1 at COP21
I think that Obama is trying to do great things in the word like trying to help poor countries around the word. But he has not done anything in all time all he is doing is just sitting in the white house in his big chair and just watching the bad things that are happening to our country and not doing anything about it! So like my mom said that she can't watie untill obama is not the president any more. Did you know that my brother Robert is woring for him! That thing that had happen in paris I heard that he was just clebreating that he had just bomed the place were the bad people are and that is why the bad people had bomed paris. My mom also said that the only reason why they are doing this and hurting people is becasue Obama is a mulism. So why isnn't Obama doing anything to help our country.
Moderator Response:[PS]
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Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
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wideEyedPupil at 00:50 AM on 9 December 2015There is no consensus
One of the human finger prints cited in the first week of the Denial course was that the atmospheric warming this century is unique in the fact of warming lower atmosphere and cooling upper atmosphere. What evidence from past warming episodes establises that this is unique to the current warming. How do we know what happened in the upper stmosphere in the past warming/ increased CO2 events?
Moderator Response:[Rob P] - A cooling upper atmosphere and warming lower atmosphere is a signature unique to the enhanced (increased) Greenhouse Effect. If we had a Tardis, we would be able to go back in time to the Paleoecene-Eocene Thermal Maximum (PETM) about 55-56 million years ago, a time of substantial natural global warming, and observe the Greenhouse Effect growing stronger.
The enhanced Greenhouse Effect we are now measuring is a human fingerprint because the source of it is the continued emission of greenhouse gases, primarily carbon dioxide, produced by industrial activity. See the SkS post: Climate Change Cluedo.
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wideEyedPupil at 00:43 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
#78 foolonthehill
the technology to reduce the enteric fermentation in your cattle does exist, fed them some grain. various studies have looked at this and other inteventions. of course the grain also has emissions associated with it and if synthetic fertlizers have been used destruction of the soil biota and therefore short term carbon cycle is part and parcel their use.
I recommend you download the (free) Zero Carbon Australia Land Use Plan as it covers every aspect of Land Use emissions and sequestrations in what I would describe as great detail for anybody who doesn't study emissions in ag system. -
wideEyedPupil at 00:27 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
#69
I would like a reference to that paper you refer to that demonstates ruminet ag is a net sink not a net source of emissions. Many permaculutralists repeat this assertion as an article of faith, so it's not like its a new one for me but I've never seen the convincing evidence and plenty to contradict it.
You make this assertion liberally but I can't find your citation 'up above', yet.
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wideEyedPupil at 00:24 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
#69
Every vegan I ever met except one was completely incapable of making the connection. But this is what needs to happen to turn agiculture from the net emissions source it is now to a net sink. It is also what needs to happen to reduce the deforestation that is happening to support animal husbandry.
I wonder if that's because you make a dubious anaolgy with ten fat cows and five skinny cows and make no attempt whatsoever to decribe any mechanism by which the overgrazing leads to fatter cows! Have they been there longer, were they rotated through fields, so many variables in farming and you talk of riddles. I assume you are attempting a paraphrasing of the Savory assertion, yet to confirmed with science in any commenrical farming system anywhere in the world.
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wideEyedPupil at 00:11 AM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
From the systems science POV, when you remove the animal from the pasture and put them in a confinement system, you break part of the methane cycle, causing a nuanced chain of interactions with soil biota, quantifiably decreasing ecosystem function. Net result? You turn a net methane sink into a net methane emissions source. So it is very important to be very precise when discussing "intensive" agriculture. Managed Intensive Rotational Grazing is an intensive agriculture, but is very different than intensive agriculture reliant on expensive AGW causing inputs. Properly done, MIRG can actually help mitigate AGW, not cause it.
@RedbaronZCA Land Use Report specifically rejected this Alan Savory type argument. they found that dietry interventions can reduce methane emissions significant;y, but only can be used in lot feed systems, I've recently read that studies by diary industry have found that small amounts of grain feed eaten in the milking shed or afterwards can reduce enteric fermentaion by some significant amount but not entirely. Another thing they point out about Savory's assertions is that if you had farm workers moving temporay fences every day it would remove profitibility from the vast pasteral operations with large head counts that rarely see humans let alone get daily management in small mobile herds. Nobody has replicated the Savory assertions in a commercial livestock operation any place in the world in a study that can varify the claims around sequestration.
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wideEyedPupil at 23:58 PM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
The Zero Carbon Australia Land Use Report published by Beyond Zero Emisisons and Melbourne Sustainable Society Instititue (University of Melbourne) pegged Land use emissions at 55% (using 20 year GWP) of Austrlia's national GHG emissions once complete examination of all flows of emissions and sequestration are accounted for. Their methodology went well beyond the methodology of UNFCCC specification that is typically used for these accounting exercises. Even using 100 yr GWP (which tends to obscure the effects of methane on a climate system that is already set for very dangerous weather) the emissions will approact 50% within years on present trend.
It's a while since I read it but because I was working with the principle authors I'm aware that they found sufficent evidence for them to reject the hypothesis often possed (the source of which is apparently a paper that contained an magnitude of ten error) that oxidation of methane by water vapour above grass neutralises the effects enteric fermentation (highest in pasture fed ruminets not lot animals as someone here seems to be claiming). Most cattle in Australia are lot fed for the last year or two of there lives to increase their weight for profit motive. They also rejected what is often refered to as the Alan Savory method by permiculutre types who like to think that zero emssions ruminent production is realsitic proposition. Of that 55% of national GHG emissions, emissions associated with livestock were calculated to be 90% i.e. 50% of national emissions associated with livestock production. Major emissions sources were land clearing, savanana burning and enteric fermentation.
The Land Use Report began a feasibility study of what kind of reforestation would be requierd in each IBRA Sub-region to offset the emissions assoicated with the predominant agriculutral use for the region.
it's interesting to me that this area of climate science is both one fo the least studied and one fo the most heatedly contested amoughst scientists and others who otherwise accept the general IPCC positions on human induced climate change (even if some of us think the IPCC has been ultra conservative in it's communication of the science).then you have scientist like Dr Elaine Ingham who claim vast potential for organic sequestration if we stoped killing our soils with synthetic fertilizers and exposeur to the sun. by vast she claims equivilent contemproaraeous to human emissions.
my understanding is that the ZCA Land Use Report was supervised within MSSI and peer reivewed, though its publication was by BZE and MSSI not in a journal.
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Tom Curtis at 23:25 PM on 8 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Further to my post @48, based on Figure 9 of the IPCC FAR (below), the increase of temperture in 2015 relative to 1990 is 0.7 C for scenario A (BAU), 0.5 C for scenario B, and 0.4 C for scenario D. These in turn correspond to trends of 0.26, 0.18 and 0.17 C/decade respectively. The Gistemp trend from 1990 to current is 0.169 +/- 0.066 C per decade, ie, closest to scenario D but consistent with all scenarios except A. The less than global HadCRUT4 trend is 0.155 +/- 0.066 C/decade, ie, slightly undershooting scenario D but again fully consistent with all scenarios except A.
It becomes clear why Charlie A is so tenacious in insisting that scenario A is the only one that matters and the "IPCC prediction" despite the clear indication that it was relative to a particular scenario and other projections were also made. Absent the absurd idea that BAU for 1990 was actually what happened, it becomes clear that the 1990 temperature projections stack up very well relative to observations.
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RedBaron at 21:23 PM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
OK Fair enough. Here is some evidence that leads me to believe it is not the ruminant at all, but rather the feedlot production system, including both the feedlot and the grainfields supporting the feedlot, and the petroleum derived chemical fertilizers supporting the grainfields, ie that whole "factory farming" system, that is to blame. Even when it comes to methane.
Starting with this comparing nitrogen fertilizers instead of organic fertilizers.
Environmental impacts on the diversity of methane-cycling microbes and their resultant function
"In a temperate agricultural soil, long-term fertilization with ammonium nitrate reduced methanotroph abundance by >70%, resulting a similar decline in methane oxidation rates (Maxfield et al., 2008; Seghers et al., 2003a) observed a similar pattern that was associated with reductions in the abundance of low-affinity type I methanotrophs. Different groups of methanotrophs may show different responses to fertilization, as observed in rice field and forest soils where type II methanotrophs were more strongly inhibited by mineral N fertilization than type I methanotrophs (Mohanty et al., 2006). In contrast, organic fertilizer addition can increase methanotroph abundance and associated rates of methane oxidation (Seghers et al., 2005)."
Here is the evidence that leads me to believe that this really is nuanced enough and the emergent properties of the system large enough to completely offset the CH4 produced when managed properly.
"Under field conditions, heavy autumnal rain in 1998 led to a dramatic increase of soil CH4 concentrations upto 51 microliters l-1 at a depth of 5 cm. Nevertheless, no CH4 was released when soil surface CH4 fluxes were measured simultaneously. The results thus demonstrate the high CH4 oxidation potential of the thin aerobic topsoil horizon in a non-aquatic ecosystem."
And here is the evidence that the whole grassland ecosystem including the animals and the atmosphere can be included in my claim:
IMPACT OF METHANOTROPH ECOLOGY ON UPLAND METHANE
BIOGEOCHEMISTRY IN GRASSLAND SOILS"At a global scale, soil uptake is the most important biological sink of atmospheric methane, offsetting emissions by about 30 Tg y-1 (Denman et al. 2007). Without this sink, Ojima et al. (1993) estimated that atmospheric methane through the 1990‘s would have increased at 1.5x its observed rate."
and
Cenozoic Expansion of Grasslands and Climatic Cooling
"Grasslands and their soils can be considered sinks for atmospheric CO2, CH4, and water vapor, and their Cenozoic evolution a contribution to long-term global climatic cooling."
So rather than blame the animals for the increase in atmospheric methane, rather blame Haber process nitrogen, something that is not needed in a properly managed pasture. From the systems science POV, when you remove the animal from the pasture and put them in a confinement system, you break part of the methane cycle, causing a nuanced chain of interactions with soil biota, quantifiably decreasing ecosystem function. Net result? You turn a net methane sink into a net methane emissions source. So it is very important to be very precise when discussing "intensive" agriculture. Managed Intensive Rotational Grazing is an intensive agriculture, but is very different than intensive agriculture reliant on expensive AGW causing inputs. Properly done, MIRG can actually help mitigate AGW, not cause it.
I believe it was foolonthehill that mentioned drought. Turns out that holistic planned grazing can also have a substantial positive influence on water content of the soil as well, making the system more resistent to drought. Here is that evidence:
Effect of grazing on soil-water content in semiarid rangelands of southeast Idaho
Of course at least in the USA, there is well managed, poorly managed, and non managed land. So even though 95%+ of all animal husbandry in the USA is the CAFO business model which I consider to be poor management, here is the evidence that leads me to believe all the land taken together is a net sink and thus refutes the myth that 'animal agriculture and eating meat are the biggest causes of global warming.'
"Agriculture (9% of 2013 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production.
Land Use and Forestry (offset of 13% of 2013 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit." [1]Finally you asked me about what is considered the active fraction and stable fraction of carbon in the soil. I am using the Soil Food Web model taught by the USDA-NRCS. There are other models like the Century model. Either way the stable or long term cycle carbon is called humus which lasts from hundreds on into geological time measured in millenia, as long as the soil is not disturbed.
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MA Rodger at 20:40 PM on 8 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @47.
You respond to TonyW@46 who was accusing "contrarians" generally of happliy "lying about the facts and, of course, cherry picking" as though your comment @42 were the target. This does raise the question as to whether you feel you are here to discuss/argue the science or simply here to argue the contrary position. Do be aware that the latter can very quickly lead to the insincere argument described by TonyW.
Further in #47 you suggest there was "erroneous conversion from emissions to forcing" within the FAR scnarios. Could you expand on that comment? I would add that I recall the FAR scenarios did begin life by being roughly specified in terms of level of forcings by certain dates so the process of their creation could be considered strange. But "erroneous"?
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chriskoz at 20:22 PM on 8 December 20152015 SkS Weekly Digest #49
To further emphasize Tom's point, COP21 will not, does not even intent to solve climate change problem. A modest or medium emision reductions they are going to agree on, is just a start albeit very important one. We know the comprehensive solution, in the implied 200ky timeframe, or even shorter 100y timeframe, is zero or even negative emissions. Future COPs will have plenty of opportunities for more effective solutions.
At the moment, it looks like a long term process, regardeless of COP21 outcome: future generations will have to deal with total emission control. On a long/implied timescale, any sustained positive emissions even 5-10% of current level may still be too fast to stabilise the climate. The level of natural emissions of "old" geospheric carbon by volcanoes is just 1% of current antropo.
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foolonthehill at 15:42 PM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
@michael sweet
Jumping in for no other reason than that I can...
I think you will need to narrow down quite a few variables before any quantitative decision could be made. The first would be 'small flock' - your piece of string may be of a different length to mine :-)
What forage is in the paddock? how old are the animals? are you rearing them for milk or meat? will your climate necessitate supplementary feeding in winter? do you intend to use fossil fuel derived fertilisers? Even the breed of animal is another complication to be factored in.
Any reliable calculation will be a very personal one.
It's likely that there will be a tertiary agricultural institute somewhere in your country that will be able to give you information that is better tailored to your situation.
You could take a different route with non-ruminants and get some pigs/chickens... Maybe bacon and eggs can salve a possible guilty conscience?
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michael sweet at 12:48 PM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
Scaddenp,
I have a small paddock that could support 2 cows or a small flock of sheep or goats. Would a small flock of either sheep or goats emit more/less/same greenhouse gasses than cows?
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Tom Curtis at 11:34 AM on 8 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A, @47, continues to insist that it is emissions rather than forcing which is the direct driver of temperature change. He also continues to insist that in determining the relevant scenario for comparison, only CO2 emissions should be considered, thereby excluding the very large reductions in CFC and CH4 emissions in the observed data relative to those projected in the FAR BAU scenario. Further, he insists the forcing comparison from Table 2 here is invalid because "the erroneous conversion from emissions to forcing caused a best match between forcing projections and observations if we use scenario D". (Note again, forcing is a function of GHG concentrations, not emissions so that this objection is entirely wrongheaded.)
As it happens, the table (reproduced below) does contain one inaccuracy, and is out of date to boot - covering the period to 2010 only.
Table 2: FAR Figure A.6 radiative forcing projections from 1990 to 2010
Scenario Change in forcing, 1990-2010 BaU +1.23 W/m² B +0.78 W/m² C +0.70 W/m² D +0.63 W/m² Actual +0.63 W/m² Adressing the second issue, by pixel count on Fig 1.6 of the IPCC FAR, the approximate forcing changes from 1990-2015 are:
BAU: 1.5 W/m^2
B: 0.9 W/m^2
D: 0.8 W/m^2
'Actual': 0.77 W/m^2
The plot for C is indistinguishable from those of B and D at that time, so I have not data for C.
The article says, "The actual forcing increase of +0.63 W/m² is from NOAA's Annual Greenhouse Gas Index." Of course, that excludes changes in forcing from changes in albedo and/or insolation. They are likely to be negative over that period, however. Further, they are not included in the FAR model projections, so using the GHG only forcing gives the best apples to apples comparison.
So far we continue to track at about the level of scenario D. That is unsurprising given that CO2 industrial emissions have tracked the BAU scenario projections from 2010 to present, while CFC concentrations continue to track well below even scenario D levels.
That said, the data above is taken from the IPCC FAR Fig 6, which used the simplified formulas given in Table 2.2 (page 52) to calculate forcings from concentrations. The constants in those tables have been updated since then, based primarilly on the work of Myhre et al (1998). In particular, the formula for CO2 has changes from 6.3*ln(CO2/CO2_initial) to 5.35*ln(CO2/CO2_initial). To account for this, the 'actual' forcing should be increased by 18% for a true apples/apples comparison. Alternatively, the projected forcings should be reduces by the reciprocal amount. That gives us a current comparison of:
BAU: 1.5 W/m^2
B: 0.9 W/m^2
D: 0.8 W/m^2
Adjusted 'Actual': 0.91 W/m^2
In 2010, the adjusted actual value was 0.74 W/m^2. Therefore actual forcings are now tracking closer to scenario B than to Scenario D. However, they are still tracking 40% below the BAU scenario.
I have not been confident enough to attribute the best comparison to any scenario (and still am not), based on the differences between scenarios B through to D being to small at this stage relative to the error from pixel counting on a photocopied sheet from pages that were not always flat. Actual forcings may be tracking as low as scenario D, or then again, they may be tracking higher than scenario B. However, they are certainly not tracking as high as scenario A (BAU) - and are almost certainly tracking closer to B than to A (even if above B).
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gws at 09:18 AM on 8 December 2015Lamar Smith, climate scientist witch hunter
In his new oped in the San Antonio News Express, Smith repeats his unfounded accusations and doubles down. Suggest head-vice while reading ... can a politician be sent a cease-and-desist letter when he keeps accusing a whole group of people, in this case climate scientists, of malfeasance without any evidence, affecting their public reputation?
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ecohen at 08:20 AM on 8 December 2015Animal agriculture and eating meat are the biggest causes of global warming
Thanks for this great discussion.
Check out this Eshel paper-Climate impact of beef: an analysis considering multiple time scales and production methods without use of global warming potentials- R T Pierrehumbert1 and G Eshel2
Published 4 August 2015 • © 2015 IOP Publishing Ltd • Environmental Research Letters, Volume 10, Number 8
http://m.iopscience.iop.org/article/10.1088/1748-9326/10/8/085002/meta
The study conclusions include that certain forms of pastured beef have substantially lower climate impact than feedlot systems.
To full address climate change impacts, we need to consider different types of livestock management — for their threats and potential benefits — ghg emissions reductions/sequestration as well as natural water storage, flood mitigation, and biodiversity enhancement...
It seems we should eat much less beef and when we do eat it, we need to it the right kind...
Also, my understanding is that all agriculture (not just livestock) GHG emissions are estimated at 15% of global total by FAO 2013; and 13% by UNEP 2015.
Moderator Response:[PS] fixed link.
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scaddenp at 08:05 AM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
RedBaron - would your labels "stable" and "active" be equivalent to "immobile" and "mobile" from point of view of carbon flux? What is the form of the "stable" carbon?
The trouble with intensification of grazing from emissions point of view is more animals and thus more methane. Because methane is more radiatively active than CO2, you need sequester a lot of carbon to offset the extra methane. Again, I dont see evidence presented so far that says any form of intensive grazing achieves this. Where is the evidence for "All that extra grow is short term sequestered carbon canceling out the effect of increased emissions". To be convincing, a paper needs to show carbon stored per hectare per year is more than CO2e emitted per hectare per year.
For example, in the 20-30 year study on SOC change I linked to above, the best SOC gain was about 200g/m2/year (upland grazing). I make that 5480g/hectare per day for a CO2e of 20,000 gCO2e/ hectare/day. Compare that to emissions of 170g per day of CH4 per beef upland animal . With a stocking rate of 2/ha that would be 170x2x28 = 9520gCO2e/hectare/day. Now that is really offsetting CH4 and goes into the countries GHG inventories as an offset.
However, most soils showed much lower SOC gains and even losses, especially when grazing was intensified. Not only does stocking rate go up but emissions per animal increase as well. SOC gain of 100g/m2/yr, 4/ha and 190g CH4 per animal and suddenly it is 10,000gCO2/hectare versus 21,200gCO2e/ha emitted.
It is also worth noting that GHG inventories do take CO2 sequestration in grasslands into account. See here for the methodology used by IPCC.
That said, we need food, and farming practices that minimize total emissions in producing it are definitely part of the solution.
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foolonthehill at 04:59 AM on 8 December 2015How much does animal agriculture and eating meat contribute to global warming?
@RedBaron
I have only recently started farming on my present land and testing the soil carbon will definately be part of my plan. I would think that this testing would need to be done over a number of years to get an idea as to what is going on. We are expecting a drought this year and I would expect that would affect plant growth and hence carbon sequestration. My situation is complicated by the fact that my land has a wildly varying contour so to get the best calculation I will need to take many samples over a large area.
Then compare the carbon you are sequestering in the soil against the carbon from fossil fuels you use.
And to complete this calculation as regards climate forcing I will also need to calculate the amount of methane my cows emit and enter this into the equation too.
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Charlie A at 00:13 AM on 8 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
#46"quite happy lying about the fact and, of course, cherry picking"
Interesting response in that my "lie" is a post of the IPCC graph of projected emissions, and my cherry picking is to show the driving force of humans — emissions — rather than the incorrectly calculated forcing.
the dramatic reductions in CO2 emissions of scenario D did not happen, but that is the scenario which several people have said should be treated as the IPCC 1990 prediction. Why? Because the erroneous conversion from emissions to forcing caused a best match between forcing projections and observations if we use scenario D.
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RedBaron at 22:08 PM on 7 December 2015How much does animal agriculture and eating meat contribute to global warming?
@Foolonthehill
So measure it. You don't need to be a scientist to measure your own operation. simply take soil samples in a carbon protocol, (carbon testing protocol is slightly deeper than standard soil tests) that gives you the sequestration side with a simple calculation. Then you obviously have your utility and fuel costs. Another simple calculation. Then compare the carbon you are sequestering in the soil against the carbon from fossil fuels you use. You won't be able to tell others what they are emitting/sequestering, but you will know what you are.
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andyelwes at 20:40 PM on 7 December 2015Book review: Climate Change, What Everyone Needs to Know
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TonyW at 20:16 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
It really is pointless arguing with contrarians (to use an uncontroversial description) because they are quite happy lying about the facts and, of course, cherry picking. They also have no single coherent theory to explain the warming since pre-industrial times, but that doesn't stop them.
However, the publishing of a Matt Ridley article on the new Scientific American site (which doesn't appear to allow comments) is sad, indeed. Sci Am generally publishes sound articles on the subject, so I was a bit taken aback that they would include an article by a prominent contrarian that is riddled with errors. It is any wonder that it's so hard to get significant action on this issue?
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MA Rodger at 19:41 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @42.
You will be pushing your luck trying to make a comparison between the different Scenarios and the measured outcome using the FAR emissions graphs. Those graphs aren't that accurately drawn. The atmospheric consentrations graphs provide a more robust comparison and in particular the CO2 graph (as shown @41). Scaling that shows 400ppm CO2 hits 400ppm in 2007 for Scenario A & 2019 for Scenarios B, C & D. Precisely when we did arrive at 400ppm CO2 depends on where you are measuring. The NOAA global measure latest NOAA global measure (September) is still a month or so short of the 400ppm. But taking MLO as the likely candidate measure for somebody in 1990, we reached 400ppm this March. This, with the comparisons for other GHGs, is the basis my comment @38. -
Tom Curtis at 19:31 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @42, first, and most fundamentally, the most basic graph for this issue is the projected change in radiative forcing due the the change in all GHG concentrations (third graph in my post above). Given that the observed change in radiative forcing is significantly smaller than that projected for scenario A, it is a distortion of the IPCC FAR projections to use scenario A as their equivalent to what realy happened.
Sticking just to CO2, the most basic graph is CO2 concentrations. That is because change in forcing, and hence change in temperature, is a function of change in CO2 concentration - not in CO2 emissions.
Change in concentration is in turn, to a close approximation equal to change in cumulative emissions multiplied by the airbourne fraction. Therefore, if the IPCC FAR did indeed underestimate CO2 emissions, that in turn means they are using too small an airborne fraction with the two errors approximately cancelling out. And because they approximately cancel out, they have negligible impact on the model/observation comparison.
In fact sometimes this self cancelling pair of errors is used to deliberately simplify projections. That is, rather than estimating total anthropogenic emissions (ie, LUC emissions plus industrial emissions), an estimate of industrial emissions alone is used, with a larger airborne fraction used. The difference in the net increase in CO2 concentration between the two techniques turns out to be negligible.
What is more, that appears to be what has been done in the IPCC FAR scenarios. In particular, Fig 1.5 (page 13) shows the estimated annual average industrial and LUC emissions for the decade, 1980-1989 as 5.4 and 1.6 GtC per annum respectively. The combined total, 7 GtC per annum is 0.4 GtC larger than the 1990 emissions estimate for Scenario A (BAU). Had the scenarios estimated both emissions, the starting estimate should have been 7 GtC plus 0.5 the decadal trend in emissions, or approximately 7.7 GtC. Instead it is 6.6 GtC, approximatley the 1987 estimate plus trend for the intervening years.
If that is what has been done, the apples to apples comparison is observed industrial emissions to projected industrial emissions. In that case, observed industrial emission begin lower than projected (6.1 vs 6.6 GtC) and rise more slowly. The gap therefore increases, with projected emissions exceeding observed by 1.3 GtC in 2000. Thereafter the more rapid observed increase in the 2000s closes the gap until they crossover in 2010 (the last year of observed data I have). Projecting the oberved trend, by 2015 the gap widens so that by 2015 observed emissions exceed projected emissions by 0.7 GtC. Although projected emissions are less than observed emissions in the final year, however, projected cumulative emissions always exceed observed cumulative emissions. And it is cumulative emissions which is the critical value for determining CO2 concentrations, and hence radiative forcing.
If we include LUC and industrial emissions, as can be expected by the initial projected values falling short of the mean for the previous decade, observed emissions and cumulative emissions always exceed projected emissions. But in this case, there must have been an error in the airborne fraction that more than cancels this error as noted above.
So, in the one (more likely case) projected cumulative emissions exceeds obeserved cumulative emissions throughout; while in the other case twin errors more than cancel out so that explecit emissions estimates are irrelevant.
What it looks to me that you are doing at the moment is, faced with a mass of evidence showing what actually occured was not the 1990 BAU projection, you are desperately seeking to cherry pick the one graph that might allow you hold to that belief, no matter how much contrary evidence you need to ignore. If that is indeed what you are doing, say so. "A man convinced against his will is of the same opinion still", and if you are resorting to grasping straws to retain your beliefs, clearly you are at best being "convinced against your will" and I have no wish to waste further time on you. But if that is not what you are doing, it is about time you acknowledged the mass of contrary evidence to your opinion already shown above.
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Eclectic at 18:16 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Joel_Huberman @22 : thanks Joel, for your link to Professor Curry's website ~ though I am not sure I would describe it as "better" than WattsUp site. Certainly, Curry's site is more upmarket than WUWT ~ the comments posters seem to be twice as educated and half as rabid as those of WUWT. Not that that's saying much!
It is more than a year since I previously looked at the Curry site. Not much has changed there. She continues with a multi-pronged attack on the mainstream climate science: At times she takes a Lomborgian It-won't-be-bad-ist position / other times she does a lot of fence-sitting by using the "Uncertainty" gambit / other times she follows the usual denier meme by cherry-picking and elephant-ignoring.
Just in case anyone should think Professor Curry is not a gold-medal climate science denier :- please consider a few of her (recent) quotes:
" . . . we need to open up the debate on the causes of the warming." [my emphasis]
"I think that by 2030, temperatures will not have increased all that much."
"The differences between the U.S. Democrats and Republicans on this issue [AGW] is rooted in their preferred policies, not so much the mainstream science." [my emphasis]
Yes, the Curry website is much, much lower-key than the typical mouth-frothing denier website. But as you read into it, you find that her website simply uses a different approach in obfuscating of science and of clear thinking about the issues. It is an approach which uses obfuscation through a chaotic welter of words.
Yes, it is "different" ~ where the average [American] denier complains that Science Is Being Politicised . . . we find that Curry complains politics is being "scientized". [Marvellously droll, eh? How dare any politics be influenced by scientific facts!]
Alas, if you want practical, useful information, then you will find that neither Curry or WUWT is worth going to.
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foolonthehill at 17:05 PM on 7 December 2015How much does animal agriculture and eating meat contribute to global warming?
Thank you for your comment RedBaron. I am not a scientist but I am interested in climate change and my contribution toward it. I appreciate the participation of those on the same journey.
As far as I can tell from what I have been reading, on a very basic level, my farming practices affect climate change primarily through the cycling of carbon and its compounds (and to some extent nitrogen).
As I understand it, the methane that my cows (by virtue of being ruminants) emit, acts as a forcing for a short period until it is oxidised to CO2. This CO2 is not a forcing.
If I wish to reduce this forcing from their methane emissions, I can lower my stock numbers. Alternatively I can rely on some as yet non-existant technology to reduce the amount of methane my current number of cows produce.
The grazing of my stock may or may not increase the carbon content of the soil. It would be wonderful if that were the case, as it would contribute to the mitigation of their methane emissions. Even better would be that the quantity of carbon sequestered back in the soil was sufficient to completely offset the methane emitted.
Unfortunately, I still havent seen enough evidence that convinces me that any method of pasture management achieves this goal. Studies are ongoing and that situation may change. Until then, it appears to me that I am contributing to climate change. I hope that I, like everyone else, can make changes to reduce that as much as possible.
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Charlie A at 16:59 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
You omitted the most basic graph -— the one showing the IPCC FAR projected emissions for the various scenarios.
When I get time I'll add the actual emission lines to the graphs, but as I noted above, I'm pretty sure that the actual emissions exceeded the BAU scenario. They _definitely_ exceeded the Scenario D that is being used as the scenario with the forcings that most closely matched observed.
Moderator Response:[AS] Fixed picture width. Please keep all figures no more than 550 pixels wide. Thanks!
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RedBaron at 15:55 PM on 7 December 2015How much does animal agriculture and eating meat contribute to global warming?
@ scaddenp & foolonthehill Last several posts
Holism in science or systems science in agricultural management systems has absolutely nothing to do with magic or faith. It has to do with the very agressive and expanded comprehensive monitoring and how that data is applied to the adaptive management plan as a whole. I don't even know where you got the idea that it has anything to do with faith? Maybe because any science/technology sufficiently advanced seems like magic to those uneducated in that field? For example, quantum physics seems like magic to me, because it is beyond my field of expertise. Intellectually I understand it isn't magic, but I don't understand how it works. So it still seems mystical and I have to take it on faith those scientists know what they are doing. That's a different kind of faith though. That's faith with evidence as opposed to faith in the absense of evidence. Standard Newtonian physics I understand quite well. It was part of my general education. To someone well educated in conventional agricultural systems, carbon farming/ecoagriculture may seem mystical because it heavily relies on systems science and holism, but it is based on evidence.
Please read the definitions and short descriptions of these terms here, so we have a common foundation to communicate: systems science , holism We can discuss the exact nature of this monitoring and the context in which that data obtained applies to any adaptive agricultural management plan, but this is a bit outside the context of the thread. All that needs understood is that this is designed to obtain information about ecosystem function by monitoring key indicators. By tracking how changes in the adaptive management plan effect these key indicators over time, the plan is capable of being adjusted to optimize those beneficial aspects and minimize the negative. It is a given that no plan starts out optimised, nor is every change beneficial, but because of the monitoring, they improve over time. Over time as this is applied, the plan and thus the ecosystem function, profit, yields etc... improve. And yes that includes, but is not limited to, the carbon sequestration into the soil, which is a key component to any terrestrial agricultural system and actually any terrestrial natural ecosystem as well. This is what is important in the context of this thread.
Now to address the other questions about the carbon cycle. It is fundamentally a self adjusting complex biological system. Yes we humans can effect changes in how it functions, but it still remains a self adjusting complex biological system, and as such systems science is required to understand how it functions. This is nothing new to climate scientists. There are all sorts of complex forcing and feedbacks that must be taken into account in any climate model. Those models are dependant on systems science. Climate deniers are the ones who tend to cherry pick one part out of context to mislead people. But most conventional agricultural science is not based on systems science. With the exception of the newer carbon farming/ecoagriculture, most of that information is a bit antiquated or modern but not applicable, focused primarily on mechanization technology, genetics and simple chemistry, not ecosystem function.
No scientist can know every field though, so sometimes that antiquated information when plugged into the climate models can be deceiving. One of the most deceptive parts is the encouraged myth that the current somewhat antiquated agricultural production models are required to meet demand, so climate scientists are told to focus on fossil fuel emissions instead. Emissions are only 1/2 the cycle. It is fail from the start. It can help, but it can never succeed. And unfortunately, leads to further misleading things like what is being debunked in this thread. We do need to eat. So as long as that myth prevails, it keeps people away from looking to closely at the environmentally destructive agricultural practises. It is sidelined to "land use change" and it's impact minimized to only that part of the agricultural land that is newly added, or lost, not the bulk that has been in continuous production for many years. Unfortunately, minimizing its impact also minimizes the benefit of changing it and/or what changes need to be made. So this is what gets me aggravated and annoyed and it is not any vegan or vegetarians fault, they are being misled as much as anyone else. To any climate scientist reading this, I understand you cant be expert in all fields, and must take it on faith that the information you obtain from agricultural scientists is reliable. Just remember the difference between faith with/without evidence, and look at the condition of agricultural soils worldwide for your assesment about how reliable the information you are receiving. If they knew what they were talking about, the agricultural soils worldwide would not be in such poor condition. After all, the highly educated farmers in developed countries are following their instructions, and those soils are in general getting even worse at a faster rate than uneducated farmers from developing countries. OK sorry for the rant, but it had to be said to partly explain where the misleading information is coming from.
Carbon can be broken up into two parts, the active cycle and the stable cycle. Obviously fossil fuels is part of the stable carbon. So is about 30-50 % of the soil carbon, the stable fraction.
Atmosphere and biomass both living and decaying, above and below the soil line is all part of the active cycle or active pool that exchanges relatively quickly. (There are other pools with limited to no part in agriculture like methane clathrates, limestone, ocean floors and permafrost etc)
Living biomass gets its energy from photosynthesis and absorbs carbon from the atmosphere, both CO2 and Methane or from the processes of decay. So you have two sides, the living growing side, and the dead decaying side. But life on this planet is carbon based, so it is all part of the active carbon cycle. This active biological cycle being a complex self regulating adaptive system. If for example a large part dies, the biomass responcible for biological decay grows and emissions of C increase. Also that biomass has a life cycle too and parts of it dies, all resulting more C emissions, but also more nutrient release, fertilizing the other side of the carbon cycle, which pulls out C from the atmosphere. Or if you get more vegetative growth, that pulls out C from the atmosphere, but eventually dies, increasing emissions. So anything you do to one side of the active cycle, increase or decrease, eventually is roughly countered by the other side. Increase methane emissions causes increased methanotroph growth, increased CO2 increases plant growth which leads to more decay when that additional growth dies, bringing you right back where you started, all else equal. So the vast majority of the active cycle is approaching carbon neutral. Any push you make on one side for good or for bad is countered roughly equally by the other side. You can speed up the cycle or slow down the cycle, but harder to increase one side while slowing the other side down. To do that you must break a link in the cycle. Animals are an important part of that cycle, they are responsible for increasing the rate of decay, which in turn increases the rate of growth. If you remove them, you slow the whole cycle down. Yes the rate of emissions decrease, but so does the rate of sequestration. Functionally think of it like this, a grass plant grows sets seed and then above ground leaves die. But if an animal grazes it before it can produce seed, it regrows and attempts again to set seed. This can happen several times in a season before the grass finally gives up and waits to try again next season. All that extra grow is short term sequestered carbon canceling out the effect of increased emissions. Slightly different with methane. more methane increases methanotroph growth, but that fertilizes plant growth when the methanotrophs die and decay. I would call that getting nowhere, but faster.
So ask yourself this, what does matter? Well 2 things really. Each ecosystem has a total biomass. So regreening a human caused desert, or reforesting some land does increase the total biomass that is living growing and dieing decaying. In both cases, once the new larger biomass reaches equilibrium, it becomes saturated and approaches net neutral again. OR causing desertification/deforestation does the reverse, decreasing total biomass which then also approaches net carbon neutral again. Those do either add or subtract to atmospheric carbon, but are limited to the increase or decrease in total biomass before reaching net neutral again.
However there is another part of the carbon cycle involving the stable pools. Fossil fuels are 100% stable pool carbon. ~30-50% of the soil carbon is the stable fraction. Normally this carbon does not cycle with the active carbon, but exchanges very slowly. When we burn fossil fuels, we are turning stable carbon into active carbon. Reforestation increases the biomass pool, but the biomass pool has limited effect due to reaching a saturation point. A new grassland reaches that biomass saturation point even faster! Both are active cycle.
But there are processes that turn active carbon back into stable carbon. It is a much smaller amount, but is additive and never really reaches a saturation point. In fact, in the right conditions, it accelorates. In a grassland that is more than in a forest, because the majority of the biomass of the grassland is below ground, while in a forest the majority of the biomass is above ground. So when grassland biomass finishes decaying, more gets trapped in the soil and less reaches the atmosphere. (unless the soil gets disturbed)
What matters long term is the net flux between the stable carbon cycle and the active carbon cycle. So to improve that positively we try to limit disturbance, maximise total active biomass, reach that saturation point as quickly as possible, then cycle it as quickly as possible without disturbing the soil. This way that small % that leaves the active cycle and enters the stable pool in the soil also increases. The biomass is saturated yes, but the stable pool just keeps adding and adding. The observation is that SOC increases. Once SOC reaches a certain point and starts tapering off, then the A horizon of the soil begins to get deeper and deeper. B horizon (sub soil) is being converted to A horizon (top soil). This is why natural grassland soils are much deeper A horizons than forest soils. But in agriculture we can do it even faster and deeper than natural grasslands, because we are optimizing as many parts of that cycle as we can. That's why it is called intensive, even though requiring less outside inputs, little to no fertilizers or pesticides or fossil fuel use etc... like most other forms of intensive agriculture people are familiar with.
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Tom Curtis at 14:45 PM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @40,
1)
I find it very difficult to believe that the 1990 IPCC First Assessment Report explicitly adopted as BAU the 1997 Kyoto Protocol. Indeed, based strictly on temporal logic, it cannot even have allowed for the 1992 UNFCCC which preceded Kyoto.
Your confusion appears to relate to mine, in that I incorrectly referred to the Kyoto Protocol (which was also implimented, and is another difference between BAU and what actually happened) and the Montreal Protocol, which is indeed referred to in the IPCC FAR, which states with regard to the BAU scenario:
"For CFCs the Montreal Protocol is implimented albeit with only partial participation." (My emphasis). How partial can be seen by comparing the BAU projections for CFC 11:
with what actually happened (fourth panel):
You will notice that in reality CFC 11 concentrations peaked at just above 250 ppt prior to 1995, and then when into decling. The projection, in contrast has BAU concentrations at 400 ppt by 2010, ie, 60% higher, and still rising rapidly. Every IPCC FAR scenario significantly overstates CFC 11 concentrations relative to what happened. So, even correcting for the appropriate protocol, my statement was substantively correct, and far less misleading than stating that "FAR explicitly says that they assume [Montreal] Protocol will be implemented in most countries as part of the business-as-usual scenario" without massive further qualification.
2)
Here are the IPCC FAR CO2 concentration projections:
It shows CO2 concentration in 2015 of 415 ppmv for BAU, 15 ppmv greater than has actually happened. That difference is made up of a much slower than projected rise in the 1990s partly compensated by a faster than projected rise in the 2000s due to China's rapid economic growth. While the overestimate relative to what actually happened is smaller for CO2 than for CFCs and CH4, it is still an overestimate.
Overall, adding all forcing together the CO2eq concentration has increased in line with scenario B rather than BAU:
3)
The 'headline' prediction of the IPCC FAR was, and I quote:"Based on current model results, we predict:
- under the IPCC Business-as-Usual (Scenario A) emissions of greenhouse gases, a rate of increase of global mean temperature during the next century of about 0 3°C per decade (with an uncertainty range of 0 2°C to 0 5°C per decade), this is greater than that seen over the past 10,000 years This will result in a likely increase in global mean temperature of about 1°C above the present value by 2025 and VC before the end of the next century The rise will not be steady because of the influence of other factors
- under the other IPCC emission scenarios which assume progressively increasing levels of controls rates of increase in global mean temperature of about 0 2°C per decade (Scenario B), just above 0 1°C per decade (Scenario C) and about 0 1 °C per decade (Scenario D)"
That is, the 'prediction' was tied to a particular scenario, with the effect that no explicit prediction is made if the scenario did not occur. There is no further prediction that BAU will occur. Saying that "the headline/main/executive summary prediction was for BAU" is a straightforward misrepresentation.
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scaddenp at 11:24 AM on 7 December 2015How much does animal agriculture and eating meat contribute to global warming?
Interesting. I will keep my eyes open more on this.
The location of the study with increasing SOC would be typical for Canterbury plain, but very different from most dairying areas. Forest lost around 800 years ago instead late 19th C; would have been under tillage for grains for much of 20th C in area known for windblown soil loss. So probably a very degraded soil before dairying and irrigation introduced. Irrigation alone has probably improved SOC.
By contrast, see this paper on long term (2-3 decades) SOC loss/gain under grazing with biggest losses under intensive dairying and gains on low intensity hill country grazing. 31 profiles from many parts of the country.
Perhaps reducing dairy consumption is more important the reducing meat.
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foolonthehill at 10:27 AM on 7 December 2015How much does animal agriculture and eating meat contribute to global warming?
Haven't seen grain fed in supermarkets. I noticed it on the menu of a couple of rather expensive restaurants and also in a couple of deli's. I assume it is imported but there's nothing to stop a local farmer from using a point of difference to make a better profit. It seems that anything that is slightly out of the ordinary is highly sought after by the real estate barons of Auckland...
The farming papers (NZ Farmer, Farmers Weekly, Rural News) are well worth a read to check how the agricultural pulse is beating. Palpitations are a common feature when it comes to climate change issues. They are free circulations but maybe you need a rural delivery address to receive them?
The long term evaluation of this study will be interesting to see. Maybe the vast increase in government science funding of $20million will be enough to ensure it's completion... Surely the price of a decent coffee, per capita, is sufficient for such a weighty matter? Or should a flag referendum take precedence?
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Charlie A at 10:07 AM on 7 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
#39 Tom says BAU scenario assumes "3) No Kyoto protocol with the consequent massive reduction in CFC emissions; :"
That is incorrect. FAR explicitly says that they assume Kyoto Protocol will be implemented in most countries as part of the business-as-usual scenario.
Later on I will extract the FAR BAU scenario assumptions on carbon/CO2 emission and compare them to actual. IIRC, the CO2 emission have actually been higher than those assumed in FAR's Business as usual scenario, in spite of things like reduction in British coal mine production.
The main problem with the prediction made by the IPCC in 1990 is that they ignored aerosols.
Yes, if you go back and correct the predicted forcings to something closer to what they actually have been, then the _revised_ predictions are more in line with what happened, but the headline/main/executive summary prediction was for BAU. Not for scenario B. Not for the more aggressive emissions reduction scenario C. And definitely not the most aggressive possible emissions scenario simulated, Scenario D.
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