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RedBaron at 14:37 PM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp #117
I gave you two studies already (one focusing on water holding capacity which is directly related to carbon in the soil and the other here[1]), as far as anything comprehensive that includes all the various forms of MIRG in all the various climatic and soil conditions, I haven't seen that quantified anywhere yet. It might be a good thing for someone to do. The closest to that I have found is this
"Rates of C sequestration by type of improvement ranged from 0.11 to 3.04 Mg C·ha−1 yr−1, with a mean of 0.54 Mg C·ha−1·yr−1, and were highly influenced by biome type and climate. We conclude that grasslands can act as a significant carbon sink with the implementation of improved management.[2]" And even that includes all sorts "improvement", and doesn't really simply compare MIRG to set stock rate continuous grazing.
This isn't really a scientific study, but might be useful to you in helping show you the mechanics behind how to properly start. Then of course if you applied holistic management as described post #77 with the monitoring and adaptive management plan, it would help you personally optimise it for your own particulars: "This bulletin covers the basic principles underlying all types of rotational grazing. Management intensive rotational grazing will be emphasized because it offers a number of advantages over both continuous grazing and less intensive rotational systems.
These include
■ more stable production during
poor growing conditions (especially
drought),
■ greater yield potential,
■ higher quality forage available,
■ decreased weed and erosion
problems, and
■ more uniform soil fertility levels.
There are many names for intensive rotational grazing: Voisin grazing, Hohenheim grazing, intensive grazing management, management intensive grazing, short duration grazing, Savory systems, strip grazing, controlled grazing, and high-intensity, low-frequency grazing. Although each term implies slight differences in management, they all refer to some sort of intensive rotational grazing system."..."Rotational grazing also can increase the amount of forage harvested per acre over continuous grazing by as much as 2 tons dry matter per acre.[3]" Keep in mind while this is harvested forage and no figures were given for carbon sequestration, An increase of 2 tons harvested means ~4 tons above ground increase in vegetation with and even larger increase below ground+an additional 30% in root exudates that feed the soil food web. As we discussed before that is active fraction, not stable, but the below ground is where the stable fraction forms. So at least in Minnisota that's big increases.Specifically for sequestered carbon I would send your soil scientist friend to contact Jay Furher. I know he did and is still doing some case studies for the USDA that are measuring carbon.
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Pfc. Parts at 14:12 PM on 10 December 2015There is no consensus
It would be very nice if this site allowed comments to be edited.
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Pfc. Parts at 14:05 PM on 10 December 2015There is no consensus
I was proof reading my post here on the last page of comments when I encountered this gem:
"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"
Not sure who came up with this but it's trully choice. So how many folks were measuring the temperature of Earth's stratosphere 200 years ago? 500 years ago? 2000? 20,000 years ago?Whoever made up that fun fact should get a prize, it's a real whopper.
Moderator Response:[PS] try reading for understanding rather than demostrating misunderstanding before banding about accusations. The surface temperature of any planet can be altered by changing solar input, albedo, GHG composition or aerosols. Increases in GHG composition is unique in that it is only forcing change that will warm the surface but cool stratosphere.
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Pfc. Parts at 13:58 PM on 10 December 2015There is no consensus
"Tom" doesn't make it possible. "To make"
"methodology" not "mehtodology"
"vapor" not "vaport"
"suborbital" not "soborbital"
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Pfc. Parts at 13:52 PM on 10 December 2015There is no consensus
John writes: "Science achieves a consensus when scientists stop arguing"
Actually that's a bit simplistic. A scientifi consensus is formed after a series of scientists are able to reproduce the work of the scientist advancing a hypothesis. This is done by publishing confiming/denying results in refreed journals. Tom make that possible, the person advancing the hypothesis first fully explains it, then describes how it was tested (the "mehtodology"), the observed data and the results.
A scientific consensus isn't formed by simple agreement between scientists, it's evidence based and very much dependent on repeatable experiment. So while the consensus that CO2 is a "greenhouse" gas, meaning that like water vapor and methane it absorbs and radiates solar energy in known quanta, there is no consensus on the effect or "sensitivity" Earth's climate has to increases or decreases in it. Which is the problem.
We know CO2 absorbs IR. Water vaport (H20) observes much more, so much more that IR astronomers put their telescopes as high as possible, on Mauna Kea, Medium Altitude soborbital platforms like the KAO and SOPHIA, and in low Earth orbit in order to get above H20. IR astronomers aren't particularly worried about CO2 because its effect is so small it just doesn't matter.
Moderator Response:[PS] Myths about water vapour are addressed under "water is the most powerful greenhouse gas". Make your arguments there. Offtopic comments will be deleted.
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scaddenp at 13:06 PM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
Nuts. On closer examination, the high SOC gains were only short term. On decadal scale SOC was either stable or reducing. but depends on soil type.
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scaddenp at 12:39 PM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
Was discussing this with a landcare scientist and we would be really interested to hear about SOC accumulation rates under MIRG. If land is not under constant irrigation support then meaningful data must cover dry spell. Apparently there is interesting data (ie high SOC) coming in for some irrigated or high rainfall intensive grazing regimes here.
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Digby Scorgie at 11:53 AM on 10 December 2015The Road to Two Degrees, Part Three: Equity, inertia and fairly sharing the remaining carbon budget
This has been a fascinating trilogy of articles. My overall impression is that considerable sacrifices will have to be made, especially by the rich, if we are to stay below two degrees of warming; meanwhile, everyone is pretending like crazy that the necessary adjustments can be made without anyone needing to make any sacrifices at all.
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scaddenp at 10:33 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
That would be called moving the goalposts. Pre-1970 doesnt count? Paddy coverage has also be fairly stable. It is good that until recently Ch4 emissions have been relatively stable since early 1990s. Noone is blaming AGW on agriculture. CO2 from FF is unquestionably the main problem, but you cant ignore CH4 either.
If you want to show that say, MIRG, is benign, then need to show that:
(CO2e emissions/ha/yr now - Co2e emission/ha/yr pre-industrial ) < SOC increase/ha/yr
The CO2e emission pre-industrial is tied down pretty well by earlier reference. "CO2e emissions /ha/yr now" = emission/head/yr * stocking rate - oxidation/ha by methanotrophs/ha/yr (the latter tied by del Grosso). The main numbers I am missing is SOC change for MIRG - you got reference for that? - and stocking rate which I cant seem to tie down.
As to methanotrophs, I have already given you references to fact that methane oxidation is relatively insignificant to ruminant emissions, but by all means include it. To show grazing better than grain, then you need to show that SOC loss and methane oxidation loss is greater than previous grazing emission load. However, I notice plenty of papers showing increase in SOC under grain cropping by using no-tillage and/or better rotation farming.
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Tom Curtis at 10:14 AM on 10 December 2015Betting against global warming is a sure way to lose money
ryland @8:
UAH tlt v6.0 beta4:
1994-2004 0.094
2000-2010 0.105
2004-current 0.129In fact the realclimate article offering the bet states:
"The basis for the temperature comparison will be the HadCRUT3 global mean surface temperature data set used by the authors in their paper."
HadCRUT3v
1994-2004 0.337
2000-2010 0.411
2004-2014 0.422Basicaly it does not matter which surface dataset, or satellite tlt dataset you use - the bet would have been lost by Keenlyside et al. And the payout, if the bet were accepted, would not have been based on "perception" but reality - the reality of the HadCRUT3 dataset which has not been adjusted.
And, speaking of which, Ryland @7, I would believe you are just raising concerns about perception if there was even the slightest evidence that you dispelled false perceptions in favour of reality on this or any other website. If you do, I certainly have not seen that evidence. Rather, you appear to want to use a perception as a cloak against reality - repeatedly.
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RedBaron at 09:53 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
@Scaddenp
Total emissions from agricultural ruminants went from a little less than 2GT CO2e in 1970 to a little more than 2.3GT CO2e in 2010: less than 20% in 40 years. Meanwhile there are no hard numbers, but wildlife ruminants actually decreased over that same time period and species after species runs precariously close to extinction. But even ignoring that, it is an increase easily offset by simply putting those animals back on pasture where they belong and managing it properly.
Meanwhile what do you suppose the emissions from other things actually causing AGW were during that same time period? Tripled. 300%
More importantly 1970s is when Nixon's Agriculture Secretary Earl Butz favored increased agricultural exports of grain and basically started the whole new business model of over production of grain as an international political tool/weapon. Any country with a differing political view? Just dump cheap grain on them and drive their idigenous farmers out of business. He went all over the country telling farmers to "get big or get out" and to plow up their fallow fields and start planting "fence row to fence row" That destructive business model then exported to other countries as well. Of course with all the fields plowed up, that meant we had to start feeding all that glut of excess grain to cattle and the even more destructive CAFO business model was developed and also exported around the world. All that extra land that before then was capable of mitigating AGW, now in a production model that contributes to AGW. I already gave you the links showing over 70% reduction in methanotrophs, but equally bad was similar reductions of Mycorrhizal fungi and other soil biota which also helps mitigate AGW.
If you are insistent on blaming agriculture, don't blame the cow, blame Earl Butz.
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scaddenp at 09:44 AM on 10 December 2015Betting against global warming is a sure way to lose money
The prediction about cooling that bet was based on, was for modelling of global surface temperatures. The appropriate data set to compare against the model prediction is GISS. Satellites attempt to measure measure lower troposphere (lower 4-6 km) temperatures. Besides the usual issues with satellite measurements, the troposphere is much more sensitive to ENSO variations than surface temperatures.
The precise nature of the prediction was that: "over the next decade, the current Atlantic meridional overturning circulation will weaken to its long-term mean; moreover, North Atlantic SST and European and North American surface temperatures will cool slightly, whereas tropical Pacific SST will remain almost unchanged." The slow rate of warming in satellite records is due largely to preponderance of La Nina pattern in pacific.
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scaddenp at 08:38 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
Not just bison, but they were the dominant ruminant by far in pre-industrial praire. deer and sheep are ruminants, but praire dogs and grasshoppers arent. I am certainly not reading vegan literature. I am meat eater and all for better agricultural management. I also believe we need food and that you cant grow protein groups on soils that we graze sheep on. What I am reading is IPCC reports and associated literature. No problem is solved by pretending it doesnt exist.
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ryland at 08:22 AM on 10 December 2015Betting against global warming is a sure way to lose money
@5 I'm not sure that anyone answered my original query if the bet was based on ground or satellite based readings but satellite doesn't UAH 6 show a decrease in the temperature trend since 1998? Even though other data sets showed warming that UAH data could have lead the cool bettors to suggest that the bet should be annulled
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scaddenp at 08:12 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
Sorry, but you are making assertions that not at all supported by the literature. (Ch6 of IPCC AR5 WG1 is index into this).
"AGW methane increases are mostly from mining, natural gas, fracking, melting methane clathrates, melting permafrost etc..." -
Um, no they are not. Those account for <30%. Expansion of paddy and ruminant no.s are the main contributors. Globally megafauna skyrocketed after industrial revolution from 0.2E12 kg to 1.4E12kg (here, fig 5).
Of course methane was produced from animals pre-human even, but it is the vast increase in no.s post industrial rev that is the anthropogenic part of emissions.
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ryland at 08:08 AM on 10 December 2015Betting against global warming is a sure way to lose money
Tom Curtis. You clearly never have heard the phrase "perception is reality." The point I'm making has nothing at all to do with the data per se but only to the perceptions of "foul play" that alterations to the data might have caused. I hope I have now made that clear to you. And I'm not saying or even insinuating there was any foul play. As the altered data showed warming the cool bettor could be suspicious of the result and had it shown cooling the warm bettots might have had their suspicions.
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RedBaron at 07:46 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
Not just bison also elk deer moose bighorn sheep antelope over 40 extinct species of megafauna, prairie dogs, extinct species of grasshoppers and on and on. You are reading Vegan "exterminate the evil cow" unholy alliance with AGW deniers propaganda again.
But at least you did say at the end "cattle in feedlots". Feedlots being the key component that actually at least is part of AGW.
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RedBaron at 07:34 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
No no no it is not the lions share. It's not even the cow. Rather in so much as the little bit that did increase is related to animal husbandry, it is the methods by which those cows are raised. AGW methane increases are mostly from mining, natural gas, fracking, melting methane clathrates, melting permafrost etc... Even in agriculture, the haber process nitrogen we spread on fields killing over 70% of the methanotrophs (the only biotic methane sink) has a larger effect than the cow.
I guess you are going to have to trust me on this, because I can't find a scientific study that explicitly states it, but even before mankind existed as a species, animals were belching, farting, breathing and rotting after they died. All of which is "emissions" by that AGW denialist rhetoric.
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scaddenp at 06:27 AM on 10 December 2015How much does animal agriculture and eating meat contribute to global warming?
Everything is AGW is really compared to pre-industrial. Methane concentration in the atmosphere has more than doubled since pre-industrial (0.8 to 1.85) with increase in ruminants taking the lion share. As you point out, CH4 is short-lived so this represented substantial, sustained change of flux. The GWP for methane used to calculate CO2e takes into account the lifespan of CH4 in atmosphere.
Just looking at US rangeland, you think that change from 30M bison (emitting 72g/d CH4) to 90M cattle (emitting 170-240g/d CH4) really supports "methane from ruminants contribute nothing to the current AGW,"? The Follet et al 2001 reference above also notes overall loss of SOC since settlement. This report puts cattle in feedlots at 14%
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Tom Curtis at 01:44 AM on 10 December 2015Betting against global warming is a sure way to lose money
Knaugle, using WoodforTrees, the relevant means for RSS are:
1994-2004: 0.196
2000-2010: 0.225
2004-Current: 0.239
2005-Curent: 0.242
I have included the last as a better approximation to a decadal value.
In any event, with RSS it remains a clear win for the 'warmists', although the margins are not as large.
As an aside, the bet was that each period would be warmer, with a payout to Keenlyside et al if temperatures were tied (had they taken the bet).
As is so often the case with ryland's comments, he adopts a position that retains its reasonableness only by scrupulously not looking at the data. If you play unfair and look at the data, you find all he is left with is empty rhetoric.
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Pete12981 at 01:34 AM on 10 December 2015Sea level is not rising
I wonder how Monkton or anyone with a graph they believe disproves rise would care to explain how come the North Norfolk coast is getting increasingly flooded from the North Sea, and the golf course at Brancaster, just to cite one place, is expecting to lose its course by 2020 as it's close to the sea with just dunes protecting. And as no houses on the seaward side of the coast road can get mortgages.
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Pete12981 at 01:28 AM on 10 December 2015Sea level is not rising
Something has been bothering me for a while, but I've found no mentions in the literature. Maybe someone here has knowledge.
We know with increasing storms and precipitation causing massive flooding, landslides and topsoil degrading, the latter is talked about as harming agriculture. All the soil washed away eventually ends up in rivers and then the sea. It has volume, it is increasing. Archimedes?
Is anyone attempting to estimate the volume of loss and its effect on sea level rise added to all the other causes we know about? There are figures for soil loss annually, which one site claimed was the size of Wales, but no volumes and I know nothing about soil scince or erosion. However small, it's bound to add. Additionally, there's coastal erosion which is also adding annually to the eureka effect.
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knaugle at 23:59 PM on 9 December 2015Betting against global warming is a sure way to lose money
With respect to ryland's comment, looking at Cowtan's temperature plotter and the RSS data since 1994, it is slightly possible that the Real Climate folk would have won that bet as well. Remember the bet was1. 2000-2010 >= 1994-2004 and
2. 2005-2015 >= 1994-2004While it is certainly true some (like Ted Cruz) can point to RSS data and say "no warming" the past 18 years, even RSS clearly shows "no cooling" as well, certainly since 1994. The El Nino years in 2010 and present certainly balance the massive one in 1998 and the period 2001 to 2007 works to the advantage of the Real Climate folk.
So far as Ryland's altered horse track comment, note that RSS does not seem to publish version numbers, but I would be surprised if their methods have been locked in stone since 1994. UAH on the other hand is far more open. Their version 5.6 was much more in agreement with the surface data sets, but version 6.0 moved its data significantly in the direction of RSS data. THAT as well is an altered horse track.
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Kevin C at 23:05 PM on 9 December 2015Betting against global warming is a sure way to lose money
OK, here are the results using both the previous SST dataset (ERSSTv3b), and the one before that (HadR2):
1994-2004 2000-2010 2004-2015
ERSSTv3b 0.492 0.591 0.619
HadR2 0.458 0.557 0.589
SkS 0.451 0.553 0.587I took the dates from the RC post, which claims they are decadal. However the last period seems to be an unusual 11-year decade.
If you want to go further the next step would be to use the SkS temperature calculator to calculate a pure unadjusted record from HadSST3-unadjusted and GHCN-unadjusted. That way we can ensure that no changes in adjustment or calculation method play a role. I've listed those in the final row of the table.I'm not endorsing those numbers - Zeke and I have already provided two independent analyses supporting the existence of a cool bias in the SSTs over the period. They should therefore be treated as a lower bound on the warming over that period.
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RedBaron at 22:19 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp
I slept on it and I think I figured our why we are at odds. I believe it is a failure to communicate and I am willing to take the blame. I really failed to express to you what I mean by "net sink". Obviously there is always going to be some methane entering the atmosphere. But we are talking about AGW. In other words how humans have effected that cycle. So when I say net with regards to methane it means something different than when I say net with regards to carbon dioxide.
Methane from animals is the short cycle. There always was and always will be emissions of methane from the short cycle, just replacing what gets oxidized abiotically. So because methane has such a short 1/2 life in the atmosphere, to actually be a cause of AGW, the emissions rate would have to exceed pre industrial emissions rates. Anything with a lower emissions rate than that can be seen as a net reduction. That doesn't mean no emissions, just less emissions. For that reason methane from ruminants contribute nothing to the current AGW, but rather the factory farm production model that removed those ruminants from the land.
This is different than CO2, because CO2 is stable in the atmosphere. It basically does not oxidize abiotically.
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Eclectic at 21:41 PM on 9 December 2015Betting against global warming is a sure way to lose money
Let's hope "the bet" outcome will not be much different, for old versus new, on the Cowtan Totalisator.
I'm expecting that the [Ryland] horse racetrack length will have suffered only a few metres' alteration in toto, over the years. Not enough to worry any genuine punter, anyway.
Plus, we have already witnessed the cumulative race results in recent decades . . . and the stewards have confirmed the results :- It's getting warmer. No pawse, just hoofbeats ~ and let's pray it is not the biblical four horse race :-)
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Kevin C at 21:04 PM on 9 December 2015Betting against global warming is a sure way to lose money
Fortunately GISS still distribute the ERSSTv3b grids, and the software to blend them into a land-ocean record. They're at the bottom of this page. Look for the link labelled "Sea surface air temperature (ERSSTv3b), previously used". So we can easily find out whether the bet would also have been won with the old GISTEMP.
I've got the calculations running now.
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ryland at 20:25 PM on 9 December 2015Betting against global warming is a sure way to lose money
To forestall any criticism, let me say upfront I don't believe alterations to temperature records have been made solely to hide a "hiatus" or "pause "or exaggerate a warming trend. A question-was the bet based on temperature calculations from satellite measurement or ground station observations? In view of the adjustments that have been made to temperature readings for whatever reason, it is probably a good thing the bet was not made. Adjustments to temperature records which did occur after the bet had been suggested, would and quite rightly should, have raised doubts in all of those placing the bet whatever the temperature trend showed. A bit like having a bet on a horse only to find finding the track had been altered after the bet had been placed but before the race had been run.
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scaddenp at 18:54 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
foolonthehill. I dont have NZ no.s but grazing/farmland in US takes up CH4 at <1.5kg/ha/yr (the del Grosso reference). 226g/head/day is 82.5kg/head so you should be able to work out from your stocking rate /ha. (which is what by the way? I found it very hard to get info on US stock rates which seem to be 0.2-0.3 on rangeland. NZ intensive dairy goes to 3.5-4 I think.)
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scaddenp at 18:45 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
Redbaron, your conjectures are not supported by the actual measured methane oxidation rates, nor (so far) by actual measurements of SOC increase. No SOC increase, no sequestration. Now the results I had were from survey of NZ soils. Prairie soils are a different beast so if you can find comparable multi-decade survey showing SOC rates big enough to offset the number of ruminants, then I would be delighted to see it. The best I could find was Follet et al 2001.
This notes the issue with intensity
" light stocking intensities (1.2 AUM/ha) did not have any effect on the SOC content after 44 years of grazing; however, heavy (2.4 AUM/ha) and very heavy (4.8 AUM/ha) grazing significantly reduced the SOC in the foothills of southwestern Alberta. They believe the heavy grazing intensities “jeopardized the sustainability of the ecosystemby reducing the fertility and water holding capacity."
However, the study mostly considers the potential for increasing SOC and its recommendations for practise look truly excellent. Overall,
"We estimated ... that 10.2Mha of U.S. pastures use improved grazing management systems, with sequestration rates of 300 to 1300 kg C/ha/yr and total sequestration of 3.1 to 13.3 MMTC/yr. "
While this is good news, a dry-cattle low-end emission is 170g CH4/day, = 62kg/year or =1737 kg Co2e/year. So the stocking rate is vital. 0.29 head per ha is 500kg CO2e/ha/yr. At that rate, SOC can keep ahead. No way if stocking rate is even 1/ha. Increased SOC seemed to come from better grazing management, fertilizer and water inputs which I would also associate with higher stocking.
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Tom Curtis at 18:39 PM on 9 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @51 draws attention to three purported sources of "erroneous conversion from emissions to forcing", one of which (different estimate of radiative forcing relative to change of concentration) is valid and is discussed at 48 above. It represents an 18% overestimate of FAR radiative forcing for change in concentration relative to current estimates for CO2 forcing, although less than that for all WMGHG. It is the major factor as to why scenario B rather than scenario D is the closest relevant factor.
To that valid concern, he adds two specious concerns. The first is an assumed overestimate of the retained fraction of CO2 in the atmosphere. However, the IPCC FAR BAU scenario represents a retained fraction of 55% of the specified emissions. Those emissions are industrial emissions, as argued @48 above, for which the retained fraction on modern observations is also 55%. The retained fraction would be too high if (and only if) the CO2 emissions specified in the scenarios were intended to be the combined industrial plus LUC emissions, a possibility contradicted by the fact that the states emissions in 1990 are well less than the combined emissions averaged over the preceding decade as specifice in the FAR.
The second specious concern is that the model used for the prediction did not incorporate aerosols as a forcing. That could be a valid concern if anthropogenic aerosol forcings increased significantly from 1990-2015. Unfortunately I cannot test that, but from the IPPC AR5 Figure 8-18 (below), it can be seen that anthropogenic forcings in addition to WMGHG has decreased by 2.4%. Furthermore, overall forcings have decreased relative to WMGHG as well. The IPCC FAR included only anthropogenic WMGHG because rates of change in other anthropogenic forcings, and in natural forcings, was expected to be small relative to anthropogenic WMGHG, a supposition born out by AR5 data.
Finally, Charlie A lets forth with a rhetorical cannard, suggesting we are comparing IPCC FAR predictions by applying their two box model to historical forcings. Of course, nothing is further from the truth. What we are doing is comparing historical forcings to the four IPCC scenarios to see which one most closely matches history. That is what we are supposed to do. That is the whole point of constructing different scenarios and generating a range of projections instead of just one prediction.
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MA Rodger at 18:22 PM on 9 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Charlie A @51.
You actually signal four objections to the FAR. Objecting to the abilities of the FAR climate models to provide anything useful does rather trump all that goes before. Do you feel the predictive abilities achieved by FAR to date are then just coincidental?
But let us be "instructive" and begin by addressing initially your first point. The Airborne Fraction AF (as it is referred to these days) has remained remarkably steady over period of Atmospheric CO2 instrument data, something that wasn't that clear a quarter of a century ago. Another difficulty facing the FAR was the emissions from LUC which they greatly underestimated. Thus the numbers used to calculate the AF were not the ones we would use today and would indeed suggest a rising AF. However, these data problems do cancel each other out over initial decades.
Also note that the FAR did not begin by defining emissions. That was not a part of the "Task A" brief required of WGIII whic was more to check that the climate forcings in their brief were realistic. Some of the numbers they considered were extreme by today's standards but those were generally averaged out of the final scenarios.
Given this situation, your position on this first point is not clear. Are you then actually arguing that the scenarios, presumably specifically Scenario A is some form of straw man?
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Charlie A at 17:12 PM on 9 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
#49 MA Roger. "you suggest there was "erroneous conversion from emissions to forcing" within the FAR scnarios. Could you expand on that comment?"
1. Errors in calculating concentrations that result from given emissions.
I have not calculated the specific impact of this, but it appears that FAR overestimated the fraction of anthropogenic CO2 that would remain the atmosphere.
2. Errors in calculating radiative forcing for given concentrations Is CO2 radiative forcing 3.7W/m2/doubling or is it 4.3W/m2/doubling. Obviously, if one uses 4.3 (as did FAR) instead of 3.7 one calculates higher forcings than if one uses the currently accepted 3.7 number.
3. Ignoring aerosols. Yes, FAR radiative forcing calculations completely ignored aerosols. I have not caclulated the specific impact of this. In 1990 the was uncertainty as to whether aerosols were even a positive or negative forcing: "In view of the above uncertainties on the sign, the affected area and the temporal trend of the direct impact of aerosols, we are unable to estimate the change in forcing due to troposphenc aerosols. " Page64 FAR WG1, forcing chapter.
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The goal of governmental policies are to control emissions, since that is the human "input" to the ecosystem.
First, from emissions we make assumptions, and calculate concentrations. Secondly, from those calculated concentrations we then calculate radiative forcings. In a third step, from the radiative forcings we then calculate expected temperature changes.
While it is instructive to ignore errors in the first two steps and then see if the calculations from forcings to temperature changes are correct, it sheds very little light on the overall accuracy of FAR predictions/projections. This is particularly true since the FAR predictions are the output of a simple 2 box model. While many seem to assume that the GCMs were used to make the FAR predictions, in reality they were done by an extremely simple two box model.
Provided that I get to choose my forcings, I can do a very accurate projection of global temperatures using a simple multiplier and a single exponential lag. Even the two box model is overkill. Of course, my projections become exceedingly accurate if I get to adjust the forcings to those observed, as others have done in their comments.
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Some further details, .....
A crude examination of assumed emissions vs project PPM CO2 leads me to believe that FAR assumed higher percentage of anthropogenic CO2 would remain in the atmosphere than actually remained. I haven't bothered to see where the discrepancy comes from, but I did note that the FAR expected a "saturation effect" to take place which would lead to a rise in the percentage of anthropgenic CO2 remaining in the atmosphere (about 1/2 stays in atmosphere and 1/2 is absorbed into biosphere and oceans).
Another error is simply the radiative forcing formula used for CO2. Yes, this is basic physics, but the consensus has changed as to the correct value. For example, the TAR (2001) uses delta-F = 5.35ln(C/C0). (This leads to the more often used 3.7W/m2/doubling of CO2)
In 1990 the FAR used delta-F = 6.2ln(C/C0).
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foolonthehill at 16:15 PM on 9 December 2015How much does animal agriculture and eating meat contribute to global warming?
This is why they are superior at soil building to other types of herbivores.
Until the arrival of cattle in 1814, New Zealand was devoid of ruminants. Would you expect our soils to be low in carbon? Do you think that the arrival of cattle would have improved the carbon content of our soils? Bear in mind that our cattle are almost all pasture fed and always have been.
The measured amount of enteric methane release from 26 month old steers in New Zealand averages 222g per head per day. Could you give me a percentage of this methane that you think is being consumed by the methanotrophs and converted into soil carbon. I know my stock numbers so if it is all being captured at source I should be able to get a handle on how much my soil carbon mass will increase by.
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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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