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Trevor_S at 09:55 AM on 5 December 2015How much does animal agriculture and eating meat contribute to global warming?
The other thing of note is that we have to eat, we do not have to fly (aside from the very self important) for example and we can cycle, or use renewanle energy (in Austrialia everyone is offered the option and very few take it up) but we still have to eat.
Cut out lamb and beef, substitute those meals for vegan meals and that's a great start. Often overlooked are meat eating pets, vast CO2e emisions from owning a large dog for example, about the same as an SUV
abcnews.go.com/Technology/pet-dogs-damaging-environment-suvs/story?id=9402234
so own one, or the other but not both.
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michael sweet at 09:25 AM on 5 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
When I search for this article on the internet I find no reference to the WSJ publishing it. It is too bad that WSJ refuses to present the mainstream scientific opinion to its customers.
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ryland at 07:58 AM on 5 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Apologies I sent this before I saw your correction @ 2
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ryland at 07:57 AM on 5 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
@1 Your comment "It is tragic when a media source that really should strive to ensure its readers are well aware of what is going on" is entirely correct but does it encompass contributions such as those by Bjorn Lomborg currently being published in the Australian (see here) to "ensure its readers are well aware of what is going on"?. Or do such contributions and indeed the Australian itself, fall into your category "rather than being a populist gossip rag, resorts to publishing misleading information because it suits some short-term unsustainable damaging objectives a few wealthy and powerful people"?
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One Planet Only Forever at 07:48 AM on 5 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Correction in my comment:
Replace "populist gossip rag" (which I now understand should have been Capitalized) with "popularity pursing gossip rag".
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One Planet Only Forever at 07:39 AM on 5 December 2015Scientists' open letter to the Wall Street Journal re: Ridley and Peiser
Some Main Stream Media sources provide more helpful infromation for their readers, if readers actually want to better understand what is going on.
The NYTimes article "Short Answers to Hard Questions About Climate Change" , is just one recent example.
It is tragic when a media source that really should strive to ensure its readers are well aware of what is going on, rather than being a populist gossip rag, resorts to publishing misleading information because it suits some short-term unsustainable damaging objectives a few wealthy and powerful people.
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billev at 07:27 AM on 5 December 2015Study drives a sixth nail into the global warming ‘pause’ myth
The NOAA Temperature record starting in 1880 shows pauses in warming from 1880 until 1910 and from the mid 1940's until the mid 1970's and from 2002 until the present. This appears to be a pattern of alternating periods of warming and pauses in warming with each period about 30 years long. If this pattern continues through the current century then this century will experience only 40 years of warming.
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reuns at 04:38 AM on 5 December 2015Global warming not slowing - it's speeding up
look at http://www.bom.gov.au/climate/glossary/soi.shtml
the SOI could be decreasing in mean value.
what if the present warming is enough to let the ocean stay in a negative Southern Oscillation Index (SOI) state, resulting in much more atmospheric heat absorbed by the deep ocean layers, and thus a much slower atmospheric warming ?this way, we would attain the +2°C in 2100 and the global warming would have much less negative effects, letting enough time for people and nature to adapt.
that's an hypothesis that looks cool if true, and because everybody thinks SOI is quite random (even if it is supposed to cancel out itself on longer periods), there is no fundamental obstruction to the hypothesis that what we are seeing today is an adjustment of SOI's mean-value to a negative index.Moderator Response:[Rob P] A negative Southern Oscillation Index (SOI) persistently below -8 typically suggests a more El Nino-like state in the tropical Pacific Ocean. During El Nino, the subtropical cell and the subtropical gyres spin down. This corresponds to reduced poleward transport of warm tropical surface water and reduced Ekman pumping (convergence & downward transport of surface water) in the subtropical gyres.
This is the opposite of what you have suggested.
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Jim Eager at 01:30 AM on 5 December 2015How much does animal agriculture and eating meat contribute to global warming?
Saleshrao wrote: "our continued enslavement and exploitation of animals."
Ah, now we get to the root of saleshrao's argument. It's not about climate at all.
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One Planet Only Forever at 01:17 AM on 5 December 2015Uncertainty is Exxon's friend, but it's not ours
Adding to my previous comment, there is another difference between a person who legitimately identifies an uncertainty and a person who tries to raise unjustified doubts.
A person legitimately raising an uncertainty will accept an explanation that clarifies that the claimed uncertainty is not valid or justified (including when new reseach focused on addressing the uncertainty is developed, such as the better understanding that the mention of a warming haitus was regarding the rate of warming when measured up to 1998 vs. a slower rate after 1998, and that even that is no longer valid because of more recent research and the most recent very warm years).
A person trying to raise doubt will continue to make an unjustified claim after they have been provided with an expalantaion of why the claim is not justified. Doubt raisers will continue to try to abuse the false claim for as long as their research indicates it is having the desired result (in public opinion and actions of leadership that is swayed by 'popularity' rather than 'understanding and the responsibility to develop a lasting better future for all'). Also, doubt raisers will not make mention of any new research related to a false claim they are trying to 'milk' benefit from.
The deliberate raisers of unjustifiable doubt are clearly 'unhelpful to the advancement of humanity to a lasting better future for all'. They clearly need to be identified and be generally understood to be the trouble-makers that they are. Hopefully legal procedings will not be required to effectively block the success of such people because it is known that illigitimate wealth and power can and do distort the legal process, keeping it from effectively limiting the pursuits of wealthy powerful people.
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OnceJolly at 00:52 AM on 5 December 2015How much does animal agriculture and eating meat contribute to global warming?
saleshrao @58: " The missing biomass must have been metabolized, which works out to 4.69 Gt. Assuming that half the biomass is carbon, this is 2.35 GtC or 8.62 Gt CO2, which is pretty close to the Calverd estimate."
Not everything that is metabolished is respired; some of that carbon will be incorporated in the mass of the fauna. In any case, Smil makes reference to a peer-reviewed estimate of respiration by <a href="http://www.biogeosciences.net/4/215/2007/bg-4-215-2007.pdf">Prairie and Duarte (2007)</a>, which estimates livestock respiration at 1.5GtC (5.5 GtCO2). Smil argues that their underlying estimates of animal mass are inflated. These figures (and the FAO's own estimate of 3.2 GtCO2) were available when Goodland and Anhang were conducting their analysis.
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One Planet Only Forever at 00:45 AM on 5 December 2015Uncertainty is Exxon's friend, but it's not ours
It may be better to say that what the Exxon executive did was attempt to 'raise doubts' about the changes required by the developing understanding of the climate change impacts caused by human burning of fossil fuels.
There is a significant difference between 'identifying uncertainty' and 'raising doubt'.
Identifying valid uncertainty needs something to be shown to deserve to be considered an uncertainty requiring clarification of understanding. It requires a decent degree of understanding to be the basis for identifying the ucertainty.
Raising doubt simply requires a willingness of an audience to accept a claim, and such claims do not even require an understanding of the actual facts of the matter, just an understanding of how to influence the beliefs of people (the science of marketing).
The people who actually better understand an issue yet deliberately try to raise unjustified doubts about it deserve to be considered to be criminals (people who wilfully did something that they could understand was unacceptable) or perhaps be given the benefit of the doubt and be considered to be lower level criminals who did something unacceptable but did not have the ability to understand its unacceptability (A person in a position of leadership should not be able to claim they belong in this second category unless they give up their position and any wealth they got that they obviously did not deserve to get ... and agree to develop the change of mind that is required for them to qualify to be in such powerful positions of responsibility for the welfare of others before they take on another leadership role).
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OnceJolly at 23:47 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
saleshrao @57 & 58,
Calverd (2005) is a one-page editoral from someone with no expertise in carbon accounting who makes no claims about disequilbrium between respiration and photosynthesis. Furthermore, he doesn't provide a value of 8.77 GTon...this is from Goodland and Anhang, who apply his 21 percent figure to the WRI's estimate of total GHG emissions for the year 2000, rather than (as Calverd actually does) the 21 percent of CO2 from the combination of fossil fuel combusion and respiration of humans and livestock. Despite not using the FAO's own estimate of respiration, they further inflate this figure by 12 percent (for after period increases in livestock tonnage) and 10 percent (for alleged undercounting of animals by the FAO, though there is no indication that Calverd's actually uses these estimates to obtain his own figure).
My understanding is that no one is making the equilbrium assumption that you're asserting. The degradation of surface and soil carbon sequestion is included in the land use category of greenhouse accounting. Goodland and Anhang provide no evidence that there were 10.8 Gton of *net* CO2 emissions missing from the GHG inventories in 2000 that can be attributed to land use and land use change due to livestock. In a follow-up to their original World Watch article, when asked how previous GHG inventories missed 22 GTon of CO2e, Robert Goodland writes: "“If respired GHGs are counted as a proxy for foregone carbon absorption, then most of the 22 billion tons of emissions that we claim were previously not counted can be understood as a potential carbon sink rather than an actual carbon source.”"
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MA Rodger at 23:26 PM on 4 December 2015Murry Salby finds CO2 rise is natural
Dikran Marsupial @22.
How does Salby get that data? I think we can safely conclude that the green CO2 data presented variously by Salby (your Figure 2) is a short slice of a genuine atmospheric CO2 record (presumably MLO) but after it has been passed through a Fourier analysis & stripped of unwanted frequencies. Thus he gets a nice clear sine-type wobble.
We also know that the majority of the blue trace, the "lion's share" he tells us, is global temperature so if it is derived from actual data, it will have been likewise filtered through a Fourier analysis and also shifted a few months because of the lag between temperature & CO2 that Salby helpfully illustrates at 22:00 (although it is less than the 10 months he states in his talk).
Mind, as Salby is at best entirely untrustworthy in these presentations of his, being in error at almost every turn (and so untrustworthy and error-prone that it is very difficult not to consider his talk as an insincere pack of lies), it might be a simpler task to answer InnocentSmithReturns by pointing out "specifically where he (Salby) goes right in this presentation."
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RedBaron at 20:53 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
@saileshrao #57
That brings up an important point. Just because there are unsustainable foods in our marketplace does not mean we have to stop producing those foods, all it means is we need to change the production methods. The overgrazing you mentioned and the environmental harm it creates, supports less animals, not more. Certainly overgrazing creates desertification, and that adds to AGW, and reduces yields from that land. ie less animal production, not more. The key is education. There are alternative intensive models of production to almost every form of intensive agriculture that actually yield more food per acre, not less. Most of them include animal husbandry too.
Rice was mentioned earlier as another source of AGW. Certainly intensification of rice production in the green revolution increased yields, but at a cost to the environment. More modern forms of rice intensification though like SRI, yield even more that the old antiquated green revolution intensification, but without the environmental harm.
In a post earlier #52 #56 I had to clarify the difference between the standard intensification of animal husbandry which uses CAFOs and has an associated negative impact on the environment and climate, and more modern forms of animal husbandry intensification like MIRG which can actually regenerate the environment and help mitigate AGW.
Even though most current intensive rice production does in fact add to AGW at least somewhat, no one would say everyone needs to stop eating rice. It is a silly fallacious argument. Claiming everyone needs to stop eating meat is equally silly. And so is the fallacious argument that all intensive agriculture must end because it is a source of AGW. And so is the argument that our current antiquated forms of green revolution intensification must be done to meet demand of a growing population. They are all lunatic fringe arguments that use poor logic skills and often unreasonable misleading statistics as well. One, animal husbandry, is being rightfully debunked right here in this thread.
Yes, intensive agriculture is required to meet worldwide demand. But there are alternative forms of intensification that yield more, reduce emissions, and increase profits for almost every major food crop.
Typically the major things preventing this change to new modern ecologically sound systems include education, subsidies for competing antiquated systems to keep them economically viable, misguided onerous regulations, and occasionally but not often infrastucture changes are needed.
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saileshrao at 20:10 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
OnceJolly @51,
Also with respect to Calverd's "faulty calculations," the IPCC AR5 WG3 CH11 land use block diagram (Fig 11.9, page 836) confirms that the breathing contribution of livestock is around 8.77 Gt CO2.
The annual net dry matter biomass input to the livestock sector is 7.27 Gt, while the net dry matter biomass output is 0.4 Gt and the waste stream is 2.18 Gt. The missing biomass must have been metabolized, which works out to 4.69 Gt. Assuming that half the biomass is carbon, this is 2.35 GtC or 8.62 Gt CO2, which is pretty close to the Calverd estimate. -
saileshrao at 19:53 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
OnceJolly @51:
Vaclav Smil is making the assumption that livestock production is in equilibrium with the environment, similar to Ray Pierrehumbert making the assumption that the methane concentration is decaying exponentially in the atmosphere.
I invite Vaclav Smil to accompany me to Rajasthan, India, on my upcoming field trip later this month as we work with people to reverse the expansion of the Thar desert. I would be happy to show him how livestock production is decidedly not in equilibrium with the environment as livestock production has been rapidly desertifying pasturelands through overgrazing. Annually, the UNCCD reports that 30 million acres of land gets desertified mainly through livestock overgrazing, but this CO2 emissions is counted as part of the human contributed 11.6 GtC red arrow in the IPCC carbon cycle block diagram (insert diagram from IPCC AR5 WG1 CH6), accompanied by the caption, "Total Respiration and Fire".
This post by Dana Nuccitelli and the comments have illustrated many of the numerous forms of denial (FLICC) that were discussed in the excellent EdX course: Making Sense of Climate Denial, but directed towards our continued enslavement and exploitation of animals. Vaclav Smil is not a land carbon expert and therefore, using his statement to justify that livestock breathing is part of the "natural carbon cycle," could fall under the "False Experts" category of denial, discussed in the course. -
RedBaron at 12:16 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp #53 In ref to my post #52
I was specifically refering to Managed Intensive Rotation Grazing, not other forms of agricultural intensification. MIRG
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scaddenp at 12:15 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Reason_4, if you mean that CH4 from ruminants is different from CH4 from say fugitive natural gas, then I agree with you. The methane counts as greenhouse forcing until is oxidized, after that it is no different from CO2 from respiration. Fugitive gas by comparison is adding net new carbon into the atmosphere, first as CH4 and then as CO2.
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Jim Eager at 12:02 PM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Saileshrao, thank you for the link to Barnosky's PNAS paper on prehistoric megafauna, I will look at it tomorrow.
And thanks to OnceJolly for the quote from the Smil book that says pretty much the same thing I said: livestock respiration adds no new CO2 to the atmosphere.
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scaddenp at 11:51 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
RedBaron - are you actually claiming that the total amount of soil organic carbon has increased this century due to intensification of agriculture and expansion of farmland into natural vegetation? Or are you just claiming grazing is better for retaining SOC than say crop tillage?
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RedBaron at 10:46 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
@ scaddenp #49
Not at all, just the opposite conclusion should be drawn from those studies. In the soil you can simplify it and think of it this way. There are basically 2 pools of carbon in the soil, an active fraction and a stable fraction. The active fraction of the carbon pool in soils can safely be largely ignored as a cause of AGW as it will return to the atmosphere anyway and then back to the active fraction again via photosynthesis and so on as a relatively short term cycle. It is only temporarily stored and thus not part of the long term carbon cycle. The stabilized organic matter fraction is however part of the long term carbon cycle and is much more important to calculating AGW.
Intensive grazing effects this rapidly cycleing fraction both by increasing live biomass production and by increasing the rate of decay BOTH. This actually increases the quantity of carbon leaving the active fraction and turns into stable humus that can no longer decay and is stable for thousands of years unless disturbed.
Remember the only part of soil carbon that actually is important to AGW is the stable fraction. By increasing the rate of decay, that small % that get sequestered into the soil after all the processes of decay are finished also increases. It speeds up the whole system, and the system as a whole is a net sink of carbon into the soil. So that part of the system speeds up as well. The more biologically active a soil is, the more long term stable carbon is sequestered... Unless one disturbs that soil with a plow or other means of course.
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OnceJolly at 10:35 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
saileshrao @50:
From Vaclav Smil's book, "Should We Eat Meat? Evolution and Consequences of Modern Carnivory"
"On the other hand, Goodland and Anhang (2009) argued that CO2 from livestock respiration is an overlooked source of the gas and that overall greenhouse gas emissions attributable to livestock should be much higher, accounting for no less than half of the total. Unfortuanately, they accepted some faulty calculations by Calverd (2005) who concluded that farm animals generate about 21% of all CO2 attributable to human activities."
and
"In any case, CO2 emissions from livestock metabolism are not, much like those from human respiration, considered as anthropogenic sources of a greenhouse gas. They result from the metabolism of phytomass that aborbed the gas from the atmosphere and that will again sequester it once it will have been respired and are thus a part of relatively rapid sub-cycle of the global carbon cycle that does not result in any significant net addition to atmospheric CO2 burden."
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KeenOn350 at 10:22 AM on 4 December 2015New research finds that global warming is intensifying wildfires
Typo needs fixing - in quote from the summary -
2014 was the second longest largest in
DaveW
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denisaf at 09:09 AM on 4 December 2015Deep Ocean: Climate change’s fingerprint on this forgotten realm
This discussion of what is irrevocably happening in the oceans due to the unintended, deleterious consequences of industrialization is just one of the symptoms of what has gone wrong. However, the efforts of the likes of Levy can well contribute to society slowly waking up to making sound adaption and amelioration decisions. Hopefully, the Paris talks will see a little progress in that direction.
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saileshrao at 08:16 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Jim Eager @46:
Please see, e.g., Anthony Barnosky's paper in PNAS,
http://www.pnas.org/content/105/Supplement_1/11543.full
and Vaclav Smil's book, "Harvesting the Biosphere: What We Have Taken From Nature":
http://www.amazon.com/Harvesting-Biosphere-What-Taken-Nature/dp/026201856X -
scaddenp at 07:23 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Redbaron - please see this paper. Soil carbon loss under intensive dairying is a substantial issue here in NZ and the subject of research eg (here). It looks like intensification of agriculture is not good for carbon soil stocks.
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Reason_4 at 06:55 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
@Jim Eager @47
Not sure how I can explain this better, but lets make it even simpler.
If I release 1 ton of methane (yes regardless of source) that results in a certain amount of forcing ... right?
If I release 1 ton of methane AND at the same time sequester 5 tons of CO2 there is still some NET forcing ... but not as much as in the first example ... right?
This net result is why we (of course) don't count CO2 emissions from respiration (not just because CO2 is a less potent GHG than methane, but because the net result is zero)
This is my very simple question regarding emissions from livestock. Why do we not look at the emissions AND the source of the carbon in those emissions AND any associated sequestation that arises as a result of raising livestock - and then arrive at a net figure for the whole operation.
Fossil fuel sourced methane is simple - we know the source, so no short term carbon cycle to allow for there ... right? and until there is finally some actual commercial CCS projects run in association with extraction, there is no sequestration adjustment necessary to arrive at a net forcing either ... right?
If we don't examine the net forcing arising from 'animal agriculture', how can we say that we are addressing the question raised by Dana in the title of this article ... accurately?
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One Planet Only Forever at 02:08 AM on 4 December 2015Uncertainty is Exxon's friend, but it's not ours
A clarification of my comment@11.
The event that flooded Calgary ion 2013 included large amounts of rain falling at higher elevations in the mountains that would have been a snow acumulation at that time of year if it was just a bit cooler. Also, the ground at higher elevations was still frozen which is not uncommon in the late spring but may have been due to a lower than normal thickness of snow insulating the ground from freezing during the winter (thicker snow will reduce the depth of freezing in the ground it covers) ... Lots of added uncertainty with rapid rates of climate change, including the interactions between different factors.
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One Planet Only Forever at 01:33 AM on 4 December 2015Uncertainty is Exxon's friend, but it's not ours
knaugle@9
The example you presented can be repeated for every climate related weather behaviour that affects a built item. But it is important to understand that there is even more involved in a dam design than how much total volume will end up being held behind the dam.
In addition to the basic design rule of a once in 100 year rain event volume being the 'regular upper limit on water levels', every dam is also evaluated for its ability to hold back more than a one in 1000 year event without being 'overtopped'. Associated with the evaluation of the overtopping is the rate of safe by-pass through the feature designed to safely allow flow to by-pass the dam to avoid catastrophic over-topping.
The 2013 flooding of Calgary was the result of a very intense rain event in the mountains upsteam of Calgary early in the spring. The result was an impossible to respond to rate of water trying to pass through the Calgary waterways. The many dams upstream of Calgary were not able to mitigate the event. Scientific evaluations have been performed to try to determine what run-off events could occur and what features may best mitigate those potential events, and rapid climate change adds significant uncertainty to those evaluations.
There have also been cases in Calgary of very recent wind events resulting in parts of buildings, including window panels, being blown off of already completed buildings that have been standing for many decades.
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Jim Eager at 00:50 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Reason_4: "I am still mystified why fugitive CH4 from fossil fuel extraction or transport seems to be treated in the same way that CH4 from ruminant livestock is treated or accounted for."
Simply because the atmosphere does not care where the CH4 comes from, the additional forcing is the same regardless. -
Jim Eager at 00:46 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
Saileshrao, sorry, but simply asserting that livestock respiration is anthropogenic does not make it so. It is still atmospheric CO2 in, atmospheric CO2 out. Overgrazing degradation of range land and desertification are serious but separate issues.
saileshrao: "biomass of livestock megafauna today is 5.5 times the biomass of ALL megafauna from prehistoric times!"
Citation please. The pre-European population of North American bison alone was in the order of 20-30 million.
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bjb11213 at 00:19 AM on 4 December 2015Uncertainty is Exxon's friend, but it's not ours
In most legislations, ignorance is no defence.
I wonder if there is a case in US or world courts for suing Exxon for their share of the climate damage done since 1980, when they became aware of the consequence of their actions. I say this with some reluctance as I'm well aware that the primary beneficiary of any action would be lawyers hired by both sides of the argument.
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Tom Curtis at 00:18 AM on 4 December 2015How much does animal agriculture and eating meat contribute to global warming?
CBDunkerson @44, an excellent summary. It is, however, a little over pessimistic. Research is being undertaken into how to reduce methane from enteric fermentation and from rice cultivation. Further, given that amospheric methane concentrations must be near the equilibrium value for current emissions (else the plateau of concentration over the 1990s would not have occured) such measure may feasibly limit future growth in CH4 concentration - although it is dubious, in the face of the need to feed a more than doubling of the human population, that they will permit a decease in concentration. Of greater concern in that regard is NO2, whose longer residence time means it is nowhere near equilibrium, and where reduction of agricultural emissions is more limited in potential scope.
The point remains, however, that the key task in to reduce CO2 emissions. That is not only because it is CO2 emissions alone that will cook us long term, but also because tackling CO2 emissions is likely to lead to the technology to generate slightly negative net emissions of CO2 as a compensation of whatever persistent forcing from CH4 and NO2 exists.
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knaugle at 23:19 PM on 3 December 2015Uncertainty is Exxon's friend, but it's not ours
@One Planet Only Forever
Another way to explain your point would be to consider dam construction. In my area, state law requires dams to be able to withstand a 100 year flood. That would be something like what Hurrican Camille did to Virginia back in the 1960s. However, if climate change makes the 100 year flood more like whatis now a 1000 year flood, then everything we build is rather underdesigned. Even in this case, there well always be someone who thinks a 50 year flood is plenty.
It is not that there is uncertainty in climate, weather changes one year to the next, but that climate change itself quantitatively changes the uncertainty in weather parameters that must be assumed in the design process. It may well be that today's robust design in 50 years is woefully inadequate.
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CBDunkerson at 22:48 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
I think we have established that the long term impact of livestock methane emissions is likely to be very low (when we consider that it will decay to CO2), zero (when we consider that the emitted carbon is essentially re-cycled from the atmosphere to begin with), or even negative (when we consider carbon sequestration from waste).
Given this plausible range of 'very little harm' through 'some benefit' it seems clear that we can pretty much ignore the issue. Long term, methane from livestock isn't going to be a problem. The same can probably be said, for similar reasons, of methane from rice production and even landfills. Methane from fossil fuels doesn't have the 'recycling' and 'sequestration' conditions, but it still decays to CO2 and thus will have a small long term impact... especially as it will inherently decline if/when we get the much larger direct CO2 emissions from fossil fuels under control.
Ergo, I would argue that we can all but ignore methane for long term planning purposes. We need only look at its 'short term' (e.g. through 2100) impact. Unfortunately, given Tom's analysis and IPCC flow diagram, there I do see a problem. So long as the human population continues to grow I see very little chance of preventing methane emissions from livestock, rice, and landfills from also growing in response. That will mean continually increasing emissions and atmospheric levels. In one sense, these human activities which temporarily convert some of the CO2 to methane are one of the 'sinks' slowing the growth of atmospheric CO2 levels... which unfortunately results in a net warming increase. That means, short of radical changes to the global food supply and/or waste handling, the 'short term' warming from methane will continue to grow so long as the global population does.
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Dikran Marsupial at 22:17 PM on 3 December 2015Murry Salby's Correlation Conundrum
BTW from figure 1, you can see that the net natural sink has been growing over time, which suggests that the net natural sink is a response to increasing anthropogenic emissions. If you extrapolate backwards I suggest you will find that the net natural sink would hit zero sometime in the 19th century. In reality a small net natural sink has been in existence for rather longer, but the rate of increase isn't exactly linear, so the extrapolation doesn't give a precise estimate.
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Dikran Marsupial at 22:08 PM on 3 December 2015Murry Salby's Correlation Conundrum
"If the earth system is a net sink for CO2, and if human contribution prior to the industrial revolution was insignifigant, then shouldnt the long term trend of atmospheric CO2 prior to that point in time be headed towards zero ? "
No, the carbon cycle has feedback mechansims that tend to increase the amount of CO2 in the atmosphere and others that tend to decrease it. So if you leave the carbon cycle to its own devices, it eventually finds an equilibrium atmospheric concentration and stays fairly constant (which is what we observe in the ice core records, during interglacials, the level returns to more or less the same level each time). However, if you do something to upset the balance (e.g. fossil fuel emissions), then the various feedback mechanisms tend to act to try and return the atmospheric levels back to normal (this is apparently known as LeChatellier's principle). The reason natural emissions and uptake are out of balance is because anthropogenic emissions have perturbed the previously stable equilibrium. In pre-industrial times, natural emissions and natural uptake were approximately balanced, and so atmospheric CO2 levels were relatively stable.
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Reason_4 at 22:01 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp and Jim Eager @ 34 and 35
I'm well aware of the difference in warming/forcing potential between CO2 and CH4.
I am still mystified why fugitive CH4 from fossil fuel extraction or transport seems to be treated in the same way that CH$ from ruminant livestock is treated or accounted for.
Yes, both have the same forcing potential, but one is at least carbon (not forcing) neutral while the other ... isn't.
Let me try another way. We have yet to raise ruminant animals on our mini farm, but more from lack of knowledge and unwillingness to be tied to the property 365 days a year than for any environmental concern. But it is in the long term plan.
When we do I want to be well armed to defend our choice against those that say we are destroying the planet by keeping cattle or sheep. I will hopefully convince someone from the local Uni to take some before and after soil samples to demonstrate the increased carbon sequestration nutrients from large animal manure helps create. If we can point to greater carbon sequestration than is likley to be emitted, and there is no need for externally sourced feed or fertilisers, we would be justified in stating the meat we produce is carbon negative ... right?
If we can justifiably make that claim ... again, just why is fossil fuel sourced methane treated exactly the same as livestock sourced - because if that is all that is counted, our carbon negative cattle ... are anything but. Right?
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Dikran Marsupial at 21:53 PM on 3 December 2015Murry Salby finds CO2 rise is natural
The first factual error he makes is at 1:15 and is the first piece of scientific information given in the talk. He says:
"The IPCC position is exclusive; the increasing CO2 results from anthropogenic emissions entirely"
This isn't actually true, in AR5 says (page 493)
"With a very high confidence, the increase in CO2 emissions from fossil fuel burning and those arising from land use change are the dominant cause of the observed increase in atmospheric CO2 concentration"
The reasons they say "only "dominant" is because there are also emissions from cement production, but also to allow for the possibility of some component due to ENSO (I know this because I asked for clarification). So Salby misrepresents the IPCC in the very first statement. Not a good start.
The fact that the natural environment is a net carbon sink is, somewhat ironically, established by the equations he gives on the slide from 5:12. If instead of plugging in the IPCC estimates for natural fluxes, you use the observed growth rate to infer the difference between natural emissions and natural uptake, you find that natural uptake is always greater than natural emissions. This directly refutes Prof. Salby's conclusions, and he has been informed of this, but he contines to ignore that and doesn't mention in in his talks. You can find an explanation of why in my article on an earlier talk (I sent him a copy for comment before publishing it, but recevied no reply).
My article also explains his mathermatical error that starts with the following slide (note he never states exactly how he gets the data for that graph, and ignored my request for clarification).
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saileshrao at 20:08 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
Jim Eager @ 35,
Livestock is NOT in equilibrium with the environment as the accelerating desertification of grasslands and pasture lands clearly shows. Indeed, the biomass of livestock megafauna today is 5.5 times the biomass of ALL megafauna from prehistoric times! Therefore, the breathing contribution of livestock is an anthropogenic contribution to the imbalance in the Earth's carbon cycle.
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saileshrao at 20:00 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
Tom Curtis @28, HK @ 33,
Pierrehumbert's argument is that methane concentrations in the atmosphere will decay exponentially with a short half-life of 12.4 years. That is clearly not the case in reality as we continue to pump fresh methane into the atmosphere year after year, while pretending that methane is benign compared to CO2.
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RedBaron at 19:53 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp #39
That is an excellent point. Sometimes people, even great scientists, get so wrapped up in the minutia of detail, they overlook the the bigger picture. The same thing that can be asked about rice paddys can be asked about meat production. How is it that the grassland/grazer biome responcible for long term global cooling on the planet, is now contributing to warming? (see post #21) What has changed since the industrial era? If you approach the problem from that perspective, I think the science is where the change in production methods might change the fundamental balance in the carbon cycle. That's where your interesting research can be found. What are the differences between a grassland/grazer biome and a cropland biome where the animals have been removed and instead raised in CAFOs? Rather than blame the animals themselves for AGW, I personally think the only conclusion anyone can make is the production methods have changed.
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bozzza at 16:05 PM on 3 December 2015Uncertainty is Exxon's friend, but it's not ours
@4, uncertainties change. The problem is no one can put their finger on any solid numbers with enough certainty to warrant investor panic.
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bozzza at 16:00 PM on 3 December 2015Uncertainty is Exxon's friend, but it's not ours
@1 the point you raise is, I suspect, even more poignantly significant, if not terribly ironic, than you first thought.
Ignorance of the law is no excuse: but of the moral law apparently not so!
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scaddenp at 12:12 PM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
What matter with paddy production though is how much is it changing? Absolute emissions arent as interesting as how much change has occurred in 20-21 century.
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Digby Scorgie at 11:01 AM on 3 December 2015The Road to Two Degrees, Part Two: Are the experts being candid about our chances?
Tom Curtis, I think your final paragraph is the one that's really relevant. It relates to the very first graph in the above article, from which we see that we only have about two decades in which to make drastic reductions in fossil-fuel use. And there are some parts of the fossil-fuel system that are built to last quite a bit longer than two decades — ships, aircraft and coal-fired power stations are some that come to mind.
Anyway, Tom, I don't know about you, but I find myself in the position of someone having an interesting philosophical discussion on the deck of the Titanic — after the ship has hit the iceberg. But then, being an old man, I can afford to take a dispassionate view of the whole catastrophe.
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Mal Adapted at 10:47 AM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
Thanks to scaddenp for the reference to table 6.8 (not 5.8, sorry), on page 507 of the AR5 WG1 report. It shows that in the interval 2000-2009, rice cultivation contributed 36 Tg/year to the total 331 Tg/year of anthropogenic methane emissions, compared with 89 Tg/year for ruminants. I'm not surprised that vegans aren't calling for an end to rice production, however.
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scaddenp at 10:22 AM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
RedBaron, i am in no way claiming that ruminants are only source of biological methane. I am really claiming that if you increase the number of ruminants (in particular since pre-industrial benchmark), then you are getting more methane into the atmosphere than if you had left them at preindustrial level. Increase in methane from any source is a concern, but the to-date, increase in ruminants is a major source. Numerous papers on this cited in IPCC report and working groups on methane. A review paper here could be starting point. Other sources of anthropogenic methane including paddy agriculture, landfills, manmade lakes/wetlands and waste treatment are considered in CH4 inventories. Table 5.8 in IPCC AR5 WG1 report lists source of methane with references. (Ruminants contributing 89 Tg/year of the total anthropogenic source of 331). The same table also lists natural sources but for consideration of change in methane level (and hence warming), it the change from pre-industrial at matters.
Note also that 2/3 of methane production from cattle is enteric rather than from manure.
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RedBaron at 09:48 AM on 3 December 2015How much does animal agriculture and eating meat contribute to global warming?
@scaddenp #34
Please supply some citation showing that this statement "there is more GHG effect than you would have if you had no animals (or no ruminants)." has been properly analysed and is true. Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. That certainly is true. But they are certainly not unique to ruminants. In fact methogen archaea are ubiquitous in the environment and soils. In some areas for example termites far exceed the methane production of any ruminants. Nor are methogen archaea the only source of methane produced by decomposition and incomplete oxidation of the products of photosynthesis. Nor is methane oxidation in the atmosphere the only way to reduce methane to CO2 as methanotroph prokaryotes are also ubiquitous in many environments. I have yet to see any documentation of any analysis of methane production that proves ruminants increase atmospheric methane over other forms of decomposition or incomplete oxidation of organic material except in the artificial feedlot/cess pool production model. And even then the methane can be collected and used as a biofuel.
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