Replying to a comment! Again!

This is another reply to another great comment posted on the 'Free the Turkeys! Put down that fork!!!' post made on Christmas Eve! Yulia K wrote:

"I agree, the last video you posted is very insightful, reminding us of the priorities. I like the idea of using pee for P and hope it materilizes, as this will provide us with a renewable source of P, alleviating one of the numerous global problems. However, your last three posts also made me realize something more gloomy, which is that in reality people choose to lead an unsustainable lifestyle, such as choosing to consume meat, and shift the blame for problems such as the global food shortages onto factors like biofuels, for example, which is what I am writing about in my blog. 

It takes 3-4 times more P to support a meat-based diet and also more land to cultivate meat, as land is needed to produce cattle feed too. This means that meat production uses more natural resources, indirectly resulting in the food shortages. If we evaluated what our priorities are and all took responsibility for our own actions, would it not make more sense to lead a less meat-intensive diet, as this would free up the natural resources, such as land and P? 

I find this issue very relevant to biofuels, as decreasing our meat consumption and food waste would likely result in less food shortages and free up more land for activities such as sustainable biofuel cultivation, which should result in GHG emissions savings and greater energy security. Would this not be more useful than leaving all as it is at present i.e. blaming so much on biofuels, for example, as the Gallagher Report (2008) seems to do, preventing the cultivation of biofuels, carrying on with our meat-intensive diet and high P consumption to then realize in the future that food shortages are still increasing as more and more people consume more, P and fossil fuels are running out and we are not prepared for that, and our GHG emissions have not decreased.

While I am also a hypocrite promoting a vegetarian diet here, my point is that I feel that too much emphasis is placed onto blaming industrial activities for the global problems and very little onto us, the consumers, which is not always useful. Therefore I very much agree with you that we should take greater action as citizens (I think this is what you were trying to say, if I understood correctly), even though technological fixes may help."

My Reply:

Thanks for this EPIC post!

You are right; if we did eat less meat, then it would be significantly justifiable to produce more biofuel. However like every other resource or commodity it falls down to the distribution of the meat that is important. If the cost of meat actually took ecosystem service costs into consideration as well as environmental valuations then the cost would increase and there are potentially two outcomes: decrease in demand, reducing consumption; increase in 'innovative' ways at maximising profits to reduce cost production and increase consumption through economies of scale.

The first way would disproportionately affect those who have the lowest incomes as cheap meat is sometime the only source of protein in a diet as most substitutes cost a lot more. The second would lead to further environmental and ecological degradation as intensive farming would become more intensive at the cost of land quality, animal welfare and pollution.

The second point is relevant due to the EU 'wide' ban onBattery hen egg farming. A reported 80 million hens are being 'freed' (some are going to be slaughtered) due to new legislation preventing the use of the current intensive hen cages to produce eggs; a new 'enriched' cage (37% bigger) has to be used.

This results in a just bigger than a sheet of A4 paper space per chicken in a cage. Not that nice! (some info on ending factory farming here).

If we all became concerned consumers and thought about our individual actions then we would achieve a lot more than holistic legislation which is passing the buck of responsibility to people we pay and elect to act for us. I agree with you. Consumption is the problem; and as consumers, we are the ones who have to change OUR habits.

I hope this reply isn’t too bad! I like posting long posts too! :D

Add a little P, get a load more Poo! Part 4: P reserves and losses!

Cordell et al. (2009)’s paper on the story of phosphorous is a MUST READ! 

It is packed full of information on the subject… but I will try my best to extract the useful information. Being half Moroccan (half Italian), I can’t help but rub my hands with glee… the largest stores of P are locating in the country (regardless of what anyone says, Western Sahara does not exist in Morocco; we call the southern provinces… moving swiftly on…!) as shown in the figure below from Elser and Bennet (2011). 

This is however a big problem in terms of global securities and power balances. With turmoil in north Africa and the apparent ‘revolutions’ reaching their 1^st birthday, it is more important than ever that food and the fertiliser used, does not fall into the same fate as it did 3-4 years back with the large prices rises in grains (Elser and Bennet, 2011). 700% price rise in P coupled with the price rise signalled a warning light to governments worldwide. However, as Cordell et al. (2009) and Elser and Bennet (2011) note, the world still is not reacting to this train wreck; they can’t even pull their act together on gas emissions and the Kyoto agreement (COP Durban 2011 round of talks).

One thing is for sure is that if we use less, costs will go down and we are less dependent on another out-sourced commodity that everyone needs. If we all became vegetarian, then we would require significantly less P than a meat based diet, and most of the crop can easily be returned to the soil as residue, recycling most of the P used as a fertiliser. Even so; the largest wastage of P originates in the poor application of fertilisers to soils (8 million tonnes, MT). Leeching of the synthetically produced nutrients results in massive inefficiencies in P management; contaminating ground, surface and coastal waters with high levels of nutrients had led to vast amounts of eutrophication.

Eutrophication is when nutrients (either via leeching direct from fertilisers or poor waste management) added to water bodies causes the growth of organisms; algal blooms are a common example of added nutrients altering the natural ecology of a body of water (lake, sea, estuary, etc.). (Smithand Schindler, 2009) The blooms photosynthesis at high rates, starving most other organisms of oxygen (increased when the blooms die and decompose); creating a hypoxic environment.

Please read more on eutrophication in these sites:

• http://rtseablog.blogspot.com/2011/03/eutrophication-mapping-first-steps-that.html
• http://feastingonnaturalresources.blogspot.com/ This blog, by Megan Smith is great! She also talks about agriculture and environmental issues surrounding the wider debate. I highly recommend her post on Coastal Eutrophication – The impact of Agriculture in Chesapeake Bay

Back to wastes of P and as the figure above (Cordell et al. 2009) suggests, 14/17.5 MT of P go to agriculture; of that only 3 MT make it to our forks. 8 MT is wasted through poor application, and of the 3 MT we consume as food, 1 MT is wasted as spoiled food. By just eating within our means we save 1 MT. through better fertiliser management techniques with save an extra 8 MT. It is easier said than done, but through accurate monitoring of soil nutrient levels, we can guage whether or not the land needs to be fertilised, saving energy, money and effort as well as P. Using more natural fertiliser we can solve some of the problems, by no means is sh… poo a panacea for eutrophication/power insecurities/commodity prices/waste management/agricultural productivity and the like, but it is a step in the right direction!

Reserves of P aren't well documented globally, in fact many researches, scientists, geologists and mad hatters disagree as to how much P there is under ground. Cordell et al. (2009) explores this using a number of different scenarios showing just how long it would take, depending on how much P we need, to finally hit the last nail on the head of the coffin that would be global inorganic P reserves. 

Next part coming soon!

Free the Turkeys! Put down that fork!!!

Less than 1 hour to go, I fear that there is not enough time… the turkeys/chicken/pigs/sprouts are already dead and in your fridge…MURDERERS! (lol jk!)

So… whilst you tuck in to your no doubt incredible spread for Christmas dinner/lunch (or even breakfast-weirdoes!) and maybe saying grace, spare a thought about the meat you’ll be eating - not about the most probably sad lives they had running, well squeezed walking, cooped up in a large industrial scale production house – but the emissions they produced and the smell *coughs*.

I could give you a lecture on ethics of meat production but that would be so hypocritical I should be arrested (although there is an interesting resource of literature and media on this very subject I would strongly advise you to read and look at like this site!)… so instead let’s talk about Christmas dinner! From the material highlighted in the videos shown and the post earlier; all livestock, like any animal produces emissions directly and indirectly. Christmas comes but once a year; unfortunately for us, but fortunately for the environment and those lovely, tasty succulent…*drools*… om nom nom… err…those birds.

Poultry (chickens/geese/ducks/turkeys) accounted for 61 million tonnes of CO₂ in the year 2002, and numbered around 17 billion (a head) globally (LLS, FAO 2006)…weird thinking they’ve all almost certainly have been eaten. That number astonishes me! And that was nearly 10 years ago! Our love of poultry is incredible, 29.06 kg/capita/year is consumed in the UK alone for the year 2007 (great stat website! http://faostat.fao.org/). That’s a load of emissions; not to mention the fertiliser gone into producing feed (such as corn) for the poultry.

Once a year is acceptable, but maybe we should begin to scrutinise our lifestyles. Poultry is by no means the worst offender; on the contrary it is more emission efficient than ruminants like cows (where’s the beef?). Like most things in life, the case of moderation persists.

This website also shows some meat consumption data in map form (I love maps I do!), and there is always the great worldmapper site!

Livestock production, as I hope to have shown throughout this blog touches upon a wide variety of topics; whilst on the subject of phosphorous, the next posts will be on resources, depletion and pollution… more still to come!

So wherever you are, whatever you may be doing… have a Merry Christmas!

Replying to a comment!

I felt this deserved a whole post because I wrote too much to respond in a comment; the comment too (by Emily Smith who has a great blog called Treading on thin ice; about glacial melt and it's consequences - its great please take a look, I am not doing it justice!) highlights some issues that we face in the coming decades.

Her original comment was: 

"You're right it is a really provocative video. I hadn't even heard of the riots in 2008, let alone known they were partially due to phosphorus shortages. It really makes you think about our priorities, especially if the peak could be reached by 2035. Even if the peak is in 300-400 years like the Fertiliser Agency stated, its the wrong attitude to pass it off to future generations to deal with. Saying that, I'm not sure how many people, me included would be willing to give up meat. And even if they did, if it's a finite resource, I wonder what proportion of the population can be sustained when the phosphorus resource has run out? Not 7 billion I expect."

My Response:

It is very true, I personally love to eat meat occasionally, but how much meat we eat I feel is the question. Humans have always eaten meat, and in some parts of the world, meat is reared without the use of extensive amounts of resources, for instance well within the ‘carrying capacity’ of certain countries; especially subsistence farming.

Intensive agriculture has resulted in massive amounts of fertiliser being used when it is not even required (Europe for instance; I have read this in a journal article but fail to remember at the moment!). We eat a lot of meat, but by just looking at any reduced aisle in any supermarket we can see huge amounts of meat wasted; no one buys every meat product. Just think, how many times have you walked past a butchers or a deli counter in a supermarket and thought about buying meat a few days to expiration and left it? Or even thrown out some left over gone off meat? Please do not think I am accusing you personally of this (lol!) but society is wasteful, regardless of how conscious we are individually.

By reducing waste in the consumption of meat, I’m guessing (not very academic here!) that we will naturally produce less meat, or meat per capita. The alternatives of a low-meat high-protein diet result in either large shifts in diets to legumes/beans/soya (which the cows generally eat as feed now) or fish. Fish is one of the most consistently exhausted and depended upon food sources we have, adding more pressure could cause greater depletion of an already controversial ‘commons’ resource.

The fact that meat production will almost certainly increase in line with demographic change requires a renewable source of P, that’s where natural fertilisers come in. Like the video material has shown, P is not really absorbed by our body, so most of it passes straight out; the P used to make the meal for one person is now available to be used to make food for another person. We just need to roll this out on a large scale, thanks to urbanisation; the feasibility of capturing P from human waste is easier from cities. There is a great potential in harnessing P; and there are just as interesting ways of utilising this resource which I hope to explore in greater depth soon!!!

Sorry for the long reply! :D And I hope you do not mind me using your comment!

Add a little P, get a load more Poo! Part 3: Video time...AGIAN!

This video is from an Australian Broadcasting Corporation (ABC) did a special on... you guessed it, peak P!


It is a really interesting video investigating the potential for utilising urine for nutrient extraction. I love the toilet! However, the man said that men will have to sit down... errr has anyone ever told him men can aim where they pee? This is very disturbing....


There is also a related article on the website. Please read!

Add a little P, get a load more Poo! Part 2: Video time!

This video summarises the main arguments around P, and it's in green (my favourite colour!). I particularly like the part about doing your part whilst sitting...just one letter away from what you're actually doing!

Add a little P, get a load more Poo! Part 1: The whole debate around fertiliser.

Livestock feed on animal feed which is produced from some main ingredients which include: corn, soybeans, sorghum, oats and barley. The more cows you want to milk, the more plants you need to grow to turn into feed for the cows.

Plants, like every other living creature, needs nutrients to live, grow and reproduce. This is where the whole debate around food security comes in, and an element we call Phosphorous (P).

P is necessary for living organisms, in the case of plants, phosphorous is used not just energy pathways (respiration) but also growth and most constrainedly, root growth and so uptake of other vital nutrients.

Now agriculture is a business...a very big agri-business. To maximise crop production and yield, you do not want the amount of P in the soil to limit growth, this is the same for the other vital nutrients (Nitrogen and Potassium). NPK fertiliser is added to soils to allow plants to grow. But where does this fertiliser come from... we have known for millennia that poo is just as good a fertiliser as anything else, once more it's natural and we have loads of the stuff!

The mining of P for decades has started to make people wonder... we have had a peak in oil production...will the same happen for phosphorous? Short answer yes. With any finite resource, which P is one, there will always be a peak, and a downward trend following it.

So as I begin to shed light on the nutrient side of things, here is an article calling peak phosphorous into the light, and the implications it might have on foreign policy and food security... who'd 'a thought it... cow poo is related to international relations eh?!?

POO POWER! Part 3: Thames Water using our crap!

Thames Water are harnessing the power of sewage waste that comes from our toilets... that's right one man's waste is another companies fuel.

The article, from the guardian, explores the potential for energy production at the plant:

"The company estimates that 16% of its electricity needs will be covered in the current financial year by so-called poo power – enough to run about 40,000 average family homes – from a total energy requirement of 1,300 gigawatt hours."

Expanding this technology to all waste treatment works will save a lot of unnecessary carbon dioxide emissions from either producing energy from conventional combustion processes or letting the waste decompose anaerobically producing methane.

POO POWER! Part 2: Motorcycles, S**t whilst you ride?!?

Hold the toilet! What's this?!?


In an earlier post I said don't start peeing/crapping into your Mercedes... well now you can into your new toto motorcycle!


Ever had the urge to poo while riding down the motorway?


Do you get s**t scared when riding with your motorcycle buddies?


Well this is for you!

This new motorcycle, produced by toto operates using a "one in, one out" policy. You put food in one end (your mouth) and get fuel out the other (your... well if you don't know by now where it comes out SHAME ON YOU, I refuse to degrade this post to enlighten your curiosity about bowel movements).

The vehicle breaks down the poo into biogas (methane) and runs on the combustion of that fuel; reducing emissions from what would have otherwise been used, petrol/oil.

The only downside is privacy... and I really wouldn't want to be behind this driver in a traffic jam!

Meat the truth! Documentary Time!

This documentary, presented by a Dutch MP (Dutch Party for the Animals - might be a little biased) explores the role livestock plays in GHG emissions; pretty much what this blog is designed for!

The whole documentary is a great watch, please do!

To eat or not to eat meat… That is the question! Part 1: is it all demand?

When people debate the issue around livestock and the negatives of increasing production of meat and livestock associated products many say we should reduce meat consumption.

REALLY?!?

Now sure, one way we COULD reduce emissions from livestock is to cut down on our sausages, chicken legs and kebabs; after all, less cows and sheep farting, less direct methane emissions. But there are other issues around more animals on the planet that feed our hunger for meat. This paper by McApline et al. 2009 looks at environmental degradation in Colombia, Brazil and Australia due to expanding beef production and the deforestation it causes.

A big issue around emissions from livestock is the fact that there are large indirect GHG emissions from forest clearance and land use changes. The paper looks at factors that have increased beef production and surprisingly, in some countries like Brazil, it is not supply and demand which dictate beef production and emissions; its land prices. Land policy in Brazil has made it more profitable to clear once natural rainforest and keep it clear than let it be. The cheapest way to keep vegetation from establishing again is to regularly cut regrowth… cows are surprisingly good at turning grass into milk, meat, leather and other useful products for human consumption. This not only has a dramatic effect on local ecosystem services and physiography; the global consequences include depletion of the capacity for natural carbon sequestration.

Meat is big business. Curtailing meat production will directly affect the economies which rely mainly on agriculture and the primary sector. This is a controversial topic as if a country is able to utilise its natural resources within its territory for economic means and development ‘at the expense’ of the environment, who are we to judge? We chopped down our ‘oak’ forests centuries ago to fight wars with continental Europe. With the specific driver of meat production in this context being land management, economical profitability and natural lawn mowers; there is an assumption that if the main driver of livestock (beef) expansion being the one stated, then whether you eat the meat or not, there still will be emissions from it, albeit highly inefficient per capita of digestion. In the case of Australia, land management reform in the favour of protecting old growth forests has reduced the profitability in expanding cheap, subsidised (through tax incentives) cattle ranches. This protection has worked, again regardless of whether Sheila or Russell eat steak or love veggie burgers.

However, with all business, it is fundamentally based on a market; therefore demand. If demand for meat (whatever the reason) decreases; then production and emissions would – economically speaking – decrease too.

I will explore more arguments around decreasing dependence on livestock as a food source. However, I am guessing it isn’t as straight forward as I think it’s going to be!

POO POWER! Part 1: Cars powered by poo!

For those of you who like to drive but are concerned about the rising costs of fuel and environmental issues around its production, this is for you!

This video and this news article in the Guardian explains all!

A water treatment plant in Bristol, part of the Wessex Water group of companies, is producing methane from human waste flushed down the loo! The biogas could resolve some sustainability issues around fuel for cars, as the man at the end of the video says:

 "As long as there are people, cows and chickens, they'll be methane."

I agree...

However! Even though biogas is sustainable and is beneficial in terms of dealing with increasing amounts of waste that we will produce, the fundamental problem is the fact that it is still a form of combustion; combustion = CO₂. 

So, on the one hand it's sustainable and uses the methane that would otherwise contribute a more to global warming in the short term. On the other, it doesn't address the underlying dependence on carbon dioxide producing processes which will inevitably exacerbate climate change. 

PEE POWER! Part 1: MCFs

The moment we have all been waiting for is here!

Pee can be used as a fuel... revolutionary! The article  looks at the potential of using the compounds in urine to produce electricity using microbial fuel cells (MCFs). These little packages of micro-organisms use the biomass in urine and converts it into a form of renewable energy; renewable in the sense that as long as we're living, we're peeing!

Ieropoulos et al. (the authors of the article) go on to highlight the importance of this research and the wider implications of this technology. It offer one was or extracting N, K and P nutrients from urine which are often at high concentrations and out them to good, fertilising use; rather than spending billions to treat this waste water straight away, we could utilise more of the power from it and it will push treatment costs down; energy security, it just so happens where more people live, who all demand energy, more pee is, what a coincidence!

Animal urine can also be used... the possibilities are endless! But don't start filling up your car with the yellow stuff just yet...

Fossilised farts (and other agroGHGs)! Part 3: The critiques of fart records: it’s ALL NATURAL.

Now both articles (Fuller et al., 2011; Ruddiman et al., 2011) and their side of the debate have critiques. From these graphs (from Ruddiman et al., 2011) they become evident:

In the first (A) graph you can see that the relationship between CH₄ concentrations and population is not constant. Initially CH₄ per capita increased proportionally, then methane rose steadily whilst population was rising exponentially. This decoupling is down to (what Ruddiman et al. 2011 note from Ellis and Wang in 1997) different land production efficiencies and priorities. With increasing intensification techniques, like rearing cattle, more land and plants are needed as well as primitive ruminants who haven’t been selectively bred to maximise meat or milk production yet. These inefficiencies which increase CH₄ release (IPCC, 2006) where only dealt with during the latter half of the Holocene, this is just one argument supporting anthropogenic methane emissions prior to the Anthropocene; this decouples methane and population, whilst explain the change in rates. Also land use per capita dropped, as seen in the second graph, that is not to say that the early human pastoralists had large herds of cows farting across the once green, bread-basket of the Sahara, it just highlights primitive techniques of farming. Quantifying the contributions of CH₄ into rice agriculture and livestock rearing category is hard as more research needs to be undertaken (Fuller et al., 2011; Singarayer et al., 2011).

Picking up on the point of the inter-polar gradient (IPG), Chappellaz et al. (1997) investigated the difference between the polar records of methane concentrations. Studying the Arctic GRIP ice core and the Antarctic BYRD and D47 ice cores, they attributed the changes in the IPG to initially (5.7 and 2.5 – 5 ka) lower atmospheric CH₄ levels due to the on-going drying of the tropical regions combined with massive peat land growth in the northern boreal regions after 5 ka. With a recent period (ca. 1 ka) increases due to increased wetness and significant anthropogenic emissions. Harder et al. (2007) investigates this further, coupling a GCM with information on the sinks of methane; volatile organic compounds (VOC) and the sea (changes in sea surface temperature, SST). Another vital sink, the largest in fact (and one I hope to investigate further is the hydroxyl radical (­^●OH). Stressing the importance of changes in the various other sources and sinks, Harder et al.’s research show that the IPG changes are the result of dynamics within the ‘methane cycle’, between the balance between the sources/sinks. However, they draw attention to the necessity to improve understanding about how methane may react with other GHGs especially considering the fact that the hydroxyl radical is the sink for many other GHGs. Any anthropogenic influence on the changing methane concentrations either at 5 ka or in the IPG has been sidelined.

This point is underlined by Singarayer et al. (2011) as concluding remarks describe the lack of model evidence successfully calibrating predicted and observed data sets, with an anthropogenic input providing a correct outcome. It goes even further saying, and I quote:

“The late Holocene increase in methane can be primarily ascribed to increasing emissions from the Southern Hemisphere tropics. In the late Holocene, unlike the last interglacial, these increases are not counteracted by equivalent decreases in Northern Hemisphere emissions. We suggest therefore that direct anthropogenic influences are not necessary to explain the late Holocene methane record.”

Rather than the idea of cows farting (as it is quite hard to believe!); Singarayer et al. (2011) looks into possible overlooked variables. Exploring such variables like: glacial extent, and how it may effect subtle changes in the source regions; seasonality of the SH tropical wetland, and the resulting emissions; but most importantly, the link to the Eemian period where the orbital configuration is comparable to the present (and where models attempting to show the anthropogenic link fall short). They reaffirm their point that SH emissions were not counteracted with NH CH₄ emission decreases.

Even Burns (2011) discusses the possibility of an ‘all-natural’ 5 ka methane rise due to tropical produce methane causing the deviation from the expected. Burns looks at speleothem records to infer monsoonal strengths. It shows that the monsoons did migrate southwards, so making the highly productive tropics and areas south of the equator increasingly waterlogged and, ergo, greater CH₄ productive. It does seem that it is a one or the other theory approach… Neo can only take either the red or blue pill. There is no such thing as a purple one. But here, I would suggest that even though evidence is in favour of an all-natural approach. In my opinion one cannot exclusively write out the other, and the debate will go on for ages; but archaeological evidence shows the techniques expansion. Whether you like it or not, ruminants fart, producing methane, as well as humans might I add!

I would like to think that thousands of years ago my ancestors around the Mediterranean were herding farting sheep, farting cows and farting chickens, contributing to increasing methane concentrations in the atmosphere. It was a simpler time; it was a less fartier time!

Reference list for the 3 parts of Fossilised Farts (and other agroGHGs)!

Brook, E. J., Sowers, T. and Orchardo, J., 1996, Rapid variations in atmospheris methane concentration during the past 110,000 years, Science, 273, 1087-1091 pp.

Burns, S. J., 2011, speleothem records of changes in tropical hydrology over the Holocene and possible implications for atmospheric methane, The Holocene (special issue), 1-7 pp.

Chappellaz, J., Blunier, T., Kints, S., Dallenbach, A., Barnota, J., Schwander. J., Raynaud, D. and Stauffer, B., 1997, Changes in the atmospheric CH­₄ gradient between Greenland and Antarctica during the Holocene, Journal of Geophysical Research, 102, D13, 15,987-15,997 pp

Ellis, E. C. and Wang, S. M., 1997, Sustainable traditional agriculture in the Tai Lake region of China, Agriculture Ecosystems and Environment, 61, 177-193 pp.

Fuller, D. Q., Manning, K., Castillo, C., Kingwell-Banham, E., Weisskopf, A., Qin, L., Sato, Y. and Hijmans, 2011, The contribution of rice agriculture and livestock pastoralism to prehistoric methane levels: An archaeological assessment, The Holocene, 21, 743-759 pp.

Harder, S. L., Shindell, D. T., Schmidt, G. A. and Brook, E. J., 2007, A global climate model study of CH₄ emissions during the Holocene and glacial-interglacial transitions constrained by ice core data, Global biogeochemical cycles, 21, GB1011, 1-13 pp.

IPCC, 2006, CH4 Emissions from enteric fermentation,in Guidelinesfor National Greenhouse Gas Inventories Volume 4 Agriculture, Forestry andOther Land Use, writtenby Gibbs, M. J., Conneely, D., Johnson, D., Lasse, K. R. and Ulyatt M.J., , 297-320 pp. 

Ruddiman, W. F., Kutzbach, J. E. and Vavrus, A. J., 2011, Can natural or anthropogenic explanations of late-Holocene CO₂ and CH­₄ increases be falsified? The Holocene, 21, 865-879 pp.

Schlit, A., Baumgartner, M., Schwander, J., Buiron, D., Capron, E., Chappellaz, J., Loulergue, L., Schupbach, S., Spahni, R., Fischer, H. and Stocker, T., 2010, Atmospheric nitrous oxide during the last 140,000 years, Earth and Planetary Science Letters, 300, 33-43 pp.

Singarayer, J. S., Valdes, P. J., Friedlingstein, P., Nelson, S. and Beerling, D. J., 2011, Late Holocene methane rise caused by orbitally controlled increase in tropical sources, Nature, 470, 82-86 pp.

Sowers, T., 2010, Atmospheric methane isotope records covering the Holocene period, Quaternary science Reviews, 29, 213-221 pp.

Wolff, E. W., 2011, Methane and Monsoons, Nature, 470, 49-50 pp.

Fossilised farts (and other agroGHGs)! Part 2: The expansion of Livestock and the debate around the Anthropocene.

Now, studies by Brook et al. (1996); Schlit et al. (2010); Sowers (2010); Burns (2011); Singrayer et al. (2011) and Wolff (2011) all show ice core records and other proxies (analogues for past environmental records) like speleothem (calcite deposits) to show CH₄ and other GHGs like N₂O over the Holocene (11 ka BP; Sowers, 2010) to 140 ka (Schlit et al. 2010). These records show the link between precessional cycles and CH₄ concentrations; but up until 5 ka, the CH₄ concentration deviated from what is expected due to the precessional cycle. The NH has been at an insolation minima due to the precessional cycle being in a NH negative stage (i.e. the southern hemisphere, SH, has more intense summers and winters).

This discrepancy between expected and observed therefore does not follow the natural process. Now shoot me if you must, but I agree with research put forward by Ruddiman, and I am joining in the argument/debate on the Anthropocene. In an article by Ruddiman et al. in a special issue Holocene published in June 2011 (where some of the other 2011 articles from Holocene are taken) attempts to falsify anthropogenic and natural increases in CO₂ and CH₄. The case states that only one other (stage 11) deglaciation has a similar increase in methane after the initial peak and decreasing tail (which would be due to a natural or at least non-anthropogenic process). All of the records (except stage 11) show a decrease of CH₄ in line with NH summer insolation minima. Stage 1 (our current Holocene/Anthropocene) does not follow this trend. Due to the rise and spread of humans through the globe, the establishment of civilisations and the first age of modernity through agricultural development, Ruddiman et al. (2011) and Fuller et al. (2011) show that it is expansion of agricultural practices of wet-rice farming and livestock intensification which is responsible for the anomalous rise in atmospheric methane contribution. This is significant for this blog as it shows (even among scientists like myself… ok I am only a student) humans have had an effect on the greater environment and the Earth’s ecosystems through a variety of anthropogenic process; relating this to livestock they include deforestation (increasing CO₂) and increased agricultural production (increasing CH₄ and later with the green revolution N₂O). This rise is evident 5 ka; that is why I believe that humans have had a significant impact on the earth before 250 yrs BP, it’s been 5 ka that’s how far the Anthropocene extends. This is shown in the graph taken from Fuller et al. 2011. 

Graph showing CH₄ predicted (NH insolation records) and measured CH₄ in GRIP ice core over time.

The Fuller et al. (2011) article looks at agricultural (pastoral and arable) contributions to prehistoric methane levels, using archaeological evidence to match it to the GHG records. This graph from their article shows the deviation from the predicted methane concentrations from the GRIP ice core. The black square points represent actual methane concentrations. The difference between the two data sets is ‘potentially’ cow farts and other anthropogenic processes (causing the deviation). They go deeper, investigating the spatial distribution of the technologies and knowledge of the more intensive (and greater GHG producing) agricultural techniques over time. Here are some maps showing the expansion of livestock practices:

Southern and Eastern Asia Livestock technique dispersal Fuller et al. 2011

Africa Livestock technique dispersal Fuller et al. 2011 

Southern Asia Livestock technique dispersal Fuller et al. 2011

The increased expansion of these farming practices means that more food was able to be cultivated, for direct food (like rice) or indirect food (like livestock feed).  This archaeological evidence shows the actual distribution of the increasing anthropogenic CH₄ sources. Another integral point (that will be elaborated on in part 3 of Fossilised farts) is the fact that the inter-polar gradient (IPG) between ice core records of CH­₄ concentration in Greenland and Antarctica begin to equate (Chappellaz et al., 1997; Burns, 2011). If for instance the NH boreal arctic polar circumference began to emit greater amounts of CH₄, then Greenland’s ice cores will have a greater concentration of the gas than Antarctica’s cores due to the proximity and difficulty of inter-polar diffusion. The fact that the IPG is levelling out shows that the source is low latitude; agricultural expansion into Africa, Southern Asia and South-Eastern Asia can be an explanation to this. Coupled with greater CH₄ emissions from the amazion basin (due to a stronger SH summer) and other low latitude CH₄ sources; this could explain the 5 ka rise. 

Fossilised farts (and other agroGHGs)! Part 1: The natural sources of methane in the past.

Records of trapped gas (of which some are fossilised farts) come from ice cores. GISP2 and GRIP (central Greenland) and the Vostok cores (Antarctica) show GHG levels fluctuating for millennia; stadials and interstadials (Brook et al., 1996). Focusing on methane and nitrous oxide (nitrous oxide will become increasingly significant during the green revolution and greater use of fertilisers), the role which livestock domestication and increased production has played on levels of those gases has been increasing over the late Holocene, correlating with the increasing human population and complementarily food demand.

Butt (pardon the pun), there are a variety of natural and other anthropogenic process which produce CH­₄ (and N₂O). To add to the debate about when humans had a global effect on the planet, we must be able to distinguish the gases between the various human and natural process, and that’s  where the magic happens…err, the science I mean.

The earth has always been able to regulate the gases in the atmosphere thanks to dynamic equilibrium. A long time ago, in a land quite close to home, early Homo sapiens sapiens lived as hunter gatherers and there was no such thing as an economic crisis. Over the last 140 ka (Schlit et al., 2010), atmospheric concentrations of greenhouse gases has varied naturally (as they have done before human mastery of emitting vast amounts of GHGs) due to feedback processes which are triggered by either external (orbital cycles, volcanic eruptions) or internal (organisms, Dansgaard-Oeschger cycles, Heinrich events, oceans) processes (Brook et al. 1996).

In the prior blogs I (hope to) have shown the main anthropogenic sources of the GHGs methane and nitrous oxide (as well as CO­₂, but due to its greater abundance in the atmosphere and number of sources is hard to quantify what proportion is due to livestock processes). These two gases in particular are good indicators of livestock production and other agricultural process as they can have a signal specific to the process of formation and as natural methane is dependent on the precessional cycle of the earth (explained further in part 2) it is relatively easy to predict and categorise as it increases and decreases in line with the earth’s precession. The main sources of methane come from the humble bacteria. Decomposers, who (as the name suggests) decompose organic matter (dead plants, leaves, bodies…err cow poo or rice stalks, to name but a few) anaerobically (without oxygen) which produces methane.

The best way of removing oxygen from soil (where tonnes of organic matter meet with anaerobic decomposers) is through water-logging/increasing the water table. Like any other organic process involving enzymes; the warmer the environment, the greater the rate of the process occurs, ergo more methane.

More organic matter + higher temperatures + greater water logged soils + decomposer bacteria = a load of natural methane!

The greatest sources of natural methane are large areas on earth (where else?) where temperatures are sufficient to allow decomposition to occur, have large stores of organic carbon in the soil and are highly water-logged. The source of the organic material is the crux of the matter, if it comes from cows stomachs via the rectum (LOL) then increasing the cow population directly increases methane produced from anaerobic decomposition, as well as their farts of course.

Tropical/sub-tropical and boreal (peat land) wetlands are the largest sources of natural methane. Other natural sources include termites, wild fires, wild animals farting, methane hydrate release and oceans (Ruddiman et al., 2011). In the ice core records, the direct correlation between the CH₄ concentration and precessional cycle boils down to the northern hemisphere summer insolation. The precessional cycle dictates the amount of summer temperatures in each hemisphere, governing the seasonal intensity (temperatures/precipitation) and the monsoons. As the direction of the tilt of the earth towards the sun changes cyclically over 22-26 ka (Ruddiman et al., 2011), when the northern hemisphere (NH) is pointed towards the sun when at the same time the earth is closest (the perihelion) to the sun then the NH summer insolation is high, increasing temperatures and precipitation, as seen in speleothem records across the tropics (Burns, 2011). Due to the inter tropical convergence zone (ITCZ) shifting northwards, NH precipitation increases the water logged state of the tropical/sub-tropical rainforests and greater insolation heats and melts permafrost in the boreal band across North America and Eurasia; paving the way for those nasty bacteria to unlock the frozen carbon in the form of the by-product that is CH₄.

You see… all those old-fashioned climate sceptic and climate change deniers are right… it’s not the fault of humans; we just have to destroy all those evil decomposer-bacteria that produce this bad gas, get the Dettol at the ready!

Contributions to global GHG emissions in a flow chart!

This flow diagram shows global GHG emissions from different sectors including agriculture; each sector is then divided up into end use/activity which produce GHGs, in this case 'livestock and manure' which is accountable for 5.1% of total GHG emissions directly (i.e farting); not including indirect forms of emissions from deforestation, feed or indeed energy used in their transportation (this is a separate flow).

From this image it is easy to see where the largest cuts in emissions could be from energy generation, especially when considering we have alternatives to conventional (but deadly) fossil fuel combustion.

The image is from: http://www.wri.org/chart/world-greenhouse-gas-emissions-2005.

So what is the problem with excessive farting (also burping, urinating and excreting)?

Why is it even an issue worth discussing in a blog dedicated to the world of excrement? Well the fundamental problem we face, not just as a species, but as inhabitants of earth, is climate change. We humans use the planet as our only home, kitchen, garden and toilet. Like any other confined space, when you begin to change the chemical make-up of the gas enclosed in that volume, you begin to change the overall physical, chemical and thermal properties of that gas. In the case of excrement, methane (CH₄) and nitrous oxide (N₂O) is produced through a variety of processes (as is carbon dioxide, CO₂) which contribute to the greenhouse effect (Popp et al., 2010). Carbon dioxide is the most significant anthropogenic produced GHG due to the sheer quantity that is emitted into the atmosphere from human activities.  

However, as I touched upon in the previous post, over 100 years, the same amounts CO₂, CH₄, and N₂O have varying potencies due to their thermodynamic properties. This property is applied as a ration of heat trapped by one unit mass of the GHG compared to one unit mass of CO₂; this is called the Global Warming Potential (GWP) (Pitesky et al., 2009). As it a ratio, CO₂ has a GWP of 1; CH₄ has a GWP of 23 (in the previous post I wrote that the potency of methane was 20 times that of carbon, it was wrong sorry!); N₂O is 296 (FAO, 2006). From this data, it shows how important methane and nitrous oxide produced from livestock production, and in particular from poo, will be an increasing problem, not just as the total number of GHGs (CO₂ and non-CO₂) is set to increase from projected and modelled figures (Popp et al., 2010). In addition, with populations estimated to reach 9 billion by 2055 (World Bank, 2011) and increasing qualities of life reflecting greater demand for meat in the diet; livestock rearing is set to increase; that equates to a whole load of shhhhh… excrement.

The United Nations Food and Agriculture Organisation (FAO) commissioned a report on the impact livestock production has on the planet,Livestock’s long shadow (FAO, 2006). As a whole, livestock (either directly or indirectly) is responsible for 18% of total anthropogenic GHG emissions (FAO, 2006); those figures broken down into individual GHG include:

·  Carbon dioxide (CO₂) 9% of global anthropogenic emissions.

·  Methane (CH₄₎ 35 – 40% of global anthropogenic emissions.

·  Nitrous oxide (N₂O) 65% of global anthropogenic emissions.

·  Ammonia (NH₃) 64% of global anthropogenic emissions.

However, as I will investigate later on in the blog (or further towards the top of the blog), Excretion and everything  does not just play an integral role to GHG emissions, it also plays a vital role in the nutrient cycle, particularly phosphorous and nitrogen. Phosphorous (P), as well as nitrogen (N) in the form of nitrates and other vital macronutrients like magnesium (Mg), potassium (K) and calcium (Ca) are required as well as a variety of other micro nutrients (Robinson, 2004). Phosphorous is often a limiting factor in plant production, due to its vital role as an ingredient in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), the building blocks of life; and in the Adenine triphosphate (ATP) which is the primary method of intracellular energy release and storage (Biology-Online, 2011), so we can all move, keep warm and most importantly… LIVE! Also, specifically to plants, P is necessary for healthy root growth, vital for the uptake of water and the other nutrients. The role fertiliser plays is significant, and indeed focusing on one of the nutrients, phosphorous, an increasingly important point has surfaced. Livestock (cows for example) need to eat; feed is created from plants; high amounts of land and biomass is required to produce vast amounts of feed; limited land resources dictates more intensive farming methods; greater dependence on higher yields; synthetic fertilisers created to provide the vital nutrients for plant growth; mining of phosphates from a finite source requires large amounts of energy whilst depleting the source.

As you can see, just from scratching the surface, cow (and other animals’) farts and poo pose a more serious problem than the humorous connotations applied to them suggest. Over the next few weeks and posts I hope to show you a greater insight in to the world of climate change, nutrients (re)cycling, pollution, eutrophication, renewable energy and many, many more uses, and subjects, which poo influences.

This blog may overlap with others, in fact it will. A post by fellow GEOG3057 blogger Emma (I hope she is Ok with me using her name), touches on the renewable potential of methane gas from… well cow farts. Another blog dedicated to the debate around biofuels can also shed light on the increasing diversification of energy sources, by another fellow GEOG3057 blogger Yulia. But those topics are for another time!

Next I hope to give you an insight into past methane releases and the relationships between the potent GHG and the atmosphere, looking at palaeo records of methane…essentially fossilised cow farts… Ok well some of the methane was produced by pre-modern time cows farting. Until then… watch those deadly emissions!

References:

Biology Online, 2011, ATP Definition. Available from: http://www.biology-online.org/dictionary/Atp. [Online] accessed 24/10/2011.

FAO, UnitedNations, Food and Agriculture Organisation, 2006, Livestock’s Long Shadow: Environmental issues and options, FAO-UN:Rome.

Pitesky, M. E., Stackhouse, K. R. and Mitloehner, F. M. 2009, Clearing the Air: Livestock’s contribution to climate change, Advances in Agronomy, 103, 1-40 pp.

Popp, A., Lotze-Campen, H., Bodirsky, B., 2010, Food consumption, diet shifts and associated non-CO₂ greenhouse gases from agricultural production. Global Environmental Change, 20, 451-462 pp.

Robinson, G. 2004, Geographies of Agriculture: Globalisation, restructuring and sustainability. Harlow: Pearson Publications Limited.

World Bank, Development Research Group, Human Developmentand Public Services Team, (Das Gupta, M., Bongaarts, J. and Cleland, J.) 2011, Population, Poverty and SustainableDevelopment: A Review of the Evidence, World Bank: Washington D.C., WPS5719.

If you find this sh.... stuff interesting then you might find these blogs interesting to! 

Please check them out, as I try to myself!

Agriculture: Human Health and Earth Health: http://robs-agriculture.blogspot.com/ 

Biofuels: Way Ahead or Blind Alley: http://biofuels-wayaheadorblindalley.blogspot.com/

Fixing Climate Change: http://fixingclimatechange.blogspot.com/