Alternatives to Meat? Watch this!

Video from the infamous One Show! Please Watch!!

This video sums up the arguments for and against meat alternatives. It is an easy and fun watch... in fact I remember watching this when it first aired on tv... how sad am I!?!?!

Next up... a reply to another comment! I would love to see more! :D

And remember, if we can send a man to the moon any thing is possible, even reducing our consumption!

Add a little P, get a load more Poo! Part 5: P reserves and productivity!!

More on the reserves of P!

Van Vuuren et al.’s (2010) highlights predicted use of P from 1970 to 2100. Clearly they think that P reserves are going to last a while; they come to the conclusion that:

• There are no signs of short-term to medium-term depletion
• In the longer term, the depletion of low-cost and high-grade resources will have consequences for future production trends
• Given the impact of resource uncertainty on the assessment of risks associated with P depletion, it is important to pay more attention to data on P resources. Uncertainty was found to play a role in data on P production,
• Phosphate rock depletion may lead to concentrating production to a few countries, thus increasing production costs.
• Major reductions in the use of fertiliser P can be achieved by improving plant nutrition management, better integrating of animal manure and recycling P content in human and/or animal excreta

What is most interesting about the article is that it highlights the different scenarios of P depletion; the figures show their findings:

Cordell et al. (2009) also look at the geopolitics; inequality; economics and relative irony of it all – peak oil has received a lot of attention and it is only necessary for energy and cars (I know hear me out!) whilst P is integral to crop growing, and that ever vital necessity that is food.

The figures below (taken from Cordell et al. 2009) include a pretty graph showing Phosphorous sources over time; it just shows how dependant, or as Cordell et al. puts it ‘addicted’ (2009, 292). 

With high grade P reserves being depleted (Cisse and Mrabet, 2004), and our addiction (Cordell et al. 2009), the debate as to where the next lot of P will come from, which just adds to increased food insecurity and environmental degradation due to a potential in greater mining; this leads to:

• Greater energy use – fossil fuels and GHG emissions.
• Greater waters usage and wastage – particularly in countries where safe water supplies are already an issue.
• Rising prices – of P, fertilisers, agriculture and fundamentally the cost of food).

Inorganic fertiliser alone is not sufficient in restoring soil organic carbon (SOC) that forms through decomposition in situ of organic materials , and attaining the highest yields in crop production  (Su et al, 2006; Liu et al., 2010). SOC is an integral part to the soil and provides plants with capacity to grow due to its properties or absorbing water and nutrients. Fertilisers cannot provide that level of SOC; just another benefit of using manure and other waste material to fertilise the soil.

Turnerand Leytem (2004) looked into phosphorous compound sequestration from, of all things, urine. Their success in fractionating the compounds in two steps furthers the research in attaining P from readily available resources, excrement. Admittedly, this is a much more energy intensive way as well as poorly cost-effective; but it opens the doors to greater utilisation and indeed valuation of what we all poop and pee out.

So a variety of sources point to manure and other forms of excreta as a sustainable and beneficial source of P; not to mention an eventual necessary source!

Happy New Year!!! Lets hope there are a lot less cows farting this year!

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?!?

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!