Diving into the murky waters of the Earth Sciences usually provides me with some entertainment [and a few laughs] during my researches.
Researching methane has been no different.
There are some wonderful nuggets of information buried in a mountain of manure and hot air.
Paleoclimatology research published in Current Biology suggests that flatulence from dinosaurs may have warmed the Earth.
Dinosaurs passing wind may have caused climate change
Medium-sized sauropods weighed about 20 tonnes and lived in herds of up to a few tens of individuals per square kilometre.
Global methane emissions from the animals would have amounted to around 472 million tonnes per year, the scientists calculated.
The figure is comparable to total natural and man-made methane emissions today. Before the start of the industrial age, about 150 years ago, methane emissions were around 181 million tonnes per year.
Modern ruminant animals, including cows, goats, and giraffes, together produce 45 to 90 million tonnes of methane.
Sauropods alone may have been responsible for an atmospheric methane concentration of one to two parts per million (ppm), said the scientists.
Daily Telegraph – 07 May 2012
The story from the Daily Telegraph [which is the source used by Wikipedia] is a wonderful example of the mainstream’s [diverting] emphasis on flatulence, random lists and dodgy numbers.
The eclectic mix of ruminants [“cows, goats, and giraffes”] makes you wonder what they’re smoking. This impression is reinforced by the mathematical precision [“45 to 90 million tonnes”].
However, the concept of scientists wading through 145 million years worth of pre-historic census returns from Sauropods might explain a predilection for wacky baccy and pulling numbers out of thin air.
But I digress.
Let’s look for a more solid starting point for this investigating into the origins of methane.
Let’s go hardcore mainstream and get a definition from the Fossil Fuel brigade.
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms.
The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.
Fossil fuels contain high percentages of carbon and include coal, petroleum, and natural gas.
They range from volatile materials with low carbon:hydrogen ratios like methane, to liquid petroleum to nonvolatile materials composed of almost pure carbon, like anthracite coal.
Methane can be found in hydrocarbon fields, alone, associated with oil, or in the form of methane clathrates.
The theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the Earth’s crust over millions of years (see biogenic theory) was first introduced by Georg Agricola in 1556 and later by Mikhail Lomonosov in the 18th century.
So there we have it.
Methane is formed by “natural processes” [plural] but they only mention one [singular] process: the “anaerobic decomposition of buried dead organisms”.
Curious. Keep that in the back of your mind for later.
But don’t worry now because the Fossil Fuel brigade finally pins it down and eradicates all doubt because methane [aka natural gas] is “formed by the anaerobic decomposition of remains of organisms including phytoplankton and zooplankton” and is converted into a “gaseous hydrocarbons in a process known as catagenesis”
Petroleum and natural gas are formed by the anaerobic decomposition of remains of organisms including phytoplankton and zooplankton that settled to the sea (or lake) bottom in large quantities under anoxic conditions, millions of years ago.
Over geological time, this organic matter, mixed with mud, got buried under heavy layers of sediment.
The resulting high levels of heat and pressure caused the organic matter to chemically alter, first into a waxy material known as kerogen which is found in oil shales, and then with more heat into liquid and gaseous hydrocarbons in a process known as catagenesis.
Let’s follow this thread and check out the process called Catagenesis.
Catagenesis is a term used in petroleum geology to describe the cracking process which results in the conversion of organic kerogens into hydrocarbons.
This chemical reaction is believed to be a time, temperature and pressure dependent process which creates liquid and/or gaseous hydrocarbon Hc from primary kerogen X…
It is generally held that the dependence on pressure is negligible…
Several generally unrecognized but important controlling parameters of metamorphism have been suggested.
A great deal of future research is required to isolate the parameters which are most significant for inducing the Catagenetic process.
It looks like the Fossil Fuel brigade has been trying to bury the “generally held”, “have been suggested” and “is believed to be” phrases in the Catagenesis section of Wikipedia.
No wonder a “great deal of future research is required”.
It sounds more like Genesis than Catagenesis.
Let’s try another opening gambit: the Wikipedia entry for Methane.
Here we are reassured that methane is “mainly produced” by another Genesis process.
This time it’s called: Methanogenesis.
So let’s have a look at Methanogenesis
Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens.
Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria.
The production of methane is an important and widespread form of microbial metabolism.
In most environments, it is the final step in the decomposition of biomass.
It’s looking good so far, with bonus marks for turning CO2 into Methane.
Unfortunately, we get another one of those random lists that imply a finite number of known sources.
Methanogenesis occurs in the guts of humans and other animals, especially ruminants.
In the rumen, anaerobic organisms, including methanogens, digest cellulose into forms usable by the animal.
Without these microorganisms, animals such as cattle would not be able to consume grass.
The useful products of methanogenesis are absorbed by the gut, but methane is released from the animal mainly by belching (eructation).
The average cow emits around 250 liters of methane per day.
Some humans produce flatus that contains methane.
In one study of the feces of nine adults, only five of the samples contained archaea capable of producing methane. Similar results are found in samples of gas obtained from within the rectum.
Even among humans whose flatus does contain methane, the amount is in the range of 10% or less of the total amount of gas.
Some experiments have suggested that leaf tissues of living plants emit methane.
Other research has indicated that the plants are not actually generating methane; they are just absorbing methane from the soil and then emitting it through their leaf tissues.
There may still be some unknown mechanism by which plants produce methane, but that is by no means certain.
Methanogens are observed in anoxic underground envirmonents, contributing to the degradation of organic matter.
This organic matter may be placed by humans through landfill, buried as sediment on the bottom of lakes or oceans as sediments, and as residual organic matter from sediments that have formed into sedimentary rocks.
Methanogenesis is responsible for a significant fraction of natural gas accumulations.
However, the disputed involvement of plants [there are a lot of plants in the world] plus a very sparse list of studied animal species coupled with the unquantifiable involvement of methanogens in anoxic underground environments means that viable methane production estimates can only be based upon wild guesswork.
I can understand that studying faeces and flatulence is not an attractive proposition but there are a lot of animals in the world and only studying the faeces of nine humans seems very half-hearted when there an estimated 7.124 billion people living on Earth [sourced from Wikipedia].
Thankfully, the Natural Gas guys provide a very succinct précis of the “settled biology”.
Methanogenic archaea are responsible for all biological sources of methane.
Some live in symbiotic relationships with other life forms, including termites, ruminants, and cultivated crops.
Other sources of methane, the principal component of natural gas, include landfill gas, biogas, and methane hydrate.
When methane-rich gases are produced by the anaerobic decay of non-fossil organic matter (biomass), these are referred to as biogas (or natural biogas).
Sources of biogas include swamps, marshes, and landfills (see landfill gas), as well as agricultural waste materials such as sewage sludge and manure by way of anaerobic digesters, in addition to enteric fermentation, particularly in cattle.
Unfortunately, the inventive Earth Sciences aren’t quite done yet with methane because the Atmospheric Chemists have picked up the tab [at our expense] for defining the Global Methane Cycle.
A. Permafrost, glaciers, and ice cores – A source that slowly releases methane trapped in frozen environments as global temperatures rise.
B. Wetlands – Warm temperatures and moist environments are ideal for methane production. Most of the methane makes it past methane-consuming microorganisms.
C. Forest fire – Mass burning of organic matter releases methane into the atmosphere.
D. Rice paddies – The warmer and moister the rice field, the more methane is produced.
E. Animals – Microorganisms breaking down difficult to digest material in the guts of ruminant livestock and termites produce methane that is then released during defecation.
F. Plants – While methane can be consumed in soil before being released into the atmosphere, plants allow for direct travel of methane up through the roots and leaves and into the atmosphere. Plants may also be direct producers of methane.
G. Landfills – Decaying organic matter and anaerobic conditions cause landfills to be a significant source of methane.
H. Waste water treatment facilities – Anaerobic treatment of organic compounds in the water results in the production of methane.
I. Hydroxyl radical – OH in the atmosphere is the largest sink for atmospheric methane as well as one of the most significant sources of water vapor in the upper atmosphere.
J. Chlorine radical – Free chlorine in the atmosphere also reacts with methane.
The outlined Methane cycles includes three “citation needed”, some random [but targeted] examples, three spectacular omissions and a couple of interesting titbits.
The first titbit is that there are “methane-consuming microorganisms” which appear to be half starved because most of the methane miraculously “makes it past” these microbes.
There is no cited reference for this but Wikipedia can fill in a few details.
Methanotrophs (sometimes called methanophiles) are prokaryotes that are able to metabolize methane as their only source of carbon and energy.
They can grow aerobically or anaerobically and require single-carbon compounds to survive.
Methanotrophs occur mostly in soils, and are especially common near environments where methane is produced.
Their habitats include oceans, mud, marshes, underground environments, soils, rice paddies and landfills.
They are of special interest to researchers studying global warming, as they are significant in the global methane budget.
So the Microbe Modellers are directly contradicting the Atmospheric Chemists by stating methanotrophs “are significant in the global methane budget”
What a surprise – not.
The second titbit is the methane released by forest fires.
The quoted reference just repeats the assertion but an internet search located a published paper where one of the authors is from that bastion of post-normal scientific prudence: NOAA Climate Monitoring and Diagnostics Laboratory [doesn’t that just make you feel all warm and cuddy before you start reading].
The global boreal forest region experienced some 17.9 million ha of fire in 1998, which could be the highest level of the decade.
Through the analysis of fire statistics from North America and satellite data from Russia, semimonthly estimates of area burned for five different regions in the boreal forest were generated and used to estimate total carbon release and CO2, CO, and CH4 emissions.
Different levels of biomass, as well as different biomass categories, were considered for each of the five different regions (including peatlands in the Russian Far East and steppes in Siberia), as were different levels of fraction of biomass (carbon) consumed during fires.
Finally, two levels of flaming versus smoldering combustion were considered in the model. Boreal forest fire emissions for 1998 were estimated to be 290–383 Tg of total carbon, 828–1103 Tg of CO2, 88–128 Tg of CO, and 2.9–4.7 Tg of CH4.
The higher estimate represents 8.9% of total global carbon emissions from biomass burning, 13.8% of global fire CO emissions, and 12.4% of global fire CH4 emissions.
Russian fires accounted for 71% of the total emissions, with the remainder (29%) from fires in North America.
Emissions of carbon dioxide, carbon monoxide, and methane from boreal forest fires in 1998. Eric S. Kasischke, Lori P. Bruhwiler – J. Geophys. Res. – 2002
Unfortunately, the paper openly admits it is studying an outlier year  with estimated parameters which contain a huge geographic bias [71%] focussed on Russia.
This has all the hallmarks of another post-normal modelling exercise [aka SNAFU] based upon computer models all the way down.
One of my personal bugbears is the “environmentalist” peccadillo for blaming humans for starting every biomass fire in the world. There really needs to be some balance here.
The “environmentalists” never credit humans with permanently removing huge swathes of biomass which would otherwise be contributing to the recurring cycle of biomass fires.
Humans also have a wonderful habit of building fire breaks.
Some of these fire breaks are purposely constructed [as in forests and urban environments] while others are the incidental by-products of urbanisation, agriculture, canals, railways, roads and airports…
Finally, there are the unknown numbers of fire fighters [full time and reserve] around the world who specialise in fire prevention and extinguishing all forms of fire – including biomass fires.
Let’s get back to the “global methane cycle” plot.
As previously mentioned there are three spectacular omissions from the “global methane cycle”.
Two of these omissions have been banished [by the mainstream] into other space.
The Atmospheric Chemists have banished the atmospheric photodissociation of Methane [and Water] to the “interstellar medium” because it undermines their carefully constructed settled science regarding ozone, carbon dioxide and methane.
The second process banished into outer space by post-normal science is serpentinization.
Unsurprisingly, Olivine is also a “common mineral in the Earth’s subsurface”.
The mineral olivine (when of gem quality, it is also called peridot and chrysolite) is a magnesium iron silicate with the formula (Mg+2, Fe+2)2SiO4.
There is one specific reaction that produces Serpentine, Magnetite and Methane.
Taking a closer look at Serpentine we discover that ultramafic rocks from the oceanic crust and uppermost mantle “contain abundant serpentine”.
The serpentine group are greenish, brownish, or spotted minerals commonly found in serpentinite rocks.
Samples of the oceanic crust and uppermost mantle from ocean basins document that ultramafic rocks there commonly contain abundant serpentine.
Magnetite is a mineral, one of the two common naturally occurring iron oxides (chemical formula Fe3O4) and a member of the spinel group.
Magnetite is the most magnetic of all the naturally occurring minerals on Earth.
Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, and this was how ancient people first noticed the property of magnetism.
Small grains of magnetite occur in almost all igneous and metamorphic rocks.
It is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and a black streak.
No wonder post-normal science needed to bury methane production in the “uppermost mantle” and its association with the Moho discontinuity.
the upper mantle (starting at the Moho, or base of the crust around 7 to 35 km downward to 410 km)…
The top of the mantle is defined by a sudden increase in seismic velocity, which was first noted by Andrija Mohorovičić in 1909; this boundary is now referred to as the “Mohorovičić discontinuity” or “Moho”.
The uppermost mantle plus overlying crust are relatively rigid and form the lithosphere, an irregular layer with a maximum thickness of perhaps 200 km.
Below the lithosphere the upper mantle becomes notably more plastic.
In some regions below the lithosphere, the seismic velocity is reduced; this so-called low-velocity zone (LVZ) extends down to a depth of several hundred km.
Additionally, the “widely distributed” serpentine soils indicate that methane production via serpentinization has a long and fruitful history on planet Earth.
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth’s mantle.
Serpentine soils are widely distributed on Earth, in part mirroring the distribution of ophiolites.
Although it covers only about 1 percent of the state’s surface, the state rock of California is serpentine.
One such area in California is the Edgewood Park and Natural Preserve.
Serpentine soils also are present in small but widely distributed areas on the eastern slope of the Appalachian mountains of eastern North America.
Serpentine-rich rock or serpentinite has a mottled, greenish-gray color with a waxy feel to it. These rocks form by the reaction of olivine-rich rock, peridotite, with water.
It forms in oceanic crust near the surface of the earth, particularly where water circulates in cooling rock near mid-ocean ridges: masses of the resulting ultramafic rock are found in ophiolites incorporated in continental crust near present and past plate tectonic boundaries.
Unlike most ecosystems, in serpentine barrens there is less plant growth closer to a stream, due to toxic minerals in the water.
Now, a very obvious question arises here.
Is serpentinization currently active on planet Earth?
The answer to that question is a resounding YES because Serpentine “forms in oceanic crust near the surface of the earth, particularly where water circulates in cooling rock near mid-ocean ridges” where the basalt magma contains both olivine and magnetite.
The mineralogy of basalt is characterized by a preponderance of calcic plagioclase feldspar and pyroxene.
Olivine can also be a significant constituent.
Accessory minerals present in relatively minor amounts include iron oxides and iron-titanium oxides, such as magnetite, ulvospinel, and ilmenite.
Because of the presence of such oxide minerals, basalt can acquire strong magnetic signatures as it cools, and paleomagnetic studies have made extensive use of basalt.
Unfortunately, the prejudices of the mainstream Earth Scientists prevent them from seeing the evidence.
Do you recall that Wikipedia quotation about Serpentine?
“It forms in oceanic crust near the surface of the earth, particularly where water circulates in cooling rock near mid-ocean ridges”.”
Here the mainstream simply assumes that all of the water is just re-circulated ocean water.
Unfortunately, for the mainstream, the presence of Serpentine means methane is being produced via serpentinization and the heat from the lava ensures methane will oxidise to produce carbon dioxide and water.
Therefore, some of the water and carbon dioxide emitted by hydrothermal vents will [most definitely] have been produced via the oxidation of methane.
A hydrothermal vent is a fissure in a planet’s surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots.
White smokers emitting liquid carbon dioxide at the Champagne vent, Northwest Eifuku volcano, Marianas Trench Marine National Monument
This brings us nicely to the third spectacular omission in the global methane cycle: Volcanism.
The second posting in this series introduced Mud Volcanoes and leaking fissures.
Remarkable amounts of methane, estimated in the order of 40–60 Tg yr−1, are naturally released into the atmosphere from the Earth’s crust through faults and fractured rocks.
Natural emissions of methane from geological seepage in Europe
Giuseppe Etiope – Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
The term mud volcano or mud dome are used to refer to formations created by geo-excreted liquids and gases, although there are several different processes which may cause such activity.
Hot water mixes with mud and surface deposits.
Mud volcanoes are associated with subduction zones and about 700 have been identified.
Temperatures are much lower in these processes than found at igneous volcanoes.
The largest mud volcano structure, Indonesia’s Lusi, is 10 kilometres (6 mi) in diameter and reaches 700 metres (2,300 ft) in height.
About 86% of the gas released from these structures is methane, with much less carbon dioxide and nitrogen emitted.
Ejected materials are often a slurry of fine solids suspended in liquids which may include water, which is frequently acidic or salty, and hydrocarbon fluids.
Mud volcano in Hormozgan, south of Iran
Here, again, we have Methane associated with water and carbon dioxide.
The cooler temperatures associated with Mud Volcanoes [and the high levels of emitted methane] indicates that only low levels of methane have been [exothermally] oxidised.
When high levels of methane are oxidised then there is more heat, more water, more carbon dioxide and a greater potential for an explosive eruption.
Ash plumes reached a height of 19 km during the climactic explosive eruption at Mount Pinatubo, Philippines in 1991.
The principal components of volcanic gases are water vapor (H2O), carbon dioxide (CO2), sulfur either as sulfur dioxide (SO2) (high-temperature volcanic gases) or hydrogen sulfide (H2S) (low-temperature volcanic gases), nitrogen, argon, helium, neon, methane, carbon monoxide and hydrogen.
Other compounds detected in volcanic gases are oxygen (meteoric), hydrogen chloride, hydrogen fluoride, hydrogen bromide, nitrogen oxide (NOx), sulfur hexafluoride, carbonyl sulfide, and organic compounds.
Exotic trace compounds include mercury, halocarbons (including CFCs), and halogen oxide radicals.
In summary, the mainstream global methane cycle specifically excludes:
The atmospheric photodissociation of Methane
The production of methane via serpentinization
All forms of volcanism: fissures, hydrothermal vents, mud volcanoes and volanoes
Therefore, the global methane budget is pure fiction based upon omission, cherry picking and wild guesswork.
UPDATE 16 November 2013
The methanogenesis process should really score double brownie points.
Firstly, it converts CO2 into Methane [as previously mentioned].
Secondly, it also converts CO into Methane.
Methanosarcina acetivorans is a versatile methane producing microbe which is found in such diverse environments as oil wells, trash dumps, deep-sea hydrothermal vents, and oxygen-depleted sediments beneath kelp beds.
Only M. acetivorans and microbes in the genus Methanosarcina use all three known metabolic pathways for methanogenesis.
Methanosarcinides, including M. acetivorans, are also the only archaea capable of forming multicellular colonies, and even show cellular differentiation.
As of 2006, the genome of M. acetivorans is the largest of all sequenced archaeal genomes.
In 2006, James Ferry and Christopher House discovered that M. acetivorans uses a previously unknown metabolic pathway to metabolize carbon monoxide into methane and acetate using the well known enzymes phosphotransacetylase (PTS) and acetate kinase (ACK).