The Psychology of Your Future Self and How Your Present Illusions Hinder Your Future Happiness

The Psychology of Your Future Self and How Your Present Illusions Hinder Your Future Happiness

by Maria Popova

Original link:  http://www.brainpickings.org/index.php/2014/06/18/daniel-gilbert-happiness-future-self/
 

“Human beings are works in progress that mistakenly think they’re finished.”

Philosopher Joshua Knobe recently posed a perplexing question in contemplating the nature of the self: If the person you will be in 30 years — the person for whom you plan your life now by working toward career goals and putting money aside in retirements plans — is invariably different from the person you are today, what makes that future person “you”? What makes them worthy of your present self’s sacrifices and considerations? That’s precisely what Harvard psychologist Daniel Gilbert explores in this short and pause-giving TED talk on the psychology of your future self and how to avoid the mistakes you’re likely to make in trying to satisfy that future self with your present choices. Picking up from his now-classic 2006 book Stumbling on Happiness (public library), Gilbert argues that we’re bedeviled by a “fundamental misconception about the power of time” and a dangerous misconception known as “the end of history illusion” — at any point along our personal journey, we tend to believe that who we are at that moment is the final destination of our becoming. Which, of course, is not only wrong but a source of much of our unhappiness.

Human beings are works in progress that mistakenly think they’re finished. The person you are right now is as transient, as fleeting and as temporary as all the people you’re ever been. The one constant in our lives is change.

Gilbert explores this paradox in greater, pleasantly uncomfortable-making, strangely reassuring detail in Stumbling on Happiness — one of these essential books on the art-science of happiness. He writes:

What would you do right now if you learned that you were going to die in ten minutes? Would you race upstairs and light that Marlboro you’ve been hiding in your sock drawer since the Ford administration? Would you waltz into your boss’s office and present him with a detailed description of his personal defects? Would you drive out to that steakhouse near the new mall and order a T-bone, medium rare, with an extra side of the really bad cholesterol?

The things we do when we expect our lives to continue are naturally and properly different than the things we might do if we expected them to end abruptly. We go easy on the lard and tobacco, smile dutifully at yet another of our supervisor’s witless jokes, read books like this one when we could be wearing paper hats and eating pistachio macaroons in the bathtub, and we do each of these things in the charitable service of the people we will soon become. We treat our future selves as though they were our children, spending most of the hours of most of our days constructing tomorrows that we hope will make them happy. Rather than indulging in whatever strikes our momentary fancy, we take responsibility for the welfare of our future selves, squirreling away portions of our paychecks each month so they can enjoy their retirements on a putting green, jogging and flossing with some regularity so they can avoid coronaries and gum grafts, enduring dirty diapers and mind-numbing repetitions of The Cat in the Hat so that someday they will have fat-cheeked grandchildren to bounce on their laps. Even plunking down a dollar at the convenience store is an act of charity intended to ensure that the person we are about to become will enjoy the Twinkie we are paying for now. In fact, just about any time we want something — a promotion, a marriage, an automobile, a cheeseburger — we are expecting that if we get it, then the person who has our fingerprints a second, minute, day, or decade from now will enjoy the world they inherit from us, honoring our sacrifices as they reap the harvest of our shrewd investment decisions and dietary forbearance.

[But] our temporal progeny are often thankless. We toil and sweat to give them just what we think they will like, and they quit their jobs, grow their hair, move to or from San Francisco, and wonder how we could ever have been stupid enough to think they’d like that. We fail to achieve the accolades and rewards that we consider crucial to their well-being, and they end up thanking God that things didn’t work out according to our shortsighted, misguided plan. Even that person who takes a bite of the Twinkie we purchased a few minutes earlier may make a sour face and accuse us of having bought the wrong snack.

This gives another layer of meaning to Albert Camus’s assertion that “those who prefer their principles over their happiness, they refuse to be happy outside the conditions they seem to have attached to their happiness.” Our in-the-moment principles and attachments, after all, may be of no concern to our future selves in their pursuit of happiness.

In the remainder of Stumbling on Happiness, Gilbert, who argues that “the mistakes we make when we try to imagine our personal futures are also lawful, regular, and systematic,” explores the sometimes subtle, sometimes radical changes we can make in our everyday cognitive strategies in order to avoid ending up unhappy and disappointed by unlearning because we set goals for the people we are when we set them rather than the people we become when we reach them.

Scientists Propose Using Lasers to Fight Global Warming From Space

Written by

Brian Merchant

Senior Editor

August 22, 2014 // 06:00 AM EST

 

Original link:  http://motherboard.vice.com/read/scientists-propose-using-lasers-to-fight-global-warming-from-space?trk_source=homepage-lede

 

At the world's first major geoengineering conference, two separate scientists put forward proposals to use lasers to modify the Earth's climate and fight global warming, from space.

One suggested that a satellite equipped with a high-powered laser could grow clouds in the atmosphere below; the other proposed lasers that would blast greenhouse gases from orbit to effectively erase the agents of climate change.

The highly theoretical proposals are still in their early stages, and easily count as the more radically ambitious of the already radically ambitious climate engineering schemes discussed by scientists. These plans don't concern gadgets that absorb carbon pollution or spreading particles in the sky, after all—we're talking about space lasers powerful enough to alter the climate.

And European Space Agency fellow Isabelle Dicaire studies them full time. She traveled to Berlin this week to discuss how a satellite equipped with high-powered LIDAR lasers may prove useful for researching—and maybe eventually actually orchestrating—climate engineering.

LIDAR is remote sensing technology that blasts a laser at a target, then analyzes its reflection to accurately measure distances. It's already widely used here on Earth (on things such as Google's driverless car), and by NASA's CALIPSO satellite. Dicaire is interested in what we could do with a much more powerful LIDAR positioned in space; theoretically, it should be able to better detect the movement of particles in clouds, and maybe even make new ones.

this would be the first step if you'd like to do laser cloud seeding

Among the most widely discussed geoengineering ideas of recent years is so-called cloud-brightening. A cloud is just a mass of water vapor that's condensed into droplets around particles floating in the air—and the more droplets in a cloud, the more sunlight gets bounced off of them.
So, geoengineers figure that if you can increase the surface area of clouds, or seed more of them altogether, you could begin to reflect back enough sunlight to cool the globe. Research into the subject has been limited, and Dicaire says a powerful LIDAR would help scientists better understand the science. Beyond that, it could be used to carry out the cloud-seeding itself.

"Another application is to use the effects that are happening inside the plasma filaments to do some exotic stuff. For instance, laser-based cloud seeding," she said. Researchers at the University of Geneva, Dicaire says, have demonstrated that lasers can produce droplets.

"They are generating nano-sized water droplets from the laser," she said. They're doing it in a lab, though. "I'm monitoring the field to see what we could do from space."

So, theoretically: "You can use the Earth Observation System to target or find where you have your clouds, what kind of clouds you would like to seed, and then from that, aim the beam towards these clouds." Bear in mind that the idea ESA is examining here is entirely theoretical, and no laser even exists in orbit capable of performing such a feat. But it's not unthinkable, technologically speaking—the political and economic hurdles are probably larger.

"So far you can only find these laser sources on the ground. Eventually, if someone would like to put them in a satellite, they would have to space qualify them. So this is something that some industries are looking into. And this would be the first step if you'd like to do laser cloud seeding."

This would likely be a pretty expensive way to make clouds brighter—older proposals suggest using boats to spray seawater skyward—and you'd need an awful lot of cloud-growing laser satellites. But Dicaire, for now, is more interested in the underlying research LIDAR could help scientists perform.

Image: NASA

"It's a very basic concept. The only one looking at it at the moment is ESA, and it's very preliminary. We just want to see if it's possible to send your beam from the satellite to the ground. If it's possible then, yeah, we'll look more closely into this," she said.

Alternatively, we could use another type of laser-toting satellite to blast away the greenhouse gases already in the atmosphere. That's what Aidan Cowley, a professor at Dublin City University, proposes, anyhow. He believes that a solar-powered satellite equipped with a plasma laser could hone in on heat-trapping gases in order to get them to break apart into less harmful ones.

"We've already observed here on earth that plasma ionization approaches, for example, air plasmas, can essentially dissociate long-lived pollutants: SF6, carbon dioxide. This is something we've observed, and it's been well reported in literature," Cowley told me. "Plasma essentially will excite whatever gas it's traveling through, and just by giving energy to these gases, these molecular species, they'll break up—in the case of SF6, they'll become S, and become more benign greenhouse gases."

It's an alluring idea, of course; SF6 is a potent and long-lasting greenhouse gas. And our immense CO2 output is driving climate change toward a cliff; it'd be convenient if we could just zap them away with a laser. So why haven't we done it already, if plasma ionization has proven to scatter the building blocks of our climate crisis?

"The problem about using [lasers] as a means of actually addressing climate, greenhouse gases per se, is that the energy used to strike those plasmas has to be generated here on Earth. So essentially you're burning fuel to destroy the emissions that you're producing anyway, and it ends up being a net positive to the emissions profile anyway. So you have to come up with a low cost, energy-free scenario that frees you from that paradigm. And that's where the idea of using space solar power to do so comes into it."

A satellite outfitted with high-efficiency solar panels should do the trick.

there's nothing crazy about it, solar power in space

"Essentially by using abundant power that's available in orbit, to drive ionization phenomenon in the atmosphere, you can neatly size up the problem of doing the same thing here on the ground, and you have a nearly unlimited supply of energy to do so. You just need to develop the technology and tap it for that," he said.

Now, there are other pitfalls here; those greenhouse gases are already pretty diffuse in the atmosphere, so it'd be hard to target them effectively with a laser. Cowley says you'd probably need multiple units to do it effectively. Then there's the vast expense of building, testing, and deploying the machines, of course.

Cowley also says his satellite would be useful for creating ozone, to patch up the holes we've left by overusing aerosols. "You could use it to create ozone, too," he said. "Pretty strong pedigree for producing ozone. It's a very easy trick." Then again, he adds, the technology could be used to the reverse effect, too.

"Conversely, from a military perspective, you could also use it to destroy the ozone as well, if you do it the right way," he said. "It could potentially open the holes in the atmosphere of your not too friendly neighbors."

So does Dr. Cowley think his greenhouse gas-blasting satellite is feasible?

"I still think it will take a long time. It's got an underground movement to a certain degree, so I think it will continue to be developed, going forward. Space solar power has got a fairly good future for certain applications, and, I think, eventually, like most technology, it will be the niche that drives the mainstream adaptation," he said. "Find one good niche and make it work, and people will go, 'oh that's not so crazy after all.' And there's nothing crazy about it, solar power in space. It's not science fiction."

Methane

From Wikipedia, the free encyclopedia

Methane
IUPAC name[hide] Methane[1](substitutive) Tetrahydridocarbon[1] (additive)
Other names[hide] Carbane Marsh Gas
Identifiers
CAS number	74-82-8
PubChem	297
ChemSpider	291
EC number	200-812-7
UN number	1971
KEGG	C01438
MeSH	Methane
ChEBI	CHEBI:16183
ChEMBL	CHEMBL17564
RTECS number	PA1490000
Beilstein Reference	1718732
Gmelin Reference	59
3DMet	B01450
Jmol-3D images	Image 1
SMILES [show]
InChI [show]
Properties
Molecular formula	CH4
Molar mass	16.04 g mol−1
Appearance	Colorless gas
Odor	Odorless
Density	0.656 g/L at 25 °C, 1 atm 0.716 g/L at 0 °C, 1 atm 0.42262 g cm−3 (at 111 K)[2]
Melting point	−182.5 °C; −296.4 °F; 90.7 K
Boiling point	−161.49 °C; −258.68 °F; 111.66 K
Solubility in water	22.7 mg L−1
Solubility	soluble in ethanol, diethyl ether, benzene, toluene, methanol, acetone
log P	1.09
kH	14 nmol Pa−1 kg−1
Structure
Molecular shape	Tetrahedron
Dipole moment	0 D
Thermochemistry
Specific heat capacity C	35.69 J K−1 mol−1
Std molar entropy So298	186.25 J K−1 mol−1
Std enthalpy of formation ΔfHo298	−74.87 kJ mol−1
Std enthalpy of combustion ΔcHo298	−891.1–−890.3 kJ mol−1
Hazards[3]
MSDS	External MSDS
GHS pictograms
GHS signal word	DANGER
GHS hazard statements	H220
GHS precautionary statements	P210
EU Index	601-001-00-4
EU classification	F+
R-phrases	R12
S-phrases	(S2), S16, S33
NFPA 704	4 1 0
Flash point	−188 °C (−306.4 °F; 85.1 K)
Explosive limits	4.4–17%
Related compounds
Related alkanes	Methyl iodide Diiodomethane Iodoform Carbon tetraiodide Ethane Ethyl iodide
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
(verify) (what is: /?)
Infobox references

Methane (/ˈmɛθeɪn/ or /ˈmiːθeɪn/) is a chemical compound with the chemical formula CH
4 (one atom of carbon and four atoms of hydrogen). It is the simplest alkane and the main component of natural gas. The relative abundance of methane makes it an attractive fuel, though capturing and storing it may pose challenges due to its gaseous state found at normal conditions. In its natural state, methane is found both below ground, and under the sea floor, where it often finds its way to the surface and in the earth's atmosphere where it is known as atmospheric methane.^[4]

History

In November 1776, methane was first scientifically identified by Italian physicist Alessandro Volta in the marshes of Lake Maggiore straddling Italy and Switzerland, having been inspired to search for the substance after reading a paper written by Benjamin Franklin about "flammable air".^[5] Volta captured the gas rising from the marsh, and by 1778 had isolated the pure gas.^[6] He also demonstrated means to ignite the gas with an electric spark.^[6]

Properties and bonding

Methane is a tetrahedral molecule with four equivalent C-H bonds. Its electronic structure is described by four bonding molecular orbitals (MOs) resulting from the overlap of the valence orbitals on C and H. The lowest energy MO is the result of the overlap of the 2s orbital on carbon with the in-phase combination of the 1s orbitals on the four hydrogen atoms. Above this level in energy is a triply degenerate set of MOs that involve overlap of the 2p orbitals on carbon with various linear combinations of the 1s orbitals on hydrogen. The resulting "three-over-one" bonding scheme is consistent with photoelectron spectroscopic measurements.

At room temperature and standard pressure, methane is a colorless, odorless gas.^[7] The familiar smell of natural gas as used in homes is a safety measure achieved by the addition of an odorant, usually blends containing tert-butylthiol. Methane has a boiling point of −161 °C (−257.8 °F) at a pressure of one atmosphere.^[8] As a gas it is flammable over a range of concentrations (4.4–17%) in air at standard pressure.

Chemical reactions

Main reactions with methane are: combustion, steam reforming to syngas, and halogenation. In general, methane reactions are difficult to control. Partial oxidation to methanol, for example, is challenging because the reaction typically progresses all the way to carbon dioxide and water even with incomplete amounts of oxygen. The enzymes methane monooxygenase can produce methanol from methane, but they cannot be used for industrial scale reactions.^[9]

Acid-base reactions

Like other hydrocarbons, methane is a very weak acid. Its pKa in DMSO is estimated to be 56.^[10] It cannot be deprotonated in solution, but the conjugate base with methyllithium is known.

A variety of positive ions derived from methane have been observed, mostly as unstable species in low-pressure gas mixtures. These include methenium or methyl cation CH+
3, methane cation CH+
4, and methanium or protonated methane CH+
5. Some of these have been detected in outer space. Methanium can also be produced as diluted solutions from methane with super acids. Cations with higher charge, such as CH2+
6 and CH3+
7, have been studied theoretically and conjectured to be stable.^[11]

Despite the strength of its C-H bonds, there is intense interest in catalysts that facilitate C–H bond activation in methane (and other low alkanes).^[12]

Combustion

Methane's heat of combustion is 55.5 MJ/kg.^[13] Combustion of methane is a multiple step reaction. The following equations are part of the process, with the net result being:

CH₄ + 2 O₂ → CO₂ + 2 H₂O (ΔH = −891 kJ/mol (at standard conditions))

1. CH₄+ M^* → CH₃ + H + M
2. CH₄ + O₂ → CH₃ + HO₂
3. CH₄ + HO₂ → CH₃ + 2 OH
4. CH₄ + OH → CH₃ + H₂O
5. O₂ + H → O + OH
6. CH₄ + O → CH₃ + OH
7. CH₃ + O₂ → CH₂O + OH
8. CH₂O + O → CHO + OH
9. CH₂O + OH → CHO + H₂O
10. CH₂O + H → CHO + H₂
11. CHO + O → CO + OH
12. CHO + OH → CO + H₂O
13. CHO + H → CO + H₂
14. H₂ + O → H + OH
15. H₂ + OH → H + H₂O
16. CO + OH → CO₂ + H
17. H + OH + M → H₂O + M^*
18. H + H + M → H₂ + M^*
19. H + O₂ + M → HO₂ + M^*

The species M^* signifies an energetic third body, from which energy is transferred during a molecular collision. Formaldehyde (HCHO or H
2CO) is an early intermediate (reaction 7). Oxidation of formaldehyde gives the formyl radical (HCO; reactions 8–10), which then give carbon monoxide (CO) (reactions 11, 12 & 13). Any resulting H₂ oxidizes to H₂O or other intermediates (reaction 14, 15). Finally, the CO oxidizes, forming CO₂ (reaction 16). In the final stages (reactions 17–19), energy is transferred back to other third bodies. The overall speed of reaction is a function of the concentration of the various entities during the combustion process. The higher the temperature, the greater the concentration of radical species and the more rapid the combustion process.^[14]

Reactions with halogens

Methane reacts with halogens given appropriate conditions as follows:

X₂ + UV → 2 X•

X• + CH₄ → HX + CH₃•

CH₃• + X₂ → CH₃X + X•

where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation. It is initiated with UV light or some other radical initiator. A chlorine atom is generated from elemental chlorine, which abstracts a hydrogen atom from methane, resulting in the formation of hydrogen chloride. The resulting methyl radical, CH₃•, can combine with another chlorine molecule to give methyl chloride (CH₃Cl) and a chlorine atom. This chlorine atom can then react with another methane (or methyl chloride) molecule, repeating the chlorination cycle.^[15] Similar reactions can produce dichloromethane (CH₂Cl₂), chloroform (CHCl₃), and, ultimately, carbon tetrachloride (CCl₄), depending upon reaction conditions and the chlorine to methane ratio.

Uses

Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied natural gas, or LNG). While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component.

Fuel

Natural gas

Methane is important for electrical generation by burning it as a fuel in a gas turbine or steam boiler. Compared to other hydrocarbon fuels, burning methane produces less carbon dioxide for each unit of heat released. At about 891 kJ/mol, methane's heat of combustion is lower than any other hydrocarbon but the ratio of the heat of combustion (891 kJ/mol) to the molecular mass (16.0 g/mol, of which 12.0 g/mol is carbon) shows that methane, being the simplest hydrocarbon, produces more heat per mass unit (55.7 kJ/g) than other complex hydrocarbons. In many cities, methane is piped into homes for domestic heating and cooking purposes. In this context it is usually known as natural gas, which is considered to have an energy content of 39 megajoules per cubic meter, or 1,000 BTU per standard cubic foot.
Methane in the form of compressed natural gas is used as a vehicle fuel and is claimed to be more environmentally friendly than other fossil fuels such as gasoline/petrol and diesel.^[16] Research into adsorption methods of methane storage for use as an automotive fuel has been conducted.^[17]

Liquefied natural gas

Liquefied natural gas or LNG is natural gas (predominantly methane, CH₄) that has been converted to liquid form for ease of storage or transport.

Liquefied natural gas takes up about 1/600th the volume of natural gas in the gaseous state. It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability after vaporization into a gaseous state, freezing and asphyxia.

The liquefaction process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid at close to atmospheric pressure (maximum transport pressure set at around 25 kPa or 3.6 psi) by cooling it to approximately −162 °C (−260 °F).

LNG achieves a higher reduction in volume than compressed natural gas (CNG) so that the energy density of LNG is 2.4 times greater than that of CNG or 60% of that of diesel fuel.^[18] This makes LNG cost efficient to transport over long distances where pipelines do not exist. Specially designed cryogenic sea vessels (LNG carriers) or cryogenic road tankers are used for its transport.

LNG, when it is not highly refined for special uses, is principally used for transporting natural gas to markets, where it is regasified and distributed as pipeline natural gas. It can be used in natural gas vehicles, although it is more common to design vehicles to use compressed natural gas. Its relatively high cost of production and the need to store it in more expensive cryogenic tanks have hindered widespread commercial use.^[19]

Power to gas

Power to gas is a technology which converts electrical power to a gas fuel. The method is used to convert carbon dioxide and water to methane, (see natural gas) using electrolysis and the Sabatier reaction.^{[clarification needed]} The excess power or off peak power generated by wind generators or solar arrays could theoretically be used for load balancing in the energy grid.^{[citation needed]}

Liquid methane rocket fuel

In a highly refined form, liquid methane is used as a rocket fuel.^[20]

While investigations of methane use have existed for decades, no production methane engines have yet been used on orbital spaceflights.^[21] This is changing, and liquid methane has recently been selected for the active development of a variety of bipropellant rocket engines.

Since the 1990s, a number of Russian rockets have been proposed to use liquid methane.^[22][23] One 1990s Russian engine proposal was the RD-192, a methane/LOX variant of the RD-191.^[23]

In 2005, US companies, Orbitech and XCOR Aerospace, developed a demonstration liquid oxygen/liquid methane rocket engine and a larger 7,500 pounds-force (33 kN)-thrust engine in 2007 for potential use as the CEV lunar return engine, before the CEV program was later cancelled.^[24][25][26]

More recently the American private space company SpaceX announced in 2012 an initiative to develop liquid methane rocket engines,^[27] including, initially, the very large Raptor rocket engine.^[28]

Raptor is being designed to produce 4.4 meganewtons (1,000,000 lbf) of thrust with a vacuum specific impulse (I_sp) of 363 seconds and a sea-level I_sp of 321 seconds,^[29] and is expected to begin component-level testing in 2014.^[30]

In February 2014, the Raptor engine design was revealed to be of the highly efficient and theoretically more reliable full-flow staged combustion cycle type, where both propellant streams—oxidizer and fuel—will be completely in the gas phase before they enter the combustion chamber. Prior to 2014, only two full-flow rocket engines have ever progressed sufficiently to be tested on test stands, but neither engine completed development or flew on a flight vehicle.^[29]

In October 2013, the China Aerospace Science and Technology Corporation, a state-owned contractor for the Chinese space program, announced that it had completed a first ignition test on a new LOX methane rocket engine. No engine size was provided.^[31]

One advantage of methane is that it is abundant in many parts of the solar system and it could potentially be harvested on the surface of another solar-system body (in particular, using In Situ Resource Utilization on Mars^[32] and Titan), providing fuel for a return journey.^[20][33]

NASA's Project Morpheus has developed a restartable LOX methane rocket engine with 5,000 pounds-force (22 kN) thrust and a specific impulse of 321 seconds suitable for inspace applications including landers. Small LOX methane thrusters 5–15 pounds-force (22–67 N) were also developed suitable for use in a Reaction Control System (RCS).^[34][35]

Chemical feedstock

Although there is great interest in converting methane into useful or more easily liquefied compounds, the only practical processes are relatively unselective. In the chemical industry, methane is converted to synthesis gas, a mixture of carbon monoxide and hydrogen, by steam reforming. This endergonic process (requiring energy) utilizes nickel catalysts and requires high temperatures, around 700–1100 °C:

CH₄ + H₂O → CO + 3 H₂

Related chemistries are exploited in the Haber-Bosch Synthesis of ammonia from air, which is reduced with natural gas to a mixture of carbon dioxide, water, and ammonia.
Methane is also subjected to free-radical chlorination in the production of chloromethanes, although methanol is a more typical precursor.^[36]

Production

Biological routes

Naturally occurring methane is mainly produced by the process of methanogenesis. This multistep process is used by microorganisms as an energy source. The net reaction is:

CO₂ + 8 H⁺ + 8 e⁻ → CH₄ + 2 H₂O

The final step in the process is catalyzed by the enzyme methyl-coenzyme M reductase. Methanogenesis is a form of anaerobic respiration used by organisms that occupy landfill, ruminants (e.g., cattle), and the guts of termites.

It is uncertain if plants are a source of methane emissions.^[37][38][39]

Serpentinization

Methane could also be produced by a non-biological process called serpentinization^[a] involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars.^[40]

Industrial routes

Methane can be produced by hydrogenating carbon dioxide through the Sabatier process. Methane is also a side product of the hydrogenation of carbon monoxide in the Fischer-Tropsch process. This technology is practiced on a large scale to produce longer chain molecules than methane.

Natural gas is so abundant that the intentional production of methane is relatively rare. The only large scale facility of this kind is the Great Plains Synfuels plant, started in 1984 in Beulah, North Dakota as a way to develop abundant local resources of low grade lignite, a resource which is otherwise very hard to transport for its weight, ash content, low calorific value and propensity to spontaneous combustion during storage and transport.

An adaptation of the Sabatier methanation reaction may be used via a mixed catalyst bed and a reverse water gas shift in a single reactor to produce methane from the raw materials available on Mars, utilizing water from the Martian subsoil and carbon dioxide in the Martian atmosphere.^[32]

Laboratory synthesis

Methane can also be produced by the destructive distillation of acetic acid in the presence of soda lime or similar. Acetic acid is decarboxylated in this process. Methane can also be prepared by reaction of aluminium carbide with water or strong acids.

Occurrence

Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore. It is the major component of natural gas, about 87% by volume. The major source of methane is extraction from geological deposits known as natural gas fields, with coal seam gas extraction becoming a major source (see Coal bed methane extraction, a method for extracting methane from a coal deposit, while enhanced coal bed methane recovery is a method of recovering methane from non-mineable coal seams). It is associated with other hydrocarbon fuels, and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) forms by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, sediments buried deeper and at higher temperatures than those that contain oil generate natural gas.

It is generally transported in bulk by pipeline in its natural gas form, or LNG carriers in its liquefied form; few countries transport it by truck.

Alternative sources

Apart from gas fields, an alternative method of obtaining methane is via biogas generated by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste (including landfills), or any other biodegradable feedstock, under anaerobic conditions. Rice fields also generate large amounts of methane during plant growth. Methane hydrates/clathrates (ice-like combinations of methane and water on the sea floor, found in vast quantities) are a potential future source of methane. Cattle belch methane accounts for 16% of the world's annual methane emissions to the atmosphere.^[41] One study reported that the livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane.^[42] Early research has found a number of medical treatments and dietary adjustments that help slightly limit the production of methane in ruminants.^[43][44] A more recent study, in 2009, found that at a conservative estimate, at least 51% of global greenhouse gas emissions were attributable to the life cycle and supply chain of livestock products, meaning all meat, dairy, and by-products, and their transportation.^[45] Many efforts are underway to reduce livestock methane production and trap the gas to use as energy.^[46]

Paleoclimatology research published in Current Biology suggests that flatulence from dinosaurs may have warmed the Earth.^[47]

Atmospheric methane

2011 methane concentration in the upper troposphere^[48]

Methane is created near the Earth's surface, primarily by microorganisms by the process of methanogenesis. It is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in the atmosphere is naturally checked – although human influence can upset this natural regulation – by methane's reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor. It has a net lifetime of about 10 years,^[49] and is primarily removed by conversion to carbon dioxide and water.

Methane also affects the degradation of the ozone layer.^[50][51]

In addition, there is a large (but unknown) amount of methane in methane clathrates in the ocean floors as well as the Earth's crust. Most methane is the result of biological process called methanogenesis.

In 2010, methane levels in the Arctic were measured at 1850 nmol/mol, a level over twice as high as at any time in the 400,000 years prior to the industrial revolution. Historically, methane concentrations in the world's atmosphere have ranged between 300 and 400 nmol/mol during glacial periods commonly known as ice ages, and between 600 to 700 nmol/mol during the warm interglacial periods. Recent research suggests that the Earth's oceans are a potentially important new source of Arctic methane.^[52]

A Bristol University study published in Nature claims that methane under the Antarctic Ice Sheet may yet play an important role globally. Researchers believe these sub-ice environments to be biologically active, in that microbes are converting organic carbon to carbon dioxide and methane.^[53] Possible adverse effects projected as the gas escapes into the atmosphere are estimated to have the potential of a sixty trillion dollar impact on the world economy.^[54]

The newest IPCC study determined that methane in the Earth's atmosphere is an important greenhouse gas with a global warming potential of 34 compared to CO₂ over a 100-year period (although accepted figures probably represent an underestimate^[55][56]). This means that a methane emission will have 34 times the effect on temperature of a carbon dioxide emission of the same mass over the following 100 years. And methane has 33 times the effect when accounted for aerosol interactions.^[57]

Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20-year time period is 72. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases (these gases don't include water vapor which is by far the largest component of the greenhouse effect).^[58] Usually, excess methane from landfills and other natural producers of methane is burned so CO₂ is released into the atmosphere instead of methane, because methane is a more effective greenhouse gas. Recently, methane emitted from coal mines has been successfully utilized to generate electricity.

Clathrates

Methane is essentially insoluble in water, but it can be trapped in ice forming a similar solid.
Significant deposits of methane clathrate have been found under sediments on the ocean floors of Earth at large depths.

Arctic methane release from permafrost and methane clathrates is an expected consequence and further cause of global warming.^[59][60][61]

Safety

Methane is not toxic, yet it is extremely flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogen, and some halogen-containing compounds.
Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below about 16% by displacement, as most people can tolerate a reduction from 21% to 16% without ill effects. The concentration of methane at which asphyxiation risk becomes significant is much higher than the 5–15% concentration in a flammable or explosive mixture. Methane off-gas can penetrate the interiors of buildings near landfills and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture this gas and vent it away from the building.

Methane gas explosions are responsible for many deadly mining disasters.^[62] A methane gas explosion was the cause of the Upper Big Branch coal mine disaster in West Virginia on April 5, 2010, killing 25.^[63]

Extraterrestrial methane

Methane has been detected or is believed to exist on all planets of the solar system, as well as on most of the larger moons. In most cases, it is believed to have been created by abiotic processes. Possible exceptions are Mars and Titan.

Methane on Mars – "potential sources and sinks" (November 2, 2012).

• Mercury – the tenuous atmosphere contains trace amounts of methane.^[64]
• Venus – the atmosphere contains a large amount of methane from 60 km (37 mi) to the surface according to data collected by the Pioneer Venus Large Probe Neutral Mass Spectrometer^[65]
• Moon – traces are outgassed from the surface^[66]
• Mars – the Martian atmosphere contains 10 nmol/mol methane.^[67] The source of methane on Mars has not been determined. Recent research suggests that methane may come from volcanoes, fault lines, or methanogens,^[68] or that it may be a byproduct of electrical discharges from dust devils and dust storms,^[69] or that it may be the result of UV radiation.^[70] In January 2009, NASA scientists announced that they had discovered that the planet often vents methane into the atmosphere in specific areas, leading some to speculate this may be a sign of biological activity going on below the surface.^[71] Analysis of observations made by a Weather Research and Forecasting model for Mars (MarsWRF) and related Mars general circulation model (MGCM) suggests that it is potentially possible to isolate methane plume source locations to within tens of kilometers, which is within the roving capabilities of future Mars rovers.^[72] The Curiosity rover, which landed on Mars in August 2012, is able to make measurements that distinguish between different isotopologues of methane;^[73] but even if the mission is to determine that microscopic Martian life is the source of the methane, the life forms likely reside far below the surface, outside of the rover's reach.^[74] Curiosity’s Sample Analysis at Mars (SAM) instrument is capable of tracking the presence of methane over time to determine if it is constant, variable, seasonal, or random, providing further clues about its source.^[75] The first measurements with the Tunable Laser Spectrometer (TLS) indicated that there is less than 5 ppb of methane at the landing site at the point of the measurement.^{[76][77][78][79]} The Mars Trace Gas Mission orbiter planned to launch in 2016 would further study the methane,^[80][81] as well as its decomposition products such as formaldehyde and methanol. Alternatively, these compounds may instead be replenished by volcanic or other geological means, such as serpentinization.^[40] On July 19, 2013, NASA scientists reported finding "not much methane" (i.e., "an upper limit of 2.7 parts per billion of methane") around the Gale Crater area where the Curiosity rover landed in August 2012.^[82][83][84] On September 19, 2013, NASA scientists, on the basis of further measurements by Curiosity, reported no detection of atmospheric methane with a measured value of 0.18±0.67 ppbv corresponding to an upper limit of only 1.3 ppbv (95% confidence limit) and, as a result, conclude that the probability of current methanogenic microbial activity on Mars is reduced.^[85][86][87]
• Saturn – the atmosphere contains 4500 ± 2000 ppm methane^[88]
  • Iapetus
  • Titan – the atmosphere contains 1.6% methane and thousands of methane lakes have been detected on the surface.^[89] In the upper atmosphere the methane is converted into more complex molecules including acetylene, a process that also produces molecular hydrogen. There is evidence that acetylene and hydrogen are recycled into methane near the surface. This suggests the presence either of an exotic catalyst, or an unfamiliar form of methanogenic life.^[90] An apparent lake of liquid methane has been spotted by the Cassini-Huygens probe, causing researchers to speculate about the possibility of life on Titan.^[91] Methane showers, probably prompted by changing seasons, have also been observed.^[92]
  • Enceladus – the atmosphere contains 1.7% methane^[93]
• Uranus – the atmosphere contains 2.3% methane^[94]
  • Ariel – methane is believed to be a constituent of Ariel's surface ice
  • Miranda^{[citation needed]}
  • Oberon – about 20% of Oberon's surface ice is composed of methane-related carbon/nitrogen compounds
  • Titania – about 20% of Titania's surface ice is composed of methane-related organic compounds^{[citation needed]}
  • Umbriel – methane is a constituent of Umbriel's surface ice
• Neptune – the atmosphere contains 1.5 ± 0.5% methane^[95]
  • Triton – Triton has a tenuous nitrogen atmosphere with small amounts of methane near the surface.^[96][97]
• Pluto – spectroscopic analysis of Pluto's surface reveals it to contain traces of methane^[98][99]
  • Charon – methane is believed present on Charon, but it is not completely confirmed^[100]
• Eris – infrared light from the object revealed the presence of methane ice^[101]
• Halley's Comet
• Comet Hyakutake – terrestrial observations found ethane and methane in the comet^[102]
• Extrasolar planets – methane was detected on extrasolar planet HD 189733b; this is the first detection of an organic compound on a planet outside the solar system. Its origin is unknown, since the planet's high temperature (700 °C) would normally favor the formation of carbon monoxide instead.^[103] Research indicates that meteoroids slamming against exoplanet atmospheres could add organic gases such as methane, making the exoplanets look as though they are inhabited by life, even if they are not.^[104]
• Interstellar clouds^[105]