Methane (CH4) is by far the most important non-CO2 greenhouse gas - a relatively potent greenhouse gas responsible for nearly as much global warming as all other non-CO2 greenhouse gases put together. Methane is created naturally near the Earth's surface by microorganisms by the process of methanogenesis and carried into the stratosphere by rising air in the tropics. It is important because of the potential harm it has for global warming, but it also has value as an energy source. There is much less methane in the atmosphere than CO2: about 1800 parts per billion (ppb), compared with an estimated 390 parts per million of CO2. However its potential for global warming has been estimated at 25 times greater than CO2 . While CO2 emissions are estimated to contribute 75% to global warming effects, methane is a distant second at 15%. And as with other greenhouse gases, methane levels have been rising; they are now more than twice what they were in the early 1800s when methane levels were closer to 715ppb. Half of current emissions is human-related which includes landfills, agriculture and coal mining.

Latest news:

May 12 2016: EPA begins crackdown on methane emissions. The Environmental Protection Agency announced new rules to significantly reduce methane emissions from new oil and gas facilities as well as those undergoing modifications. The regulations are the first federal standards aimed at curbing methane emitted by oil and gas production. New regulations cover new oil and gas facilities, but methane from existing sites remains unregulated, a crucial step to reaching greenhouse gas reduction goals. link



  • Science of methane
  • Benefits of methane
  • Trapped methane danger
  • Methane from animals/agriculture             

Science of methane

Methane is roughly 86 times as potent as CO2 as a driver of climate change over a period of 20 years, or 35 times as potent over the span of a century - link

January 2011: Science advancing on methane's behavior in carbon cycle.  Scientists admit that their knowledge about methane’s sources and movements through the carbon cycle is still incomplete. Two new studies published earlier this month in the journal Science chip away at this lack of knowledge. One study shows that freshwater sources, such as lakes and streams, contribute more methane to the atmosphere than previously thought, the other clarifies how methane is consistently cleansed from the atmosphere. Together, they provide a clearer window on methane’s behavior in two places in the carbon cycle, improving the tool set scientists can use to track and measure the contribution of the greenhouse gas on warming global temperatures.

Methane is produced in environments with little or no oxygen by bacteria that feast on decomposing organic matter, such as grasses and wood. Almost half of the world’s methane comes from natural sources such as wetlands, rivers and streams, gas hydrates on the ocean floor, and permafrost. Termites, surprisingly, are the second largest source of global natural methane emissions; they produce the gas as part of their normal digestive process.

According to the EPA, methane remains in the atmosphere approximately 10-12 years and is over 20 times more effective in trapping heat than carbon dioxide (CO2) It has a half-life of seven years (if no methane was added, then every seven years, the amount of methane would halve). The Intergovernmental Panel on Climate Change (IPCC) estimates that atmospheric concentrations are about two and a half times those seen in pre-industrial times. "A fifth of all greenhouse gas-induced global warming has been due to methane since pre-industrial times," said Australian climate scientist Paul Fraser, where ruminant farm animals belch out vast amounts of the gas. link  

February 2015: U.S. tied to global spike in methane emissions. The U.S. is responsible for as much as 60% of global methane emissions growth over the last decade according to the latest study.  Failing to act could jeopardize commitments made as part of the Paris climate agreement’s goal of keeping global warming to below 2C.  Robert Howarth , a Cornell University ecologist and methane researcher  said. “the increase almost certainly must be coming from the fracking and from the increase in use of natural gas.” link

Permafrost methane time bomb

August 2013: Arctic methane time-bomb. Debate over the plausibility of a catastrophic release of methane in coming decades due to thawing Arctic permafrost has escalated following a New Nature paper warned that exactly this scenario could trigger costs equivalent to the annual GDP of the global economy. Scientists of different persuasions remain fundamentally divided over whether such a scenario is even plausible.  There is an emerging consensus among East Siberia Arctic Shelf specialists based on continuing fieldwork,  highlighting a real danger of unprecedented quantities of methane venting due to thawing permafrost.  A 2010 scientific study led by the UK’s Met Office recognised the plausibility of catastrophic carbon releases from Arctic permafrost thawing of between 50-100 Gt this century, with a 40 Gt carbon release from the Siberian Yedoma region possible over four decades. link

Permafrost methane time bomb. A vast expanse of permafrost in Siberia and Alaska has started to thaw for the first time since it formed 11,000 years ago. It is caused by the recent 3+C rise in local temperature over the past 40 years - more than four times the global average. Peat bogs cover an area of a million square miles (or almost a quarter of the earth's land surface) to a depth of 25 meters. Those in Siberia are the world's largest. What was until recently a barren expanse of frozen peat is turning into a broken landscape of mud and lakes, some more than a kilometre across. All only in the past 3 or 4 years. link

September 2015: EPA may be underestimating landfill methane. Landfills may be emitting more methane than previously reported because the Environmental Protection Agency may be drastically underestimating how much garbage is being deposited in landfills across the U.S., according to a new Yale University. link

March 2016: EPA aims to cut methane leaks from natural gas companies. The Obama administration announced a new partnership with 41 energy companies that have agreed to voluntarily reduce methane emissions from natural gas operations to help combat climate change. The Environmental Protection Agency unveiled the Natural Gas STAR Methane Challenge Program at this week's Global Methane Forum held in Washington.  link

February 2013: Major methane release is almost inevitable.
We are on the cusp of a tipping point in the climate. If the global climate warms another few tenths of a degree, a large expanse of the Siberian permafrost will start to melt uncontrollably. The result: a significant amount of extra greenhouse gases released into the atmosphere, and a threat - ironically - to the infrastructure that carries natural gas from Russia to Europe. The Arctic region is home to enormous stores of organic carbon that trap methane. Climatologists have long warned that this will cause positive feedbacks that will speed up climate change further. The Siberian permafrost is a particular danger. A large region called the Yedoma could undergo runaway decomposition once it starts to melt.  In short, the melting of Yedoma is a tipping point: once it starts, there may be no stopping. link

April 2014: Methane hydrates - dirty fuel or energy savior?  Methane hydrate, otherwise known as fire ice, presents as ice crystals with natural methane gas locked inside, and is a hydrocarbon unlike any other we know. They are formed through a combination of low temperatures and high pressure, and are found primarily on the edge of continental shelves where the seabed drops sharply away into the deep ocean floor. The deposits of these compounds are enormous. "Estimates suggest that there is about the same amount of carbon in methane hydrates as there is in every other organic carbon store on the planet," says Chris Rochelle of the British Geological Survey. In other words, there is more energy in methane hydrates than in all the world's oil, coal and gas put together. But as with any fossil fuel source, there are risks and technical problems. link

EPA - page on Methane
August 2015: U.S. set to propose regulation to cut methane emissions The Obama administration is to propose the first-ever federal regulation to cut emissions of methane. The proposed rule would call for the reduction of methane emissions by 40 to 45% over the next decade from 2012 levels. The new rules on methane could create a tougher regulatory scheme on the nation’s fossil fuel production, particularly on the way that companies extract, move and store natural gas.  link  

March 2016: Canada and USA agree reductions on methane. The EPA will limit methane emissions from existing oil and gas facilities, a huge move by the federal agency, announced in conjunction as President Obama’s met with Canadian Prime Minister Justin Trudeau. The new rule will help the two countries achieve their goal of cutting methane emissions from oil and gas by 40 to 45% below 2012 levels by 2025. link

Methane and inaction by the EPA prior to May 2016

December 2012: The EPA has found that climate change caused, in part, by methane has “increased air and ocean temperatures, changes in precipitation patterns, melting and thawing of global glaciers and ice, increasingly severe weather events, such as hurricanes of greater intensity, and sea level rise.”  In 2009, EPA determined that methane and other greenhouse gases endanger the public’s health and welfare. Pound for pound, methane warms the climate 22 times more than CO2 over a 100-year period. The oil and gas industry is the single largest emitter of human-caused methane in the United States and the second largest industrial source of domestic greenhouse gas emissions behind only electric power plants. The EPA’s decision not to directly address the emissions of methane from oil and natural gas operations, including hydrofracking, leaves nearly 95% of these emissions uncontrolled. The EPA has determined that oil and natural gas production wells, gathering lines, processing facilities, storage tanks and transmission and distribution pipelines emit over 15 million metric tons of methane annually – the equivalent of the annual greenhouse gas emission of 64 million cars. link

June 2013: Methane scrutiny may hamper gas drilling. Duke University researcher Rob Jackson researched evidence that natural gas is not quite the climate champion President Obama claimed this week. Replicating a study he did in Boston, Jackson said leaks may undercut much of the climate benefits of gas. “First and foremost this is a greenhouse-gas question,” Jackson said. “What we are trying to find out is how big a problem this is for cities.” Obama called for an accounting of leaks across the natural gas production and transport sector at the same time calling natural gas the transition fuel that can power the economy with less carbon pollution. However the White House climate plan calls for an “interagency methane strategy” that could complicate the industry’s growth, such as a closer look at the scope of leaks from gas wells, pipelines and compressor plants. (The EPA in April 2013 changed its calculation of methane’s climate intensity to 25 from 21, a change that would increase the official estimate of U.S. emissions, which had been declining.)  link

January 2013: Methane leaks erode green credentials of natural gas.
Scientists are once again reporting alarmingly high methane emissions from an oil and gas field, underscoring questions about the environmental benefits of the boom in natural-gas production that is transforming the US energy system. If methane is leaking from fields across the country at similar rates, it could be offsetting much of the climate benefit of the ongoing shift from coal- to gas-fired plants for electricity generation. “We were expecting to see high methane levels, but I don’t think anybody really comprehended the true magnitude of what we would see,” says Colm Sweeney, a member of the study at NOAA’s Earth System Research Laboratory in Boulder. link

Human-related activity is responsible for the other half of global emissions. Methane is released from the extraction and burning of fossil fuels for electricity and transportation; from rice paddies, landfills, and from cattle. Atmospheric methane levels were relatively constant from 1999 to 2006, but in 2007 to 2009, globally averaged methane levels began to increase.  

Benefits of methane

October 2010:  Methane to Markets Partnership  was launched in 2004 with 14 partner countries and has since expanded to include 38 governments, which together represent approximately 70% of the world’s estimated anthropogenic methane emissions and include the top 10 methane emitting countries. link  
Methane to Markets Partnership countries account for approximately 60% of global methane emissions.

January 2015: Obama action on methane emissions misses 90% of pollution. In a further use of the president’s executive authority, the White House unveiled a strategy aimed at cutting methane, one of the most powerful heat-trapping gases, by 40% to 45% over the next decade. However, the plan applied only to future oil and gas wells and infrastructure, and not the thousands of existing sites which are leaking methane, campaigners noted. link

March 2013: Japan successful at extracting natural gas from frozen methane. Japan says it has successfully extracted natural gas from frozen methane hydrate off its central coast, in a world first. Methane hydrates, or clathrates, are a type of frozen "cage" of molecules of methane and water. The gas field is about 50km away from Japan's main island, in the Nankai Trough, and could provide more than a decade of Japan’s gas consumption.  Other countries including Canada, the US and China have been looking into ways of exploiting methane hydrate deposits as well. link

September 2010: Japan looks to drill for frozen methane. In a bid to shore up its precarious energy security, Japan is looking at deep drilling for controversial frozen methane. The methane lies hundreds of meters below the sea, and deeper still below sediments. Concern have been raised that digging for frozen methane would destabilise the methane beds which contain enough gas worldwide to snuff out most complex life on earth. link

Trapped methane dangers

January 2012: Amount of methane frozen unknown. We don't know the total amount of methane frozen deep beneath the ocean, but we suspect it could rival the rest of fossil fuels combined. And we don't know how much is frozen in the Arctic's thawing permafrost and lake sediments. We do know those methane deposits are seeping into the atmosphere, however. And the possibility of a catastrophic release is of, course, what gives methane its power over the imagination. We have seen methane bubbling from the sea floor in the Arctic. Lakes provide an escape path for the methane by creating “thaw bulbs” in the underlying soil, and lakes are everywhere appearing and disappearing in the Arctic as the permafrost melts. Yet so far we haven't seen iron-clad evidence of greater methane releases due to anthropogenic warming, though such an event is certainly believable for the coming century. This brings us to the key question: What effect would a methane release have on climate? The impact depends on whether methane is released all at once or in an ongoing, sustained manner. link  

January 2016: Aliso Canyon company ordered to offset damage. Natural gas is composed primarily of methane, a potent greenhouse gas that, in the first two decades after it is released, is 84 times more effective at trapping heat in the atmosphere than CO2. The Aliso Canyon leak in California is currently leaking the equivalent of the emissions of six coal-fired power plants each day.  The U.S. entire oil and gas industry currently leaks more than 7 million tons of methane a year, not counting the ongoing Aliso Canyon leak. The effect that these numerous, smaller leaks have on climate change over a period of 20 years is equal to that of 160 coal-fired power plants over the same time period.  link

Permafrost, or soil that is permanently frozen, covers about 63% of Russia, but has been greatly affected by climate change in recent decades. In the next 25 to 30 years, the area of permafrost in Russia may shrink by 10-18%. By the middle of the century, it can shrink by 15-30% and the boundary of the permafrost may shift to the north-east by 150-200 kilometres. Predictions suggest that temperature of the zones of frozen soil in oil and gas-rich western Siberia territories will rise by up to two degrees Celsius to just three or four degrees below zero.  link

March 2010: Vast East Siberian Arctic Shelf methane stores destabilizing. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming according to the National Science Foundation. Methane release from the not-so-perma-frost is the most dangerous amplifying feedback in the entire carbon cycle. Research published in the journal Science finds a key “lid” on “the large sub-sea permafrost carbon reservoir” near Eastern Siberia “is clearly perforated, and sedimentary CH4 [methane] is escaping to the atmosphere.” Scientists learned last year that the permamelt contains a staggering 1.5 trillion tons of frozen carbon, about twice as much carbon as contained in the atmosphere, much of which would be released as methane. Methane is 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years. The carbon is locked in a freezer in the part of the planet warming up the fastest. Half the land-based permafrost would vanish by mid-century on our current emissions path. link.   (Photo - methane bubbling up - source ) [No climate model currently incorporates the amplifying feedback from methane released by a defrosting tundra.]  More than 50 billion tons of methane could be unleashed from Siberian lakes alone, more than 10 times the amount now in the atmosphere.  

August 2011: Temporary drop of methane in atmosphere. Scientists say that there has been a mysterious decline in the growth of methane in the atmosphere in the last decades of the 20th Century. Researchers writing in the journal Nature have come up with two widely differing theories as to the cause. One suggests the decline was caused by greater commercial use of natural gas, the other that increased use in Asia of artificial fertiliser was responsible. Both studies agree that human activities are the key element. And there are suggestions that methane levels are now on the rise again. link

January 2009: Siberian methane release begins. Siberia's shallow shelf areas are increasingly subjected to warming and are now giving up greater amounts of methane to the sea and to the atmosphere than recorded in the past. Until recently the undersea permafrost was considered to be stable but now scientists think the release of such a powerful greenhouse gas may accelerate global warming. A worst-case scenario is one where the feedback passes a tipping point and billions of tonnes of methane are released suddenly, as has occurred at least once in the Earth's past. link 

A frozen peat bog in Siberia, the size of France and Germany combined, contains billions of tonnes of greenhouse gases and has started to melt for the first time since it formed 11,000 years ago at the end of the last ice age. Carbon that accumulated over this time is stored in permafrost soils which occupy more than 60% of Russia's 17 million square-kilometre land area. Researchers who have recently returned from the region found an area of permafrost spanning a million square kilometers. According to Larry Smith, a hydrologist at the University of California, Los Angeles, the west Siberian peat bog could hold some 70 bn tonnes of methane, a quarter of all of the methane stored in the ground around the world. Stephen Sitch, a climate scientist at England's Met Office in Exeter, calculates that even if methane seeped from the permafrost over the next 100 years, it would add around 700m tonnes of carbon into the atmosphere each year, roughly the same amount that is released annually from the world's wetlands and agriculture. link  

August 2009: Scientists say they have evidence that methane is escaping from the Arctic sea bed. Researchers say this could be evidence of a predicted positive feedback effect of climate change. As temperatures rise, the sea bed grows warmer and frozen water crystals in the sediment break down, allowing methane trapped inside them to escape. The gas is normally trapped as "methane hydrate" in sediment under the ocean floor. The most significant finding is that climate change means the gas is being released from more and deeper areas of the Arctic Ocean. Most of the methane reacts with the oxygen in the water to form carbon dioxide, another greenhouse gas. In sea water, this forms carbonic acid which adds to ocean acidification, with consequent problems for biodiversity.  link

October 2010: Reservoirs a neglected source of methane emissions. As an example, a reservoir on the Aare in Switzerland produces 150 tonnes of methane a year. This is about the same amount as is emitted annually by around 2,000 cows. "So hydropower isn't quite as climate-neutral as people have assumed in the past," says environmental chemist Tonya Del Sontro. link

Methane from animals & agriculture

March 2016: Eat less meat to avoid dangerous global warming. Growing food for the world’s burgeoning population is likely to send greenhouse gas emissions over the threshold of safety, unless more is done to cut meat consumption, a new report has found. Intensive livestock-rearing is a major cause of greenhouse gases, in part because of the methane produced by the animals and the massive slurry pits that accompany large farms. It also diverts water and grains to animal-rearing, which is less efficient than directing the grains towards direct human consumption. link

Is grass-fed beef worse for the environment than grain-fed beef? Techniques to measure the animal production of methane, a potent greenhouse gas, have serious limitations. Cows, sheep and other ruminants are thought to be responsible for around one-fifth of global methane production but the precise amount has proved difficult to quantify. Methane production from animals is often measured using respiration chambers, which can be laborious and are unsuitable for grazing animals. link  
Enteric fermentation is fermentation that takes place in the digestive systems of animals. In particular, ruminant animals (cattle, buffalo, sheep, goats, and camels) have a large "fore-stomach," or rumen, within which microbial fermentation breaks down food into soluble products that can be utilized by the animal. The microbial fermentation that occurs in the rumen enables ruminant animals to digest coarse plant material that monogastric animals cannot digest. Methane is produced in the rumen by bacteria as a by-product of the fermentation process. This CH4 is exhaled or belched by the animal and accounts for the majority of emissions from ruminants. Methane also is produced in the large intestines of ruminants and is expelled. There are a variety of factors that affect CH4 production in ruminant animals, such as: the physical and chemical characteristics of the feed, the feeding level and schedule, the use of feed additives to promote production efficiency, and the activity and health of the animal. It has also been suggested that there may be genetic factors that affect CH4 production. Of these factors, the feed characteristics and feed rate have the most influence. link

The debate is still open. Water consumption, methane gas emissions, the impacts of growing grain for feed, transportation impacts, air and water quality impacts from feed lots … the list goes on. Washington State University researcher Judith Capper found that feeding cattle grain on feed lots uses less land than feeding them only grass. It shortens the amount of time it takes to raise cattle to market weight, which means each cow requires less water and produces less methane. She also found that grain-fed cattle produce a third less methane than grass-fed because of how they digest the different feeds, a finding that is backed up by an Australian study. The studies, however, have been challenged - grass-fed cattle help sequester carbon in pasture, and that the impacts to water and air quality are worse on feed lots. The Environmental Working Group concludes, after a lifecycle analysis of beef and other meats, that grass fed beef is better for the environment. link   

November 2006. According to a new report published by the United Nations Food and Agriculture Organization, the livestock sector generates more greenhouse gas emissions as measured in CO2 equivalent, 18%, than transport. It is also a major source of land and water degradation.  link   The number one source of methane worldwide is animal agriculture. On a global basis, according to the FAO livestock is responsible for some 18% of all greenhouse gases emitted. Methane is the most important greenhouse gas on a dairy farm. The FAO estimates that about 52% of all greenhouse gases from the dairy sector is in the form of methane. link   

November 2013: Emissions of methane in U.S. exceed estimates. Cattle may be a bigger problem than US government thought. The nearly 90 million cattle in US feedlots are the country's largest source of methane from anthropogenic (human-caused) emissions according to the EPA. A new report published by Harvard University scientists estimate they may release 50% more methane into the atmosphere than the government had estimated. The new report finds that ruminant animals generate twice as much methane as the EPA supposed. The report comes on the heels of a decision by the EPA to reduce its estimates – by 25 to 30% – of the atmospheric carbon released by the natural-gas industry. link

September 2013: Better farming methods can reduce emissions by 30%. Greenhouse gas emissions from livestock could be cut by up to 30% if farmers adopt better techniques without having to overhaul entire production systems, according to a new study by the FAO that said emissions associated with livestock added up to 7.1 gigatonnes (GT) of carbon dioxide equivalent (CO2-eq) per year – or 14.5% of all human-caused greenhouse releases, slightly less than its controversial estimate in 2006: then the FAO said global meat production was responsible for 18% of greenhouse gas emission. link (December 2013: New survey shows cattle are the biggest source of greenhouse gases, accounting for more than three-quarters of all emissions from global livestock. link)

More than half of methane released each year comes from human activities, notably farming. The Journal of Animal Science says that ruminant animals produce between 250 and 500 liters of methane gas every day. The combined environmental effect of the world’s livestock is enormous. There are around 1.5 billion cattle on our planet - more than double the number 30 years ago. Normally a cow's stomach is pretty inefficient - 80% of food ingested comes out as waste or methane. There are also over a billion sheep and some 800 million goats. Animal agriculture produces more than 100 million tons of methane a year and many organizations urge a vegetarian diet to help avert climate catastrophe. Changing the ruminants' diets is another approach. A trial in Scotland on lamb recently obtained a 70% decrease in methane formation, while in New Zealand, where agriculture accounts for almost 50% of the country's greenhouse gas emissions, scientists are working on reducing methane by getting rid of the microbes in animals' stomachs that produce methane. link

           The world’s total meat supply was 71 million tons in 1961. 
           By 2007 it was estimated to be 284 million tons. 
           It is expected to double again by 2050.    
           Producing meat takes up 70% of the world's farming land
            . . .  and generates a fifth of greenhouse gas emissions.

There is a counter argument
Don't blame dairy cows for greenhouse gas emissions - new study
Eating less meat and dairy products won't have major impact on global warming, expert argues. Read here

Across the globe, chickens and pigs are doing their bit to curb global warming. But cows and sheep still have some catching up to do. "It's been argued that the reductions from methane are potentially cheaper than from carbon dioxide," said Bill Hare, climate policy director for Greenpeace. link  However, manure from pigs (as well as chickens) emit methane which we should be harnessing for fuel. link  According to a recent report from the UN Food and Agriculture Organization, livestock production, dominated in the West by large-scale factory farming, is responsible for 18% of the world's greenhouse gas emissions; a bigger share than all of the world's transport. link

Interesting fact: Cows emit a massive amount of methane through belching, with a lesser amount through flatulence. Statistics vary regarding how much methane the average dairy cow expels. Some experts say 100 liters to 200 liters a day while others say it's up to 500 liters a day. more

Australian scientists are hoping to breed sheep that burp less as part of efforts to tackle climate change - about 16% of Australia's greenhouse emissions come from agriculture and 90% of the methane that sheep and cattle and goats produce comes from the rumen, and that's burped out. link

Researchers in Argentina, which has more than 55 million cows, discovered methane from cows accounts for more than 30% of the country's total greenhouse emissions. Guillermo Berra, a researcher at the National Institute of Agricultural Technology, said every cow produces between 800 to 1,000 litres of emissions every day. Scientists are now carrying out trials of new diets designed to improve cows' digestion and hopefully reduce global warming. Silvia Valtorta, of the National Council of Scientific and Technical Investigations, said that by feeding cows clover and alfalfa instead of grain "you can reduce methane emissions by 25%".  link

Eat kangaroo to 'save the planet'...

Kangaroos could be good for the planet. Kangaroos produce virtually no methane because their digestive systems are different. BBC    
A sustainable quota of 15-20% of the 30-50 million kangaroos is harvested each year. 70% of kangaroo meat (high in protein and low in fat) is exported, mainly to W. Europe. It is produced only from free ranging wild animals and is not farmed.
Objections to the harvesting, or culling, comes in a study from Sydney University - link

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