Methane Myths

Myth 1.: Little or no methane is venting in the Arctic, so there's "nothing to worry about".

Reality 1.: Methane is venting from the seabed of the Arctic Ocean, but it can be hard to detect how much and where it originated from, in terms of source and location. Some satellites circle around Earth above the equator, making that they watch the Arctic through a thicker layer of atmosphere, which can mask detection of methane in the Arctic. Furthermore, since methane can quickly rise in the atmosphere and move with the wind, releases could be missed by flask and in situ measurements at surface levels unless measurements happen to be taken in close proximity to the point of release. Too little measuring is taking place and more should be done to monitor this.

The images below were made with polar-orbiting satellite data, which are better at monitoring the situation in the Arctic. The image below, from a post at the Arctic-news blog, shows methane over the Arctic Ocean on December 3, 2013.

[ click on image to enlarge ]
Above image indicates that methane is rising from the seafloor of the Arctic Ocean; the methane couldn't have been blown by winds to the Arctic from elsewhere, since there weren't any large spots with high methane levels at other locations.

On December 3, 2013, methane reached levels as high as 2425 parts per billion (ppb). On December 6, 2013, levels were as high as 2524 ppb. On November 9, 2013, methane reached levels as high as 2662 ppb. The current period of extremely high levels of methane over the Arctic Ocean has lasted for months, as is also evident from the images further below, and is expected to continue beyond January 2014.

Below a combination of images showing methane levels over five earlier years (2009 on the left, to 2013 on the right), each time for the same period (January 21-31) - images by Dr. Leonid Yurganov.

[ Click on image to enlarge - from: Dramatic increase in methane in the Arctic in January 2013 ]
The big worry is what will happen as temperatures rise even further. Warming due to higher concentrations of greenhouse gases in the atmosphere is occurring much more vigorously in the Arctic than elsewhere on Earth. Waiting for further proof that methane is increasingly venting from the seabed of the Arctic Ocean carries the risk that it will be too late to do much to reverse the process by the time such research is completed. As is evident from the images below, methane is already venting from the seabed of the Arctic Ocean in large quantities.

[ click on image to enlarge - from: Methane over deep waters of Arctic Ocean ]
[ from: Locating sources of the world's highest methane levels - click on image to enlarge ]
Moreover, there is a wealth of evidence from scientists such as Igor Semiletov and Natalia Shakhova who have - year after year - been taking measurements in the East Siberian Arctic Shelf, complete with first-hand reports that methane plumes have been detected.

"We've found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said, "We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale - I think on a scale not seen before. Some of the plumes were a kilometre or more wide and the emissions went directly into the atmosphere - the concentration was a hundred times higher than normal."  -  Vast methane 'plumes' seen in Arctic ocean as sea ice retreats, by Steve Connor in The Independent, December 13, 2011.

The image below shows a cluster of methane plumes, over one km in diameter, that appeared in the Laptev Sea end September 2011. The image is part of a paper on the unfolding "Methane Catastrophe".

Myth 2.: Hydrates cannot exist in water as shallow as in the East Siberian Arctic Shelf; therefore, "no methane could be venting there".

Reality 2.: Waters in the Arctic are relatively cold, compared to elsewhere; they are warming up, increasing the danger of methane release; anyway, as long as waters remain cold, hydrates can exist in sediments below the waters, even at shallow depths. Methane hydrates in the East Siberian Arctic Shelf can exist at depths as shallow as 20 m, while methane can be held both in the form of free gas and hydrates in the sediment underneath the seabed.

Myth 3.: Global warming heats up the water in the Arctic from above, where there are no hydrates. It will take "hundreds of years" for this heat to reach the bottom of the sea.

Reality 3.: While the sun does heat up the waters in the East Siberian Arctic Shelf (ESAS) from above, the waters are quite shallow, making that surface heat can be mixed down to the seafloor more easily than in deeper waters. Additionally, warmer water enters the Arctic from the Atlantic and Pacific Oceans, and from rivers in Siberia and North America. As the sea ice disappears, more open water allows more storms to develop that mix the waters, while tidal pressure differences will also become more pronounced.

At a presentation on November 30, 2010, Natalia Shakhova warned that the ESAS is now 5°C warmer, while additional factors enhance permafrost destabalization in the ESAS:

1. Decreasing sea ice extent;
2. Change in hydrological pattern:
- increasing frequency of high speed winds;
- increasing frequency of deep convection events (mixing to the bottom) during summer;
3. Warming of bottom water (up to 3°C during the last three decades)

Another study observed that more summertime open water in the Laptev Sea in 2007 caused more vertical mixing of the water column during storms in late 2007 -- bottom water temperatures on the mid-shelf increased by more than 3°C compared to the long-term mean.

The image below is from a study published in Nature on November 24, 2013, showing water temperatures measurements taken in the Laptev Sea from 1999-2012.

Water temperatures in Laptev Sea. Red triangles: summer. Blue triangles: winter. Green squares: historic data.
From Shakhova et al., (2013) doi:10.1038/ngeo2007
For further discussion of this topic, see the post Ocean Heat Depth.

Myth 4.: Even if heat did reach the seabed, it would take "hundreds of years" for the heat to penetrate the sediment.

Reality 4.: It can indeed take a long time for heat to propagate down the sediment. But it can also occur very rapidly, when heat is transferred down fluids in cracks and openings in the rock and sediment, called pingos, which were formed by local accumulation of hydrate (ice) below the sediment surface in the past, and by methane migrating upwards through conduits. Pingos and similar structures can link to deep-rooted plumbing systems that allow thermogenic fluid migration from several-kilometers-deep sedimentary basins.

Paull et al. describe pingo-like-features on the Beaufort Sea Shelf, adding that a thermal pulse of more than 10 degrees Celsius is still propagating down into the submerged sediment and may be decomposing gas hydrate as well as permafrost.

Hydrates can not only become destabilized by a rise in temperature, but also by pressure changes, such as caused by earthquakes or landslides. Furthermore, when methane escapes a hydrate, it expands to 160 times its earlier volume; this explosive expansion itself can cause further destabilization of sediments that contain methane in the form of hydrates and free gas.

Myth 5.: Even if methane did escape from the seabed, "most of it" would be oxidized in the water - like in the Deepwater Horizon event - before reaching the atmosphere.

The IPCC highlights this in AR5, as shown on the image below.

Reality 5.: Methane won't get broken down easily in the Arctic, as this requires the presence of bacteria that can oxidize the methane, as well as free oxygen in the water. Once depleted, oxygen isn't quickly replenished in the Arctic. Lack of bacteria and depletion of oxygen in the waters of the Arctic could make it hard for oxidation to take place of methane that rises in the waters there.

In the Arctic, low temperatures mean there are less bacteria that need more time to break down the methane. In other places, currents may bring bacteria back to the location of the methane plume repeatedly. In the Arctic, many currents are long, so once bacteria flow away from the location of the plume, they may have been driven out of the Arctic Ocean or may return only after a long time, i.e. too long to survive in Arctic waters which are cold and often ice-covered, so a lot of time little or no sunshine penetrates the waters.

As discussed under myth 1., methane is already venting from the seabed of the Arctic Ocean, as also described at posts such as:

In the Arctic, the danger is much larger that methane releases will overwhelm the capacity of bacteria to break it down in the water. In case of large abrupt releases, the danger is that much of the methane will reach the atmosphere unaffected, for a number of reasons, including:
- shallow waters mean that the methane has to travel through less water to enter the atmosphere
- most of the year, Arctic waters are cold, so less microbes are present to break down methane
- long sea currents make it less likely that such microbes will return to a location where methane is rising
- in case of abrupt releases, a lot of methane rises at once, giving microbes less opportunity to break it down
- methane released from hydrates is very concentrated, making that where more methane rises, methane is proportionally more prominent, compared to the presence of oxygen and microbes

Myth 6.: Methane has a short lifetime in the atmosphere. It will be broken down in "about a decade". 

The suggestion that methane only stays in the atmosphere for "about a decade" downplays methane's importance. An example is this publication (2011) in Nature:

Reality 6.: According to the IPCC (AR5, 2013), the perturbation lifetime for methane is 12.4 years.

This is an upgrade from the 12 years stated in IPCC AR4 (2007).

The IPCC figures do take into account the fact that methane extends its own lifetime by depleting hydroxyl. However, this is an average figure. Large abrupt releases will overwhelm the system, especially in the Arctic where there is already very little hydroxyl present.

Large emissions extend the lifetime of all the methane that is present in the atmosphere, especially locally, as in case of large abrupt release in the Arctic. Hydroxyl levels in the Arctic are very low. Methane can remain active in the Arctic for decades at a very high warming potential, while the resulting summer warming (when the sun doesn't set) is likely to keep triggering further methane releases in the Arctic.

Myth 7.: Methane is "only 20 or 21 times" as potent as carbon dioxide. 

Among others, the EPA has been spreading this myth for many years, as illustrated by above image.

Meanwhile, the EPA has meanwhile changed its website somewhat, as illustrated by above image, which notes that methane has a GWP of 84 to 87 over 20 years.
Yet, at the same time the EPA website still features a figure of 25 as methane's GWP, as illustrated by the two images on the right.

This despite this letter in which leading climate scientists urge the Obama administration to accurately account for warming effects of methane.

Even worse are statements such as the following, from a paper published in 2011 in Nature:

Reality 7.: IPCC AR5 (2013) used the following figures for methane's Global Warming Potential (GWP) and or its lifetime. The IPCC also mentions higher figures (87 and 36) for methane's GWP (over 20, respectively 100 years).

Earlier IPCC figures did not reflect oxidation of methane to carbon dioxide, which contributes to the CO2 burden. Furthermore, methane increases its own lifetime through OH depletion, enhances stratospheric water vapor and increases tropospheric ozone (both potent greenhouse gases).

In 2009, Shindell and others further improved methane's GWP by including both direct and indirect effects, increasing methane's GWP to 105 over 20 years. (Shindell, 2009)

Furthermore, in case of large abrupt release in the Arctic, local methane concentrations can be expected to remain higher for a long time. Over shorter periods than 20 years, methane's GWP is even higher, as also described at:

Unlike CO2, methane's GWP does rise as more of it is released and as methane levels rise in the atmosphere. Responses by ecosystems could increase methane's warming potential even further, especially in the Arctic where methane releases could accelerate the decline of snow and ice cover and trigger further methane releases, as also described at The potential impact of large abrupt release of methane in the Arctic.

It's also worth noting that the IPCC in AR5 gives methane a Radiative Forcing of 0.97 W/m2 (up from 48 W/m2 in 2007), as illustrated by the image below.

The image below tells the story.
[ image from: Arctic Hit By Ten Tipping Points - click to enlarge ]

Myth 8.: "Not much methane" is stored in the Arctic; releases would be "low and gradual". 

How much methane is present in sediments under the seabed of the Arctic Ocean, in the form of free gas and hydrates? On this, the IPCC says in AR5 WG1 FAQ6:

That's quite an understatement, if not a deliberate downplaying of the danger by the IPCC.

Reality 8.: The amounts of methane stored in the Arctic are vast. Natalia Shakhova et al. (2010) estimate the accumulated potential for the East Siberian Arctic Shelf (ESAS) region alone (image on the right) as follows:
  • organic carbon in permafrost of about 500 Gt
  • about 1000 Gt in hydrate deposits
  • about 700 Gt in free gas beneath the gas hydrate stability zone.
Natalia Shakhova et al. (2008) consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. By comparison, the total amount of methane currently in the atmosphere is about 5 Gt.

Below, a screenshot from an interview of John Mason with Natalia Shakhova, published at:

Events in which most, if not virtually all methane that escaped from the seabed did enter the atmosphere have been studied in 2002 and published in 2006, as reported at:
and at:

Myth 9.: Methane levels have "not risen (much) over the past few years".

Among others, NOAA has contributed to this myth, as illustrated by the screenshot below:

Reality 9a: Methane levels have been rising strongly over time, as illustrated by the images below.

(view more images at the methane page)
Reality 9b.: Historically, atmospheric levels of methane (CH4) have risen much faster than those of carbon dioxide (CO2) and nitrous oxide (N2O), as illustrated by the image on the right.

Granted, the (rapid) rise of methane did 'slow down' for a few years from about 2000, but then it picked up its pace again. This temporary 'slow-down' is often focused on by deniers and it's often attributed to stronger energy-related emission controls in the late 2000s, in sectors such as fossil fuel drilling and distribution, and its use in transport and electricity-generation.

However, levels have risen strongly again since about 2008, as illustrated by above image. Furthermore, as said, methane levels have historically risen even faster than levels of carbon dioxide and also when looking at the overall time span from 1750 to 2015.

While this historic rapid rise of methane levels is very worrying, future levels may rise even more rapidly, due to large abrupt releases of methane from the Arctic seabed.

Myth 10.: Global warming was "not caused by human emissions". Methane emissions, in particular, are "natural". 

Myth #10 types of myths are different than the other myths on this page. Responses to other myths on this page show the mounting evidence that high methane levels over the Arctic Ocean are caused by global warming which in turn is caused by people. Importantly, while other myths seek to deny that global warming is the result of polluting emissions by people, these types of myths do not deny that global warming is taking place, they merely seek to put the blame on scapegoats, in an effort to eulogize and thus perpetuate the use of polluting products. These myths seek to divert the attention away from polluting products as the cause of global warming. So, while other myths seek to spread the idea that global warming was a hoax, most of these myths seek to spread the idea that climate change was not caused by polluting products, but was instead caused by other things, such as chemicals deliberately added to contrails, by HAARP, by population growth, industrial growth or growth of civilization, by changes in planetary orbits, by capitalism, by communism or by human activity in general.

Reality 10.: Global warming is caused by specific polluting products. Apart from their impact on the climate, these products also inflict horrendous damage to our health, to our energy and food security, to our wallets and to global peace and prosperity. Global warming is real, it's taking place now, and this has been pointed out by scientists over and over again. There is no scientific doubt as to what is the cause: Global warming is caused by emissions from burning of fossil fuel and biomass, by the use of Portland cement and nitrogen fertilizers, by livestock and by cutting and burning forests to raise more livestock, etc., and by the feedbacks resulting from the consumption of such products. Current methane releases from what-used-to-be-permafrost and from seafloor sediments are much higher than what they were historically, and global warming is to blame for that. Moreover, without comprehensive and effective action, methane releases look set to skyrocket.

As said, global warming is caused by consumption of specific polluting products. Energy use itself doesn't necessarily cause polluting emissions, instead it's the use of specific products (such as burning fuel to produce energy) that does cause the polluting emissions, while use of specific alternative products to produce energy will not cause such polluting emissions. The conclusion therefore is that action is needed to facilitate ways to shift away from polluting products toward clean products.

Scarcity of resources can be a challenge in the necessary shift to energy production that does not cause polluting emissions. Nonetheless, this is no excuse to abandon clean energy targets or extend them further in the future. Instead, it should double our efforts to look for alternative ways to produce products, as illustrated by the video below in which Elon Musk describes the resources needed to produce the Tesla electric vehicles.

Instead of spreading myths that reductions in emissions were counter-productive, there is no doubt that emissions by people can and should be reduced rapidly, by shifting to clean products.

[ from the Biochar Economy ]
Having said that, emission cuts alone will not suffice, given the high levels of greenhouse gases already in the atmosphere and oceans, and given that many feedbacks have already started to kick in.

Furthermore, greenhouse gas pollution is part of a wider problem of waste management and without effective ways to tackle waste, we're facing near-term mass extinction of most, if not all species (including humans).

In many ways, we have already entered a mass extinction event. In conclusion, comprehensive and effective action is needed as described in the Climate Plan, which calls for local feebates to clean up urban areas and also transform rural areas, as illustrated by above image that offers a further idea how to implement local feebates.

Myth 11.: "Peak temperatures in the past were higher than they are now; there were no methane eruptions from the seafloor then, so there won't be any now either." 

It is sometimes suggested that peak temperatures were higher during the Holocene and the Eemian. Such suggestions are often incorrect and based on crude graphs that lack accuracy.

Reality 11.: The current temperature rise dwarfs the peaks of the Holocene and Eemian, both in terms of height of the temperature peaks and in terms of the speed of the temperature rise.

The image below, from an earlier post, shows that temperatures were not higher than 1°C above preindustrial during the Holocene, until recently.

[ click on images to enlarge ]
In a 2017 paper, James Hansen et al. conclude that temperatures also weren't more than 1°C above preindustrial during the previous interglacial, the Eemian, which implies that temperatures haven't been more than 1°C above preindustrial for the entire 200,000 years that modern people, i.e. the species homo sapiens, have existed, and that temperatures have only recently rising to levels more than 1°C above preindustrial. Quite likely, to find temperatures as high as today's, one would have to go back some 3 million years.

Furthermore, the speed at which the current temperature rise takes place is important. Biosystems have evolved over long periods of stable temperatures and they now face collapse, not only due to the magnitude, but also due to the rapidity of the current rise, which threatens to result in loss of habitat and subsequent extinction for many species, including humans.

Eruptions of methane from the seafloor are common now and they have occurred commonly in the past as well. They may not show up in ice cores, but there are reasons for that. In the past, methane levels on the atmosphere were often low, so even when high amounts of methane entered the atmosphere, the methane could be more easily broken down by hydroxyl over time. Since methane rises rapidly, high levels of methane may have accumulated at higher altitudes, where the methane got broken down, while levels closer to sea level remained relatively low, making that such eruptions did leave little or no trace in ice cores.

Right now, vast amounts of methane are present in sediments that have until now remained stable due to low temperatures and high pressure. As temperatures keep rising, the chances of eruptions of methane from the seafloor keep increasing. The precautionary principle should lead to action to prevent this from happening.

1 comment:

  1. The Climate Plan calls for comprehensive action through multiple lines of action implemented across the world and in parallel, through effective policies such as local feebates. The Climate Plan calls for a global commitment to act, combined with implementation that is preferably local. In other words, while the Climate Plan calls for a global commitment to take comprehensive and effective action to reduce the danger of catastrophic climate change, and while it recommends specific policies and approaches how best to achieve this, it invites local communities to decide what each works best for them, provided they do indeed make the progress necessary to reach agreed targets. This makes that the Climate Plan optimizes flexibility for local communities and optimizes local job and investment opportunities.

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