Methane is Up. It’s Not from the Arctic. Where Then?

March 14, 2019

LA Times describes scientist’s general uneasiness about a rise in atmospheric methane. Problem is, no one knows where it’s coming from – and we’re pretty sure it’s not from the fabled Arctic “Methane Bomb”. (wrong isotopic signature)
In a postscript to my interview with Carolyn Ruppel of the US Geological Survey, Dr. Ruppel raised the issue of increased out put from wetlands as, with hydrological changes, increased rainfall in some areas, and sea level rise, wetland areas could increase their out put of methane – one of the primary suspects in the ongoing detective story.

LATimes:

This enigma involves methane, a potent greenhouse gas. Twenty years ago the level of methane in the atmosphere stopped increasing, giving humanity a bit of a break when it came to slowing climate change. But the concentration started rising again in 2007 — and it’s been picking up the pace over the last four years, according to new research.

Scientists haven’t figured out the cause, but they say one thing is clear: This surge could imperil the Paris climate accord. That’s because many scenarios for meeting its goal of keeping global warming “well below 2 degrees Celsius” assumed that methane would be falling by now, buying time to tackle the long-term challenge of reducing carbon dioxide emissions.

“I don’t want to run around and cry wolf all the time, but it is something that is very, very worrying,” said Euan Nisbet, an Earth scientist at Royal Holloway, University of London, and lead author of a recent study reporting that the growth of atmospheric methane is accelerating.

Methane is produced when dead stuff breaks down without much oxygen around. In nature, it seeps out of waterlogged wetlands, peat bogs and sediments. Forest fires produce some too.

These days, however, human activities churn out about half of all methane emissions. Leaks from fossil fuel operations are a big source, as is agriculture — particularly raising cattle, which produce methane in their guts. Even the heaps of waste that rot in landfills produce the gas.

For 10,000 years, the concentration of methane in Earth’s atmosphere hovered below 750 parts per billion, or ppb. It began rising in the 19th century and continued to climb until the mid-1990s. Along the way, it caused up to one-third of the warming the planet has experienced since the onset of the Industrial Revolution.

Scientists thought that methane levels might have reached a new equilibrium when they plateaued around 1,775 ppb, and that efforts to cut emissions could soon reverse the historical trend.

“The hope was that methane would be starting on its trajectory downwards now,” said Matt Rigby, an atmospheric scientist at the University of Bristol in England. “But we’ve seen quite the opposite: It’s been growing steadily for over a decade.”

That growth accelerated in 2014, pushing methane levels up beyond 1,850 ppb. Experts have no idea why.

“It’s just such a confusing picture,” Rigby said. “Everyone’s puzzled. We’re just puzzled.”

wetlandsmethane

Scientists measured methane emissions from the Bangweulu wetlands of Zambia using a research plane. Wetlands like these are the largest source of methane on Earth and may be behind its recent rise. (Pat Barker / University of Manchester)

Scientists have come up with various explanations. Could it be growing emissions from fossil fuels or agriculture? An uptick in methane production in wetlands? Changes in the rate at which methane reacts with other chemicals in the atmosphere?

Nisbet and his team examined whether any of these hypotheses synced up with the changing chemical signature of methane in the atmosphere.

Some molecules of methane weigh more than others, because some atoms of carbon and hydrogen are heavier than others. And lately, the average weight of methane in the atmosphere has been getting lighter.

That seems to implicate biological sources such as wetlands and livestock, which tend to produce light methane. Daniel Jacob, an atmospheric chemist at Harvard who was not involved in Nisbet’s study, said that explanation squares with his own research. His results suggest most of the additional methane comes from the tropics, which are home to vast wetlands and a large proportion of the world’s cattle.

Estimates of emissions from coal mines and oil and gas wells suggest that fossil fuel contributions are rising too, but those sources usually release heavier molecules of methane, which would seem to conflict with the atmospheric observations.

Some researchers have proposed a way to resolve this discrepancy. Fires create an even heavier version of methane, and agricultural burning — particularly in developing countries — appears to have decreased over the last decade. A drop in this source of ultra-heavy methane would make atmospheric methane lighter on the whole, potentially masking an increase in emissions from fossil fuels.

Finally, reactions that break down methane eliminate more of the lighter molecules than the heavier ones. If that process has slowed down — causing methane to build up in the atmosphere — it would leave more light gas behind, possibly helping explain the overall trend.

Nisbet and his colleagues concluded they can’t rule out any of these explanations yet. “They might all be happening,” he said.

One possibility is conspicuously missing from the list. Scientists have long feared that thawing Arctic sediments and soils could release huge amounts of methane, but so far there’s no evidence of that, said Ed Dlugokencky, an atmospheric chemist at the National Oceanic and Atmospheric Administration who worked on the study, which will be published in the journal Global Biogeochemical Cycles.

Nisbet said he fears the rising methane levels could be a sign of a dangerous cycle: Climate change may cause wetlands to expand and allow the environment to support more livestock, leading to even more methane emissions.

“It clearly seems as if the warming is feeding the warming,” he said. “It’s almost as if the planet changed gears.”

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33 Responses to “Methane is Up. It’s Not from the Arctic. Where Then?”

  1. Keith McClary Says:

    “All over China, a huge change has been taking place without any of us noticing. Rice paddies have been (and are being) converted at an astonishing rate into aquaculture ponds to produce more protein for the worlds growing populations. …
    Paddy fields produce huge quantities of methane when decaying plant material is broken down by microbes called methanogens in the oxygen-free waterlogged paddy soils. But in the aquaculture ponds that are replacing the paddy fields, vast quantities of food are added to feed the crabs and fish that are being grown in them, and that massively increases the amount of rotting material for the methanogens to produce even more methane.”

    https://phys.org/news/2019-03-rice-fields-threaten-global.html

  2. dumboldguy Says:

    Another source is dead and dying trees. Check out the “Mathane Mania” piece on Wit’s End. Read the comments—-no A Throwups there.

    http://witsendnj.blogspot.com/

  3. Anton Stålberg Says:

    Hi Peter!
    Not really todays topic (Apologise in advance for what could be an extremely stupid question), but I wonder if you could clarify a statement from dr Anthony in your “Methane bomb” video from january. In the video dr Anthony states (lightly edited) “so if we had 1.6 degrees of warming 10 000 years ago, the modells suggest that in the next 80 years we could have 7 to 8 degrees of warming in the arctic…”.

    Is dr Anthony suggesting:

    a) that if we had “1.6 degrees of warming 10 000 ago” today we would see such a fast warming of the arctic?

    or

    b) that the models when “looking 10 000 years back” suggest that if the world had warmed to 1.6 degrees then the fast warming of the arctic would occur 80 years later?

    Sorry if I am just a dumbass, but this quote really confused me…

    • greenman3610 Says:

      apologize – I know that might have been confusing, but adding the context might
      have been more so.
      Dr Anthony is talking in the context of the “Holocene Warm Period”. Briefly, as described
      by Richard Alley in the first minute or so of this

      the planet started a periodic “nod” towards the sun about 20 thousand years ago or so,
      which was a major factor in bringing the planet out of the last glacial period.
      That “nod” warming peaked about 10,000 years ago, at which time, the
      arctic was probably, as Dr. Anthony says, 1.6 or so degrees warmer than now –
      and we see this in the record. Probably sea ice was lower than today.
      And we see that there was an impact on permafrost, which was forming lakes
      at a faster pace then, than currently.
      Since then, the planet’s slow motion change has been in the very gradual
      direction of cooling the arctic, but human caused greenhouse gas changes
      have overwhelmed that tiny forcing, and are leading a warming effect, which,
      as Dr. Anthony suggests, could lead to very major arctic warming in coming
      decades.
      let me know if that’s not clear.

  4. J4Zonian Says:

    Whatever the causes, these observations point to ways we can decrease emissions fast, since methane settles out of the atmosphere so much faster than CO2. Reducing leaks from the gas system; reducing meat eating, especially beef; and restoring wetlands to step back from coastal areas that will be flooded soon anyway. Its’ a way to coordinate several problems and solutions in ways that might even get past Republicans.

    • rhymeswithgoalie Says:

      “…methane settles out of the atmosphere so much faster than CO2.”

      Much of atmospheric methane converts to atmospheric carbon dioxide. CH4 residence time is ~9 years, where CO2 stays for centuries.

      Note: One reason that CH4 is such a potent GHG is because it blocks a different part of the infrared spectrum than CO2, and it breaks down relatively quickly. The CO2 band has saturated to the point where additional CO2 must increase nonlinear to produce a modest increase in heating.

      • J4Zonian Says:

        Yes, I was aware as I was typing it that “settles out…” was a huge simplification. It points to the effect, and the point remains–that we can reduce global warming relatively quickly and turns things around relatively effectively by stopping methane emissions as fast as possible. While the long-term continuation of the increased temperature caused by the long life of CO2 in the atmosphere is important, it’s also long term, which means it’s not the most serious problem now, and it can be reduced in the long term through organic permaculture and reforestation. Methane, being a much more powerful gas in the short term, can stimulate the feedbacks already begun, and kick us into new ones which then add more warming, which further stimulate the feedbacks already begun and kick us into new ones… and so on.

        Short term powerful GHGs need to be reduced in short term powerful ways. (A point lost on the reflexively defensive meat-addicted writers here and elsewhere.) We have to reduce meat production quickly, especially that not grown on waste and wasteland, through reduced subsidies, increased taxes, rationing, and whatever other means are available. We should also apply whatever means are available to reduce other methane sources–above all replacing gas production and transport with efficiency, wiser lives, and clean safe renewable energy. Although more egalitarian and necessary than most meat production, rice cultivation’s share of methane should also be reduced wherever possible.

        • dumboldguy Says:

          What is also a “huge simplification” is the statement “….While the long-term continuation of the increased temperature caused by the long life of CO2 in the atmosphere is important, it’s also long term, which means it’s not the most serious problem now, and it can be reduced in the long term by….”.

          One thing you and I agree on is that we are not moving fast enough to cut emissions from burning fossil fuels in the short term, and that only increases the long-term impact of all GHG’s. The unknown tipping points are still out there, and we are getting closer to them every day because of our failure to act.

          (Thank you also for the Doctor Obvious comment that “Methane, being a much more powerful gas in the short term, can stimulate the feedbacks already begun, and kick us into new ones which then add more warming, which further stimulate the feedbacks already begun and kick us into new ones… and so on”. It’s always nice to hear echoes of things that we learned 20 years ago).

          Cutting meat production, promoting organic permaculture, reforestation, WOULD help if only the world’s humans would do it. Unfortunately, factory farming, DE-forestation, and eating more meat is what’s happening in the developing countries that are home to more than half the human population. (They WILL be happy to hear that you do give them a small break with this bit of meaningless condescension—- “Although more egalitarian and necessary than most meat production, rice cultivation’s share of methane should also be reduced wherever possible”. LMAO!) It’s not happening much in the developed world either.

          PS You are being awarded yet another oak leaf cluster for your Order of the Perfumed Sleeve Hanky ribbon—-for the arrogance of your “reflexively defensive meat-addicted writers here and elsewhere” comment.

      • Sir Charles Says:

        Nonetheless, fossil methane has a global warming potential of 87 (87 times as strong as CO2) over a 20-year period.

        Some scientists say, even that is too low.

        And as the next few decades are decisive for the Paris accord we have to concentrate on the short term warming potential.

  5. Terry Donte Says:

    How about humans, all that poop creates methane a whole lot of methane. The animal hypothesis has a fundamental problem. Before the humans increased and started raising cattle, the world had a whole lot of other animals which humans have decreased like Buffalo. Billions of animals decreased and were replaced by cattle so the net is more likely than not to be about even in methane output.

    • greenman3610 Says:

      ruminants like Buffalo in natural circumstances are net carbon sinks, for example see the 6 foot deep soils of the Great Plains, laid down by millennia of Buffalo grazing, stomping, and pooping.
      Human animal husbandry, particularly factory farms, is much more of a source, and if anything, depletes soils of carbon even further.
      This doesn’t have to be the case in the future, if we get our act together.

  6. Ann Says:

    I noticed there was no mention of Indonesia’s massive burning of their bog areas for growing palms. Is that problem not as large as I thought I had read. It sure sounded like it was!

  7. Gingerbaker Says:

    Termites? They are responsible for more CO2-equivalent GHG emissions, from methane, than the entire global transportation sector. (!)

    And they just found a termite colony the size of Great Britain in Brazil:

    https://weather.com/news/news/2018-11-20-hidden-termite-mounds-size-of-great-britain


  8. […] Big IF, but, IF we can get human emissions under control, natural emissions from, say, arctic permafrost, could be manageable. Need to quantify current contributors to methane emissions, as I pointed out yesterday. […]

  9. redskylite Says:

    So we are all theorizing where the mysterious increase is coming from, but not from the Arctic we note. Maybe termites, fracking ? I just wish we could have some dependable and visible monthly stats from this so called well mixed gas. Maybe it is not high enough now to warrant the attention CO2 is getting, but if it continues it may get the elevated attention.

    Meanwhile we should focus on CO2, and hope the world’s politicians are getting the message. The kids have got it.

    • Sir Charles Says:

      Any study on that termites hypothesis? Or is it just transfer of a myth somebody threw in here randomly?

      • dumboldguy Says:

        People HAVE studied termites believe it or not, (just as proctologists study actual anal orifices and political scientists study metaphorical ones called Republicans).

        Termites are not as significant a source of CH4 as many other natural and human sources, but so little is known about the topic that they can’t just be discarded. Do some googling—-the Wiki entry gives a broad look:

        https://en.wikipedia.org/wiki/Atmospheric_methane

        do some googling

    • revoranger Says:

      Well you just cannot dismiss it. This year after Katowice I visited relatives in NE Poland. One nature preserve called Białowieza is normally in deep freeze. In early January none of the streams were frozen over and the deep snow was missing and the peat bogs were pretty open.

  10. revoranger Says:

    There was a study looking at methane hydrates also off the coast of California from Big Sur north to Oregon. Thought it was interesting and asked if perhaps there was another reason why Coastal Redwoods grew well throughout that same rough range but onshore. Were they also capable of using methane rising with the coastal fog belt water? If so, there would be a very good reason to plant those trees back asap.

    • dumboldguy Says:

      Don’t think Coast Redwoods have any particular affinity for using atmospheric methane—-most plants don’t. They grow well because there is plenty of rain and fog in that area, soils are good—-they’re just well adapted.


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