Calling the Methane Bomb Squad

October 15, 2014

This is an important post, which I’ll be updating soon. This is part one. See other parts here.

Part 2
Part 3
Part 4
Part 5
————-

It’s ironic that in the course of spending most of my time trying to raise awareness about how serious the climate issue is, recently I’ve had to be on the side of seeking to tamp down unnecessary alarm and fatalism that I’m seeing, particularly online.

I’ve been planning to do a piece on the whole “undersea methane bomb” idea, and have been interviewing key scientists in this area for quite a while. I was not planning to release a finished piece for some time- as this is an area where I feel the need to step very carefully.

I’ve posted before that I believe the cottage industry that has developed around catastrophic scenarios of methane bombs, burps, and belches is probably not accurate, and definitely not helpful at this time.

bombsquadNow in the last two weeks there’s been a bit of a kerfuffle following Dr. Gavin Schmidt’s presentation at a conference in the UK, where he trained some pretty intense fire on the whole issue, and in the process made some pretty good points – most compellingly, that when we look back at previous interglacial periods, even when where it has been warmer than today for long periods, when we are pretty sure significant amounts of land ice melted, and sea levels were considerably higher, – we don’t see a methane belch.
Gavin has since been attacked in some rather conspiracy-flavored blog posts, basically with the idea that alternative views were somehow not allowed at the conference, although Dr. Peter Wadhams, who is associated with the so called Arctic Methane Emergency Group, and very much on the side of alarm for this issue, did present.

There is a rather vigorous back channel discussion going on around this, most serious people coming down on the side of some concern, no burning hair or clothing, but wanting more info.

I’m by no means ready to go with a carefully digested piece on this, but given the fooferaw going on now, I thought I would start sharing some of the interviews I have with credible scientists on this issue. Above, one of the most credible, Dr. Carolyn Ruppel, who chairs the US Geological Survey gas hydrates research group. Dr. Ruppel was an author of the recent, widely publicized finding of methane seepage along the US East Coast:

US Geological Survey:

Natural methane leakage from the seafloor is far more widespread on the U.S. Atlantic margin than previously thought, according to a study by researchers from Mississippi State University, the U.S. Geological Survey, and other institutions.

Methane plumes identified in the water column between Cape Hatteras, North Carolina and Georges Bank, Massachusetts, are emanating from at least 570 seafloor cold seeps on the outer continental shelf and the continental slope.  Taken together, these areas, which lie between the coastline and the deep ocean, constitute the continental margin.  Prior to this study, only three seep areas had been identified beyond the edge of the continental shelf, which occurs at approximately 180 meters (590 feet) water depth between Florida and Maine on the U.S. Atlantic seafloor.

Cold seeps are areas where gases and fluids leak into the overlying water from the sediments.  They are designated as cold to distinguish them from hydrothermal vents, which are sites where new oceanic crust is being formed and hot fluids are being emitted at the seafloor.  Cold seeps can occur in a much broader range of environments than hydrothermal vents.

“Widespread seepage had not been expected on the Atlantic margin. It is not near a plate tectonic boundary like the U.S. Pacific coast, nor associated with a petroleum basin like the northern Gulf of Mexico,” said Adam Skarke, the study’s lead author and a professor at Mississippi State University.

The gas being emitted by the seeps has not yet been sampled, but researchers believe that most of the leaking methane is produced by microbial processes in shallow sediments.  This interpretation is based primarily on the locations of the seeps and knowledge of the underlying geology.  Microbial methane is not the type found in deep-seated reservoirs and often tapped as a natural gas resource.

Most of the newly discovered methane seeps lie at depths close to the shallowest conditions at which deepwater marine gas hydrate can exist on the continental slope.  Gas hydrate is a naturally occurring, ice-like combination of methane and water, and forms at temperature and pressure conditions commonly found in waters deeper than approximately 500 meters (1640 feet).

“Warming of ocean temperatures on seasonal, decadal or much longer time scales can cause gas hydrate to release its methane, which may then be emitted at seep sites,” said Carolyn Ruppel, study co-author and chief of the USGS Gas Hydrates Project.  “Such continental slope seeps have previously been recognized in the Arctic, but not at mid-latitudes.  So this is a first.”

Most seeps described in the new study are too deep for the methane to directly reach the atmosphere, but the methane that remains in the water column can be oxidized to carbon dioxide. This in turn increases the acidity of ocean waters and reduces oxygen levels.

Shallow-water seeps that may be related to offshore groundwater discharge were detected at the edge of the shelf and in the upper part of Hudson Canyon, an undersea gorge that represents the offshore extension of the Hudson River. Methane from these seeps could directly reach the atmosphere, contributing to increased concentrations of this potent greenhouse gas.  More extensive shallow-water surveys than described in this study will be required to document the extent of such seeps.

Some of the new methane seeps were discovered in 2012.  In summer 2013 a Brown University undergraduate and National Oceanic and Atmospheric Administration Hollings Scholar Mali’o Kodis worked with Skarke to analyze about 94,000 square kilometers (about 36,000 square miles) of water column imaging data to map the methane plumes.  The data had been collected by the vessel Okeanos Explorer between 2011 and 2013.  The Okeanos Explorer and the Deep Discoverer remotely operated vehicle, which has photographed the seafloor at some of the methane seeps, are managed by NOAA’s Office of Ocean Exploration and Research.

“This study continues the tradition of advancing U.S. marine science research through partnerships between federal agencies and the involvement of academic researchers,” said John Haines, coordinator of the USGS Coastal and Marine Geology Program “NOAA’s Ocean Exploration program acquired state-of-the-art data at the scale of the entire margin, while academic and USGS scientists teamed to interpret these data in the context of a research problem of global significance.”

The study, Widespread methane leakage from the sea floor on the northern US Atlantic Margin, by A, Skarke, C. Ruppel, M, Kodis, D. Brothers and E. Lobecker in Nature Geoscience is available on line

To the question of “what about undersea methane hydrates?” – most common answer heard is that microbial action takes a pretty substantial bite out of methane seeps. Now we have a new study focused on that, and finding a lot of previously unidentified actors.

Oregon State University:

CORVALLIS, Ore. – Since the first undersea methane seep was discovered 30 years ago, scientists have meticulously analyzed and measured how microbes in the seafloor sediments consume the greenhouse gas methane as part of understanding how the Earth works.

The sediment-based microbes form an important methane “sink,” preventing much of the chemical from reaching the atmosphere and contributing to greenhouse gas accumulation. As a byproduct of this process, the microbes create a type of rock known as authigenic carbonate, which while interesting to scientists was not thought to be involved in the processing of methane.

That is no longer the case. A team of scientists has discovered that these authigenic carbonate rocks also contain vast amounts of active microbes that take up methane. The results of their study, which was funded by the National Science Foundation, were reported today in the journal Nature Communications.

“No one had really examined these rocks as living habitats before,” noted Andrew Thurber, an Oregon State University marine ecologist and co-author on the paper. “It was just assumed that they were inactive. In previous studies, we had seen remnants of microbes in the rocks – DNA and lipids – but we thought they were relics of past activity. We didn’t know they were active.

“This goes to show how the global methane process is still rather poorly understood,” Thurber added.

Nature:

The biochemical reactions involved when the microbes process the methane and sulphate causes the water surrounding the organisms to become more alkaline, which in turn leads carbonate ions to precipitate out of the water and form minerals such as calcium carbonate (CaCO3), the stuff of ordinary chalk. The presence of the minerals in sediments around methane seeps — sites where waters containing the dissolved gas leaks out of the sea floor — have long been used as evidence for past methane consumption, helping scientists to estimate the length of time such seeps have been or were active2.

But the study by Orphan and her colleagues strongly suggests that the carbonates are not just dead rock. The researchers analysed two dozen samples collected in and around deep-sea methane seeps off the coasts of Oregon, California and Costa Rica. Tests revealed the presence of genetic material associated with methane-consuming microbes, says Orphan.

Those results alone do not divulge whether the genes came from living or dead microbes, so the team ran further tests in the lab. They bathed samples of the carbonate rock in sea water infused with methane. But instead of ordinary methane, they used methane that included the radioactive isotope carbon-14, rather than the stable, and much more common, carbon-12. Over time, the carbon-14 was incorporated into the carbonate minerals. This was a sign that there were methane-munching microbes living in the samples — even in relatively nonporous rocks in which the microbes would have had little access to the radioactive methane, says Orphan.

Scientists already knew that such carbonates lock away carbon from a greenhouse gas that might otherwise warm the planet’s atmosphere. But the team’s results suggest that the reservoir is much more active than previously suspected.

“These data are very believable,” says John Pohlman, a biogeochemist with the US Geological Survey in Woods Hole, Massachusetts. “Maybe we’ve been underestimating the amount of methane oxidation going on in the sea-floor setting.”

I’ll be posting more excerpts from this and other interviews as I get them prepared. Juggling several balls here right now.
New Yale video coming very soon as well.

20 Responses to “Calling the Methane Bomb Squad”


  1. This is intensely interesting. There is actual research breakthrough going on here. It could help us to study and understand biological sinks and interactions. Methanogens are part of the rich history of biological evolution. Thanks for reporting this Peter. We need to know what’s going on with methane in the oceans.

    • dumboldguy Says:

      Yes, it IS “intensely interesting”, and you need to study it more so that you can fully understand what it’s all about. Talking about “It could help us understand biological sinks and interactions” and saying “Methanogens are part of the rich history of biological evolution” without mentioning methanotrophs makes one think that you have only a superficial understanding of what this post is talking about.

      MethanoGENS are methane producers, and are what the researchers believe is behind only some of the Atlantic coast seeps. They’re not sure yet, and some could be caused by global warming induced releases from clathrates. More studies need to be done, but this does not look like very good news. The only slightly positive thing there is that most of the methane is being oxidized to CO2 before it reaches the surface, and much of that CO2 is dissolving in the oceans.

      Far better news is found in the later portion of the post that deals with methanoTROPHS, which are methane consumers. They are what is consuming methane and sequestering CO2 in rock “sinks”, a very good thing.

      And remember too that all of this post is speaking mainly to what’s happening in the oceans at the mid-latitudes, not the methane releases from the arctic ocean sea-bed or the melting permafrost, which is another and probably bigger facet of the whole “methane bomb” problem. Much of the methane released by melting permafrost goes straight to the atmosphere.

      I would also argue that Peter is perhaps overreacting a bit by saying “I believe the cottage industry that has developed around catastrophic scenarios of methane bombs, burps, and belches is probably not accurate, and definitely not helpful at this time”. Maybe I haven’t been exposed to the “cottage industry” as much as Peter, but what I’ve seen is a bunch of people who ARE worried but not going “Chicken Little” on us just yet. It IS helpful to keep methane in the forefront because it is such a potent GHG and we are also releasing so much of it with all our fracking and drilling. One of my biggest nightmares is that we WILL reach a tipping point with methane releases, and that a massive positive feedback loop will occur, and that could be “game over”.

      It is much the same as what we see going on with Ebola right now—-putter and putz around while denying the truth of what’s happening. Jimbill’s Churchill quote on another thread says it all.

      Arcus is 100% correct with “We need to know what’s going on with methane in the oceans”. (to which I’d add “and in the permafrost”)

  2. dumboldguy Says:

    WHOA! So much for getting a good night’s sleep tonight.

  3. Hank Roberts Says:

    I’ve mentioned this elsewhere: when you get down to the bottom of the scary stuff like this, from http://arctic-news.blogspot.com/2012/09/further-confirmation-of-a-probable-arctic-sea-ice-loss-by-late-2015-loss.html

    you find that this is the recommendation:

    • dumboldguy Says:

      Lord love a duck, but Figure 24 is a desperation last resort scheme, as is Figure 25. If it comes to this, we will likely be too late. Of course we will also be doing some of the other geo-engineering schemes, like space mirrors to reflect the sun’s rays and turning the sky yellow with sulfur compounds. Don’t worry, be happy—-man can overcome all obstacles.


  4. […] Calling the Methane Bomb Squad Methane Bomb Squad Part 2 – Dr Aradhna Tripati on Undersea Methane Methane Bomb Squad Part 3: Dr. Carolyn Ruppel on Siberian Shelves […]


  5. […] Calling the Methane Bomb SquadMethane Bomb Squad Part 2 – Dr Aradhna Tripati on Undersea MethaneMethane Bomb Squad Part 3: Dr. Carolyn Ruppel on Siberian Shelves […]

  6. Susan Hatch Says:

    Tweeting On Thin Ice – Reflecting On The Arctic Sea Ice Meeting At The Royal Society
    Details
    Published on Tuesday, 30 September 2014 20:41
    By Nick Breeze

    This is a good write-up of what happened. It does not sound at all good.


  7. Nice write-up.

    I wonder what difference the *speed* of warming is making, however. In past cycles, warming has taken much, much longer than in the current anthropogenic climate change era.

    Slow warming would cause sea level rise, then sea temperature rise, and the increased pressure on cold seeps due to the increased water level would suppress the seeps, meaning that that methane ends up sequestered away in clathrates, until sea level drops again, but at that point it’s colder anyway, so they stay sequestered

    Rapid warming is causing sea temperature rise while there are still extant ice sheets – this could result in seeps becoming more active due to the increased temperature and negligible increase in pressure – and if they become more active, warming accelerates, melt happens, and they stop once more due to pressure – but potentially after releasing far, far more methane than in a slow warming scenario.


    • Sorry, forgot to add – this is all down to the specific heat capacities of water and ice, respectively, and the latent heat of fusion for ice/water.

    • dumboldguy Says:

      I wonder if you are overestimating the ability of increased pressure due to sea level rise to hold down methane emissions?

      In the course of the Earth’s warming, it is also expected that sea level will rise due to melting of the polar ice caps and glacial ice. This inevitably results in greater pressure at the sea floor. The increase in pressure, however, would not be sufficient to counteract the effect of increasing temperature to dissolve the methane hydrates. According to the latest calculations, a sea-level rise of ten metres could slow down the methane-hydrate dissolution caused by a warming of one degree Celsius only by a few decades”.


  8. […] craters, says Carolyn Ruppel, chief of the U.S. Geological Survey’s Gas Hydrates Project. (see my 2014 interview with Dr. Ruppel here) But she and other scientists say the new satellite mapping suggests another explanation that has to […]


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