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Methane Gas And Climate Change


jethro

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Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl

A dedicated thread to discuss this issue.

Over to you fplks.......

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

http://news.softpedia.com/news/Increased-Methane-Levels-Recorded-in-the-Arctic-106518.shtml

http://news.mongabay.com/2008/0423-ghg.html

http://www.science20.com/news_releases/forget_co2_methane_levels_rise_again

From the end of the noughties we had a lot of folk looking at the 'new' increases in methane from the north.

We had (apparently) been running at stable levels for a few years after the earlier 'blip' in Methane levels that seemed to be linked to escaped gas from Russian pipelines (through the eighties and nineties) which had been dealt with by the late nineties/early noughties.

With attention focused on both sea areas (those off Siberia and by Svalbard) and the land based permafrosts.

Today I saw this over on Science Daily;

http://www.sciencedaily.com/releases/2010/11/101117141516.htm

I have to wonder about such mechanisms providing a positive feedback across the tundra regions (like warm water ingress to the submerged permafrost/clathrates?). With the initial heat melting back into the permafrost (and soot particles covering other snow/ice areas) followed by the darkened biomass instigating further warming across the area (promoting further melt and out gassing).

I know the teams that were working in Siberia/off the Siberian coast were at work there again this melt season so it may be interesting to see if losses continue there?

I think it was Scottish Skier who noted that we have only recently started to take such 'delicate' measures but surely if we find an increase in local methane production shadowing a global rise in methane in the atmosphere then the evidence appears compelling that we are indeed starting to outgass from the permafrosts?

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Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

Not normally my area of interest on here, but came across this .pdf briefing on methane, cattle and climate change by Dr Martin J Hodson a while a go. Sorry if it's been covered elsewhere:

464.pdf

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Posted
  • Location: Camborne
  • Location: Camborne

A paper from 2004.

Methane Clathrates and Climate

Clathrates are a class of compound that consist of a cage of molecules that can trap gases, such as methane, in a solid form. For methane, the most important "cage" is one that is made of water molecules, and so is described sometimes as a hydrate. Some key facts about clathrates make them particularly interesting to climatologists. First, they may make up a significant portion of total fossil carbon reserves, including coal and oil. Current best guesses suggest that maybe 500 to 2000 gigatonnes of carbon may be stored as methane clathrates (5-20% of total estimated reserves). Some estimates are as high as 10,000 gigatonnes. They occur mainly on the continental shelf where the water is relatively cold, there is sufficient pressure and enough organic material to keep the methane-producing bacteria happy. Most importantly, clathrates can be explosively unstable if the temperature increases or the pressure decreases — which can happen as a function of climate change, tectonic uplift or undersea landslides.

The importance of these clathrates in climate change has only recently started to be appreciated. The first clue was some puzzling data from a period 55 million years ago. In the early 1990's, Jim Kennett of Scripps Institute of Oceanography and his colleagues noticed that during an extremely short amount of time (geologically speaking) at the transition between the Paleocene and Eocene epochs, carbon isotope ratios everywhere (the deep sea, on land, at the poles and in the tropics) suddenly changed to favour the lighter 12C isotope of carbon at the expense of 13C. The rapidity and size of this change was unprecedented in the period since the demise of the dinosaurs, and this excursion was simultaneous with a short period of extreme global warming (around 3 to 4 degrees globally, more in the high latitudes).

In 1995, Jerry Dickens of Rice University suggested that the only conceivable perturbation to the global carbon cycle to fit these data was a massive input of light carbon that had been stored as methane clathrates, which are observed to be particularly high in 12C. Nothing else could be as fast-acting or have enough of the lighter isotope to have had the observed effects. Given that both CH4 and it's oxidization product CO2 are greenhouse gases, this might explain the global warming as well.

Subsequent work, including atmospheric chemistry studies by myself and Drew Shindell of NASA GISS, have confirmed that this hypothesis is still the most likely candidate, although the initial triggering mechanism is unknown. Similar ideas have been proposed to explain short term events in the Jurassic, at the Permian-Triassic boundary and in the Neo-Proterozoic, although the evidence for a unique role of methane in these cases is much weaker than at the Paleocene/Eocene boundary.

With a plausible role for methane clathrates in the Paleocene, it is only natural to examine whether they played a similar role in more recent climate changes, such as rapid climate variability during the last ice age. There are some tantalizing clues. In ocean sediments offshore of California, Kai-Uwe Hinrichs and colleagues at Woods Hole recently found geochemical traces of clathrate releases coincident with warmings in the Greenland ice core records. In some records, there are coincident spikes in the carbon isotope record, reminiscent of the Paleocene/Eocene spike but of lower amplitude. This has lead Jim Kennett to propose the so-called "clathrate gun hypothesis", that methane builds up in clathrates during cold periods, and as a warming starts it is explosively released, leading to enhanced further rapid climate warming. This idea is not yet widely accepted, mainly because the records of methane in the ice cores seems to lag the temperature changes, and the magnitudes involved do not appear large enough to significantly perturb the radiative balance of the planet. The more conventional explanation is that as the climate warms there is increased rain in the tropics and thus increased emissions from tropical wetlands which need to have been large enough to counteract a probable increase in the methane sink. There is, however, much that we don't understand about the methane cycle during the ice ages, and maybe hydrates will eventually be considered part of the rapid climate change story.

http://www.giss.nasa.gov/research/features/200409_methane/

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

Recent work off New Zealand has found one of the 'slump zones' that could be part of the Eocene warming. Obviously in an tectonically active area the type of earthquake needed to collapse the deposit (and release the methane) are relatively common. The Earth movements occurring around this time (Himalaya's and Alps along with a widening Atlantic) could all have helped create the stresses in the plate margins needed to see the kind of jolt needed to liberate the deposits.

The other areas of massive deposits are at the edges of Delta deposits (on the edge of the continental shelf) and any rapid change in deposition contents can destabilise this type of deposit again leading to catastrophic slumping of the deposits (down onto the Abyssal plain) releasing the methane in the process.

Changes in rainfall patterns (increases of sediment deposition) or rapid changes in land use (deforestation) may well provide a mechanism to enable slumping to take place and release the cargo of Methane.

As mentioned earlier Methane releases may well be behind some of the shipping/aircraft losses in the so called 'Bermuda triangle'. Flooding water with gas alters the buoyancy of vessels leading them to rapidly sink or alter the local atmospheric composition (above the release) altering the aerodynamic performance of aircraft!:)

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

Ok, before posting any hydrate comments, I think this thread should be open to all methane related climate discussion, be this peat bogs, ruminents or too many vindaloos....

I'll chuck in my tuppenceworth on methane hydrates - there is a lot of misleading info out there on them and I'll do my best to correct that. No preaching, just 10 years experience making hydrates but not funded by climate research grants I hasten to add (i.e. non-biased).

Shall follow up on the above comments shortly.

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

The other areas of massive deposits are at the edges of Delta deposits (on the edge of the continental shelf) and any rapid change in deposition contents can destabilise this type of deposit again leading to catastrophic slumping of the deposits (down onto the Abyssal plain) releasing the methane in the process.

Ok, a wee intro to methane hydrates might clear this up. Attached is a plot of the methane hydrate (structure-I) stability as a function of hydrostatic pressure / seawater depth. Assumes seawater salinity at 3.5 wt% sodium chloride (NaCl) equivalent.

Inside the orange line (the methane hydrate phase boundary) methane hydrate is stable and in equilibrium with seawater, or rather sediment pore water as hydrates occur in the sediments much more than the seafloor (reasons will follow). Outside that region, methane gas (free gas or dissolved) is in equilibrium with water. On the boundary, all three phases (water, gas, hydrate) can theoretically exist.

So, with respect to a submarine slide destablising methane hydrate...

Looking at the graph, if we take a bit of hydrate on the upper continental margin, say 750 m water depth at a T of 6 C and carry it down the slope in a slide to say 3000 m water depth and 3 C temperature, what will most likely happen?

A. The whole lot will melt releasing methane, sinking a passing ship (bermuda triangle)

B. Little or no hydrate will melt so no significant gas release

Note the conclusion should based on the graph alone at this stage....

post-9421-0-68662700-1290190330_thumb.pn

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

So the graph seems to support that past mass releases have been due to ice sheet/glaciation as the mere collapse of Continental shelf deposits will not give rise to 'unstable' clathrates?

Are we as confident of the clathrates that are housed in 'unusually cold waters (Arctic Basin) at shallow levels (off Siberia?) The loss of permanent sea ice across the East Siberian/Laptev seas and the high sea surface temp anoms we are seeing currently must set some alarm bells ringing as to the continued 'stability' of the deposits?

Over the longer time frame do we not have clathrate deposits at the bases of ice sheets?. With conditions globally approaching the same as those 125,000yrs ago the partial melt (over time) of Greenland (as 125,000yrs ago) must also be a concern if it involves methane release on top of sea level hikes?.

I have no knowledge on the base of EAIS and WAIS but I would imagine that they too contain clathrate deposits at their bases and so any partial melt in those areas would also allow the release of these deposits I imagine?

The Geological sequence seem to point to massive clathrate releases at the end of some of the major glaciations and the only way I can figure this is that the vegetation swamped by the glacial episode lies at the base of the sheets and microbes do their work there whilst the ice age rages above.Once the sheet is gone the temp/pressure is such as to allow this 'stored' carbon back out into the system?If this is so and we are heating the planet out of the partial glacial conditions (ice sheets present) then will we not be wise to accept that the loss of the sheets would lead to short term surges in the levels of atmospheric methane?

EDIT: Sorry S.S. hadn't read your first post but would agree to a wider exploration of methane issues, including our current chioce of meat once a day and the 'costs' to the atmosphere of this, would be a better Idea than exploring one type of deposit alone :)!

Edited by Gray-Wolf
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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

So the graph seems to support that past mass releases have been due to ice sheet/glaciation as the mere collapse of Continental shelf deposits will not give rise to 'unstable' clathrates?

That would be the correct assuption from the graph. If a big submarine slide carried sediments containing gas hydrates into deeper, colder waters at the bottom of the continental slope, then the hydrates would be more stable as the T is now lower and the P higher; i.e. they are deeper inside the orange bounded region.

There might be a wee bit of melting of hydrates at the surface of the debris pile that formed. However, this would not cause gas release to the atmosphere. The melting would be because seawater is not saturated with methane, thus hydrates exposed to the seawater would 'dissolve' with the methane going into solution in an attempt to equilibrate. This methane would then be rapidly oxidised/eaten by little single celled beasties that live down there, so nothing will reach the atmosphere. The hydrates that are buried in the sediment pile will not 'see' the seawater as the sediments surrounding them will severly limit gas diffusion, thus they will remain stable. Gas diffusion out from the pile might slowly cause these to melt, releasing methane slowly to be oxidised, but this would take thousands of years and again, no sudden release to the atm.

As we know, methane has a very short residence time in the atm, so for methane hydrate to release methane in big quantities/quick enough to drive climate change, we need something dramatic to happen very quickly...

I shall follow up with another graph to explain hydrate stabiltiy in sediments and other possible ways methane release could be associated with submarine slides - there are ways, but not as described above. We can then move to arctic waters and onto subpermafrost hydrates if folk are interested.

Rather than diving into the current literature straight away, I think it would be good for people to get a basic understanding of the what/where/why of hydrates first. Sound reasonable?

Cheers,

SS

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

Thanks for your time and efforts here S.S

.

I'm sure there are plenty of folk here on N.Weather that would welcome your input (and squash a few net myths as we go?)

I'd welcome a chance to explore the current situation across the tundra regions (and their shelf sea counterparts) as , for me, it is this area that is of most interest right now as we witness the changes in the Arctic climate.:)

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Posted
  • Location: Swallownest, Sheffield 83m ASL
  • Location: Swallownest, Sheffield 83m ASL

Over the longer time frame do we not have clathrate deposits at the bases of ice sheets?. With conditions globally approaching the same as those 125,000yrs ago the partial melt (over time) of Greenland (as 125,000yrs ago) must also be a concern if it involves methane release on top of sea level hikes?.

The Geological sequence seem to point to massive clathrate releases at the end of some of the major glaciations and the only way I can figure this is that the vegetation swamped by the glacial episode lies at the base of the sheets and microbes do their work there whilst the ice age rages above.Once the sheet is gone the temp/pressure is such as to allow this 'stored' carbon back out into the system?If this is so and we are heating the planet out of the partial glacial conditions (ice sheets present) then will we not be wise to accept that the loss of the sheets would lead to short term surges in the levels of atmospheric methane?

So it seems that if this does happen, it could be down to a natural event? You seem to be answering your own questions these days GW. All of these events you have mentioned could be generated purely on the back of mother nature. In short.. Yes it could happen, as it has happened before. That was a natural event and could happen again as a natural event. Your line of questioning will not meet with any form of concrete conclusion considering that we may be at the end of our nice warm (but still cold by "normal" temps) temporary climate.

I agree with the idea of starting with the basics. Can we keep to trying to understand the basics for now and leave the crystal ball in the cupboard for now please? :)

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

Ok, taking things a bit further, but sticking with seafloor hydrates…

Earlier plot attached, but now with the thermocline, geotherm and example seafloor added.

The thermocline is something like would be found in warm to tropical climates. The temperature drops very rapidly over the first couple of hundred metres as light penetration is lost through absorbance. Below that, it’s dark and cold, even in tropical regions.

The geotherm is a typical value; the geothermal gradient of course varies dependent on locality, but as hydrates are typically found on the continental margins where the crust is quite thick, the geotherm is not generally steep.

The depth of the seafloor varies too, but 1000 m is a good choice to use as an example.

Moving down through the column… In the sea itself, hydrate is not stable due to seawater being unsaturated with respect to methane. So, unless there are active gas vents (e.g. in the Gulf of Mexico), which could allow the growth of seafloor hydrate mounds, there is no hydrate until we drop beneath the seafloor. There, we have anaerobic conditions and methanogenic bacteria making methane as they eat organic matter laid down on the seafloor by outwash from river deltas etc – distal organic-rich muds, silts and clays. Unconsolidated/uncemented, potentially high porosity, but low permeability. Gas made by bacteria is called ‘bacteriogenic’ and this gas by far dominates in global hydrate deposits.

The other source of gas is conventional gas reservoirs 100's to 1000’s of metres below the seafloor. This gas is high temperature cracked kerogens from organic rich sediments buried/turned to rocks. If it can find a way up, it will, and when it enters the hydrate region can turn to hydrates. This ‘thermogeneic’ gas differs from bacteriogenic in that it typically contains higher hydrocarbons such as ethane, propane, butane. The presence of theses gases can stabilise hydrates even more, altering the structure from s-I to s-II.

As shown in the plot, the region where hydrates are found is bounded by the seafloor and by the intersection of the phase boundary with the geotherm at depth. Hydrate can grow in the pore space of the sediments here if methane is in supply. If there is excess methane below the hydrate region, this may come out of solution to form bubbles of gas. These bubbles give rise to the BSR (second attachment) – bottom simulating reflector – which appears on siemic sections and is a good identifier of gas hydrates. Basically, the velocity of sound is much lower through the gas than it is through water/sediments above/below, so this gives a big reflection. We can see the reflection cuts across the reflections of the rock layers paralleling the base of the seafloor (hence bottom simulating) as it follows the conditions where the HZS intersects with the geotherm and hydrates are no longer stable.

So, how stable are the hydrates? What if the sea warms up, will they melt? Well, from the plot you can see that hydrates just below the seafloor are actually the furthest into the region of stability. For our 1000 m seafloor depth example, we’d need a seafloor temperature rise of close to 6 C or a drop in sea level of ~400 m to cause them problems. The least stable of the hydrates are those at the base of the hydrate region. However, the geothermal gradient is not easily influenced by surface temperature changes so we would need a big drop in sea level and/or large, sustained temperature rise to melt them too. Also, this would have to happen quickly (10’s to 100’s of years), otherwise any gas released from melting at the base of the HSZ will slowly migrate up into the HSZ and form hydrate again.

Any questions?

Next…. so ok the hydrates themselves - at least the bulk of the seafloor ones - don’t seem so dangerous, but what about that gas underneath, are there scenarios where it could build up and be released suddenly?

post-9421-0-20678100-1290274472_thumb.pn

post-9421-0-54114800-1290274491_thumb.pn

Edited by scottish skier
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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

The Geological sequence seem to point to massive clathrate releases at the end of some of the major glaciations and the only way I can figure this is that the vegetation swamped by the glacial episode lies at the base of the sheets and microbes do their work there whilst the ice age rages above.Once the sheet is gone the temp/pressure is such as to allow this 'stored' carbon back out into the system?If this is so and we are heating the planet out of the partial glacial conditions (ice sheets present) then will we not be wise to accept that the loss of the sheets would lead to short term surges in the levels of atmospheric methane?

Yes, the geological record does show good evidence for widescale hydrate destabilisation - millions of years ago at least. I'll come to that in time (think big changes in sea level).

As for microbes beneath an ice sheet. I would not imagine that could occur as there would be nothing for them to eat. Ice sheets move, scraping away topsoil and unconsolidated sediments before them, leaving largely nothing but rock and ground up rock (e.g. boulder clay) underneath them. The latter material would likely be very organic poor, so nothing for microbes to feed on.

Permafrost is a different matter - it forms in-situ, so sediments stay where they are. Thus beneath the permafrost we can have something for our microbes to eat, generating methane....

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Posted
  • Location: 4 miles north of Durham City
  • Location: 4 miles north of Durham City

An interesting article on The Oil Drum concludes that initial estimates of methane hydrates in offshore deep-water drilling locations have been inflated (and we still have incomplete data on hydrate occurrences).

http://europe.theoildrum.com/node/5552

I don't know anything about this specialised subject area, so perhaps SS could explain this to me.

Seems the experts are more worried about the permafrost methane than those that reside in the ocean.

Edited by PersianPaladin
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Posted
  • Location: 4 miles north of Durham City
  • Location: 4 miles north of Durham City

If the global average temperature increases from the present 0.8 C to two degrees C, as seems likely, the entire Arctic region will warm at least four to six degrees and possibly eight degrees due to a series of processes and feedbacks called Arctic amplification.

A similar feverish rise in our body temperatures would put us in hospital if it didn't kill us outright.

"I hate to say it but I think we are committed to a four- to six-degree warmer Arctic," Serreze said.

If the Arctic becomes six degrees warmer, then half of the world's permafrost will likely thaw, probably to a depth of a few metres, releasing most of the carbon and methane accumulated there over thousands of years, said Vladimir Romanovsky of the University of Alaska in Fairbanks and a world expert on permafrost.

http://ipsnews.net/news.asp?idnews=52896

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

An interesting article on The Oil Drum concludes that initial estimates of methane hydrates in offshore deep-water drilling locations have been inflated (and we still have incomplete data on hydrate occurrences).

Seems the experts are more worried about the permafrost methane than those that reside in the ocean.

Yep on both counts. While hydrates have been blocking gas pipelines since the early part of the last century, it was only in the 70's that folk realised they occur in nature.

Research on hydrates is on the way up, and a lot has been learned in the past couple of decades, particuarly with increasing drilling investigations such as the IODP (international ocean drilling project). The more we know, the more the total amount has reduced to more conservative levels. We're still talking about a lot of gas - at least equal to current conventional gas reserves.

As for the Arctic and hydrate concerns - I'm working towards that. Basically, they are more sensitive to climate up there as they are closer to the surface. More in due course.

If you are really keen, attached is a draft of a paper I co-authored with the boss for the book Bioenergy (http://estore.asm.org/viewitemdetails.asp?itemid=762) a couple of years back. This is not focussed on climate change, but on methane hydrates as a potential energy source - gives a overview of hydrates aimed at scientists, but not experts in hydrates.

Cheers,

SS

tohidi_anderson_hydrates.pdf

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

If the Arctic becomes six degrees warmer, then half of the world's permafrost will likely thaw, probably to a depth of a few metres, releasing most of the carbon and methane accumulated there over thousands of years, said Vladimir Romanovsky of the University of Alaska in Fairbanks and a world expert on permafrost.

This looks like doomongering to me. I have to say I have never heard of Vladimir Romanovsky. He may be an expert on permafrost, but if he was an expert on hydrates, I imagine I'd have seen him at some point/come across lots of papers by him on the topic. I just doubled checked submissions for next summers ICGH - not a first author on anything. Likewise nothing from University of Alaska.

Basically, the media want a scare story and he's gone for it. It is not that what he says has some possible truths in it, rather the way it is portrayed as 'this is what is going to happen, no doubts at all, we're all doomed".

EDIT:

Straight from the horses mouth. That's more like it....

http://permafrost.gi.alaska.edu/project/dynamics-gas-hydrates-and-permafrost-eurasian-and-north-american-arctic-land-shelf-system

"Current models of climate predict a climatic warming and permafrost temperatures are known to have increased 2 - 4 °C during this century. With present knowledge, it is not possible to predict the amount of methane that is currently being released and that will be released by gas hydrate decomposition as a result of permafrost, especially subsea permafrost, degradation. We propose a research effort that will involve a survey of existing data on gas hydrate and permafrost conditions in the Russian Arctic land-shelf system to establish boundary conditions, properties, occurrence and distribution to use as input data for a two-dimensional numerical model of gas hydrates and permafrost"

Edited by scottish skier
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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

As you are probably aware I do believe that the Arctic has passed a 'tipping point' and so feel we are committed to high temp rises over a short (relatively) period of time. The sea ice "Death Spiral" has implications up to 1,500km inland (so we're told) and that brings a lot of the permafrost into the 'thaw' zone. The prospect of drying and fire (as we saw in the Article on the other thread http://www.sciencedaily.com/releases/2010/11/101117141516.htm ) will increase and so may provide another 'feedback' mechanism in the permafrost thaw.

I'm told not the scry but surely when something is beginning to occur we need to try and make sense of the implications the process may bring to us (the planet)?

Edited by Gray-Wolf
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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

The Geological sequence seem to point to massive clathrate releases at the end of some of the major glaciations and the only way I can figure this is that the vegetation swamped by the glacial episode lies at the base of the sheets and microbes do their work there whilst the ice age rages above.Once the sheet is gone the temp/pressure is such as to allow this 'stored' carbon back out into the system?If this is so and we are heating the planet out of the partial glacial conditions (ice sheets present) then will we not be wise to accept that the loss of the sheets would lead to short term surges in the levels of atmospheric methane?

As I noted earlier, I'm not aware of large volumes of methane trapped under ice sheets - at least current ones. However, there is life down there and if there are organics present, then they could flourish, producing methane. However, from my knowledge, the lack of organics (the continental shelves are constantly supplied but under an ice sheet, no new organic material is delivered) means this does not happen in a big way, at least it is not a major factor in recent times. Possibly in large scale glacial cycles of the past though....

http://www.wired.com/wiredscience/2010/03/antarctic-methane-lakes/

http://www.sciencedaily.com/releases/2008/05/080528140255.htm

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

Cool video. Looks like fun.:D

I'm guessing that's bog methane/swamp gas trapped under lake ice...

Will follow up on methane hydrate posts - but snow is coming and busy with work.

TBC...

SS

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'If the Arctic becomes six degrees warmer, then half of the world's permafrost will likely thaw, probably to a depth of a few metres, releasing most of the carbon and methane accumulated there over thousands of years, said Vladimir Romanovsky of the University of Alaska in Fairbanks and a world expert on permafrost.'

This looks like doomongering to me.

.....

Straight from the horses mouth. That's more like it....

.... With present knowledge, it is not possible to predict the amount of methane that is currently being released and that will be released by gas hydrate decomposition as a result of permafrost, especially subsea permafrost, degradation.

I personally find the second statement a lot scarier than the first.

I like to think of the methane situation as a bunch of people huddled around a fire struggling for warmth (carbon consumption fuels our society). Someone then points out that the fire is built against a massive gas tank, which could explode (methane could be released abruptly and cause a disaster). A scientist works out some sums and says that with the thickness of the metal, and lack of oxygen supply to the gas tank the fire is quite safe (current calculations on methane suggest a 0.5 degree warming in next century). The people need the fire for their well-being and its not easy to just put it out.

In such a situation I wouldn't feel completely safe with the fire close to the gas tank no matter how many assurances I had from scientists that it will not blow up. I think it would also be silly to run around in a panic expecting the tank to explode any second. Prudent would be to look for an alternate source of heat as soon as reasonably possible.

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Posted
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl
  • Weather Preferences: Snaw
  • Location: Premnay, Insch, Aberdeenshire, 184 m asl

Prudent would be to look for an alternate source of heat as soon as reasonably possible.

Could not agree more. Finite resources with possible long term climate effects we can't predict with certainty?... I'm all for renewables - just logical.

But easy on the natural occuring hydrates, honestly. I've made hydrates every day (10 years now) and know them just about as well as good reciepe you've made a thousand times. C1-C2 system on the go at present.

They are something we can't ignore - a part of the big picture - but no need to panic right now. Is all I can and will say unless you want to come and study them too....

Cheers,

SS

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  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

http://www.wmo.int/pages/mediacentre/press_releases/documents/GHG_bull_6_en.pdf

A very timely release, prior to Cancun, from the World Meteorology Organisation regarding methane from the wetlands/permafrost.

I wonder if S.S. has a take on it and it's timing (kinda opposite of 'climate-gate'?)

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  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

http://www.agu.org/cgi-bin/highlights/highlights.cgi?action=show&doi=10.1029/2010GL045184&jc=gl

I found it! (knew I'd seen it). From what S.S. said this massive release was either due to low sea levels at the height of glaciation or the warming at the end of the glaciation prior to the sea level increases? (or just very intense warming after the glaciation finished?).

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