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Fracking methane

Filed under: — gavin @ 16 April 2011

The Howarth et al paper estimating the climatic impact of shale gas extraction by hydraulic fracturing (fracking) has provoked a number of responses across the media. Since the issue of natural gas vs. coal or oil, and the specifics of fracking itself are established and growing public issues, most commentary has served to bolster any particular commenter’s prior position on some aspect of this. So far, so unsurprising. However, one aspect of the Howarth study uses work that I’ve been involved in to better estimate the indirect effects of short-lived emissions (including methane, the dominant component of shale gas). Seeing how this specific piece of science is being brought into a policy debate is rather interesting.

The basic issue is that for any real economic or industrial activity there are a variety of emissions associated with the life cycle of that activity – from construction, transport of fuels, operating emissions, end products etc. In deciding whether one activity is ‘better’ or ‘worse’ than an alternative, people need to have an assessment of the cost, the carbon footprint, other impacts etc., over that whole life cycle. There are of course different elements to this (cost, pollution, social issues) that need to weighed up, but one piece that is amenable to scientific analysis is the impact on climate drivers.

Calculating the net climate impact of an activity requires tracking many different emissions (not just CO2), and accounting for their (time-varying) impact on radiatively active components of the atmosphere or the properties of the affected land surface. While straightforward in conception, this can be complex and, inevitably, there are uncertainties in assessing all the knock-on effects. Over the years, many of the complexities have become better acknowledged which, in some cases, increases the total uncertainty, but the alternative of assuming that the indirect effects have zero impact with zero uncertainty is not tenable.

For shale gas extraction, (and indeed for most fossil fuel extraction), a big issue is fugitive emissions. These are emissions that arise by accident – mostly consisting of methane, but also other volatile organic compounds – as a function of the mining, refining, transport, or incomplete combustion. Since methane is a relatively powerful greenhouse gas whose source is dominated by anthropogenic activities at present, the impact of the fugitive emissions can be a significant component of the climate forcing associated with any activity.

The Howarth study, using admittedly poor observations (for lack of anything better), has come up with a relatively large potential for fugitive emissions from the fracking process itself – up to a few percent of the extracted gas. Converting this into an equivalent CO2 amount (for comparison with the impact of the gas once it is combusted), they have used Global Warming Potentials (GWPs) from Shindell et al (2009) (a paper I co-authored). A GWP is a kilo-for-kilo comparison of the radiative forcing associated with the emission of particular substance compared to CO2, integrated over a specific time frame. For a long-lived gas like CO2, forcing persists over a long time, while for a shorter lived species (like methane), the forcing goes down faster with time. Therefore the time frame for the GWP calculation matters a lot for the relative importance of the two gases. Methane is relatively more important for a 20 year time frame, than it is for a 100 year time frame, by about a factor of 3.

There are indirect effects from methane emissions because it is chemically reactive in the atmosphere. It contributes to increases in tropospheric ozone and stratospheric water vapour (increasing the warming impact), and by changing the oxidising capacity of the atmosphere, affects it’s own lifetime, and that of SO2 and NOx – which in turn affects aerosol formation, and indeed aerosol-cloud interactions. The IPCC (2007) report had acknowledged the potential for these indirect issues, but had not given any numbers. The Shindell et al paper was an attempt to fill that gap. As we discussed previously:

… we found that methane’s impacts increased even further since increasing methane lowers OH and so slows the formation of sulphate aerosol and, since sulphates are cooling, having less of them is an additional warming effect. This leads to an increase in the historical attribution to methane (by a small amount), but actually makes a much bigger difference to the GWP of methane (which increases to about 33 – though with large error bars).

For comparison, the GWP in IPCC (2007) was 25 – this is for a 100 year time frame. For shorter periods like 20 years, the relative increase in our numbers was somewhat higher (about 50%) over that given by in AR4.

Thus a combination of high fugitive emissions, and larger updated numbers for the impact of methane are the main components the Howarth conclusion, relating the impact of shale gas to coal. However, for an apples-to-apples life cycle comparison, one would need to also update the impacts of coal and oil to include their fugitive emissions, their impact on other short-lived components (black carbon, CO, etc). Thus, it’s not clear that the Howarth comparisons are exactly on a level playing field. Regardless, the uncertainties in some of these estimates are such that very clear conclusions are going to be elusive for some time to come.

A few further points are worth making. The estimates for fugitive emissions are uncertain because they are not being reported, either voluntarily by the industry or through regulation from the states. It is also worth stating that there is nothing inevitable about fugitive emissions. Better management (and/or regulation) can reduce these losses substantially (up to 90% in some situations) in very cost-effective ways (since lost methane is lost product in many cases).

Which brings me to the responses to this story. The industry website Energy in Depth was quick off the mark with a response that feigned surprise and shock that the emission estimates were uncertain (somewhat hypocritically since it is the same industry that has resisted almost any improvement in reporting standards). They also try to imply that the Shindell et al study was somehow suspect because it was different to the earlier IPCC GWP numbers, without any apparent interest or knowledge of why that was. Again, the industry would be better advised to deal with fugitive emissions (which also impact air pollution) rather than attacking inconvenient science. (Funnier still are the contrarian responses, for instance from “Bishop Hill” who completely agrees with the industry (again without any actual knowledge of the issues), and who can’t resist using their criticism of Howarth to condemn a whole University (and by proxy, the whole scientific enterprise). I mean, why bother with independent scientists when the industry can tell you exactly what you are supposed to think?).

Another frequent framing is the false dichotomy. Apparently, natural gas must either be perfect solve-all or worse than useless (see for instance, Keith Kloor’s take). One would think that the overwhelming consensus that there are no panaceas for decarbonising our energy supply might have at least started to make a little impact on the media. Any real policy initiative will have complex effects, and while scientists can certainly help quantify them, nothing at the scale we require is going to be completely neutral in all particulars – and the media should stop expecting it to be so. Since there will always be people who can be portrayed as having taken a black/white position on some issue, it is all too easy to frame any new result as undermining some over-optimistic idealist, which unfortunately buries the conversation related to the nuances of real issues.

Howarth et al is unlikely to be the last word on this subject, but it does highlight the need for more of this kind of research, and for further quantification of these emissions and their effects. For anyone interested in the larger issues of time-scales and the implications of combining emissions of short-lived and long-lived species in assessing impacts, I recommend reading the latest UNEP report on Black Carbon and Tropospheric Ozone mitigation (at least the summary). Another relevant read is the post by Ray Pierrehumbert on the same issue. This is not just an issue for fracking, but rather something that is far more general and affects almost all emitting activities.

88 Responses to “Fracking methane”

  1. 51


    Don’t be too sure, Ray. The courts may not be up on the science per se, or even on ‘reality’ generally, but they do have good expertise in assessing the credibility and logical consistency of witnesses.

    So hope that Steve Goddard, Anthony Waqtts, or perhaps the good Baron himself, files an amicus brief. With friends like that. . .

  2. 52
    SecularAnimist says:

    Ray Ladbury: “The question is what we are doing by having the Supreme Court rule on a matter of physical reality”

    As I understand it, the question before the Supreme Court has nothing to do with the physical reality of AGW. It has to do with whether pending EPA regulation of GHGs preempts the ability of states to sue GHG polluters under the federal common law of nuisance thereby using the judicial system to compel emission reductions. It’s a legal and political question, not a scientific question.

    EPA has already decided the scientific question with its endangerment finding, and is moving to regulate GHGs accordingly (as the Supreme Court already ruled the EPA must do if it determined that GHGs endanger public health). This case does not challenge that finding.

  3. 53
    Dan H. says:

    [edit–OT, purely political]

  4. 54
    Septic Matthew says:

    49, Ray Ladbury: The question is what we are doing by having the Supreme Court rule on a matter of physical reality.


    The Supreme Court adjudicates cases based on the relevant laws. The EPA case is about which laws apply, which laws have supremacy over other laws, whether EPA followed the determinative laws, and therefore who wins the case.

    [Response: Veering rapidly off topic, end of discussion on politics please. Thanks.–Jim]

  5. 55
    SecularAnimist says:

    While noting that the current Supreme Court case is off-topic, I would just like to say that I am very surprised that some commenters here don’t seem to understand what the case is even about.

    It has nothing to do with science, and it has nothing to do with whether the EPA followed “the law”.

    It simply addresses the question of whether the EPA’s stated intention to regulate GHG emissions from electric power plants, in the absence of any actual EPA regulation to date, preempts a lawsuit by several states that sought judicially-imposed limits on such emissions.

    [Response: Thanks for clarifying. Good place to end the discussion.–Jim]

  6. 56
    Alexander Harvey says:

    Sorry OT but, a link to a draft of:

    Earth’s Energy Imbalance and Implications (James Hansen, Makiko Sato, Pushker Kharecha) has been published at Climate Etc.

    I haven’t read it all yet, but what from what I have seen it looks damn good, and more or less what I have been waiting for expectantly. So Congrats! I will have some quibbles I am sure but hopefully nothing to cry about.

    Anyway Nice One Jim (et al.)


  7. 57
    Don Miller says:

    There is no proven and documented instance of hydraulic fracturing of a well causing ground water contamination.

  8. 58
    Vendicar Decarian says:

    There is no proven and documented instance of opening a soda bottle causing soda to go flat.

    “There is no proven and documented instance of hydraulic fracturing of a well causing ground water contamination.” – 57

  9. 59
    Thomas says:

    57: Although I doubt your statement, the issue is water contamination from fracking, but rather whether the watsewater was properly disposed of. The real pollution comes from the few operators who violate the law.

  10. 60
    Les Johnson says:

    Gavin: We can tease the human signal out of CO2 emissions, and it is increasing atmospheric CO2 content by only about 0.6% per annum.

    Using Howarth’s numbers of around 3% leakage, gives about 54 Tg of methane per year leaking. The Tropospheric methane sinks, according to the IPCC, is 490 for OH, 30 for soil and 40 for stratospheric. Other sources list Cl at 25 Tg. The total is about 585 Tg per year in sinks.

    Howarth’s supposed leaks would amount to nearly 10% of all sinks.

    And we would not see this signal?

    Again, methane levels were flat, when gas production increased 25% over a time frame of a decade. Global gas production over the last few years is flat and even down, but methane levels are up.

    There is no linkage to natural gas production and methane levels, especially with the leakage rates proposed by Howarth. We would NOT lose that 10% signal, regardless of natural variability or or other anthro emissions.

  11. 61
    Septic Matthew says:

    55, SA: It has nothing to do with science, and it has nothing to do with whether the EPA followed “the law”.

    Yeh, sorry. I confused it with a different case.

  12. 62
    Les Johnson says:

    Edward Greisch: Your

    28 Les Johnson: Just wondering: Does a valve leak more when it is partly closed than it does when it is fully open? I’m thinking a partly closed valve would have more internal pressure than a fully open valve.

    An open valve leaks more. More pressure inside a partially closed valve means more potential energy. Less pressure in an open valve means that potential has been liberated.

    What is “flowback”?

    In the case of fracturing (and some other operations), the well is flowed back after the treatment, to remove water and solids from the casing and wellbore area. Both interfere with hydrocarbon production, so they need to be removed. If the well was treated with nitrified fluid, the enrgy comes from the N2. Otherwise, tubing is lowered into the hole, and a gas, usually N2, is pumped down the tubing, and up the casing.

    Well casing gas: What is it and how does it flow through solid concrete? Or could somebody explain this stuff please?

    A well casing leak is a leak through or by the steel casing cemented in the ground to protect surface waters. The cement may be solid, but there may be mud channels that the cement bypassed when it was placed. Gas may also form channels in the cement as the cement transitions from a liquid to a solid. Or the cement may have been damaged after it set.

    The cement is not really solid, just as the rock the hydrocarbon comes from is not solid. Most producing formations have porosity of 5% to 40%. The higher the porosity, the more likely the porosity is interconnected, allowing flow through the rock. Its the same with cement, though it is usually an order of magnitude lower permeability (or more)than a producing zone. Gas though, can flow, albeit very slowly, in the some of the more permeable cements.

    Fortunately, this is a point source leak, and relatively easy to fix. It is also mandated by most jurisdictions. In Alberta, for instance, a single 30 ml bubble in 10 minutes, is enough to force the company to repair the leak. Companies are also finding that its much cheaper to NOT have the leak, than to repair it.

  13. 63
    Al says:

    Lots of fracking controversy here in CO recently

  14. 64
    AIC says:

    Industry project to improve accuracy of methane emission factors:

    There are a number of infrared methods for detecting fugitive methane, including some which supposedly can be done from a plane flying overhead. Perhaps use of such methods by industry was responsible for finding and fixing many methane leaks, and thus for the plateau of methane concentrations, until the recent increase in fracking.

  15. 65
    Meow says:

    Les Johnson @22: I think your math is wrong. You’re comparing cubic meters of natural gas — which are accounted at one or more fixed temperatures and pressures (often 0 degrees C and 101 kPa) — with cubic meters of the atmosphere, whose temperatures and pressures vary widely.

    You’ve got to convert the mass of the leaked CH4 and the mass of the atmosphere into volumes at the same temperature and pressure, then compute the leaked CH4’s volume fraction. When I did this, I got ~10.9 ppbv, which — given the various margins of error — hardly falsifies Howarth’s paper.

  16. 66
    Les Johnson says:

    Meow: I am using 1 standard m3 of natural gas. It weighs about 0.6 kg per standard m3. If 1 standard m3 of gas leaks into the atmosphere, there will still only be 1 standard m3 of gas, regardless of air temperature or pressure.

    If the globe produces 3000 billion m3 per year, that would mean that 54 billion kg of methane is released, at 3% leakage. (3000*.03*.6)

    54 billion kg is equal to 54 Tg. The volume of methane sinks and sources, and total atmospheric content, is given in the same unit; Tg. If the total leakage is equal to 10% of the total sinks, we will see the signal. Again, anthro CO2 is visible at only 0.6% addition. 10% should be highly visible.

    Nope, my math is right.

    But your number also falsifies Howarth. 10.9 ppb is greater than the observed rise the last few years.

  17. 67
    Ike Solem says:

    1) Decarbonizing the energy supply is not what we need. Stabilizing the atmospheric concentration of greenhouse gases is what the goal should be.

    What’s the difference? Well, food is an energy source for human beings, correct? Should we decarbonize the food supply? Does eating food and, in the process, converting it to CO2, raise the atmospheric CO2 level?

    No, it does not, since the food was synthesized using atmospheric CO2 as the raw material (for production of sugars, fats, proteins, etc.) by green plants.

    Hence, if you make fuel from the atmosphere using similar strategies – solar powered synthetic chemistry combing carbon (from CO2) and hydrogen (from H2O) to make, say, CH4 (methane) or longer-chain hydrocarbons, then you can burn that fuel without altering the atmospheric level of CO2.

    Put another way, one could say that the % 14C content of all hydrocarbon fuels should be identical to the % 14C content of the atmospheric CO2 pool. (Fossil fuels have been in the ground for millions of years, hence all 14C has decayed away).

    2) There is plenty of evidence that groundwater supplies have been contaminated by the fracking process:

    If this isn’t the case, than surely the gas drilling industry will be willing to give up the exemptions from the Safe Drinking Water Act and the Clean Water Act, granted by Congress in the 2005 Energy Policy Act? Who needs exemptions if there’s nothing to fear?

    3) Funny, isn’t it, that no-one has suggested building ‘zero-emission’ natural gas plants that capture and sequester all CO2, prior to pumping it back into the very same shale formations it came out of, isn’t it? Methane has more energy per C atom than coal, so it should be significantly less costly to due this.

    The reason this hasn’t been suggested is that CCS is still technologically implausible, energy costs being far too high. They can’t even build a natural gas CCS prototype for public display, much less a coal CCS system – anymore than they can build a car that drives down the street while capturing all its emissions. Nevertheless, die-hards are still plugging the notion.

    4) As far as panaceas, large-scale solar and wind plants coupled to energy storage/distribution systems are entirely capable of meeting electricity needs without resorting to fossil fuels or nuclear. Sooner or later, that’s how global electricity will be supplied, and everyone will wonder why it took so long to do. It will not be a cheap panacea, but then, fossil fuels and enriched uranium are not cheap either, and are far more expensive in the long run.

  18. 68
    Meow says:

    Les Johnson @66: It’s OK to compare mass fractions, but recognize that atmospheric concentrations are pretty much always expressed as volume fractions (e.g., ppbv), not mass fractions. Since methane’s molecular weight is ~16 g/mol and air’s is ~29 g/mol, this matters. That said, I made an error, and do now get ~21 ppbv, so this point is moot.

    On the broader question of what signal should be visible in atmospheric CH4 levels, that has much to do with the uncertainty in our measurements of the sources and sinks, as well as actual variations in sources and sinks. I don’t know those uncertainties and variations offhand. Does anyone else here know?

    Finally, you’re comparing apples and oranges when you say, “If the total [CH4] leakage is equal to 10% of the total sinks, we will see the signal. Again, anthro CO2 is visible at only 0.6% addition.” The effective annual anthro CO2 contribution is ~2 ppm (= ~0.5%) of atmospheric CO2 *content*, not ~0.5% of CO2 *sinks*. Since atmospheric methane concentrations are about 1775 ppbv (AR4 WG1 s.2.3.2), the hypothesized CH4 leakage is about 21 ppbv/1775 ppbv = 1.2% of content, not 10%. Should that be detectable over the time fracking has been widely used? I’d have to know much more about how the sources and sinks work to say. With CO2, we have a reasonably good handle on how much we add, both by accounting how much of which fossil fuels / forests we burn, and by studying changes in CO2 isotope composition (Plant-derived CO2 has a different C isotope composition than most atmospheric CO2). .

  19. 69
    Les Johnson says:

    meow: your

    (Plant-derived CO2 has a different C isotope composition than most atmospheric CO2)

    Yes, the exact same difference can be found in CH4. Biogenic CH4 generally has C14. Fossil methane does not.

    Again, anthro CO2 can be recognized at the 0.6% increase each year. If this in the 7 Gt range, that means that the signature can be detected, even though this is less than 1% of natural sinks or sources (using IPCC sources). For methane, we are talking about 10% of the natural sinks or sources, at the leakage postulated by Howarth.

    As for the CH4 sources and sinks? The IPCC seems pretty confident with the numbers I posted earlier.

  20. 70
    Les Johnson says:

    meow: and you completely muddled this up:

    (Plant-derived CO2 has a different C isotope composition than most atmospheric CO2)

    Plant derived CO2? While plants do respire CO2, they are a net CONSUMER of CO2. I assume you mean the oxidization of plant matter. I hope you mean that, anyway.

    [Response: Instead of rushing to disagree with everyone anyone else says, please note that there has been a net source of plant-derived CO2 into the atmosphere from deforestation – roughly 2 GtC per year. -gavin]

    Your main argument in this statement is totally backwards, though.

    Most atmospheric CO2 is similar to CO2 from plant decomposition, because that is where MOST of the CO2 in the atmosphere comes from. Plants take in CO2 from the atmosphere, then CO2 from the plant decomposition goes back into the atmosphere. As N14 is converted to C14 on a continuous basis in the atmosphere, the supply of C14 for plants is relatively constant. Only when the carbon is sequestered, and the C14 decays, does a measurable difference show up. ie; fossil fuels.

    But, the vast majority of atmospheric CO2 is biogenic, so has C14. Fossil fuel CO2, without C14, and added at a 0.6% ratio per annum, is detectable.

    [Response: Actually, you are confusing your isotopes. 14C does discriminate between ‘new’ carbon and fossil carbon – but this is not easily detectable in the present day atmosphere because of the 14C contamination due to atmospheric bomb tests in the 1960s. Instead, 13C is the isotope that is most used since biogenic CO2 has less 13C than background carbon (i.e. oceanic C). Fossil fuel is biogenic, so is depleted in 13C, and this has lead to a decrease in atmospheric 13C over the last century. Finally, your analogy to CH4 sources is kind of moot – If there was only one anthropogenic source then it might be ok, but there isn’t. There are large interannual variations in many of the natural sources – wetlands, Arctic lakes etc., and uncertain and varying trends in many human sources – irrigation, animals with entertic fermentation, fugitive emissions from conventional sources, landfills etc. – each of which has varied isotopic composition. My point is not that the Howarth estimates are correct – there simply isn’t the monitoring in place to say – but that back of the envelope calculations are not as straightforward as one would like. – gavin]

    I would think that 10% addition of CH4, as suggested by Howarth, would also be detectable.

  21. 71
    M says:

    Les states that “Fossil fuel CO2, without C14, and added at a 0.6% ratio per annum, is detectable”, and therefore that “I would think that 10% addition of CH4, as suggested by Howarth, would also be detectable.”

    First, I suggest that there are some subtle differences between the metrics in these two statements. The 0.6% is not directly comparable to the 10%. Also, “detecting” the signature of fossil fuel CO2 by looking at the atmospheric record is a different challenge from “detecting” the size of CH4 leaks from natural gas operations in the atmospheric record.

    Second, the key comparison should be between the expected theoretical change in atmospheric concentration due to the change in emissions, and the year-to-year variability in atmospheric changes due to poorly quantified sources (whether natural or anthropogenic). If unquantified variability is small, then moderate changes in emissions should be detectable, but that would not be true if the variability is large.

    Third, going back to CO2: yes, it is clear that the historical increase in CO2 is due to human activity. However, would we be able to “detect” a 10% change in, say, human CO2 emissions from deforestation by monitoring atmospheric concentrations? The answer for a single year is clearly “no”: the year-to-year variability in the “airbone fraction” leads to ranges between 30 and 80% (see Figure 7.4 in Chapter 7 of the IPCC AR4). Even the 5 year average varies from 40% to 60%. So, in order to “detect” a 10% change in human CO2 emissions would require that emission change to be sustained for probably at least 10 years…

    Since the AR4 states that “Past observations indicate large interannual variations in CH4 growth rates (Dlugokencky et al., 2001)”, we would not expect to be able to “detect” a 10% change in CH4 emissions any easier than a 10% change in CO2 emissions.

    Inverse modeling estimates can use atmospheric measurements to attempt to constrain CH4 emissions from different sources, but these modeling assessments are challenging and still leave a lot of uncertainty in the size of specific sources.


  22. 72
    Les Johnson says:

    Gavin: your

    [Response: Instead of rushing to disagree with everyone anyone else says, please note that there has been a net source of plant-derived CO2 into the atmosphere from deforestation – roughly 2 GtC per year. -gavin]

    Yes, that’s what I said to meow. Decomposition of C to CO2.

    I doubt though, that there is net source of CO2 to atmosphere from plants. Several studies, including NASA, show a gain of vegetation, on the order of 6%, over the last few decades. There can’t be both a net gain and a net loss.


    Instead, 13C is the isotope that is most used since biogenic CO2 has less 13C than background carbon (i.e. oceanic C). Fossil fuel is biogenic, so is depleted in 13C, and this has lead to a decrease in atmospheric 13C over the last century.

    Granted. But pyrogenic methane will also drag down C13. Or more grasses growing vs C3 plants. Or a reduction in primary production.

    What is certain, is that if a 0.6% CO2 increase (vs sinks) can be observed, so can a 10% increase in CH4. You are looking for the same isotope (or lack of) in both.

  23. 73
    Les Johnson says:

    gavin: I think you are wrong on the C14. Fossil methane should be totally lacking in C14. An increase in C14 from atom testing (or pressurized water reactors)would only show the variance to a greater extent. “New” methane will show the increased C14, “old” methane won’t.

    Granted, methane from permafrost or methane hydrates would also have a low C14, but leakage from these sources are, as of yet, still minor.

  24. 74
    Les Johnson says:

    M: your

    we would not expect to be able to “detect” a 10% change in CH4 emissions any easier than a 10% change in CO2 emissions.

    That’s the point. They can detect a change of CO2 at 0.6%, which is attributed to anthropogenic causes.

  25. 75
    M says:

    Les: 0.6% for CO2 is the change in atmospheric concentrations per year. 10% for CH4 is the quantity of CH4 from one source divided by the sinks. They are two different numbers. More importantly, you have compared neither number against the background variability from poorly quantified sources. Go look at Table 7.6 from the IPCC AR4, notice the huge differences between different inventories. It is not hard to imagine a “new” source of 10s of Tg, and a correction of several “old” sources to have less emissions. It is also not hard to imagine that while one source is increasing, another source might be decreasing.

  26. 76
    Les Johnson says:

    M; The point is that Howarth says 54 Tg of CH4 is leaking from gas wells.

    54 Tg would overwhelm all sinks except hydroxyl.

    It is hard to imagine a new SINK with the same capacity to take 54 Tg.

    Its also hard to imagine that this would not be traceable, even if a new sink took the equivalent of all the leaking gas. Especially as the “old” gas will be C14 free, and the “new” gas will be steeped in it.

  27. 77

    I suggest that burning crude oil fuel should be stop if people can find another source of fuel
    that is recyclable.According to various researchers that the huge amount oil in middle east will be drained out on a specific time.Thus it should be conserve for the next generation.

  28. 78
    Lab Lemming says:

    Can the isotopic composition of atmospheric CH4 be measured well enough to determine the source of the increase? e.g. 14C for fossil vs biological, 13C for cattle vs peat bogs, etc.

  29. 79
    Mike Roddy says:

    Walter Pearce, I’m a builder, and have worked with LEED for many years. You’re right that they do pay attention to IAQ, and LEED is not all bad. My point is that for comprehensive analysis of environmental impacts you might as well throw out LEED. Many of the professionals are well intentioned, but they lack scientific training (most are architects) and don’t understand data.

    Rick Brown, #45, I got my data from RPA (sorry I don’t have the link handy). US mortality was .8% in 1970, 1.7% in 2005 or so. The methodology is to survey sample plots all over the country every few years. There are thousands of them, so the numbers are good.

    This is very important information, especially for our climate. Climate blogs do not cover this issue well, since most are run by atmospheric guys.

  30. 80
    Bryan S says:

    “The Howarth study, using admittedly poor observations (for lack of anything better), has come up with a relatively large potential for fugitive emissions from the fracking process itself – up to a few percent of the extracted gas. Converting this into an equivalent CO2 amount (for comparison with the impact of the gas once it is combusted), they have used Global Warming Potentials (GWPs) from Shindell et al (2009) (a paper I co-authored)”

    This is a preposterous and absurd statement apparently issued with complete ignorance of the fracking process, and a total disregard for the scientific method advocated by any acceptable philosophy of science.

    First, the potential for any methane release during the “fracking” process is almost 0. There is a large hydrostatic head against the subsurface formation during pumping, and no potential for subsurface methane emerging to the surface occurs until well after the fracking procedure is ended and flowback of the frac fluids to the surface occurs. Had the authors taken the time to familiarize themselves with the basic mechanics of the process about which they write, they might have realized that their chosen vocabulary betrayed a complete incompetance and embarrasing ignorance of the subject matter they exposit.

    Only during flowback is there any potential for methane release, but since the operator of a methane well has every economic insentive to capture the methane for pipeline sales thus not allowing it to escape into the atmosphere, the conclusion that an operator would allow significant venting of gas into the air goes against all rationality. During the short times when the pipeline sales are disrupted, wellsites have a flare stack which combusts the methane minimizing release.

    It is clear that a complete abrigation of the scientific method has been committed in the first study, and that this represents no more than extreme environmental advocacy with no intent to arrive at any known objective reality. The authors of the second paper, in using junk data from an unscientific paper, have completely compromised all of their conclusions.

    The scientific value of these papers is worse than zero since almost assuredly erroneous conclusions are presented under the guise of “objective science”.

    [Response: Please calm down. Perhaps you can point us to credible estimates of the amount of fugitive emissions from the shale gas extraction process and processing? The fact that fugitive emissions are lost sales is not lost on anybody, but if you think that means that fugitive emissions must therefore be zero, you are very wrong – try looking at these operations with an infra-red camera. If your point is that we should get better numbers on these emissions – then we are in complete agreement. – gavin]

  31. 81
    Susan Anderson says:

    I hope someone more knowledgeable than I am will take a brief look at this. I’ve been enjoying my subscription to Earth Observatory reports, which just turned this up:
    “Earthquake Swarm near Hawthorne, Nevada”

    Since I’d heard there were some problems with earthquakes (I think it’s the deep injection wells, if I remember correctly, not the fracking) near shale gas operations, I took a look. Quick google on shale gas in Nevada turned up this (among others):

    Am I all about in my head?

  32. 82
    flxible says:

    Bryan – An expansion of your reasoning here: . . . the conclusion that an operator would allow significant venting of gas crude oil into the air Gulf of Mexico goes against all rationality. Not to mention against the law as well as against the common good. S#!t does happen, quite regularly in some industries.

  33. 83
    Bryan S says:


    If you would like to learn something, then I would be quite happy to help provide you with some perspective on this process. If however your idea is to grandstand, then the conversation is over and you will go away not learning much for the trouble. It will ultimately be your loss and not mine.

    Another related issue: You tell a reader that fossil fuel is “biogenic methane”. Again, your vocabulary betrays a shallowness of knowledge on this issue. In organic geochemistry related to shale gas, one must differentiate between “biogenic methane” and thermogenic methane. Most methane related to “shale gas” in the deep subsurface is not “biogenic methane” in the sense you indicate, but rather “thermogenic” methane. This process is related to the “thermal cracking” of mostly algal-derived kerogen under heat in the deep subsurface. Thermogenic methane is certainly a “fossil fuel” but is most definitely *not* isotopically light relative to “biogenic methane”. So your statement above is a muddle that communicates nothing, or worse, mis-communicates some basics.
    “Biogenic methane” is a term that refers almost exclusively to bacterial methanogenesis (such as in a garbage dump or in shallow microbial laden freshwater aquifers), and is “isotopically light” in comparison to “thermogenic” methanogenesis.

    My point to your reader is not to embarrass you, but simply point out that not all opinions on the subject of shale gas and extraction are equal. There are many opinions, but only a few are likely uttered by folks who may be competent enough in the field to deserve a hearing. I’m afraid you do not appear to have yet put in the time and effort to have learned basic terminology in this emerging area of geology, and therefore disqualify yourself (in at least my eyes) as a knowledgeable public intellectual on this issue.

    Unfortunately in this discussion, the most qualified persons to render a competent judgment at this stage of the game are likely those research scientists who are employed by the petroleum industry and have spent several years now on the front lines of this research, yet whose opinions the general public will understandably likely not regard as “objective”.

    However, it would likewise be a mistake to necessarily consider “credible”, “definitive”, or “objective” the information coming from folks who may have scientific credentials, but who are clearly “novices” in these particular areas of research.

    My advice to you is to invest in some detailed and hard-won deep research into this subject before popping off.

    P.S. If you are truly interested in learning something about shale gas, I would be happy to send you my contact information and take this discussion off line.

    [Response: I am always willing to learn. You’ll find that I have made no claim to deep knowledge about shale gas, and I’m happy to have pointers to, for instance, an isotopic study of this methane source. And if you could point to credible studies – even from the industry – of fugitive emissions, that would do everyone some good. But why you feel the need to jump in feet first with the insults is a little puzzling. Really, communication is much easier if you don’t do that. I don’t have any particular agenda here – indeed, I only wrote the piece to highlight the GWP issue where I do know what I’m talking about. If you want to increase the level of knowledge on this thread, please go ahead, but drop the attitude. – gavin]

  34. 84
    M says:

    Bryan: Why is “biogenic methane” isotopically light compared to “thermogenic methane”? Do algae (from which you say that the thermogenic methane is derived) have a different 13C selectivity than bacteria (the source of much of the biogenic methane)? Or do you selectively lose 12C during the thermal cracking process?

    (Also, in defense of Gavin’s vocabulary, I have seen “biogenic” used in the sense of “biogenic” vs. “fossil” for methane as you defend, but also in the sense of “biogenic” vs. “abiogenic” for fossil fuel formation. Google the term “biogenic theory of petroleum” or the like, with the key being that fossil fuels were ultimately formed by biological rather than geological processes. Therefore, for CO2 studies, “biogenic” vs. “abiogenic” is a useful differentiation between all CO2 sources ultimately derived from plants – both fossil and biomass burning – versus CO2 resulting from changes in ocean solubility or volcanic degassing) (and yes, it is important to know how a term is used in a specific field: eg, the confusing of engineers when confronted with climate scientist’s use of the word “feedback”: but I’d argue that in this case the use of the word is set by the context, and Gavin was fairly clear that he was using biogenic in the 2nd sense)

  35. 85
    Brian Dodge says:

    @ Susan Anderson — 28 Apr 2011 @ 2:48 PM re “Earthquake Swarm near Hawthorne, Nevada”

    The Chainman Shale formation doesn’t appear to extend as far west as the earthquake swarm near Hawthorne NV. I think that it’s more likely that the swarm has to do with basin and range block faulting transition to Eastern Sierra uplift and the volcanism associated with the Long Valley – Mono Lake – Aurora-Bodie areas.
    see discussion of Aurora-Bodie volcanic field & Mud Springs Volcano

  36. 86
    richard copeland says:

    What if mining crude oil was the reason for the Earths mantle (and oceans) heating up? What does oil do for machinery? How many gallons of crude oil spilled out into the gulf in the latest Oil platfrom mishap? How many oil platfroms/wells are there in the world?…How long have they been operating? Makes you wonder doesn’t it?…Now, who wants to tell the oil tycoons to stop mining crude oil?

  37. 87
    Susan Anderson says:

    Brian Dodge, thanks. That was exactly what I was looking for, someone who really knows what they’re talking about.

    I do worry about all the manipulations we are performing, as mentioned by Richard in 86 (or if renumbered, at 1:42 pm), but tend to think this kind of imagining goes too far. However, we are fiddling with stuff that is more out of our control than we are willing to admit, as witness the BP oil spill. I don’t think that tale is told yet, but take heart from the undoubted fact the cascade of consequences is always more complex and interesting that our worst fears and best hopes.

  38. 88
    arch says:

    richard copeland – is the mantle warming up?

  39. 89
    Ray Ladbury says:

    Richare Copeland:

    Whiskey. Tango. Foxtrot. Interrogative.