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It’s all about me (thane)!

Filed under: — gavin @ 12 November 2009

Well, it’s not really all about me. But methane has figured strongly in a couple of stories recently and gets an apparently-larger-than-before shout-out in Al Gore’s new book as well. Since a part of the recent discussion is based on a paper I co-authored in Science, it is probably incumbent on me to provide a little context.

First off, these latest results are being strongly misrepresented in certain quarters. It should be obvious, but still bears emphasizing, that redistributing the historic forcings between various short-lived species and CH4 is mainly an accounting exercise and doesn’t impact the absolute effect attributed to CO2 (except for a tiny impact of fossil-derived CH4 on the fossil-derived CO2). The headlines that stated that our work shows a bigger role for CH4 should have made it clear that this is at the expense of other short-lived species, not CO2. Indeed, the attribution of historical forcings to CO2 that we made back in 2006 is basically the same as it is now.

As is well known, methane (CH4) is the greenhouse gas whose anthropogenic increase comes second only to CO2 in its 20th Century effect on climate. It is often stated that methane is ‘roughly 20 times more powerful’ as a greenhouse gas than CO2 and this can refer to one of two (very different) metrics. If you calculate the instantaneous forcing for an equivalent amount of CO2 and CH4 (i.e. for a 1 ppmv increase in both), you find that the global forcing for CH4 is about 23-24 times as large (depending slightly on the background assumed). Separately, if you look up the Global Warming Potential (GWP) of CH4 in IPCC AR4 (the integrated forcing of a kg of CH4 compared to kg of CO2 over a 100 year period), you get a value of about 25. GWP is used to compare the effects of emissions today on climate in the future. The numbers are only coincidentally similar since the GWP incorporates both the weight ratio and the ratio of effective lifetimes in the atmosphere which roughly cancel for a 100 year time-horizon.

In the Second Assessment report (1995), the GWP for methane was 21, and it was increased in AR4 because of a greater appreciation for the indirect effects of methane on atmospheric chemistry, and in particular its role as a tropospheric ozone precursor (since increasing methane leads to an increase in low level ozone). There is also an indirect effect on stratospheric water vapour where methane oxidation is a significant source of water in an otherwise very dry region. Both tropospheric ozone and stratospheric water vapour are effective greenhouse gases so including these indirect effects made the net effect of methane greater.

In the standard ‘forcings bar chart’ such as seen in Hansen’s papers, or in TAR, or AR4 (figure 2.20), each change in atmospheric composition is given a separate column. Thus ozone and aerosol effects are denoted separately. Starting off with a paper we wrote in 2005, though, a different approach that is perhaps more useful to policy makers has also been adopted. This ’emissions-based’ viewpoint attributes the forcings to the actual emissions, rather than to the eventual concentration. Thus since some of the ozone increase is related to CH4 emissions, you get to include that under CH4. The other ozone precursors (carbon monoxide and volatile organic compounds) can also now be blamed for a portion of the ozone impact.

This was incorporated into figure 2.21 in AR4, where it is clear that the impact of methane (once some indirect effects are included) is greater than you would have thought based on the ‘abundance’ viewpoint. Note the changes basically only affect the reactive species. When thinking about the various metrics, the emissions-based view is more closely tied to GWP than the traditional abundance-based approach. A big difference is that GWP is looking forward in time, while emission-based forcings are looking back at historical events.

The increasing sophistication when it comes to attribution and GWP is strongly connected to the development of more comprehensive Earth System Models (ESM) in recent years. These are the descendants of the General Circulation Models of the climate that have been developed over the last 30 years, but that now include interactive atmospheric chemistry, aerosols (natural and anthropogenic) and sometimes full carbon cycles in the ocean and land surface. This extra machinery allows for new kinds of experiments to be done. Traditionally, in a GCM, one would impose atmospheric composition forcings by changing the concentrations of the species in the atmosphere e.g. the CO2 level could be increased, you could add more sulphate, or adjust the ozone in the stratosphere etc. However, with an ESM you can directly input the emissions (of all of the relevant precursors) and then see what ozone levels or aerosol concentrations you end up with. This allows you to ask more policy-relevant questions regarding the net effects of a particular sector’s emissions or the impact of a specific policy on climate forcing and air pollution (see here for a discussion).

Our new Science paper (Shindell et al, 2009) expands on some of the earlier work (as was discussed here) and extended consideration of the indirect effects of CH4 and CO (carbon monoxide) to aerosols as well. This is necessary since SO2 requires oxidants to transform to sulphates (and so is affected by the perturbation of the chemistry by other emissions), and it takes into account the competition between nitrates and sulphates for ammonia (which means that there is a small anti-phasing effect – increasing sulphates tends to decrease nitrates and vice versa). When we did this, 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).

Currently methane levels are relatively stable (despite small upticks in the last two years) and are running below IPCC projections made in 2001 (this of course is good news). However, CH4 is at more than twice its pre-industrial concentration and so still presents a tempting target for emission reductions which, because of our new work and the relatively short lifetime in the atmosphere, will likely be a little more effective at reducing future forcings than previously thought. Given the value of methane as a fuel, it is likely that more of it will be captured (as in this recent story).

CO2, however, is still increasing dramatically despite the slow down in the economy, and so current growth in radiative forcings is dominated by CO2 and that will very likely continue for decades. Despite our increasing appreciation of the role of other forcings (including land use for instance), the overwhelming driver of climate change in the 21st Century will be CO2 increases.

In a follow-up post, I’ll discuss the sources of methane and the implications of the new results for attribution of climate forcing to different sectors (including agriculture), where there have been some very odd (i.e. wrong) recently published numbers.

191 Responses to “It’s all about me (thane)!”

  1. 1
    Mark J. Fiore says:

    I am an amateur climate guy who reads a LOT about global warming.I went to Harvard, 1982, and Boston College Law School, 1987, and live in San Francisco.RealClimate is nice enough to let me post my opinions, which I do, a few times a year.
    So, here goes.First, this is another EXCELLENT post by Gavin.Some of my comments in the past on this site have focused on the real danger of the vast amounts of methal hydrates at the bottom of the ocean melting.The above post by Gavin shows that there are some extra warming considerations to worry about regarding methane.
    I recently attended the Dominican College booksigning event for Al Gore here in Marin County, CA, and he said something in his speech that I had only learned last year, namely, that the net carbon content of soils worldwide is four times that of all vegetation on the planet.He also said there is some connection between using all those nitrate fertilizers on the soil and the ability of the soil to bind CO2 in the future.Also, the production of meat worldwide leads to increases in methane.I know that methane excreted from the billions of livestock on the planet is a huge problem.
    It is late, and I’m now entirely unsure of where this post is going, so let’s say I’m still deeply worried that, somehow, if methane starts increasing significantly(which Gavin said ,above,the numbers, thankfully, do not show,)that there will A WHOLE LOT of other unforeseen negative feedbacks from methane, in addition to the ones posted above, which have not really made it into the mainstream press reports about methane.
    I did read that methane was bubbling up from somewhere in the Arctic, and we do know that methane is double its preindustrial levels…
    Thanks for further educating me, Gavin, and I hope for the best regarding the planet and methane emissions.However, there still seems to me to be an “aura” about methane emissions that to me is deeply unsettling.
    Mark J. Fiore

  2. 2

    When you do your follow up paper, perhaps you can comment also on Stacy Jackson’s
    recent Science (Oct 23) Policy Forum paper. She presented a figure showing
    that of our forcings, the things we do, as opposed to the things our ancestors
    did, methane forcing is similar to co2 forcing. A similar chart
    appeared in AR4 (chapter 2, p.206).

  3. 3
    PeterPan says:

    According to this paper, OH has been increasing until 1989, with a minimum in 1998 (that they blame on wildifres and an intense El Niño) and a recovery since then (2003 comparable to 1979):
    It would be interesting if you could give some context with observations (including aerosol forcing, if possible) in the upcoming post.
    (later, they also mention methane, but the variations seem small and temporary.


  4. 4
    Tim Joslin says:

    Very clear on methane, even to this amateur.

    I would like to ask a question on one incidental point, though. I notice that Fig 2.21 includes a (negative) surface albedo forcing from land use changes, but that Fig 2.20 does not.

    But land use changes (such as from tropical forest to arable land and later semi-desert) don’t just imply an albedo change. They also imply changes in surface moisture. Surely the moisture change has an effect on climate comparable in magnitude to the albedo change?

    The point, of course, is that evaporation of water at the surface absorbs heat, limiting the increase in temperature caused by the incoming solar radiation. This reduces the heat radiated away compared to dry land of the same albedo. Instead, much of the (“latent”) heat is released at altitude when the water vapour condenses, perhaps to form clouds. I’d be very interested to know the overall forcing effect arising from this process, but it clearly has the arguably desirable consequence of moderating surface temperatures and raising temperatures higher in the atmosphere: compare the surface temperatures in deserts and forests at similar low latitudes. The presence of moisture in the forest ecosystem clearly outweighs the albedo effect on temperatures at the surface, at least during the day.

    Isn’t it a little arbitrary to just consider the albedo forcing component of land use change?

  5. 5
    Inferno-fan says:

    Stop voting for RealClimate, vote for real Blog Science, vote for DenailDepot (Best Science Blog 2009:

  6. 6
    Stephen says:

    Hi Gavin,

    when you say that CO2 is increasing “dramatically”, what is the current state of play between (i) emissions and (ii) atmospheric concentration since it is (ii) that impacts climate, whilst (i) is unimportant, except to the extent that it causes changes in (ii)? My impression is that whilst emissions of CO2 have broadly increased on a “business as usual” basis, atmospheric concentration has increased somewhat less than expected. Is this so? If so, “dramatic” does not seem like a good description for a smaller than expected increase in the thing that matters.

    Thank you for any clarification.

    Kind regards,


    [Response: CO2 emissions are rising faster than expected, while concentrations are rising about as fast as expected. But this is dramatic. Increases of ~ 2ppmv/yr is 200 times faster than the rate of rise coming out of the last ice age. – gavin]

  7. 7
    Michael Maier says:

    Al Gore is a politican, i`m right?

    Why is he writing climate books?

    [Response: Because dealing with climate change is a political issue? – gavin]

  8. 8
    Mike Roddy says:

    I’m surprised there was no mention of Katey Walter’s work in Siberia and Alaska. Potential methane releases from permafrost and arctic lakes appear to be a major hazard. Walter’s results are quite scary, and I look forward to your take. There is obviously a lot of guesswork when it comes to the relationship between increased global temperatures and rates of arctic methane release, but I assume that you have looked into this as well.

  9. 9
    jhm says:

    This reminds me of a item I read about agricultural fumigation: “CAMBRIDGE, Massachusetts, March 11, 2009 (ENS) – Sulfuryl fluoride, a gas used for insect control, has the potential to contribute to future global warming at more than 4,800 times the potency of the better known greenhouse gas carbon dioxide, an international team of researchers said today.”

    I wonder if the combined effects of such non CO2 (and CH4, I guess) GHGasses are even close to CO2. In other words, is CO2 so dominant that even a collection of agents “4,800” times as effective (more accurately, there absence) can really make a dent?

    [Response: The net effect is the GWP multiplied by the number of kg emitted. Therefore chemicals that are around in concentrations in the parts per trillion are ~10^8 times less effective than CO2 if they have the same GWP, and still 10^3 times less effective with GWPs of 10,000 say. The key trace gases that make a notable difference are the CFCs, HFCs, HCFCs etc. See the figure on this FAQ for some scale. – gavin]

  10. 10
    Stephen says:

    Thanks for you in-line comment above Gavin. It is fantastic that there is a forum where one can pose a question and get an almost real-time response from leading climate scientists. I take the point about the increase in CO2 relative to emergence from the last ice age.

    On my monitor, the lines for the emissions scenarios in the chart that you link to all appear as red, so they are unfortunately indistinguishable. So I read the relevant bits of AR4 and also the Special Report on Emissions Scenarios. Have I got this right?: Scenario A1B looks most like how the world has been recently, but actual CO2 emissions are somewhat higher than this, which implies that economic development scenarios may be to modest in the amount of CO2 they generate. Whilst on the other hand, CO2 concentration has risen at a slower rate than would have been expected if there had been an accurate emissions scenario, which implies that the scenarios are too pessimistic in terms of how they translate emissions into increases in concentration (missing sinks etc)?

    Kind regards once again,


    [Response: They are pretty much indistinguishable because the differences are small. The scenarios don’t tend to diverge noticeably from each other until 2030 or so. Note too that there is more uncertainty in the emission data (particularly related to deforestation) than there is in concentration data. – gavin]

  11. 11
    tharanga says:

    Will the upcoming post also discuss methane sinks, and try to clarify why the methane concentration in the atmosphere has stabilised, for now?
    The IPCC FAR has some discussion, but I assume there’s since been some progress on understanding that.

  12. 12
    Christopher Hogan says:

    I’d like to ditto #8 above. I think the last posts here dedicated to arctic methane were from December 2005 (Methane Hydrates and Global Warming)and April 2006 (Kristof on the Apocalypse, basically a short followup to the first).

    I believe the conclusion at that time was that disaster (very rapid warming due to release of arctic methane so rapid that it built up in the atmosphere) was unlikely, and that the arctic was more likely to play a role in providing a chronic addition to GHG releases. There was a passing mention in an October 2006 post (Rasslin’ swamp gas) with the same conclusion: no plausible way to see significant methane release from ocean clathrates this century.

    Basically, whenever arctic methane has come up, the posts here have argued against the likelihood of catastrophic events. Which I deeply appreciate.

    Conversely, I looked at some videos recommended on this site (Climate Denial Crock of the Week), and came a cross a clip of Energy Secretary Chu discussing arctic warming, where he suggested that 4 – 6 degrees centigrade increase in (presumably) global temperatures would be that point at which there was high risk of unstoppable positive feedback from temperature to arctic emissions to temperature. I think he says something like arctic emissions would dwarf anthropogenic emissions. Chu’s interview is about 6:30 in on this:

    Not sure what Chu’s source is for that. And that’s all emissions not release of methane from clathrates.

    When I juxtapose Chu’s 4 to 6 degrees with the recent MIT research suggesting 5 degrees centigrade rise by the end of the century is plausible (due largely, I think, to above-trend increases in emissions), find that troubling.

    It would be nice to hear from the experts whether any information since 2005 would change the tenor or conclusion of the December 2005 post. Basically, what I’m asking is, if we actually hit the median MIT prediction, is the arctic and arctic methane more of an issue, and if so, how much more? Is Chu’s statement correct in essence?

  13. 13
    anna says:

    Hi Gavin,

    I’ve been interested in methane for a while now but something I’ve been struggling to find out is what the global warming potential of methane is, in CO2-e, over it’s *actual* lifetime in the atmosphere (which I understand to be 12 years +/- 3).

    The IPCC report gives the GWP for methane over 100 years (25) and 20 years (72), but not over it’s actual lifetime in the atmosphere. The closest I’ve found is that the GWP over a decade is ‘about 100’, which is a little vague.

    If this is something you could shed some light on I’d greatly appreciate it, I understand you’re very busy.


  14. 14
    anna says:

    Oh, and a quick response to Inferno-fan @ #5:

    Thanks for the suggestion, but sorry, you’ve totally failed to convince me that I should vote for that blog as you haven’t presented any evidence, merely an assertion.

    If you want to convince people, you really do need to present thorough, accurate evidence to them in a clear manner.

  15. 15
    Steve Missal says:

    You all might be interested in reading the following link:

    (Author)Dan Dorritie….

    A paleontological take on the problem that is worth a gander.

  16. 16
    Jonathan Mulligan says:

    I’ve read that the water storage dams of the world could be significant contributers to methane, when the vegetation rots underwater. Is the three gorges dam in China of sufficient size to account for the recent increase, after nearly a decade of static methane levels?

    I do worry that agriculture is an easy target without due regard for it’s importance by people well removed from the realities of having to feed over 6 billion mouths . I’d rather do without electricity than starve.

  17. 17
    James Staples says:

    What about me(flat screen TV’s manufacturing process releasing Nitrogen Tetrafluoride)?
    According to the GRIDA PDF that I just downloaded, it has not been assigned an ‘official’ GWP by the IPCC; but it’s estimated to have one of between 100-8000!!!
    One of my local Representatives (Earl Blumenaur – a True Friend in DC, for people like us) came into a meeting saying, It’s O.K. – it’s O.K.! The economy is healing – everyones buying New Flat Screen TV’s!!! It’ll all be OK now!”
    What a Joker!

  18. 18
    Andy Stahl says:

    Gavin, et al.,

    Congress adopted the following provisions as part of the 2010 Interior Appropriations Bill, which President Obama signed into law on Oct. 30:

    Sec. 424. Notwithstanding any other provision of law, none of the funds made available in this Act or any other Act may be used to promulgate or implement any regulation requiring the issuance of permits under title V of the Clean Air Act (42 U.S.C. 7661 et seq.) for carbon dioxide, nitrous oxide, water vapor, or methane emissions resulting from biological processes associated with livestock production.

    Sec. 425. Notwithstanding any other provision of law, none of the funds made available in this or any other Act may be used to implement any provision in a rule, if that provision requires mandatory reporting of greenhouse gas emissions from manure management systems.

    It appears that the livestock industry and its political allies have not gotten the methane message.

    My questions are 1) “Did climate activists and/or scientists know about these provisions? 2) If “yes,” what did they do to stop their adoption, or if “no,” why not?

  19. 19
    philc says:

    Methane oe CO2, I’m having a hard time interpreting what I read about global warming or climate change.
    I found this graph on logicalscience of Dr. Hansen’s original climate predictions updated with instrumental readings.( The graphs of various scenarios seem to still fall in line with the newer climate models. However, only ScenarioC falls in line with the actual temperature data. Scenario C is based on effective limitation of the major GHG’s including CO2, methane, soot, etc. The other scenarios seem to follow the predictions of later global models.

    Then there is this graph from NOAA( The observed data seems to be a pretty good match with Hansen’s for 1960-1995. But the observed data since `1995 seems to be a better match for Scenario C, which assumes large reductions in the rate of GHG emissions. What gives?

    Then we have this graph( which is the UAH satellite data which seems to be a pretty good match for the NOAA global temp data graph.

    The problem I have is that all the current climate model predictions I can find do not predict the leveling off, and possible start of a cooling trend, beginning around 2001. Looking at the historical data, the current peak could easily be similar to 1940 or 1960. The only way to tell is to wait and see, since the models all predict the temperature to continue rising from 2001 on.

    So, why believe a model prediction?

    [Response: Physics. – gavin]

  20. 20
    Marcus says:

    This is an Excel spreadsheet equation for the “Bern Carbon Cycle Approximation” for CO2, where B18 is the number of years you want to calculate:

    This is the same calculation for CH4 (with a much simpler lifetime expression!):

    Multiply the output of the CH4 cell by the CH4 forcing (3.7 * 10 to the -4), and divide it by the output of the CO2 cell times the CO2 forcing (1.4 * 10 to the -5). Multiply by 44/16 (to correct for the different masses of the gases) and multiply by 1.4 (for the ozone and stratospheric H2O corrections). If you use 100 years you get 25.5, and for 20 you get 72, matching the IPCC. For 12 years, you’d get about 88.

    Having said that, I’m not convinced that there is much meaning in calculating a GWP for the “lifetime” of the gas: we usually care about GWP in terms of timscales of impacts on the earth that we care about. 20 years is an approximation to caring about near term impacts, 100 is mid-term, and 500 is long-term.

    (to be even pickier, the CH4 lifetime of 12 years is not the “residence lifetime”, which is shorter, but rather the “perturbation lifetime”, which takes into account the fact that emissions of methane reduce the amount of methane sink available)

  21. 21
    Marcus says:

    Anna: ps. On the off-chance that your response to Inferno was serious, you should know that “denialdepot” is a parody site. I note that your response to Inferno went exactly counter to the dogma of that site: denialdepot would claim that blog science works best by assertion, not evidence, and that thorough, accurate evidence presented in a clear manner is anathema to real blog science because it is just toeing the line of those scientific ivory-tower elites.

  22. 22
    Ike Solem says:

    The short term effect on radiative forcing will depend on the rate of emissions due to feedback processes (permafrost melting leading to emissions) as well as deforestation and fossil fuel combustion

    For example, consider the last glacial termination, Monnin 2001:

    Or, see Figure 6.4 in the IPCC FAR chapter 6 – they don’t seem to have anything but the complete pdf file:

    During the YD period, centered around 12500 BP, there was a decrease in methane and an increase in CO2, at slow rates relative to today’s changes. One interpretation is that the oceans kept releasing CO2 as they warmed, but for some reason terrestrial methane production decreased – colder land temperatures could have done that. At the end of the Younger Dryas, the CH4 began to rise again, peaking around 10000 BP, which was within the Holocene thermal maximum.

    If you look at Figure 6.4(c), however, you can see that the Younger Dryas termination was just a blip in the radiative forcing, one that is dwarfed by the changes today.

    It’s also intriguing that there is a gentle rise in CO2 and CH4 prior to the industrial era, 5000 BP onwards, probably due to human land use changes – everything from rice cultivation to clearing forests to raising livestock.

    You can see that non-fossil fuel sources have some effect just by looking at India today, where dung and wood fires contribute as much as half of the black carbon aerosol pollution. This has lead some to argue that if India increases rural electrification by expanding coal combustion, it will actually help reduce warming because there will be less black carbon emissions – a very curious argument, given that India is looking to import some of the dirtiest fuel on the planet, from Australia:

    Coral reef scientist slams Brumby over ‘reckless vandalism’, Nov 9 2009

    One of the world’s leading coral reef scientists has slammed the Brumby Government’s proposal to export Victoria’s brown coal to India as “reckless vandalism”.

    John “Charlie” Veron, who discovered a quarter of the world’s identified coral species, said any move to export the state’s vast reserves of brown coal would only further endanger the Great Barrier Reef.

    “It’s reckless vandalism. Brown coal would have to be the dirtiest, nastiest form of energy there is. It is absolutely essential that it remains in the ground. That is obvious,” he told The Age.

    Unless coal-fired power plants in India will capture and bury all the emissions from that brown coal, how could building modern coal plants lead to a net reduction in forcing? How does switching to coal reduce methane emissions, and how plausible is it that Indian coal power plants will be built with European-style clean air controls, when those controls have barely made it to the U.S., thanks to industry resistance?

    Furthermore, how does replacing biomass (sourced from atmospheric CO2) with coal (sourced from geologically stable carbon reservoirs) help reduce future warming? There is really no justification for India or China to subsidize the expansion of coal-fired power, but of course the same goes for U.S tar sand pipeline subsidies, coal-to-gasoline subsidies, depletion allowance subsidies and the like.

    India is even running a PR program to support coal expansion, with the latest claim being that the glaciers aren’t really melting:

    Clearly the best solution for rural electrification program in India is solar power – the area is right in the sun belt, and instead of trading with Australia for coal, they could trade for solar panels, which also increases domestic energy security, which allows the local economic systems (farms & factories) to function – as well as the coral reef ecology.

  23. 23
    Lynn Vincentnathan says:

    I have a question. CH4 breaks down into CO2 and what else. Don’t answer if takes too much time.

    [Response: Mostly water. – gavin]

  24. 24
    Lynn Vincentnathan says:

    I remember David Archer’s earlier RC post “Methane Hydrates and Global Warming” at

    One of the points was the rapidity of the warming and melting of hydrates (and permafrost). Methane only lasts about 10 years in the atmosphere, but if enough of it is released within a 10 year frame due to the rapidity of the warming (other disasterous warming events of the past happening over much longer periods), this could spell real disaster, something not experienced in the world’s history.

    And just as with ice sheet and glacial disintegration being caused also by mechanical processes (beyond the warming), there are those undersea Storegga slide events that could also release vast quantities of methane.

    (I hope I got this somewhat right. Actually I hope I’m dead wrong.)

  25. 25

    This is a little off-topic, but maybe “on-topic” insofar as methane emissions, sources and concentrations…

    Nate Lewis at Caltech has some interesting slides, articles and talks up on his site. w.r.t. transitioning to low-carbon power, etc.

    One thing that has surprised me more than once in listening to the talks is that he seems to suggest that we can distinguish “permafrost” methane in the atmosphere based on measuring the Helium isotopes. (???) It seems to be analogous to the changing 12C/13C ratios for atmospheric CO2.

    Here is an exact quote from an article in the MRS Bulletin, Oct. 2007:
    An example of these effects is the melting of the permafrost, which we know is happening because we can isotopically date the helium being released. This He has not been released from the permafrost in at least 40,000 years.

    I have never seen or heard of this before. Some googling shows nada… Certainly it would be rather useful to be able to distinguish this.

    I posed this once before at Tamino’s and someone answered – as I recall – that the scarcity of He to begin with makes this seem unlikely. Seems reasonable…

    Anyhoo. I should probably just be asking Nate Lewis about this, but does anyone here have any insight about what he is referring to? If it’s true, I think that is something important. If not, what’s he on about???

  26. 26
    Hank Roberts says:

    For Andy Stahl, try these for starters:



    The latter is a start toward knowing the “legislative history” for that provision; your library can help you assemble that–much will be pointers to the Congressional Record.

  27. 27
    Hank Roberts says:

    Oops, I always forget double quotes break in WordPress, so the searches above aren’t clickable; copy those strings and paste them into your web browser’s search box.

  28. 28
    Eli Rabett says:

    Decreasing HO (Eli’s local model bunny friend says IUPAC don’t do OH, the more metallic element has to go first) is gonna have LOTS of greenhouse effects. For one big thing the degradation of terpenes and other complex aromatics given off by those killer trees is gonna go down, and since large organics are pretty much black bodies when it comes to IR, the greenhouse effect will go way up.

  29. 29
    CM says:

    > It’s all about me (thane)!

    That would be the Thane of Cawdor, who pithily summarized our knowledge of historical radiative forcings as well as the hydrological impact of climate change: “…all our yesterdays have lighted fools the way to dusty death.”


  30. 30
    Marcus says:

    Eli: An even bigger effect is the O3 resulting from the methane emissions not only has the radiative forcing effect included in this paper, but also attacks those same killer trees thereby reducing carbon uptake… yay for positive feedbacks!

  31. 31
    SecularAnimist says:

    Gavin wrote: “In a follow-up post, I’ll discuss the sources of methane and the implications of the new results for attribution of climate forcing to different sectors (including agriculture), where there have been some very odd (i.e. wrong) recently published numbers.”

    Would “recently published numbers” by any chance be referring to the analysis by Robert Goodland and Jeff Anhang, recently published by WorldWatch Institute (PDF), which found that “livestock and their byproducts actually account for at least 32.6 billion tons of carbon dioxide per year, or 51 percent of annual worldwide GHG emissions”?

    [Response: Yep. ;) – gavin]

  32. 32
    SecularAnimist says:

    Gavin, may I suggest that you send your upcoming follow-up post as a letter to the editor of WorldWatch magazine, as a comment on the Goodland and Anhang article re: GHG emissions from livestock production? WorldWatch does very often publish longish, substantive, detailed letters from experts in various fields who critique the articles they publish.

    Obviously there is a pretty wide disparity between the 2006 UN report which attributed 18 percent of GHG emissions to animal agriculture (which would already make it comparable to the transport sector which gets much more attention), and the Goodland and Anhang figure of 51 percent. It would be really great if you could help to clarify this question.

    It is worth noting that the various cap-and-trade proposals before Congress generally exempt “farmers” from cap-and-trade, where “farmer” is a euphemism for “gigantic corporate-owned factory farm confined animal feeding operation”. On the policy side, a question worth asking is why this one particular industrial sector should be excluded from cap-and-trade when it seems to be, by even the lower UN assessment, a major producer of GHG emissions.

  33. 33
    Hank Roberts says:

    > why this … sector should be excluded

    Here’s why there’s a law against doing anything about it–the lobbyists headed the EPA off from doing something:

    In response to the FY2008 Consolidated Appropriations Act (H.R. 2764; Public Law 110–161), EPA has issued the Final Mandatory Reporting of Greenhouse Gases Rule. The rule requires reporting of greenhouse gas (GHG) emissions from large sources and suppliers in the United States, and is intended to collect accurate and timely emissions data to inform future policy decisions.

    Under the rule, suppliers of fossil fuels or industrial greenhouse gases, manufacturers of vehicles and engines, and facilities that emit 25,000 metric tons or more per year of GHG emissions are required to submit annual reports to EPA. The gases covered by the proposed rule are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC), perfluorocarbons (PFC), sulfur hexafluoride (SF6), and other fluorinated gases including nitrogen trifluoride (NF3) and hydrofluorinated ethers (HFE).

    The final rule was signed by the Administrator on September 22, 2009. On October 30, 2009, the final rule was published in the Federal Register ( under Docket ID No. EPA-HQ-OAR-2008-0508-2278. The rule will be effective December 29, 2009. This action includes final reporting requirements for 31 of the 42 emission sources listed in the proposal. At this time, EPA is not finalizing the remaining source categories as we further consider comments and options.”


    Folks, if you care about policy, you need to be participating in policy. The science was solid on this a very long time ago; the EPA had gone through the political process as they routinely do.

    This isn’t something you can argue about at RC to any effect.

    Talk to your Representative and Senators about it, and to your state government.

    An example (just an example, you can find newer and better information) from California:

  34. 34

    re: #14

    Anna, Denial Depot even had one of the RC group fall for it — hehehe

  35. 35
    Corey Watts says:

    Thanks Gavin. Love your work.

    Surely the fact that atmospheric methane is so short-lived makes it an ideal target for emissions reductions? That is, we could make quite a difference in a short period of time, couldn’t we?

    [Response: Yes. That is exactly the point. – gavin]

    Also, can you comment on the reasons for the recent stabilisation and the more recent upswing? My understanding is that the former is something of an anomaly in the longer term trend. I read that it’s due to a mix of factors such as drought (causing emissions from wetlands to fall), increased temperatures (speeding up the destruction of atmospheric methane), reduced forest fires, a reduction in farm and fugitive emissions following economic decline in former communist countries, and higher rates of breakdown possibly due to higher temperatures.

    Have I got this right? What am I missing?

    [Response: It’s not clear unfortunately, and so future predictions of methane growth or stasis are still very uncertain. – gavin]

  36. 36
    Eli Rabett says:

    Marcus, the IR spectrum of the terpenes and a lot of other biological effluvia are considerably wider than ozone.

    Even for such molecules as the HFCs, the delay in degradation might be important, although Eli assumes their chemistry is included in the model that Gavin is talking about.

  37. 37
    Greg Robie says:

    I would value critique on the following observation concerning the methane “uptick.” When Revkin posted the BP example for capturing methane at gas wells at dotearth 10/22/09 about a gas field going from 4 billion cuft/yr to 10 million cuft/yr. I realized policies aimed at controlling methane may have been far more successful than the tabling of methane would indicate. That decade long tabling, which the ‘uptick’ relates to, is generally assumed to be do to plugging leaks in gas lines; changes in rice cultivation, and capping landfills. It relates to a measurement of the average level of methane in the atmosphere.

    The BP example may be extreme, but some of the plugs in the former Soviet Union gas lines may have been as dramatic as well. A cursory look at off set projects engaged in under Kyoto suggest a lot of them are landfill capping projects. Given that in Siberia methane was 5 times above background levels in 2003 and in the summer of 2008, up to 100 times greater over areas of the continental shelf in the Arctic, it occurs to me that the mitigation efforts may have masked an ongoing exponential increase in the release of methane in the Arctic.

    The distribution of methane in the atmospheres is strongly weighted to the northern latitudes. In the winter it seems to migrate north, being carried into the Arctic by the same atmospheric that gets other pollutants from the temperate latitudes up to the Arctic. With methane having about a 10 year life span (and Lynn #24, I have read that methane first become ethane on its way to becoming CO2 and water), such also suggests that the mitigating policies for CH4 have been more successful than appreciated.

    There is a dearth of scientists studying methane. I hear it reported from Copenhagen this past March that there are only 20 world-wide. Clearly, what funding there is has been focused on CO2. To the degree careers follow the money, such may explain both the lack of scientists and funding. The focus on CO2 would also explain why the renewed increase in CH4 might be labeled only an uptick.

    As I consider the changes in climate occurring in the Arctic, a factor I can see in play among all the others—and feeding all the others—is the overlooked ongoing methane increase. Are there any huge oversights in this analysis? If not, could it be further critiqued so we don’t continue to miss it?

  38. 38
    Antonio San says:

    Gavin will surely point out how the GWP of CO2 was “calculated” by IPCC and point out the discussions at Shepperton in July 1992… or is that debate over too?

    [Response: the GWP of CO2 is one by definition. -gavin]

  39. 39
    Steve051 says:


    I wonder if anyone could give me some quick advice — I’m looking for some kind of climate simulator on the internet that could show, on a global map, what would happen if temps rose 8 degrees C by 2100, both in terms of sea level rise and topographic / temperature changes (desertification, arctic / antarctic melting, etc).

    I tried, but they don’t have a global simulator yet, and I don’t see anything about sea level changes.

    Pardon me if my terms are off, I’m a bit of an amateur at these things, but I hope the query makes sense. Help would be appreciated.

  40. 40
    catman306 says:

    Record number of record temperatures during the past ten years. (To help prove a point.)

    Reported in subscription only Geophysical Research Letters and at the
    NY Times and NPR.

  41. 41
    Gus says:

    Kangaroos are the answer. Their gut microbes do not produce methane!! Get rid of cattle. Range Kangaroos.

  42. 42
    Marcus says:

    Steve051: You can download the MAGICC model off the internet, it is pretty good for showing temperatures and precip globally for whatever emissions scenario you want, based on the patterns from a number of big GCMs.

    Desertification and arctic melt are harder problems – i don’t think that even good research models do those well yet. Antarctic melt might be included as a parameterization component for sea level rise, but you’d have to check the documentation. Thermal expansion and non-Arctic glacial contributions should be handled well, though.

  43. 43
    Andy Stahl says:

    Hank, et al.,

    Thanks for the pointers. Professionally, I’m an environmental advocate (national forest policy), but not engaged in climate policy. My earlier post implicitly asked “If a couple hundred livestock operations can’t be stopped from legislatively exempting themselves from climate-related regulation, how the Hell does anyone expect to remake the world’s energy policies?”

    You can read the livestock industry’s success story here:

    I know this is primarily a “science” blog, but suspect there are lots of climate policy readers/advocates, too. Did you all decide to give the livestock industry a free pass this year? Or did you engage the livestock industry and simply lose in Congress?

  44. 44
    Hank Roberts says:

    Andy, are you really asking why you only found out about this after the fact?
    Do you think someone should have known sooner than you did and stopped it?

    There’s a lot of history to this. It’s like the “death tax” and “death panel” stories — use of a made-up term and a gross distortion of the facts to pretend they’re against one thing (“cow burps”) and preventing something nobody’s proposed (a “cow tax”) and then rush through an amendment that actually protects the real crap artists who were going to be dealt with — the feedlot shitpile methane sources, which are far more serious problems.

    Yeah, it was a bait-and-switch shell game. It worked. Again.

    “… House appropriators approved a $10.6 billion spending bill for U.S. EPA last night, tucking in several amendments aimed at insulating agricultural interests from the reach of federal climate regulations … [including] provisions to block EPA regulations requiring factory farms to report their greenhouse gas emissions and exempt livestock operations from possible carbon regulations.”

    There’s a history, for example here:
    “THE INFLUENCE GAME: Excuse me! Lobby wins on burps
    June 20, 2009 By DINA CAPPIELLO , Associated Press Writer
    … On Thursday, Rep. Todd Tihart, R-Kan., successfully added an amendment to the spending bill that covers the EPA to block the agency from including biological processes of livestock – including the release of methane – as part of regulating greenhouse gases.

    That’s politics at work. The “you all” who gave the ag industry this free pass did it at the last minute. They claimed for years they were protecting farmers from a “cow tax” — but they exempted the huge manure waste problem.

    You could argue that this Congressman couldn’t tell the difference between a cow (a minor source not going to be regulated) from vast acres of pigshit (a significant source due to be regulated in December) — so he rushed in this amendment and protected both the cows and the pigshit, just to be safe.

    Or you could argue he got pwned, willingly, and has accidentally protected a big problem, using a non-problem as his excuse.

    If it’s the latter, the law can be refined next year (oops, midterm elections, got to win those first or lose the whole attempt to cope).

    Or you could get a much better answer from someone who really knows what happened — I put the above together from 5 minutes with Google and it’s just a sketch, a suggestion how to go about looking this stuff up.

  45. 45
    Andy Stahl says:


    I found out about these pro-manure provisions on 9/18/09, after the House had passed the Interior bill, but before the Senate had acted. I track/lobby the Interior bill for forest-related matters and happened to see this crap. At that time, I notified a colleague who specializes in Clean Water Act lawsuits against CAFOs (confined animal feedlots). I paid no more attention to it since that’s not what I do.

    So, in answer to “Do you think someone should have known sooner than you did and stopped it?” Of course I do. What I’m trying to find out is “Does the climate activist community have its manure together?” This small example seems as good a test case as any.

  46. 46
    Anonymous Coward says:

    Andy Stahl (#43) exlicitely implied (“how the hell …”) a very good question.

    But I don’t fell I’m part of his “you all”. The question I’m asking myself is quite different: what would be the point of focusing on relatively easy methane emissions reductions at this stage? Because, the way I see it, the most serious problem is the long-lived GHGs.
    I would understand the point of tackling pig shit and such once the hard problems are seriously addressed and are in the process of being fixed, in order to shave the peak off the forcing chart (so to speak). But I’m afraid that expending the few fast-acting tricks available so soon in the game would only strengthen the delayers’ hand by delaying painful climate change. I’m also afraid that short-sighted politicians might latch onto this methane business and leave the harder problems to the sucessors. And I’m afraid that people will wish they still had pig shitpiles to get rid of the day fast-acting tweaks are desperately needed.
    Are “you all” assuming that significant action on the root causes of the real, long-term problems in the next 10 or 15 years is a done deal anyway? I’m not such an optimist.

  47. 47
    Hank Roberts says:

    Well, I certainly don’t speak for a “climate activist community” or even know who you’d mean.

    All the organizations I’ve checked so far on this problem had been addressing it over the long term. Up til the very last moment, with success — the EPA regulation was weeks away from taking effect.

    You may want to look at the history a bit differently, because this wasn’t only or perhaps even primarily a “climate activist” issue. The regulations are based on air quality problems, water pollution problems, disease problems — all the _other_ reasons for controlling agricultural industrial manure.

    This last minute amendment was packaged as a “cow burps” or “cow tax” item to sneak it by. Nobody was trying to regulate cow burps or tax cows. This is the “death panels” method of deception at work.

    The people who got nailed had worked on the public health aspects of this problem. Politics at work.

    You have to remember any bill can be amended to put in any unrelated language — this is how this crap gets done, by attaching language to important legislation at the last minute.

    If your point is that there are far more agribusiness lobbyists at work in Washington than ecologically minded citizens to watch them — so true. You can’t watch all of them all of the time. This stuff happens.

  48. 48
    Hank Roberts says:

    PS for Andy, with a reminder I really don’t know much and this isn’t the place to find out — but I’d _bet_ this last minute language screws up a lot of business plans and that it will get revised as a result. If there’s no data collected on any greenhouse gases related to agriculture, or something as sweeping as that sounds, this kind of busines plan is dead before it starts I’d bet:

    How can you pay for, or do offsets against, something the law keeps people from reporting?

  49. 49
    Andy Stahl says:


    EPA was trying to regulate livestock emission of greenhouse gases. In EPA’s own words: “A livestock facility that emits 25,000 metric tons CO2e or more per year from manure management systems must report.” The reporting rule would have regulated livestock facilities that “stabilize” or “store” manure, as distinct from spreading it on fields. Methane and nitrous oxide were also to be reported.

    This was 100% a climate activist issue. The title of EPA’s rule is “Mandatory Reporting of Greenhouse Gases.” The proposed rule has nothing to do with water pollution, disease problems, or other reasons for controlling industrial manure.

    The people “who got nailed” were the climate activist community. It does exist, e.g., NRDC, Greenpeace, 1Sky,, National Wildlife Federation, Sierra Club (a who’s who can be found at

    Unless we understand how and why significant anti-climate legislation made it so easily through Congress (was there any opposition at all?), we have little chance of passing meaningful climate legislation next year.

  50. 50
    philc says:

    RE #19- Physics FAQ doesn’t really answer the question. Why do the current climate models show increasing temperatures over the 2001-2001 period when the observations show a leveling off, or even the start of a cooling trend?

    I would expect a valid model, or set of models, since it seems a bunch of different models do a better job than just one, would show 10 year trends.

    For validation, I would expect that you would make a series of runs over the same period and get some kind of running average of results that matches the observations to some degree. The better the model the closer it matches observation, and the finer detail it captures. The observation in the physics faq that over a long period the models are fairly insensitive to initial conditions means to me that, given initial conditions from 1850 say, the models should produce an output fairly close to observations after 100 years or so. I realize it won’t get down to forecasting temperatures at individual station or individual hurricane track, but it should track the trends in the data to some degree, particularly when short term trends change direction(barring volcanoes or meteor strikes). Since the models responded appropriately to Pinatubo, when it was factored in, why not the leveling off of temperatures?

    [Response: The results can be seen at this post showing what the IPCC models actually say. We will have an update on this shortly as well. – gavin]