So if thawing Arctic regions releasing methane and frozen soil carbon are the future “long tail” what in your opinion are the current “head terms” (borrowing from SEM terminology)?
[Response:Not sure if this is what you’re asking, but I think of the CO2 trajectory as a peak (which we are embarking on now and which will persist for some centuries until the atmosphere equilibrates with the ocean) and a long tail. David]
A simple glance to the GISS data (http://data.giss.nasa.gov/ch4_fung/) indicates that the main origin of atmospheric methane is human action.
Simply speaking, methane production is more or less linked to food production and so is more or less linearly linked to the number of human beings on earth.
So, studying arctic methane production and its influence on climate is, certainly a good idea, but money spent for that could probably find a better use elsewhere. (This is, of course, a personal opinion).
[Response:Well, all of the anthropogenic methane comes from human activity, but that’s only about half of the total methane in the atmosphere today. This is great work well worth the money, though, even if the direct link to climate change today is probably small, to understand what will happen in the long term, how it worked in the past (paleoclimatology), and to make real sure we’re wrong about the short-term climate impacts being small. David]
Comment by Pierre Allemand — 14 Jun 2012 @ 4:10 PM
Fig 2 in Allen(2009) suggests that the 1200 Gt (methane) + 1200 Gt(yedoma) + 1000Gt human = 3400Gt would result in peak warming north of 3C. Is it also not true that none of the models used in the paper incorporate Hansen’s ‘slow’ feedbacks (which double the sensitivity,) and which seem to be a lot faster than hoped…
[Response:Yes, that’s true, and it takes 2 C as a target, which is no picnic, so I’ll agree with the drift of your comment and the next several that the 1000 Gton target is, what’s the opposite of the word conservative, used in this scientific sense? An overestimate of a real “safety” boundary. David]
The “maybe we’re 1/3 of the way there” appears to underestimate the situation rather too much. Allen et al 2009 are explicitly talking of “emmissions” not atmospheric values.
[Response:Ya, me too. David]
“Total anthropogenic emissions of one trillion tonnes of carbon (3.67 trillion tonnes of CO2), about half of which has already been emitted since industrialization began, results in a most likely peak carbon-dioxide-induced warming of 2 °C above pre-industrial temperatures, with a 5–95% confidence interval of 1.3–3.9 °C.”
And CDIAC give emissions (ex land use) of 340 GtC to 2007 to which 10% can be added to 2011.
I would thus suggest we are past halfway. And I’m not sure the what we’re halfway towards isn’t also an underestimation by Allen et al.
[Response:Agreed, in that 2 C is too warm, in my personal opinion. David]
How would you know if the Arctic methane is a problem or not if you did not study it? Sidds estimates of total carbon from the Arctic look pretty scary to me. If we do not know all the natural reserves we will not be able to estimate the response.
I recently looked at warming scenarios with and without methane feedbacks assuming a poisson distribution of equilibrium climate sensitivity (IPPC [2,3,4.5]) and a gaussian distribution around possible future emissions from fossil fuel sources of 6100 Gt of CO2 (burn everything we can extract).
I asked this in the unforced variations thread already, perhaps the moderators will allow a repeat of the question:
We see more methane coming out of the arctic. But methane concentrations are not rising quickly. So the methane is being efficiently oxidized. This should lead to decrease in OH- concentrations. Is the decrease visible ?
[Response:Best I understand it the estimates of global OH inventory, all indirect like abundance of trace organics in the atmosphere, has been thought to have held relatively steady through the transition from preanthropogenic to industrial atmospheres. Increasing load on the OH due to emission of CO and CH4 has been balanced, more or less, as far as they can tell, by increasing production of OH due to NOx emission. Factors of two cancelling each other out by luck, apparently. David]
I have a question to the methane release using natural gas. I have found that 0.3 per cent to over 4 per cent of the methane in natural gas is released to the atmosphere, in different sources, a rather large span. This influences the impact of fuel change from coal to natural gas on climate.
Are there now better/narrower estimates for this value? Does it depend on the way natural gas is produced (conventional vs. unconventinal) or transported (pipline vs. LNG)?
If 300 Gtonnes of C is what we have released and 1000 Gtonnes C is the limit for 2C and we are burning 10 Gtonne C per year then thats 100 Gtonne every decade and hence the alarmist future is 70 years away – surely we can avoid a 2C peak and above if we start combating emissions today?
[Response:I think technologically it would be a piece of cake, it’s just hard to make the decision to leave the coal in the ground. If there were no more coal, we’d figure a way. It would be some decades before we’d have to quit cold turkey, but realistically emission would probably have to glide down some exponential decay, cuts of x% per year. Beginning now, cuts of 2-3% per year would ramp down to a total burn of 1000 Gton C, but if we wait 10 years, maybe 5% per year would be required. The steeper the cutbacks, the more new stuff has to be built every year, the more it will cost. David]
David, are you measuring the total 1200 Gton C of methane as CO2-equivalent, or actual C?
[Response:Carbon, just mass of carbon. David]
Something BTW I was interested to read in Raypierre’s book is that methane’s apparently high greenhouse effect is largely an artifact of the fact that it exists in relatively low concentration, i.e., the more absorbing parts of the spectrum haven’t yet been saturated. See my earlier comment on methane.
[Response:If fact, I think if CO2 and CH4 were at equal concentrations, CO2 would be stronger since it’s in the middle of the Earth’s IR spectrum and methane is on the fringe. David]
“why on Earth would you assume a fixed annual increase?”
Kevin, Pete is also ignoring CO2-equivalent emissions.
[Response:Ah, but if the methane comes out slowly, it will probably have its largest impact as the accumulating CO2 rather than as the increase in methane concentration itself in the atmosphere. The equivalent-CO2 thing only applies if the methane were all released to the atmosphere at once. David]
Plus, that “300 Gt C” figure has been in use for at least as long as I’ve been following the science, which is well over 5 years now, in fact, IIRC, CDIAC was using 305 Gt C that long ago. It’s kind of like the “BP” date notation that keeps receding.
Methane leakage from the distribution system is considerable but not well measured; up to five percent maybe: http://www.pnas.org/content/109/17/6435.short
Leak detection technology is changing improving, new info ought to come in on this generally. I’ve seen studies done driving around old cities mapping areas of high methane background from leaking distribution systems.
Handheld leak detectors are fairly cheap, I just put one in the earthquake kit in case I’m foolish enough to go crawl under the house after the next big quake to check for little leaks in the old pipes.
AGW is having its most extreme impact in the polar regions, which in turn will have large positive feedbacks in the form of decreased albedo and increased atmospheric water vapor coming from an open Arctic Ocean, among others…not to mention that a large sea-level rise will occur with the rapid melting of the Greenland Icecap…yet, “methane emission fluxes…higher than previous estimates…would still be small in terms of global climate forcing”.
Non Sequitur, your facts are uncoordinated.
[Response:2% of global methane emissions going up to 5% is a small relative change. Sequitur. David]
I have been hearing this refrain often lately in the face of countervailing evidence, could it be that our current models are very deficient in this particular area?
To go even further, are we seeing a social phenomena similar to that displayed by the paleontologists who believed that “mammals ate the baby dinosaurs” in their reaction to the Alvarez father and son team’s discoveries?
Re Response @5.
Are you saying you are still happy with “1/3 the way there“?
[Response:No, didn’t say that at all. David]
According to CDIAC, the emissions since pre-industrial times are well past halfway to 1,000 GtC.
The land-use emissions 1850-2005 total 156 GtC. Add 37 GtC for the preceeding century plus 8 GtC for 2006-11 yeilds emissions of 201 GtC.
The FF & cement emissions 1751-2008 total 347 GtC. Add 27 GtC for the last 3 years to give 374 GtC.
By that count, the grand total emissions works out at 575 GtC.
[Response:The issue is how to count the land use carbon and the land uptake carbon. David]
And let’s not forget that CO2 is not the only agent behind AGW. Some are negative forcings but I would argue that the net effect of non-CO2 forcings will be positive in coming decades, adding to the urgency of responding to AGW.
A small semantic point about the transformation of permafrost as the climate warms: Strictly speaking, when permafrost warms to the melting point of ice, it is the ice in it that melts, and not the earth material. Permafrost scientists use the term “thawing permafrost”. Consider frozen hamburger meat: the ice in the meat can melt or thaw, but we thaw the meat.
The way I like to think about this problem (concerning the methane impact on the short and long term) is to decompose the problem into being a function of the size and duration of the release. Suppose we released 200 GtC into the atmosphere, all in the form of methane. That corresponds to about 90 ppm of methane. That reduces the OLR in the neighborhood of 8 W/m2, or a quadrupling CO2. Using a transient climate response of ~1.5 C/2xCO2, that gives you maybe 3 degrees of rather rapid warming. But the methane dissipates on timescales of a decade or so, and assuming it all stays in the atmosphere as CO2, then the corresponding radiative forcing is ~1 W/m2 (assuming the 90 ppm is being added to a background of 400 ppm CO2). Given the slow removal time of CO2, that can affect the long-term response; assuming an equilibrium sensitivity of ~3 C/2xCO2, that adds on another 1 C or so to the tail end.
If the methane release is on the order of 1000 GtC, then there is a rather catastrophic instantaneous response, but this is not very realistic. However, even for a slow release, that can fully double the amount of CO2 in the entire atmosphere and affect the long-term warming. Moreover, with a slow release, there will be a small but persistent CH4 radiative forcing on top of that.
P.S. Philip (#11) is absolutely right that methane only “looks like” a stronger greenhouse gas than CO2 because its local slope (on a OLR vs. concentration plot) is larger than the local slope for CO2. This is just because of the difference in background concentration. A proper comparison of, say, 100 ppm CO2 vs. 100 ppm CH4 would show that CO2 is a better greenhouse gas on Earth. This might seem like an esoteric point, but it’s one that people have messed up even in the academic literature.
Thanks for an illuminating comment, Chris C–as usual.
But the methane dissipates on timescales of a decade or so, and assuming it all stays in the atmosphere as CO2, then the corresponding radiative forcing is ~1 W/m2 (assuming the 90 ppm is being added to a background of 400 ppm CO2).
Which raises the question: what would the feedbacks during that decade do? I’m guessing it would be
“bye-bye Arctic summer sea ice” for sure, and that we’d get a secondary pulse of methane too–but how big? And what else could be expected?
Perhaps this would be ‘non-catastrophic’ (whatever that means in this context), but ‘non-negligible’ seems like a decent bet, OTTOMH.
[Response:That stuff is happening mostly because of radiative forcing from CO2. If the atmospheric methane concentration went up a few % due to the Arctic (a few % of total emissions, doubled, say), then the radiative forcing from that methane would be a few % of the total anthropogenic forcing. Worry about CO2! David]
“A proper comparison of, say, 100 ppm CO2 vs. 100 ppm CH4 would show that CO2 is a better greenhouse gas on Earth.”
Indeed, nothing currently in the atmosphere takes a deeper bite than CO2, just look at the depth of the trough it makes in the outgoing LW plot. H2O may absorb over a far wider range of wavelengths, which is why it accounts for ~80% of the greenhouse effect, but nowhere does it absorb anywhere nearly as completely as CO2 does at 14 microns near the peak of the curve.
Kevin- I would expect that the typical “fast feedbacks” of interest (water vapor, lapse rate, etc) would be of most importance on this decadal timescale. You could reduce the Arctic sea ice rapidly, but this is only a very small contribution to the total planetary energy budget. As an aside, unlike with the Greenland ice sheet, there is evidence that the Arctic sea ice loss is reversible, so I’d expect its long-term fate to be determined by the gradual tail. Dr. Archer would be much better suited to answer the other part about further methane feedback.
Jim- Indeed. You need to weight the relative absorption strength with where the Earth emits, and CO2 is a very good absorber right near the peak of Earth’s Planck emission spectrum. Methane is toward the fringe as David mentioned, but it’s still significant for Earth temperatures, and the absorption by water vapor and CO2 is not strong in that region. There’s also the vertical profile to consider. To have a greenhouse effect, you need enough absorber at altitude where the emission temperature is lower than the surface value, and water vapor is not as abundant at these altitudes.
By the way, water vapor isn’t quite 80%, not even in clear sky conditions. It’s closer to half of the greenhouse effect, and most of the rest is due to CO2 and clouds. Methane isn’t much of a contribution, although its slope (i.e, its potential radiative forcing) can be relatively large on a molecule-for-molecule basis, just like with CFC’s or a number of other gases. By the way, N2 and O2 actually contribute to about half a percent of the greenhouse effect directly (even though they are symmetric, diatomic molecules)- and in cold, dry regions like Antarctica the contribution from those gases is comparable to methane.
Re #10 – Thanks for the reply but as the west outsources more and more of its low profit manufacturing to the east and as they grow in prosperity (non OECD) we can see that emissions are actually rising globally even though the west appears to some degree to be cutting back on emissions to some degree. 2010/12 emissions have increaed globally and we are in a period of slow growth globally as the recession is still with us.
Secondly is the annual growth issue which in order to have high employment and more prosperity growth needs to be at 2-3% er year which means more energy usage of around the same increases. Therefore the cut backs of 2-3% per annum in Carbon emissions need to also take into account the annual emissions of 2-3% as well making cuts of 4-6% year more likely and as you say the more we delay the cuts needs to be 5-8% per annum to offset growth as well.
I dont doubt we have the technology but its always the same in our political partisan world. Those for the status quo and those for some change and thoise for radical change. Its a monstrous undertaking.
Could someone with access to the article explain exactly what mechanisms “conspire to” control the flow of gas into the atmosphere. Are these mechanisms completely consistent and reliable in all places and in all scenarios?
[Response:What I meant was, methane comes out when the permafrost melts thaws, and when mountain ice caps melt. No, not completely consistent in all places and all scenarios, but a statistically significant tendency in the data. David]
The stunning thing about this article to many of us is that it shows that there are vast stores of FREE methane ready to erupt into the atmosphere through just a crack in the rapidly thawing permafrost and ice cap. And the area if warming incredibly fast and getting faster. Shrubs widely distributed across the Arctic, as it turns out, grow directly into trees under warming conditions. This is happening now. So we don’t need to wait for forests to slowly migrate up from the south–they area already ready to go right there. And of course the new Arctic forests will not reflect sunlight the way the unblemished snow surface would, so the regions will warm yet faster, leading to more forest, leading to more warming…
[Response:Yes on the basic albedo change concept but it’s more complex than that; there are forest and forest type definitions, hydrological and other considerations. The study (and Supplemental) referred to is here and here, and a similar recent one is here and here. I recommend reading them both.–Jim]
And that feeds into thawing areas any one of which could have a vast pool of methane ready to burst into the atmosphere. I find nothing comforting about the abstract, but more info on the control mechanisms would be appreciated.
“… most of the methane flux from the Arctic today are of types of emission that will respond to climate warming. But the general response time of the system is slow, decades to centuries, rather than potentially poised to release a huge pulse of methane within a few years.”
What he says he read:
“… this article … shows that there are vast stores of FREE methane ready to erupt into the atmosphere through just a crack …. a vast pool of methane ready to burst into the atmosphere ….”
It appears to me that you are letting the past govern the future a bit too much here. Given the large quantity of methane in the Arctic, why should we assume gradual and orderly releases? And if 2x or 4x more is still not a big deal, shouldn’t the fact that the intersection of frozen and thawing sources lead to an expectation of much larger bursts? Isn’t it possible that forcings from 1-2C warming could result in a major permafrost and subsea methane escape event, driving concentrations upward and possibly triggering both local and global feedbacks? Recent paleo studies indicate that these events can occur with great suddenness.
When I have posed this question here before, the answer was something like “we don’t know what would trigger major short term releases”. I see no reason to find that point comforting.
[Response:Not really my aim to offer comfort I’m afraid, but there were no methane spikes during the last interglacial, and I’m not a believer in the Paleocene Eocene as resulting from hydrate release (see Pagani et al., Science 314: 1556-1557 (2006) for the reason why — the C and O isotopes don’t fit methane). David]
Mike Roddy, while there is a large frozen-in methane reservoir in the Arctic, and thus the potential for a large influx into the atmosphere, the likely hood of release is tempered by the fact that there was no such release during previous interglacials that were a degree or two warmer than present. However, when—not if—we exceed those slightly warmer temperatures we will be in uncharted territory, and we won’t be able to take so much comfort in the lack of past large scale injections of methane from permafrost and seabed clathrates.
> why should we assume gradual and orderly releases?
Nobody’s asking you to assume.
I’d ask you to assess the likelihood;
what choices made now would increase this feedback, compared to others?.
Then we avoid the steps that make rapid release begin to seem likely.
For those arguing that rapid release is imminent — whose plan do you like?
I read the “methane emergency” folks as favoring “depressurizing” (aka drill and sell) and rolling back the surface sulfate air pollution regulations.
Seriously — nobody’s asking anyone to assume.
It would be wise to try to figure out the probabilities.
Most of what we know is from previous rapid warmings in the paleo record.
Fire will burn peat, that’s a concern. How much?
Burned areas will melt permafrost faster, that’s a concern. How much?
Seabed warming will melt clathrates, that’s known to be a very slow process.
There’s lots of natural gas easy to drill around the Arctic. Who benefits?
There are clearly feedbacks missing from the current generation of climate models. Professor John Mitchell has given me 2 examples which are not included in current models (indicating that although these things may be important, they are not always easy to quantify, model, initialize and validate)
“melting permafrost – we don’t have [CO2 and CH4 emissions from permafrost] in the GCM [global climate model], but have some simple modelling of. Too early to show any results yet, but we plan to publish later this year. Bottom line is that both CH4 and CO2 will be released as permafrost thaws. The magnitude is uncertain, but likely to be significant.”
“more forest fires – We don’t do yet, but could be important for changing ecosystems response to climate.”
Now this is 2012. I don’t see how the models used for Allen et. al. could, in 2009, have accounted for these feedbacks and probably others.
Am I wrong?
[Response:These are carbon feedbacks, amplifying possibly the amount of carbon that we release. For climate modelers these usually get folded into the uncertainty in our own emissions, which are one of the largest uncertainties in the forecast. Most climate models runs specify the CO2 concentration then predict climate from there. Just as terrestrial uptake can either be subtracted from the overall source, as I did but some of the commenters didn’t, so too can future feedback emissions be sort of folded into the 1000 Gton C. But keep in mind also that today, the natural world is absorbing our fossil carbon, acting as a negative feedback on our climate provocation. It could reverse, turning into a positive feedback on longer time scales, like it did during the glacial / interglacial cycles. David]
Sorry but I’m confused by your response to #17. If, for example, we stop all land use changes, how many GtC of CO2 can be emitted while staying within the 1000 GtC? Is it about 700 GtC, which I understand from your article, or as I thought and which #17 estimates, about 425 GtC?
BTW thanks to you and Ray Pierrehumbert for your excellent textbooks.
[Response:You are most welcome! If we stopped deforestation, the land surface would become a stronger net sink than it is now. See Tans, Oceanography 22(4) 26-35, 2009 for a excellent review of historical carbon fluxes. I’d guess that any net uptake would be subtracted from Allen’s 1000 Gton C. David]
“Methane, a potent greenhouse gas, accumulates in subsurface hydrocarbon reservoirs, such as coal beds and natural gas deposits. In the Arctic, permafrost and glaciers form a ‘cryosphere cap’ that traps gas leaking from these reservoirs, restricting flow to the atmosphere. With a carbon store of over 1,200 Pg, the Arctic geologic methane reservoir is large when compared with the global atmospheric methane pool of around 5 Pg. As such, the Earth’s climate is sensitive to the escape of even a small fraction of this methane. Here, we document the release of 14C-depleted methane to the atmosphere from abundant gas seeps concentrated along boundaries of permafrost thaw and receding glaciers…
Our findings imply that in a warming climate, disintegration of permafrost, glaciers and parts of the polar ice sheets could facilitate the transient expulsion of 14C-depleted methane trapped by the cryosphere cap.”
None of which I find comforting.
By the way, I oppose drilling in the Arctic and rolling back any pollution regulations.
From what I have read methane acts a GHG over a narrow wavelength band in the 6 micron range which it shares with nitrous oxide. I know that, relative to CO2, methane is a powerful GHG but surely its narrow wavelenrth band limits its impact. Any clarification would be appreciated.
[Response:You can see a plot of the outgoing IR light from the Earth, as it gets modified by the greenhouse gases in the atmosphere, here. Methane absorbs off in the fringe, at 1300 cm-1 (wavenumbers, cycles/cm), whereas the peak of Earth’s IR emission is closer to 700 cm-1, where CO2 absorbs. David]
Will earthquakes increase in frequency and release greenhouse gasses?
The melting of the Greenland and Antarctic ice-sheets will have two effects:
1. The weight of the ice will be removed from the poles – and melt water will distribute itself round the world increasing sea-level.
2. The masses of ice will no longer be pulling up the seas around them by their gravitational pull: The ice-sheets are so massive that they has a significant gravitational pull on the seas around them. See Rising sea levels – but where?
Both effects mean that weight will be moved from the poles to the equator. More earthquakes will happen as the Earth is squeezed round the equator and released at the poles. Wikipedia has a piece Post glacial rebound
Post-glacial rebound … produces measurable effects on vertical crustal motion, global sea levels, horizontal crustal motion, gravity field, Earth’s rotational motion and state of stress and earthquakes.
Could post glacial rebound earthquakes liberate greenhouse gasses?
#34–Ron M., there is discussion of this point upthread–perhaps you missed it?
IMO, the most central point is that methane is still relatively scarce. Since the efficacy of any GHG is logarithmic–usually specified as temperature change *per doubling*–the lower the concentration of a given GHG, the less additional gas is required to achieve a specified amount of warming.
A comparative example: to double CO2 would require the addition of nearly 395 ppm; but methane concentration is on the order of 1 ppm. So 100 GT of the former would have much less effect than 100 of the latter.
(To be sure, there is still the question of what ‘bite’ each takes out of the spectrum. Dr. Pierrehumbert has previously written on RC that in this regard CO2 is the ‘better’ of the two GHGs, as your comment implies.)
Would you care to give your estimate of the “future feedback emissions be sort of folded into the 1000 Gton C”? What is it now and has it changed over the past few years?
[Response:Today it’s negative, taking up carbon. I don’t know if the forecast for the future has changed, it’s unreliable anyway.]
Is 1000 Gton C and overestimate or an undersestimate to keep within the 2 degrees C increse?
[Response:Allen et al say that there is a significant risk of exceeding 20 C if more than 1000 Gton C is released. I don’t have a strong hunch if that’s high or low.]
I thought one reason for the 2 degrees C limit was to avoid the feedbacks that would cause dangerous climate change. Are you sill happy that 2 degrees C limit or do you think there are multiple feedbacks that might interact to be “dangerous climate change before” that limit?
[Response:No, profoundly unhappy. :(]
Have you quantified the chances that the negative carbon feedback “turning into a positive feedback on longer time scales, like it did during the glacial / interglacial cycles”?
[Response:Nope. Don’t understand the glacial cycles in CO2, and anyway warming is different than cooling. Loose cannon.]
Should we expect any of these “longer time scales” to be shorter under the current man-made forcing?
[Response:Get out the magic 8-ball, I’ll tell you. David]
The width of the IR band of methane would spread if there was enough methane to saturate absorption on the center of the band. More importantly it is off the emission maximum, as is the asymmetric CO2 *stretch* ( a very strong absorber/emitter itself). The CO2 *bend* is square in the middle of the IR emission peak of earth.
Wili, don’t take this personally. I’m not saying you’re from the “Methane Emergency” group. We had one of their people here earlier, the guy arguing that sulfate pollution was a little local problem, just before the regulations restricting sulfate pollution were tightened.
I’m just saying — there are lots of emergencies out there in the possible futures, and all of them are feedbacks.
No matter which feedback event worries you — burning carbon is the path leading to making those feedbacks more likely.
If you answer to solving the “methane emergency is: stop burning carbon
Then I agree.
The answer to many possible problems is: stop burning carbon.
The answer to how to stop burning carbon is:
… well? What’s the path that leads toward that future?
Sketch out what choices need to be made soonest, and what choices made now have the best longterm consequences.
Those of us in the currently older current generation can die rich and fat leaving the pain to your grandchildren — or we can give up the benefits we got by burning so much carbon so fast and make things better.
And we’ve got to be wary of the greenwashing crap that says, let’s solve the methane emergency by — burning more carbon immediately.
“If you answer to solving the “methane emergency is: stop burning carbon
Then I agree.”
Yes, we agree on this.
I got the impression that this site was primarily focused on the science of accurately describing what is happening in the world that relates to global climate. I don’t think pointing out how bad things may be requires me or anyone else to have a nifty answer to getting out of the predicament we are in.
Generally I get the impression that the hosts do not want long digressions into the politics of nuclear power, for example, here. That can be done on other fora.
What’s the point? Perhaps it is just my academic bent, but I tend to think of knowledge as its own point.
Beyond trying to understand our situation as fully as accurately as my small brain can handle, I try to “be the difference I want to see in the world” and through giving up on meat eating, flying, most motorized travel, and a few other life-style choices, I am down to about “one earth” on the http://www.myfootprint.org site. I also am active in my neighborhood, workplace, municipal, state, national and global levels in raising GW and related concerns.
All this at considerable risk and detriment to many of my closest relationships and to my professional career.
So, yes, whatever the situation is, we all need to rapidly move to a much-lower-impact way of living while moving rapidly to a build-out of renewables.
Yet perhaps it is a personal perversion, but I still want to know the best and most accurate information on where exactly we are, without sugar coating, as things continue to disintegrate, even if I don’t have any easy-to-implement silver bullets up my sleeve to magically ‘solve’ them.
Part of how we get to the truth is by asking hard questions and probing into what may be the worst consequences, even those that many may be not emotionally equipped to face.
If nothing else, I think it is important to demonstrate that uncertainties are not always our friend. The general public gets the impression that the ‘debate’ is between those who are in total denial that GW is happening and some watered down, MSM presentation of the already-outdated-at-the-time-of-its-publication last IPCC report.
People need to know that the actual scientific debate ranges from the more-dire-than-the-latest-IPCC-report to scenarios that are far more catastrophic on a number of fronts.
Anyway, this is exactly the conversation that strikes me as being considered rather off topic on this site.
Again, thank you, hank for your many informative comments and links, and thanks again to all for responses to my impertinent questions.
(And again, for the record, I see pretty much any kind of ‘geo-engineering’ as further evidence of our utter insanity as a species and as a culture–proof that we think of ourselves as gods that can micromanage complex systems we don’t fully understand to derive maximal benefit to ourselves.)
It’s a pretty common occurrence that greenhouse gases absorb very strongly in the center of a band, with opacity decaying toward the “wings” of an absorption region.
If you look at David Archer’s MODTRAN model, you can see this with CO2. Throw 1000 ppm into the model. Notice that there is a huge reduction in outgoing radiation between roughly 600 and 800 cm^-1; but in the very center (say 670 cm^-1), there is a tiny blip where emission increases as CO2 concentration goes up (at fixed temperature). This is even more pronounced if you do 10,000 ppm CO2. This arises because the absorption is so strong in this region that you are seeing emission from the stratosphere, where temperature increases with height (This increase in emission primarily acts to cool the stratosphere). However, toward the edge, the opacity is weaker and emission comes primarily from the troposphere. Continuing to add CO2 will begin to saturate the opaque centers but there will still be room for the wings to eat up radiation. They can gradually become saturated too, but not until concentrations well in excess of anything relevant to Earth. And insofar as temperatures continue to drop with height, adding more GHGs will still warm the surface even in saturated regions.
Methane works in a similar way, except it is much weaker than CO2. It also has a weak absorption feature shortward of 500 cm^-1 (which I’m not sure is in MODTRAN). I’d expect methane’s peak absorption to begin to saturate near 10 ppm or so based on the model, with plenty of wiggle room to make things warmer after that, but its efficiency does decay pretty rapidly (see Figure 1d of Haqq-Misra et al (2008, Astrobiology) for example. This enters into deep-time climate problems such as the pre-oxygenated Earth or Neoproterozoic, where there is speculation that methane could have been much higher than today, but it gets far too much attention as a “sexy” greenhouse gas that could cause all sorts of catastrophe…in reality it can’t build up to significant concentrations in today’s oxygenated atmosphere, and it doesn’t actually solve much in deep-time either. In anoxic conditions, it’s even worse because photochemical models tend to develop haze layers once the CH4/CO2 concentrations become comparable; this acts like an anti-greenhouse effect and cools the surface (described in my post). Just another reason why I think Dr. Archer is right in that the main thing to consider with methane feedbacks is its influence on the long-term radiative forcing of CO2.
Ozone isn’t a huge greenhouse gas either on Earth, though it plays a special role in absorbing incoming UV radiation and a lot of astronomy people like it as a possible biosignature when we get spectra of extrasolar planets. By the way, the spike in the ozone band actually works a bit different than that of CO2. Opacity is a minimum here, and the “warm blip” in the emission spectrum is radiation coming from the surface, not from in the stratosphere.
Prof. Archer seems to agree that a substantial fraction of Arctic fossil carbon might be released into the atmosphere over a millenium or two. I find it quite unsettling that we may not be in a position, even if actions are taken today, to prevent this. In which case we are committed to 1400 Gton extra fossil carbon into the atmosphere. I would like to sharpen this question, can we put some numbers to the likelihood of such release, _even if all possible action_ is taken today ? This is quite important, for if we cannot prevent, we are looking at almost certainly exceeding 2C rise.
The difficulty is that arctic methane destabilization is just one of the feedbacks that might result in a worse prognosis than IPCC estimates.
I have learned a lot from your course materials and videos online. Unfortunately my humble financial situation has prevented me from picking up the texts on Amazon. But I find your posts and responses to comments illuminating and wanted to say thanks for all your hard work to make this stuff accessible.
Comment by Unsettled Scientist — 17 Jun 2012 @ 7:12 PM
It’s not often I get the urge to argue with you but I’m irritated with sites like http://www.myfootprint.org because they don’t explain enough about how carbon footprinting should be done so are of limited use in adjusting lifestyles to be “low-carbon” (a frequently misused term).
I have a stalled project, The Green Ration Book. This set up a mechanism to address the difficulties with carbon footprinting by setting up a citizen’s jury – and publishing our workings. Some of the issues that a conventional footprinting method does not address but which the informed citizen can judge on are:
1. What is the GWP of methane. (Should the timeframe be decades, making methane 105 times CO2 or centuies making methane 32 times CO2?)
2. How should embodied carbon be accounted for in products like cars or buildings? A new building can cause the emission of more than 1 tonne of CO2 per square metre (or if you build with purpose actually take CO2 from the atmosphere – build with sustainable wood!)
3. How should we account for black carbon? How bad is wood smoke for the atmosphere?
4. How bad are animal products? Which ones are worse? (Clue: don’t eat beef or lamb)
5. How should recycled material be assessed?
Our newsspace is full of greenwash (sustainable, low-carbon, environmentally friendly…). Sadly I have to admit that I make little progress against this – See some of my other rather sad efforts
If anyone wants to [help with/take over] any of these, Green Ration Book included, let me know.
I believe that informed juries should be set up by governemnts to do official but independent Green Ration Books but the best immediate action governemts can take (when we are all worried about the world economy) is to Tax carbon to create jobs
Ozone can never really build up because it is reactive (although slowly compared to say HO or other free radicals). In the stratosphere, it is destroyed by UV photodissociation. Near the surface reactions on surfaces play an important role.
You claim that about 300 billion tons of carbon have been emitted from fossil fuels and that the contribution from land use change can be ignored because of the uptake of carbon by the land and ocean. I have just re-read the paper by Allen at al (2009) and they account for carbon uptake when modeling carbon emissions. Thus the claim that land use change can be ignored is incorrect, the model considers total carbon emissions from fossil fuels, cement production and land use change. Up to 2006, about 500 billion metric tons of carbon had been emitted (this is stated in the abstract of the Allen paper).
“Total anthropogenic emissions of one trillion tonnes of carbon (3.67 trillion tonnes of CO2), about half of which has already been emitted since industrialization began, results in a most likely peak carbon dioxide induced warming of 2 6C above pre-industrial temperatures, with a 5–95% confidence interval of 1.3–3.9 C.” (Allen, 2009)
[Response:OK, I stand corrected. I guess since I don’t have much faith in forecasting natural land uptake in the future, I have a tendency to just leave land changes out, since they wash so far. Head in the sand I suppose. David]
42: Willi wrote ” I see pretty much any kind of ‘geo-engineering’ as further evidence of our utter insanity as a species and as a culture–proof that we think of ourselves as gods that can micromanage complex systems we don’t fully understand to derive maximal benefit to ourselves.”
I see geo-engineering as the only option that we are leaving to our grandchildren. Despite your personal sacrifices to reduce your carbon footprint we are doing approximately nothing to reduce CO2 emissions. Burying CO2 strikes me as quite sane.
Comment by John E. Pearson — 18 Jun 2012 @ 1:10 PM
I can’t help but want to put more emphasis on what we are actually seeing in the Arctic than what didn’t happen in the past. David, your posts on this have thankfully become closer to what the observations say, but you continue to simply discount the possibility of abrupt emissions from the Arctic despite the work of the last couple years indicating that, indeed, abrupt changes seem to already be happening.
The Arctic Ocean, itself, seems to be a bigger emitter than previously thought… or even known. Kilometer-wide seeps were found this past summer/fall while only meters-wide seeps had been found previously. Walter-Anthony stated several years ago thermokarst lakes had tripled in well under a decade.
Those changes are hyperbolic curves and it has been stated a mere 1 to 2 percent of the Arctic stores being emitted might be enough to push us into a state we cannot reverse.
Models are great, but they have consistently underestimated change overall. We are, after all, tracking the high ends of the model runs, are we not? I’d like to see a completely balanced post from you on this. IMO, your scientific reticence is causing you to favor the models and history over current events that are ominous. This is common, of course, as the Arctic has been outdoing the models, the majority of runs anyway, all along.
The planet has never been in this situation. It has never been this generally degraded and changing at this speed from other than extraterrestrial forcings, right? Personally, I don’t think we have a corollary to draw on, and given the rates of change, should look at paleoclimate as more of a low end of worse case rather than a high end. That Arctic abrupt, large releases may not have happened much before happened much before is zero comfort to me. Logically, it’s a dangerous position. It’s the type of logical fallacy that gets one beaten in a debate.
The direct observations say the Arctic is changing rapidly. Methane content is spiking per a recent paper.
Again, I’d like to see a less reticent and sanguine post on this that more directly addresses what the issues raised here mean.
* 3x increase in thermokarst lakes 2000 (or so) to 2007
* Arctic sea bed seeps a kilometer wide
* methane directly from the Arctic Ocean
* the general degradation of the planet
And, finally, in my own bailiwick, they are finding, pretty much across the board, that the Earth and its biota are more sensitive to temp changes than thought. As a permaculturist, trained to see the whole system fully interconnected, I think, “Well, duh!” I’d like to understand better why your response is more along the line of, “Well, hold on a minute; it’s not as bad as all that.” Basically, while I have noted your posts on this issue seeming to acknowledge more of the potential severity of the situation over time, I still don’t see the science of the last year fully reflected in them.
Chris Colose provided a link to a paper by the national academies which reviews several papers which link cumulative carbon emissions to warming.
My reading of that paper is that the carbon emissions due to land use change are added to other carbon emissions from fossil fuel, cement production and natural gas flaring, the uptake of carbon by the biosphere is included in the models and is not to be subtracted from emissions. The different studies come up with different estimates of cumulative carbon that will result in two degrees celcius of warming above 1850-1900 levels. Their median estimate is 1150 billion tons of carbon (GtC) with a very wide window of 800 to 1600 GtC to keep warming close to 2 C.
I didn’t quite follow all of David’s comments to my #30 and remain to be convinced that the Allen et. al. Trillion tonne is not flawed by missing feedbacks. Another, perhaps illogical, reason I am unsettled comes from Myles Allen’s comment on the Arctic sea-ice. From my BrusselsBlog:
In 2007, the summer extent of Arctic sea ice reached its lowest since satellite records began, significantly lower than previous years. Some interpreted this loss as a significant change in the speed with which sea ice is being lost. Senior Scientist Mark Serreze at the The Snow and Ice Data Centre said at the time, “The sea ice cover is in a downward spiral and may have passed the point of no return. As the years go by, we are losing more and more ice in summer, and growing back less and less ice in winter. We may well see an ice-free Arctic Ocean in summer within our lifetimes.”
In the subsequent years, 2008 and 2009, the summer extent of the sea ice was higher than the 2007 minimum. This led some scientists to criticise exaggerated claims. A Times piece quoted Vicky Pope, head of climate change advice at the Met Office as saying
“It isn’t helpful to anybody to exaggerate the situation. It’s scary enough as it is. The problem with saying that we’ve reached a tipping point is that when the extent starts to increase again — as it has — the sceptics will come along and say, ‘Well, it’s stopped’.”
Professor Myles Allen, head of the Climate Dynamics Group at Oxford, was also quoted: “Some claims that were made about the ice anomaly were misleading. A lot of people said this is the beginning of the end of Arctic ice, and of course it recovered the following year and everybody looked a bit silly.”
We face a lot of threats. There are a lot of things that could send us over the cliff. The past is important because it tells us which threats are credible. The fact that we have reached temperatures higher in the past without seeing catastrophic releases tells us we should be OK until we reach those same worst-case conditions again–in a few decades.
If we pay attention to what is going on in the Arctic at present, it doesn’t come close to catastrophic release unless we extrapolate to an extreme amount.
Geoff, yes, the myfootprint site is flawed, but I haven’t found anything better yet. But it helps to show people that, while you have to give up some things, you don’t have to live a completely ascetic life to live sustainably. (Perhaps I just like the site because they don’t say I have to give up beer ‘-)
Ultimately, any project to reduce something as complex as our relationship to the earth down to a number is going to be simplistic and reductionist, of course.
I may be interested in helping with your site, as I am in ‘transition’ in my current career. Do you want to get in touch?
I also agree that most of the stuff out in the media is…well, your term ‘greenwash’ is kind. Consuming (even ‘green consuming’) to save the planet is like fighting for non-violence, or something-else-ing for celibacy.
I’m with Killian (except for a minor quibble that the new plumes found by Semiletov and co. were about one k across, not many k, thank Goddess). The past is a guide for setting a baseline expectation for future events, but not so much to tell us what the worst case consequences of our current actions might be, since we have pushed systems beyond tipping points so much faster than anything we can find in the past and on so many fronts.
(I’ve been hoping for a different kind of tipping point–one in general human consciousness about our place on the planet–for decades now, but we seem further from such a realization than ever.)
The two most relevant questions seem to be:
1. What are the possibilities for sudden catastrophic release of game-changing quantities of methane from Arctic sources? (Shakhova has said 50 billion tons could be suddenly released at any time, iirc. Many here seem to disagree. Seems reasonable to me to say that we cannot be 100% certain it can’t happen.)
[Response:I’m skeptical it could happen but even if it did, what it would do would be to give us a preview of what 2100 will be like under business-as-usual. One that would immediately begin to subside, instead of inexorably worsening and lasting forever like the CO2 impact by 2100. Might lead to the human awareness tipping point you’re looking for. I’m much more frightened of CO2 than I am of methane. David]
2. Are we seeing what is likely to be the beginning of an exponential increase in methane release from Arctic sources, and if so, what kind of potential exponential curves might we be looking at?
To John E. Pearson at #50 who said, “Burying CO2 strikes me as quite sane.”
I would agree if you mean replanting the native prairie so it’s long roots can sequester CO2 or other such projects. I have done a good bit of that myself. I was mostly speaking against intentionally spewing additional vast quantities of aerosols into the upper atmosphere for ever, other such high-tech ‘fixes.’
But, as Hank has pointed out (in his own way), the main thing we have to do as fast as possible is to stop UN-sequestering carbon at the furious rate of ten-some billion tons a year, along with halting or greatly curtailing other practices–forest clearing, most cattle raising…–that further exacerbate the situation.
And, imho, we should stop doing that even if we heard that it is a total certainty that we are about to have a multi-billion ton emission of methane from the Arctic or elsewhere. The consequences of previous abuse should never be used as an excuse for further abuse.
wili, “Could be” does not make for a credible threat. What is more, it is unclear to me how we would attempt to mitigate this threat other than what we should be doing to avoid catastrophe resulting from CO2, since methane release is thermally activated.
It is clear that we can anticipate some substantial carbon release from melting permafrost, etc. in the not to distant future. There is no firm evidence that release will be catastrophic–at least not until temperatures are 2-3 degrees higher than they are now. At that point we will have lots of other wories as well. Let’s not abandom proper risk mitigation out of alarm.
If your admonition to curtail cattle raising refers to reducing the use of fossil carbon for the production and distribution of meat, egg and milk products, then I agree. However, this being a methane thread, if you think that the methane produced by farm animals is significant then I think you are mistaken. Steve
“The idea of repeal first came up in 2009, when leaders at the G-20 summit pledged to phase out fossil fuel subsidies over the next decade. Since then, an additional 50 countries have said they’d do likewise. Yet those promises have had virtually no effect. As a new report (pdf) from the Natural Resources Defense Council details, global subsidies have nearly tripled since 2009 — from $300 billion to $775 billion.”
Subsidies for UN-sequestering safely buried carbon have TRIPLED just since 2009.
54 Ray L said, “The fact that we have reached temperatures higher in the past without seeing catastrophic releases tells us we should be OK until we reach those same worst-case conditions again–in a few decades.”
Previous warmings were much slower, which makes the comparison potentially flawed. For example, “normally” sea level rises as temperatures increase. This tends to stabilize clathrates as higher pressure offsets temperature increases. Today, sea level rise lags far behind temperature increases, so clathrates will be more likely to disassociate. Similarly, ecosystems “normally” have time to adapt to rising temperatures. Not this time, though. It’s easy to visualize massive beetle-caused tree death and the resulting mega-fires leaving vast swaths of blackened landscape sucking up solar energy and causing the release of tremendous volumes of CH4.
[Response:Well, just to play devil’s advocate, there were abrupt climate changes in the past called Dansgaard-Oeschger events, that were very fast, climate flip-flops in just a few years recorded in Greenland ice cores. Another devil’s stick in the spokes would be that diffusion of heat into a solid body like permafrost soils is slow, so they wouldn’t probably respond much more strongly to a fast change in temperature. It would respond to the longevity of the forcing more than to the quickness off the mark. David ]
At the same time, oceans had more time to come to equilibrium (higher temperature) which would destabilize the clathrates. I just don’t see the evidence that we are near a catastrophic release.
I think people hear about km-wide regions bubbling and don’t realize that for for the types of catastrophic release people are talking, the regions involved would be a thousand times bigger.
“It’s easy to visualize…” and “This is different…” also do not establish a credible threat.
Re- Comment by Jim Larsen — 18 Jun 2012 @ 11:33 PM:
You are making some rather extravagant claims without any of the extravagant evidence required to support them. Please provide some citations of research that predicts an eminent world wide catastrophe. A review article in a respected journal by someone of the caliber of, for example, David Archer would be very helpful. Steve
Re- Comment by Geoff Beacon — 19 Jun 2012 @ 8:37 AM:
Nobeef.org is not a scientific journal and there is very little reliable scientific information there, just references to popular culture articles.
I think that Nobeef, and other agenda driven organizations, deliberately misunderstand the carbon cycle. All of the methane produced in agriculture was CO2 that was taken out of the atmosphere by the plants that were grown to feed the critters that make the methane. This is pretty much zero sum in the large scheme of things
In addition, this is an ongoing process with the methane degrading to CO2, in ten years or so, so it can be used again to make plants. The methane doesn’t increase the greenhouse effect over time except to the extent that production is increased.
Just about everything that grows eventually breaks down and releases CO2, and agriculture for human and animal food is only destructive to the extent that it releases carbon stored in the soil, or from fossil carbon. If you don’t believe this, then you should be railing against rice production, wetlands, and rampaging termites, all major methane releasers.
[Response:A lot of carbon comes out of the ground to do agriculture, too. Fuels, fertilizers, and what not. My recollection is that the overall process takes more carbon out of the ground as fossil fuels than out of the air by photosynthesis. By calories, it would be more efficient to eat fossil fuels directly. David]
I’m less concerned with the Methane being released by the melting of the Arctic Permafrost, then I am with the decomposition of Deep Ocean Methane Hydrites that’s beginning to happen as Global Warmings warming penetrates deeper into the ocean.
Also; as I wrote to you in an E-mail, after (somewhat belatedly) reading about the ‘see-saw’ effect that the Record Preserves regarding the uneven warming/melting (between the North and South Hemispheres) at the end of the last Ice Age; I’ve been wondering if the hindering, by Fresh Meltwater, of the AMOCs’ (sp?) ‘deep, cold, return flow’, and the subsequent warming of the Southern Ocean (especially at depth) wasn’t doing just that! – i.e.: Triggering the decomposition of Methane Hydrites in the Southern Ocean, and setting up a ‘Southern Hemisphere specific’ Methane Feedback Loop that would have, due to the Equatorial Bulge, accounted for more than a little of the observed ‘see-saw effect’.
One peer reviewed paper, reports from the FAO, DEFRA and the Food Standards Agency. The reports have plenty of peer reviewed references.
Can you show your references?
What worries me about methane’s short stay in the atmosphere is that over 20 years it is 105 times the GWP of carbon dioxide. As I understand it is largest part of the 50% of climate forcing that isn’t carbon dioxide. (Water vapour excluded from that). Methane’s extra warming may bring tipping points from which our descendants cannot escape.
Geoff Beacon: “So methane is the raw material for “plant food”. Have I heard that before?”
Wrong argument, Geoff. The better analogy would be the “are they going to tax breathing too” argument.
Methane from ruminant digestion is analogous to CO2 from respiration, neither are net additions. I’ll grant you the difference that CH4 has a stronger effect at current concentration, but it wasn’t all that long ago that Africa and North America supported ruminant populatins comparable to current cattle herds. And as Steve pointed out, rice production gives beef herds a run for the title. Are you going to go after rice, too?
I’m not arguing in support of over consumption of beef, just trying to place it in context with other methane sources.
Geoff Bacon @69
Yes. Methane is the second largest positive anthropogenic forcing as you suggest, but only just. Its ‘relative’ contribution has declined over the last decade as atmospheric methane levels have only risen 2% over that period.
The top three positive anthropogenic forcing as of 2010 were CO2 (55% of total), methane (15%), troposheric ozone (13%). Link here (two clicks) to my take on anthropogenic forcing (after Skeie et al 2011)
We face a lot of threats. There are a lot of things that could send us over the cliff. The past is important because it tells us which threats are credible.
The logic is wrong here: it’s a system in which the entire system is going out of balance, not part of it, thus the parts are not the problem, but interplay of them all. This is where the logic falls for almost everyone. For example, the people looking solely at climate do not consider the possible *collapse* in anthropogenic emissions should A. peak extraction have occurred or occur in the next couple decades. (Crude oil extraction has already peaked.) but then the Peak Oil folk fail to consider what gets burned if people don’t have access to oil. (The forests and anything else they can get their hands on.) This is but one example.
So, fine, we are talking only about naturally emitted methane. Still, the interplay of the continuing rise in emissions directly affects the methane emitted. As more ice melts back (and we seem on track for the @2016 80% ice loss), more runoff occurs, more warm waters enter from the large oceans, etc., this is not going to reverse itself. And, yes, while ultra-short times scales are not confirmed in the paleoclimate record, there exists no corollary with today. There is no comfort in the paleoclimate record given there is no corollary. It hasn’t so it can’t? This is simply poor logic.
The more appropriate question is, how quickly *can* emissions, particularly natural emissions forced by rising temps, rise vs. how quickly we can adapt? It is the rate of change, not the totality. On this Archer is incorrect, imo. My work involves creating anthropogenic change to our ecosystem to create sustainable communities. Rate of change is massively important in this work, and I am telling you changing the way 9 billion people live is not something that is done quickly outside of massive disruptions to the system. Here we have to understand it is the extremes we experience along that way that drive the greatest change, not the slope of the trend. As the extremes become larger and more frequent they will disrupt our human-built systems and the ecosystem, limiting the ecosystem services available. These changes *will* feed back to drive greater and faster change.
“The fact that we have reached temperatures higher in the past without seeing catastrophic releases”
Sorry, no corollary there. The deposits we are worried about have largely been laid down during the Ice Age era, correct? Only in this interglacial has mankind been around to muck up the entire ecosystem. This cannot be emphasized enough: the ecosystem is not going to respond as it has in the past because it has never been this degraded before the poop hit the fan, nor has it had to support 9 billion people.
Also there was a recent paper on large methane emissions at one of the extinctions (sorry, lost all my bookmarks when my computer crashed in January). The rate was still long by human standards, but was short and abrupt by geological standards and was indicated as a causal of warming rather than in response to warming. That is, the bulk of the warming came after the methane release.
tells us we should be OK until we reach those same worst-case conditions again–in a few decades.
See my comment above about the rate of change of human systems to adapt. It takes 5 – 7 years for a single homestead to become self-reliant, e.g. And, it absolutely does not tell us that. That would only be true if there were a direct corollary. Not only is there no somewhat similar corollary, there is none at all. The oceans are already becoming saturated at the water/air boundary. Some studies indicate this will slow absorption and increase the rate of increase in the air. Also, while we keep being told that methane is no big deal right now, the fact is it has risen in the air at several times the rate of CO2. From 700 ppb to over 2000 in some areas at certain times now (see Spitsbergen record). While CO2 has gone up some 37% or so, methane has gone up 300%, and most of that was likely without the effects of ACC. With the clathrates clearly accelerating their break down, all bets are off, aren’t they? And, let us bear in mind the local effects of methane emissions prior to becoming well-mixed (which doesn’t ever really happen at the local point of emissions so long as they continue) are potentially important in scale.
If we pay attention to what is going on in the Arctic at present, it doesn’t come close to catastrophic release unless we extrapolate to an extreme amount.
And why wouldn’t we do that? While some have said clathrates release slowly, that is incorrect, so far as I know. They are actually quite binary: a given temp and pressure combination equals stable while a small change to above the given combination threshold equals instability. I must assume the claim they release only slowly comes from (in addition to the issue of the paloeclimatic record) considering the clathrates like a block of ice where only the outside perimeter melts. Sadly, we are talking about pools of gas/liquid methane, too. And, the hydrates are not in nice, neat solid blocks, but are uneven, scattered, lumpy, infiltrated. Expecting a steady rate of emissions is not likely to bear out, imo.
Killian: I’d like to see a completely balanced post from you on this. IMO, your scientific reticence is causing you to favor the models and history over current events that are ominous.
Once we loose speculation where should it stop?
Speculation is amply staffed, the hard work of explanation not so much.
Comment by dbostrom — 18 Jun 2012 @ 4:13 PM
Do you consider looking at the science in context of the ecosystem speculation? How does that work, exactly? The rate at which clathrates and permafrost melt are directly related to what we do to the ecosystem, and not just in terms of emissions. The science of methane emissions is not just about flasks and poking holes in the ice and lighting the methane on fire, not just about looking at the paleoclimate. The issue is one and only one, if you wish to simplify: anthropogenic changes to the ecosystem. It is that rate of change that forces all others. If you attempt to separate the two, it will be impossible to understand the system you are attempting to understand.
This is anything but speculation. Have you tried, for example, extrapolating out Walter-Anthony’s finding of a tripling in thermokarst lakes in less than seven years? I wonder how much stable permafrost we’ll have left if that rate continues. I’d like to know what the estimated area of thermokarst lakes is and do the math on that. Has anyone bothered?
I understand the desire to keep to the science. What I am trying to say is, this *is* the science. The ecosystem. Tripling of thermokarst lakes and sea bed emissions sites of meters across to a kilometer or more. Ignore that science at your peril. Our peril, rather.
Ray L said, “At the same time, oceans had more time to come to equilibrium (higher temperature) which would destabilize the clathrates. I just don’t see the evidence that we are near a catastrophic release.”
Neither do I, though Dr Shakhova’s 50 gt abrupt release scenario hasn’t been refuted yet. As has been pointed out, even that wouldn’t necessarily be “catastrophic”, as it only represents a couple years worth of carbon once it degrades.
Past interglacials are good evidence, but they’re no guarantee. And, as you pointed out, that hypothetical guarantee is set to expire as we blow by previous interglacials.
64 Steve F, what extravagant claims? I said, “Previous warmings were much slower, which makes the comparison potentially flawed.” I have no clue how you interpreted not “flawed” but “potentially flawed” as “[imminent] catastrophe”. If you’d quote something from my post with which you disagree, I’d be happy to retract, support, or modify my statement.
Dr. Archer, on modern agribiz meat: “By calories, it would be more efficient to eat fossil fuels directly.”
Depressing from (at least) two distinct perspectives: environmentalist and diner.
But Kroger here has at least started offering local, grass-fed beef (and at a fairly reasonable price, too.) Of course, that just ameliorates, it doesn’t solve; everything is still transported, processed and packaged largely on FF power, this being Georgia (where energy experimentation is at a very low ebb.)
Methane from ruminant digestion is analogous to CO2 from respiration, neither are net additions.
That doesn’t matter. If we killed all the cattle and ate them now, it would buy us some time to come to our senses, cut down our carbon emissions and begin to extract carbon dioxide from the atmosphere. Of course I would “go after” rice production – when it is produced in methane producing paddy fields.
The sensible way to “go after” emissions of greenhouse gasses would be pollution taxes – or as I would prefer to call them “pollution fines”. I would try a fine of something like $300 to $500 per tonne of CO2e.
One mechanism that I like (not the only one) is Jim Hansen’s “Carbon fee with 100% dividend”. All the revenue raised would be paid back to every citizen in equal amounts. It would radically change the way we live and give our decendants a little bit of a chance to survive.
Kilian, I think I see your point but (for instance) extrapolation on what might happen to thermokarst lake expansion is not useful as a solid foundation for further research or policy evolution without a reasonably hermetic explanation of how that extrapolation is derived, which of course requires meticulous work to be performed.
Our intuition suggests to us what’s going to happen here but intuition doesn’t work when it comes to application. Intuition is often wrong and in any case it doesn’t serve as a placeholder for reason.
You ask “has anyone bothered?” in reference to doing thermokarst projections but that brings us directly back to “who is going to do those?” I don’t think there’s a deep well of idle scientists available for this.
It’s not fair or helpful to bludgeon the few people capable of producing the results you wish for with complaints that they’re not prepared to abandon their discipline and begin rattling off speculations in advance of their practice. You’re asking for shoddy output.
“I’m skeptical it could happen but even if it did, what it would do would be to give us a preview of what 2100 will be like under business-as-usual. One that would immediately begin to subside, instead of inexorably worsening and lasting forever like the CO2 impact by 2100. Might lead to the human awareness tipping point you’re looking for.”
I have often wondered about that possibility, but mostly kept it to my self, lest someone accuse me of hoping for a disaster. Given the many major disasters that have already occurred that can be pretty clearly pinned to AGW but that have failed to convinced many of the (faux-)’skeptics,’ I doubt any event or set of events in the world will ever sway their minds.
Above, I cited an article at #25 that afforestation of the Arctic is happening much faster. Now there is evidence that these will exacerbate warming for reasons beyond albedo (though see the articles Jim linked to above at #25 for the fuller, more complex picture on that.) New trees actually cause more new carbon emissions than they absorb:
“In a surprise finding, researchers have shown that as trees start to grow closer to the North Pole, replacing once-barren tundra, they release more greenhouse gases than they absorb.
The study has global implications for measuring the speed of global warming because it had previously been thought that when forests colonise the frozen Arctic, they might act to slow climate change by soaking up extra carbon dioxide from the air.
Instead, as temperatures rise and plants take root further north, the barren soils are “primed” by new growth and start to release long-held stocks of carbon. The amount of carbon activated by a change from tundra to forest outweighed that soaked up by the new trees, leading to a net increase in the amount that ends up warming the atmosphere…
The study’s findings identify just one of the complications of recent warming that could lead to much faster temperature rises this century. They include the potential release of large amounts of heat-trapping methane from thawing Arctic soils and the large-scale release of emissions from peat in the tropics.”
So not only is afforestation happening much faster than anyone thought possible, it is a double-whammy for accelerating warming–both from albedo change and by stimulating more carbon release than the trees absorb. As we all know, all these feed backs also feed on each other creating a very complex and volatile system that is is difficult to model accurately.
Killian, I know of no mechanism for clathrate decomposition that is sensitive to human population. As a matter of fact, I believe it is a purely thermodynamic process and so is driven by pressure and temperature entirely.
Now surely it is not your intent to suggest we’ve never had methane/clathrate deposits of the kind we now see. If that is the case, why did the bomb not go off in the past at temperatures comparable to the ones we see now.
And even if we were to find the bomb about to go off, what, pray, would we do about it other than what we should be doing anyway, which is limiting our own ghg output? CO2 is the control knob. It applies both throttle and brake depending which way we dial.
Killian wrote: “The deposits we are worried about have largely been laid down during the Ice Age era, correct?”
The “Ice Age Era” would be the last 2.5-2.75 million years, comprising repeated deglaciations, several of them warmer than present. But sea bed clathrates have been accumulating for far longer than that. The last sudden large jump in temperature that could conceivably have triggered large-scale clathrate releases looks to have been the sudden (geologically) thawing of the Antarctic ~25 million years ago, with reglaciation beginning ~12-13 mya, so clathrates have been accumulating for at least that long. As Hansen says, the clathrate “gun” is presently fully charged and loaded, but we know that it didn’t go off during any of the past interglacials of the Pleistocene. As I said, not until we reach and exceed those past interglacials will we be in uncharted territory, and earth’s history tells us that it’s there be the dragons, and we aren’t there yet.
This cannot be good for permafrost (very far north; the area is relatively small):
On June 18, 2012, a total of 198 wildfires burned across Russia and had charred an area that covered 8,330 hectares (32 square miles). Many were in central Russia, where firefighters have battled uncontrolled fires for months.
The latest flare-up prompted Russian authorities to declare a state of emergency in seven regions, including the Khanty-Mansiisk autonomous area, the Tyva Republic, the Sakha Republic, Krasnoyarsk, Amur, Zabaikalsky, and Sakhalin.
According to Russian authorities, many of the fires started when people lost control of agricultural fires and campfires. However, lightning sparked some of the blazes as well.
According to the environmental group Greenpeace, more land in Russia has burned this year than in 2010, a year that intense wildfires affected western Russia and produced rare pyrocumulus “fire clouds.”
Since it is a matter of interest and importance (to me, at least) to have a better grasp of the similarities and differences between the last interglacial and now, can anyone point to a paper or papers that delineates these differences?
Susan: On June 18, 2012, a total of 198 wildfires burned across Russia and had charred an area that covered 8,330 hectares (32 square miles). Many were in central Russia, where firefighters have battled uncontrolled fires for months.
One Russian President and one US Presidential candidate: When it comes to firefighters, don’t get carried away and go overboard on hiring. What possible reason could we have for more firefighters?
Russia is leading the way on monetizing their landscape and the man from Bain is paying close attention. Pay no attention to the flames.
The AR4 had a good discussion of the last interglacial here though some details are now out of date.
As a “broad brush” picture, the last interglacial is highlighted by positive insolation anomalies (incoming solar radiation) during boreal summer in the Northern Hemisphere, and austral spring in the Southern Hemisphere. Global mean annual temperature anomaly is not very well resolved due to uncertainties in the seasonal expression of proxy records, and data coverage, but possibly 1-2 C warmer than the mid 20th century (e.g., Turney and Jones, 2010; though see Rashid et al. ,2011, JQS) and larger at higher latitudes (possibly 5 C in Antarctica (e.g., Sime et al., 2009, Nature); sea levels are at least 6 m higher than present, a bit higher than values cited in the AR4, and possibly up to 9 m (see e.g., here).
(There are model simulations of this time-period post AR4 but I have not looked at them, though I believe they don’t quite get the observed magnitude of many of the changes…someone else will need to elaborate on this if you are interested).
How do you propose to feed those 7 billion, Geoff?
Answer number 1. Capitalism will provide. That is a properly guided capitalism. It will fine the polluters on their carbon emissions with the fines 100% returned to every citizen. It will not be spent by governments beholden to the powerful. This means the polluters loose and the gentle will gain. Blessed are the meek: for they shall inherit the earth. Matthew 5:5.
How do you propose to feed those 7 billion, Geoff?
Answer number 2. We are not short means to produce food. It’s the poor that starve because we eat foods that require enormous resources.
In Ireland before the famine, potatoes, with some milk and pigs could support a population density approaching 10 people per hectare. The world now has about 0.5 people per hectare. That’s about 5% of the population density of pre-famine Ireland.
How do you propose to feed those 7 billion, Geoff?
Answer number 3. Destructive foods will become expensive. Beef, lamb and venison will be priced off most people’s plates, most of the time. With my carbon dividend, I will find less destructive foods such as Quorn, TVP and beans more affordable. For desperate carnivores there are other meat options like chicken and pigs.
With ocean acidification fish in the seas may be a problem but fish farming is already coming to the rescue.
But under properly regulated capitalism, the market will determine the prices and consumption patterns. From time to time, just as an experiment, I might even try a small amount of beef jerky, which will become much more expensive.
How do you propose to feed those 7 billion, Geoff?
60 Thanks for the response, David. I agree with you, especially on the “permafrost thaws slowly” point. I’d add that the more permafrost you thaw, the harder it is to thaw some more. It takes a lot of time for heat to get down to 1000 meters. That’s perhaps a hundred thousand years+ worth of thawing to finish the job.
Anyway, just to make it clear, the OP makes sense to me and I’m not in the “methane catastrophe” camp. Yep, much of the shallow permafrost is going to thaw and as the “thaw front” advances, massive amounts of methane will be released. (though “massive” doesn’t necessarily mean big enough to make a serious difference in a gargantuan system like the Earth) Given the huge area and depth, and diverse climate and geology, large methane releases ought to be scattered in space and time, resulting in what looks like a chronic release. How big? How fast? Will it be like a bell curve with a long tail as shallow permafrost thaws ever quicker and then stuff slows down as deeper soil is better insulated? If so, we could be looking at a pulse of perhaps a few decades followed by centuries of chronic release. However, there’s the niggling special case of the ESAS and Dr S’s 50gt release scenario. I’m patiently waiting for more research to quantify the probability of her speculation.
Your point that time is [at least] as important as maximum temperature (Time * Temp C?) seems to detract from Ray’s “safe for now” argument. This stuff has been thawing for ~8,000 years, especially the ESAS. Also, we’ve debated about whether the LIA and MWP even existed. Spaghetti graphs show 0.5C deviations in estimates for global temperatures in the very recent past. What sort of deviations in time, temperature, and location are reasonable for half a million years ago? Can we say with confidence that the ESAS has received less total thawing power this time around (so far)?
Ray, you mentioned ocean thermal lag as a factor increasing clathrate stability. Limiting this to the ESAS, where we’re talking 15-50m depth, is there much lag? I’ve been of the impression that it’s mostly an iced-over or clear water issue. In the early Holocene, lots of open water and sunshine reaching the ESAS bottom. Then, slow heating as ice mostly covered the ESAS. Now, we’re entering an era where the ESAS will again be mostly open water for the whole summer.
So if I agree with the OP, what’s my fear? Why not brush this off as not big enough to worry about? Well, our 2C calculations are looking tenuous even with the assumption that the land and ocean will continue to suck up carbon, so there’s no wiggle room for beetle-kill, fires, the Amazon shrinking, permafrost and clathrates thawing and any other carbon feedbacks. So yep, it ain’t a methane catastrophe and methane will probably be just a blip on its way to transforming into more CO2, but methane and other “natural” carbon feedbacks look to be potent enough as a group to ensure we miss the 2C target.
80 Jim E said, “There’s 7 billion people on the planet, roughly half of them currently dependent on rice for most of their calories. How do you propose to feed those 7 billion, Geoff?”
You seem to be suggesting that “Since folks currently grow rice in a climate-damaging way, they should continue to do so in the future at no cost.” Well, substitute “burn coal” for “grow rice” and what’s the moral, ethical, or logical difference? I say we should have a GHG playing field as level as a rice paddy. Agricultural releases of GHGs should have no preferences over emissions from somebody who burns oil in a Hummer. Now, before someone screams about poor indigent rice farmers, I’ll point out that such folks most likely emit less than the world average GHGs and so would get checks from America and Europe and such places. Their motivation to adopt dry rice farming or grow wheat or whatnot would be to increase their annual GHG check.
To Jim Larsen at #89 who writes: “I’d add that the more permafrost you thaw, the harder it is to thaw some more. It takes a lot of time for heat to get down to 1000 meters. That’s perhaps a hundred thousand years+ worth of thawing to finish the job.”
Perhaps that is true “to finish the job,” but the main post shows that we don’t have to wait hundreds of thousands of years for methane to leak out–methane is seeping out now, and it is on the increase. The only question is how fast this increase is going to take place.
And again, the pools of free methane gas we’re talking about don’t have to wait for all of the overlying permafrost to thaw. Just a crack, perhaps from the deep roots of one of the new trees now growing in the tundra, to provide a route for its escape into the environment is sufficient.
But really, for the long-term prospect for life on the planet, a slow release is probably the worst thing. It insures that GW will be extended for many millennia or more beyond what it would have been, even if industrial society no longer poses a direct threat.
As for ““massive” doesn’t necessarily mean big enough to make a serious difference in a gargantuan system like the Earth,” I think you may want to re-read the abstract to the article.
You ask “Does this strike anyone as sound logic?” Well, if it doesn’t yet, “There’s always a first time for everything.”
Without a source for your pro-offered quote, I speculate by suggesting perhaps what was meant was the rather pedantic “It has never happened before, therefore it cannot be happening again.” which would be logically sound.
Or it could be an overly robust version of “It has never happened before, therefore I am not convinced it can ever happen.”
Then again, if your source doesn’t regard illogic comment as a problem, you will have to take a crash course in Idiotese.
Geoff B, I can’t go along with your optimism that capitalism will save everything. Why hasn’t it done so already?
Capitalism is at base an economic system that benefits capital (and those that have it), rather than a system whose goal is benefiting society (that would, of course, be social-ism). (We have yet to fully develop and economic system designed to benefit the living planet–geo-ism? eco-ism? bio-ism??)
The winners in capitalism have acquire capital=power which they always use primarily to gain more capital=power. Part of how they use their power to get more power is by influencing policy with vast quantities of money. Those who have gained power through ff (arguably the most concentrated and useful form of energy/power) will use and are using their considerable power to block any effort to increase taxes on carbon.
Industrial capitalism has proved to be a very powerful and efficient mechanism to turn our beautiful blue planet into a toxic wasteland. I am dubious that greed can be an equally efficient mechanism to restore the same.
Wili: ‘“It has never happened before, therefore it can never happen.”
Does this strike anyone as sound logic?’
It strikes me as a distortion (deliberate or not) of the argument. What is actually being said is that the physical conditions we are currently experiencing have occurred before without the realization of this phenomenon, as such we are likely not at risk until conditions become more severe.
Geoff Beacon: “We are not short means to produce food.”
Uh, actually we are, at least sustainably. We tend to take the gains of the Green Revolution for granted, but they were attained at great cost to the environment and carrying capacity of the planet. Yields are maintained by fossil-fuel derived chemicals that run off into water bodies causing algal blooms and anoxia. Aquifers are depleted. These are one-time windfalls that once depleted will be lost for good.
Feeding, clothing and housing 10 billion people without permanently degrading the carrying capacity of the planet is not a trivial problem, and cavalier suggestions of crop substitution devoid of serious study are not helpful.
Geoff, your reply sounds almost exactly like what is coming out from the lukewarmers and even the fake skeptics.
We’re talking ~3.5 billion people current dependent on rice. We’re talking large parts of southeast Asia already at or near the maximum temperature that allows successful germination of rice. We’re talking expected, nay, already observed drying of continental interiors, which will render large areas of presently arable land unsuitable for large scale agriculture as glacial reservoirs and aquifers are drawn down, simultaneous with increased occurrence of extreme precipitation events, i.e. disruption of the a predictable hydrological cycle that makes large scale agriculture possible. Your belief in the ability of capitalism and agriculture to keep up with these changes is shockingly naive.
The world has a present population density of about 0.5 people per hectare for a reason(s). We can’t farm in deserts without consuming large quantities of scarce water. We can’t farm in rain forests without clear cutting them and importing large quantities of fertilizers to compensate for the already mined-out soil. We can’t farm areas of exposed bedrock and shallow mineral soils, period. We can’t farm muskeg and tundra without first draining it and raising it’s pH. This is lying with statistics of the first order.
I share your desire for the implementation of a carbon tax & dividend system, but we’ve been waiting for a functioning carbon pricing mechanism for well over a decade now. Cap & trade systems are too easily gamed. Australia is finally taking it’s first step to a carbon tax system after a tooth and nail fight, but it could be reversed the next election. The US and Canada (at least on a national level) are still fighting it tooth and nail. It’s simply not happening fast enough.
Sorry, I just don’t share your optimistic belief that the existing political and economic systems will or even can deal with what is happening much less what will happen.
Jim Larson: “There’s no requirement for anybody to eat rice. There’s lots of different crops to choose from.”
Are there? Different crops require different growing conditions, different moisture levels, different maximum and minimum temperatures, different soil conditions and nutrient constituents, different climate zones. And those zones and conditions are already shifting for those different crops. Present alternatives may not work in the future because future conditions will be different.
No, I’m not saying “since folks currently grow rice in a climate-damaging way, they should continue to do so in the future at no cost.” I’m saying they are currently growing rice in a climate-damaging way and they are currently dependent on that rice. The replies so far would change that with the sweep of a hand without giving serious thought to what would replace those crops on a large enough scale and how, given that all agriculture is already coming under stress and shifting conditions and those stresses will continue to increase as conditions shift. Present alternatives may not work anywhere in the future.
Jim Larsen: …it ain’t a methane catastrophe and methane will probably be just a blip on its way to transforming into more CO2, but methane and other “natural” carbon feedbacks look to be potent enough as a group to ensure we miss the 2C target.
And elsewhere mentioned the word “chronic” in connection w/seeping C02.
I’ve read persuasive explanations about why we need to bring anthro C02 emissions essentially to a complete halt in order to avoid accumulation problems; “reduce by 80% by 2050” leaves a 20% ongoing remainder as an unacceptable amount of emissions. The various emissions Jim enumerates count as anthro C02, are presumably just as destructive as what emerges from a tailpipe and can’t be controlled.
Definitely feeling like we’re screwed, this morning.
Does anybody have a pointer to the actual C02 budget on rice (skipping the methane step which is transient), something reliable? I’m not quite getting from where the net -addition- of carbon from rice cultivation is derived, unless it’s synthetic fertilizer.
Re- Comment by Geoff Beacon — 20 Jun 2012 @ 7:41 AM:
Regarding the starving poor you say- “Pay them more if they give up their cattle.”
The thing about a cow on a subsistence farm is that it can provide meat and milk from land which is too poor to farm and no irrigation is available for practically no cost. The animals pretty much take care of themselves and convert cellulose from dry grass into food. There is no fossil carbon involved, the soil is actually improved in this kind of situation, and the methane released is close to net zero because it was made from CO2 that was already in the air. Such ignorance!
After just a bit of rummaging, I found this article on rice farming, which seems to tell the story reasonably well.
So where’s the net contribution of C02 coming from? Paddies appear to be working as a component of carbon flux but– short of magic– I don’t see from where the net addition to the total carbon in circulation is derived.
Expansion of paddies unlocking previously stored organic surface deposits?
Waiting to be corrected; Corporal Dunning-Kruger reporting for duty, Sah!
Pondering on paddies: ok, -duh- I get it, I think. Paddies are constantly converting relatively (!) innocuous C02 into more problematic methane.
That does seem to be something of a problem. Methane normally transient but paddies make it effectively permanent.
[Response:Well, a persistent ongoing source will lead to a persistent ongoing higher concentration in the atmosphere, but it’s not “permanent” because if you stop the source the concentration quickly responds. Persistent, however, yes. David]
Steve Fish responded to Geoff Beacon: “Regarding the starving poor you say- ‘Pay them more if they give up their cattle’.”
The “starving poor” don’t own cattle. And indeed the “starving poor” sometimes wind up starving and poor precisely because they’ve been driven from their land to make room for cattle owned by rich people.
The rapid growth in meat consumption world wide is not about the “starving poor” feeding themselves from subsistence-grazed goats. It’s about US-style industrial factory animal production spreading throughout the developing world to produce lots and lots of cheap meat for the emerging urban affluent populations. And it’s bringing with it the same disastrous environmental and public health consequences that it has brought to the US.
Comment by SecularAnimist — 20 Jun 2012 @ 12:24 PM
“…a crash course in Idiotese.”
Luckily, such are widely available at no cost online… ;-)
DB, good to see that you got it: rice paddies are man-made wet-lands, which are full of anaerobic bacteria that break down rotting organic material to produce methane just as effectively as natural swamps and bogs.
Ruddiman contends that the invention of wet rice agriculture kick-started human greenhouse gas emissions and is responsible for the slow shallow rise of atmospheric methane when it should have been going down since the Holocene Climate Optimum.
Geoff Beacon: “Pay them more if they give up their cattle.”
Hmm. 21 years ago, I had the privelege of traveling with some Samburu tribesmen through the North of Kenya. He told me about how for is initiation, he killed a cheetah that was threatening the village herd, and he had only a spear.
I am sure that you and he would have a fascinating discussion about your idea. To some cultures, cattle are more than a food source.
Ray Ladbury wrote: “To some cultures, cattle are more than a food source.”
Indeed. To vegans such as myself, cattle are intelligent and emotional sentient beings worthy of compassion and respect.
For most “consumers” in the developed west, cattle are not really a food “source” at all. Rather, they are a means for converting nutritious plant foods like corn and soybeans into meat, with a resulting loss of up to 90 percent of the original protein content, at an enormous cost in environmental pollution and public health. They are more accurately described as a food sink than a food source.
And that’s the model that is being rapidly proliferated all over the developing world.
Geoff, your reply sounds almost exactly like what is coming out from the lukewarmers and even the fake skeptics.
Ok, I’m a fake skeptic who believes that we need a high carbon price to take from the polluting rich and give to the poor to give them a decent life.
And that climate change is so much worse than most people realise that we need a high carbon price to drastically curb our flying, driving cars and eating watseful and polluting foods like beef and lamb.
Given the work of Geoff Lawton and the example of Sepp Holzer, I think we could grow food on most of the world’s land.
If we ate more healthy, sustainable food and less meat
… we would go a long way toward permitting a world population of 10 billion to have a potentially sustainable diet comparable to ours. Our food problem may be manageable with minimum pain.
I wonder what the tribsman would have done with his spear if he knew the many tonnes of carbon dioxide you air flights have created and their consequences for the climate.
20 years ago? I don’t think most peoples’ game was up to that level, at the time. Just don’t call blasting around the planet at 400 knots “eco tourism” knowing what we do today, that’s my particular small request.
Anyway, clever rhetorical tactic, though a bit nasty and it doesn’t address the implications Ray pointed out.
How about you, Geoff? When did you purchase your last airline fare? More than 20 years ago?
Sorry. Especially to Hank. I had been to a reception in UK Parliament. Too much wine and frustration – still not quite sober and calm. Flying to Africa on charitable work is a good thing to do. We, in the Pollution Tax Association, made a donation to people do just that – the flying did worry us though.
The general point stands. Our pollution does kill and it will get worse.
Yes I was nasty. Again, sorry Hank.
I haven’t flown since the summer of Hurricane Katrina. Subsequently, I was joint founder of the No Miles High Club. We never got very far.
The NMHC motto was “We promise not to fly until we break our promise.” OK, except for a few here, no-one much takes any of this very seriously – and I still eat too much climate destroying cheese. But I suppose we are still in what Colin Challen MP called climate’s “phoney war”. (The phoney war refers to the time at the beginning of WW2 when nothing much seemed to be happening. It didn’t seem like war at all.)
Anyway, after a frustrating time in Parliament with fuel poverty do-gooders and what seemed like similar on the train home from a professional “Friend of the Earth”, I am still despairing.
The fuel poverty people and the FOE are pushing energy efficiency but downplay the rebound effect to the point of denial. It is good to help the poor so they don’t have to “eat or heat” but they should not kid themselves it does much towards a low carbon economy without a decent carbon price. We are sinking in greenwash.
And in the Sahel (to name one crisis) they must decide which of the family should starve – that trumps “eat or heat” for me.
And I still eat too much planet destroying cheese.
Now that all of the personal posts have started can I ask a more general question regarding fracking and natural gas and leaks of methane. The idea is to attempt to replace much of coal with natural gas and indeed ship some of it abroad in LNG form. So huge slugs of methane from permafrost release aside is leaking methane from pipes and the LNG conversion process an issue or are the amounts too small to matter as LNG/Fracking results in around a 25% reduction in C02 emissions?
Methane is not that big a deal as its only occupies a small area in the absorption band relative to C02 and its impact is more minimal as its only hangs around for a few years whilst CO2 is the real problem >
Not all of us have the luxury of staying in place. For some of us, our work takes us far afield. In my case, I was training science teachers.
I do not think that it is realistic to expect people to change drastically deeply held cultural beliefs and traditions. Nor do I relish the idea of a world where the capability to deploy weapons of mass destruction exists without the unifying potential of travel.
Mark Twain said “Travel is fatal to prejudice, bigotry, and narrow-mindedness.”
I once suggested bartering off cultural traditions. Say India gives up their cattle if we agree to eat horse meat instead of beef. Pointless, but one wonders if such an agreement could be made. ~650 million ruminants eliminated and I’ll have Trigger rare.
There are ways to “travel” without climbing on an enormous chunk of steel that ff thrusts into the sky like a large middle finger shoved into the very face of the deity. Reading, skiping, blogging…all of these can be done at much lower impacts to the planet, especially if powered with renewable energy.
I stopped flying after (barely) surviving the ’03 killer heatwave in Paris.
Is it inconvenient sometimes? Yes.
Should we expect to be able to stop the greatest disruption of life on the planet possibly since life began with out some inconvenience?…
We could scale back 99% of flights tomorrow with very few extremely negative consequences to anyone (i.e. death, grave illness…). If we can’t conceive of making such rather minor sacrifices, how can we begin to fathom much more trying sacrifices that living within our environmental means will like call for?
I have found no way other than not flying and not eating meat to get anywhere close to ‘one earth’ on the http://www.myfootpring.org scale. (Yes, Geoff, it’s flawed, but at this point better than most other such measures out there, imho.)
If we even on this site, who are more aware of the dangers of GW than nearly anyone else on the planet, aren’t willing to make relatively minor (in the big scheme of things) adjustments in our lifestyles, what is the likelihood that anyone else will? Keep in mind that just a century ago the idea of whizzing around the world on a metal bird in a few hours was beyond the imagination of even the wealthiest and most powerful. Somehow we have gone from this to seeing it not even as a luxury but an absolute necessity.
Geoff, thanks for starting the NMHC. Is it really completely defunct? There seems to be more awareness of the issue in Europe than in the States (quelle suprise!). I liked that you included humility and humor in your motto.
Pete at 118–I don’t see anyone here saying that methane ‘isn’t that big a deal.’ After CO2, it is the major GHG. Any additions, from leaks in mining, delivery and use, to melting permafrost and clathrates, is a concern.
Tailspinning ever further off-topic it’s an absolute fact that making one journey by air will neatly obliterate a year’s conscientious behavior.
Mindfulness might help; Geoff points out the difficulty of eschewing air travel but just stopping to ask “is this flight necessary” is a step in the right direction. For somebody who flies a handful of times a year a single skipped takeoff is a significant savings in impact.
For Europeans this decision is a little easier; a dense rail network means there’s actually an alternative to intubation. Here in the US it’s overwhelmingly true that one effectively has three choices: don’t travel, travel by air, or drive. If you’ve got a child several states away who is graduating, getting married etc. you’re going to want to be there, meaning that on average you’re looking at a drive of roughly 1,250 miles if you don’t choose to fly. Sticking to scruples in the face of that is very difficult.
We used to have a reasonably workable rail network here but we were seduced first by automobiles which eliminated local intercity lines and then by air travel which killed long haul passenger rail. We’ve stepped backward in terms of freight logistics, too. Why did it work out differently in Europe?
The NMHC still has a website http://www.nomileshighclub.org.uk and one of the members started a facebook page – I just discovered it. John Cossham may have told me he set it up but these days … now what was I saying…
I keep the paying for the NMHC website just in case. Contact me via info__AT__greenrationbook_DOT_org_DOT_uk if you want to do anything with it or the Green Ration Book.
One thing that worries me about stopping all avation too soon is the issues raised in Unger et. al. Attribution of climate forcing to economic sectors.
I’m a bit suspicious of some of the conclusions – and it’s now two years old – but it’s a good read. It seems to say that an average airline flight cools the Earth for 30 years before the warming effect kicks in. See fig 2.
78 Ray L said, “Killian, I know of no mechanism for clathrate decomposition that is sensitive to human population….And even if we were to find the bomb about to go off, what, pray, would we do about it ”
The Russians have already demonstrated methods to harvest permafrost-covered methane and the Japanese are working on clathrate harvesting (as are others). So yes, clathrate decomposition can be done by humans, and we could switch from traditional CH4 harvesting to permafrost and clathrate CH4 harvesting.
90 Wili said, “the main post shows that we don’t have to wait hundreds of thousands of years for methane to leak out–methane is seeping out now, and it is on the increase. The only question is how fast this increase is going to take place…And again, the pools of free methane gas we’re talking about don’t have to wait for all of the overlying permafrost to thaw. Just a crack, perhaps from the deep roots of one of the new trees now growing in the tundra, to provide a route for its escape into the environment is sufficient.”
I disagree with the first bit. Since permafrost thaw slows down exponentially (or so) as depth increases, the question is whether the current increase will peak and then fall dramatically or not.
So, unless the “BIG” stores of natural gas are far shallower than everywhere else in the world, you’re just not going to release them via permafrost thaw in the short term. According to Wiki (permafrost article), it takes 3,500 years to build permafrost down to 719 ft and 775,000 years to build permafrost down to 2,256 ft. So, once you get below 500 ft or so, (assuming thaw rates are similar to build rates) permafrost really is PERMAfrost. Yes, there are chimneys and CH4 from below 500ft will get released, but you’d have to provide some sort of citation/data/logic to convince me that the amount will be catastrophic.
More serious is what happens at the surface. Lots of tundra is becoming wetlands. That means chronic CH4 release. Lots of the taiga will burn. That means a bunch of pretty quick CO2. So, the most likely future is a massive spike of CH4 and CO2 as the shallow permafrost thaws and the forests burn, followed by chronic release of CH4 from the new wetlands in the ex-tundra. Add in a CH4 burp and/or sustained release from the ESAS and you’ve got a mess, not a catastrophe – though adding a mess to our current situation could result in a catastrophe!
Re swearing off air travel, we did so in ’98, but then had to fly a few years back when our vacation plans were stopped cold by a rail strike and I had to scramble to book a last minute flight or forfeit all our lodging deposits. Otherwise, all travel on that trip would have been by train, ferry, bus or foot (a stretch of coastal hiking trail).
I know of two people who began to rethink air travel when I told them we’d quit. Unfortunately, I know many more who think we’re nuts.
This thread got a bit off-topic didn’t it? Air travel? I thought this was about Arctic carbon (CH2 and CO2)?
re: “And the lifetime of methane in the atmosphere is short, about 10 years, so methane doesn’t build up like CO2, SF6, and to a lesser extent N2O do.”
What happens to that methane?
re: “Walter Anthony et al. compare an estimate the amount of methane in the Arctic, 1200 Gton C, with the 5 Gton C of methane in the atmosphere. That’s the nightmare comparison, but it’s only really relevant if the methane comes out all at once.”
Define “all at once”: a year, a decade, half a century? what counts as “all at once”?
[Response:Might be a good reason to stop pissing our He (which we get from gas reservoirs) into the skies (where it evaporates to space in a decade, forever) in our cooking gas and stupid parade floats. Personal peeve of mine. David]
I visited their home page and watched the video. It was frustrating because the FIRST thing I (and probably most anybody else) want to know is how many knots they go. If it were me, I’d say “Current cargo ships average X knots. Our ships average Y knots fully loaded.” Since they declined to tell us, my assumption is they are VERY slow. (They did talk about “equivalent performance” in one sentence, but what does that mean? BE EXPLICIT!)
I found this http://www.juddspittler.com/freighterbum/engineroom2.htm which says one particular 491ft cargo ship has 13,614HP. The biggest wind turbine in the world produce 6710 HP, and that’s from a 122 meter diameter blade. Ships are moving somewhat in the direction of the wind, so that slows down the effective wind speed, and since the wind isn’t directly from the rear, the effectiveness is reduced, so they can’t harness as much power as a turbine. This reinforces my fear that B9’s ships are SLOW.
They also said that 40% of the time they run on engines just like every other ship. Since the sails always exist, B9’s freighters will be less efficient than current designs when the wind isn’t blowing from behind. Since ships can double their efficiency with a small decrease in speed, I’m not sure that the technology is better than just putting a speed limit on cargo ships. That they want to source their fuel via renewables is irrelevant. ANY ship can do the same.
It’s interesting, but without more info it seems they are asking customers of shippers to increase their costs via delays.
Jim Larsen–Thanks for the great stat on fig roots!
“So, unless the “BIG” stores of natural gas are far shallower [under permafrost]”
It is my impression that this is exactly the case, but I don’t have time right now to track down the sources. (Anyone else is free to. (Where’s Hank when you need him?)
Geoff, thanks for the links. I’ll be in touch. If anyone else has insights or links about the short and long term effects of flights on climate, I would be interested. But the same type of argument could be made about dirty coal plants.
David: Might be a good reason to stop pissing our He (which we get from gas reservoirs) into the skies (where it evaporates to space in a decade, forever) in our cooking gas and stupid parade floats.
Free market fantasists insisted (by law) it be sold at low, low prices; legislated lunacy. Resultant shortage is now threatening a myriad of applications.
In 1996, a cost-cutting Republican Congress passed legislation requiring the government to get rid of most of its massive helium stockpile, which is located underground near Amarillo, Texas, the self-proclaimed helium capital of the world. NASA, Congress proclaimed, would have to get its helium from private operators instead.
135 Ray L said, “OK, so we are going to “harvest” 50 Gtons of methane and release 137.5 Gtons of CO2, and this will be a great victory?”
For Exxon et al it will be. Like Animal Farm (and per SCOTUS), corporations’ interests are more important than ours.
However, one technique for extracting CH4 is to pump CO2 into the reservoir. The CO2 makes an even better clathrate than CH4. So it could be a closed loop. Extract CH4, burn, capture resulting CO2, pump back in, extract more CH4.
Hmm, double the wells, double the pipelines, add a step for capture… that sounds less profitable. Nope, NOT a good idea….whew, I almost put people over profit. Sorry. I won’t let that happen again.
Jim: On the B9 freighters… sailing ships have to tack…
Maintaining a steady heading in the direction of methane is like close reaching to something 20 points windward. :-)
Classifying freight is a possibility. Braeburn apples from New Zealand can wander around the Pacific longer than mangoes from Hawaii.
Preening, strutting America’s Cup owners are justifying themselves at least a little bit with their recent uptake of built foils as opposed to traditional sails. Operation, maintenance and efficiency advantages of these could well see them playing a key role in commercial logistics, down the road. Cup boat owners are financing a lot of good research.
Methane is sucked out of the air by Wikipedia, I think. Or is it explained by Wikipedia? I can never remember which.
“Methane is created near the Earth’s surface, primarily by microorganisms by the process of methanogenesis. It is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in the atmosphere is naturally checked — although human influence can upset this natural regulation — by methane’s reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor. It has a net lifetime of about 10 years, and is primarily removed by conversion to carbon dioxide and water.
“Methane also affects the degradation of the ozone layer.”
As for your second question, in very rough terms “all at once,” all emitted next year would provide a forcing something like 50x the current net man-made forcing but lasting only 10 years (although such quantities may require more time to disappear), it would be gone before its full impact is felt. So, back-of-fag-packet peak global temp increases of 20 deg C (?) which would likely kick off some interesting feedbacks of greater longevity.
Emitted over a century, the full but smaller impact would be felt of about 10 deg C (?), with longer periods pro rata. So that lead us to the question of how much extra global warming constitutes a “nightmare“?
KR, you will note that the Hindenberg did not explode–rather it burned. Here’s an experiment. Start with 2 balloons. Fill one with hydrogen or CH4 only–taking care to keep air out. Fill the other halfway with air, then fill it the rest of the way with hydrogen. Pass a spark into balloon 1 (H2 or CH4). It will burn but will not explode. Try same with balloon 2–but you might want to wear earplugs.
Ray Ladbury says: …will note that the Hindenberg did not explode–rather it burned..
As well, in plain point of fact even hydrogen-filled airships are not that likely to ignite. Outside of combat losses of airships were and still are (even for helium) down to inability to deal w/vigorous weather.
How to reliably ignite an airship employing hydrogen for lift is covered here:
In response to comment 49, you said “Ok I stand corrected.” I would suggest you edit the original article to reflect this correction because most people don’t read all the comments. We don’t have 700 Gt of Carbon left to emit, as of the end of 2011 we have emitted about 550 Gt of carbon (the Allen paper uses data through 2006 and I have added emissions from 2007 to 2011) so we have 450 Gt NOT 700 Gt left to emit to reach 1000 Gt of Carbon emissions.
I wrote B9 with my concerns, and they wrote back:
“We are currently testing the hull in a towing tank and the rig in a wind tunnel and so will be able to predict with a much higher degree of certainty our operational speeds.
Our concept design is for commercially viable ships – stated on the first line on the home page of the website. This means that they must travel at speeds cat least comparable with fossil fuel powered conventional ships.
Within a week or so we’ll have harder data verified by the Wolfson Unit at Southampton University and that will be posted on the website, so do please check back soon.”
So the issue is that they aren’t ready yet. It seems they are going for true parity. Let’s hope they make it!
Looks like more to add to the sensitivity issue, particularly highlighting linkages/connections > complexity of the system. I think this fits well with the finding by Hansen, et al., that 400 ppm might be enough to melt Greenland, though the article in question doesn’t specify any level.
Jim 139: Cutty Sark:
Her greatest recorded distance in 24 hours was 363 nautical miles (NM) (averaging 15 knots), although she recorded 2163 miles in six days, which given the weather over the whole period implied she had achieved over 370 NM some days. By comparison, Thermopylae’s best recorded 24 hour distance was 358 NM. Cutty Sark was considered to have the edge in a heavier wind, and Thermopylae in a lighter one. http://en.wikipedia.org/wiki/Cutty_Sark
The daily total would be a fair indication of her performance as that distance would be measured between two positions 24 hours apart on track. That beats super-slow steaming by a long way.
The Benigns stand a chance; besides they may be all we have.
Don’t forget that thawing surface layers tend to be a bit on the wet side, what with all that ice that has to drain away after it melts. This tends to weaken the soil, and slumping and land slips are common anywhere there is any sort of slope. (Look up “thermokarst”.) Once the surface layers are removed, more permafrost is exposed, and it will melt easily. No need to wait for the slow process of thermal diffusion to penetrate deeply when you can just move the overlying mud out of the way…
Per the original post: “The really interesting take-away from the new paper is how it shows that the near-surface geology and freezing state conspire to control the venting …” — and it’s a start toward quantifying how much of the area will change rapidly (due to meltwater drainage, slumping, lowering water levels and oxidation) or slowly (where meltwater remains in pools).
I am not as charitable as you about what I agree was a fair presentation of the anti-realist “side”. Rather than the usual 50:50 or worse, it was more like 20:80 and as as you said allowed them to make their usual misrepresentations for anyone with a mind open enough to see it, but compared to 2:98 or 3:97, it is still off.
It is clear from the comments that the truth about threats and violence rolled off the backs of people who didn’t want to admit it, or worse, felt it was justified. There are far too many anti-realists out there, and not all of them are on the fringe. We are so accustomed to thinking about things and checking sources that we fail to imagine people who simply believe what they are told if they approve of the source, and automatically disbelieve anything that contradicts that. That’s close to 50% of the population, with an error bar of as much or more than 20%. It’s a growth and education problem, with a lot of arrested development out there, and teachers are under attack too for “corrupting” the precious children (though most children I’ve met are not necessarily particularly nice until they learn tolerance and acceptance of complexity and contradiction comes even later).
As to what’s next – escalation, and blaming the victims. So what else is new?
Susan: It is clear from the comments that the truth about threats and violence rolled off the backs of people who didn’t want to admit it, or worse, felt it was justified.
Susan, of course that’s true. The very presence of those gibberish comments confirms that their authors are essentially beyond reach; if one can’t get a grip on the relatively simple basic reasoning behind AGW then increasingly complicated and elaborate explanations are not likely to work.
Most people don’t run red lights at intersections. The few that do are disproportionately influential not only in a material way via accidents but also in our perceptions; a person running a red light is highly conspicuous and thus occupies a big space in our thinking compared to all the people who sensibly obey rules.
Similarly a person who follows a scofflaw to the next intersection and then engages in an altercation is also quite unusual. Guess what? You’re one of them. :-)
Most people inconspicuously obey traffic signals because there’s a reasonable case for so doing, not because it’s a statutory requirement. The arguments presented in the PopSci piece are at an accessible level and will be folded into the thinking of a large number of persons who will never be noticed by we of the few and the loud. Some of those arguments are reasonable and some are fairly plainly not. People reading the article will draw conclusions from seeing the juxtaposition between science and fiction plainly illustrated and I think it’s safe to say that the net effect of the contrast will be positive. We’ll never hear from the beneficiaries.
I don’t think there’s benefit to be gained from pretending that nobody is arguing for wrong conclusions. Accepting that, simply repeating “they’re wrong” without any cues as to why isn’t effective. “Inhofe is wrong but I can’t tell you how or why because I don’t wish to refer to what he says.” How effective is that? At then end of the day the most plainly inaccurate telling will come from the very lips of the wrong themselves.
Thanks for the interesting discussion on CH4, which I still think is the bomb with CO2 the trigger. Also, please tell me why there is no discussion on human overpopulation of the earth since Global Warming is anthropogenic? Or, why no mention of inexpensive, time-buying solutions such as a law that all roofs and cars be white to regain some of the albedo that we have lost.?snsys
Realclimate has made its niche the provision of reliable synopses of the science that can be understood by intelligent laymen. Neither overpopulation (nor for that matter overconsumption) nor time-buying solutions fit well with that. What is more, it seems that every discussion of solutions eventually bets bogged down in nukes vs no nukes or some other distraction. And if you sought to legislate roof color, there is no doubt some idiot glibertarian would equate it with fascism and the end of human civilization.
Susan wrote: “we fail to imagine people who simply believe what they are told if they approve of the source, and automatically disbelieve anything that contradicts that. ”
Worth repeating. I find it mind-boggling what people repeat without question.
Comment by John E. Pearson — 2 Jul 2012 @ 10:15 AM
Re- Comment by Sharon Black Hawkins-Fauster—2 Jul 2012 @ 7:23 AM:
Overpopulation is the big elephant in everybody’s room. The solution is conceptually simple but expensive, and there appears to be no will to do anything about it. This board is for discussions of climate and it seems to me that if the CO2 problem is not solved there will be no chance at all of addressing overpopulation and big mama nature will take care of it in her usual direct and callous manner.
As for house and car roof albedo, the area is so small that any change in temperature would not be detectable and could easily be surpassed by using more carbon efficient transportation or insulating ones roof. Also, changing albedo is a onetime thing, while CO2 is the gift that keeps giving.
As for house and car roof albedo, the area is so small that any change in temperature would not be detectable…
Frequently misunderstood. The point of these is to reduce cooling load by making any given level of roof insulation have to isolate less transmitted heat into the interior of buildings as well as reduce “heat island” effect.
The benefit comes from less demand on generating capacity hence less combustion.
Susan Anderson wrote: “we fail to imagine people who simply believe what they are told if they approve of the source, and automatically disbelieve anything that contradicts that”
I think we often fail to appreciate the vast amount of money that has been poured into creating exactly that state of mind in millions of people over the last 30 years or so.
Can any of us smart and skeptical folks here be quite so sure of what we would believe or not believe if we had been relentlessly hammered 24×7, year after year, decade after decade, with sophisticated propaganda developed by the most insidious minds of Madison Avenue to push our carefully-researched psychological buttons, and disseminated by the most powerful mass communications technologies ever conceived, as have the particular demographic groups targeted by the so-called “right wing” media?
Steve Fish @164
I’ve not met before the metaphor “…the big elephant in everybody’s room” (presumably something important but ubiquitously unmentioned) and am further mystified by the idea that solving AGW through reducing world population could be described as “conceptually simple but expensive.” It did however raise some intriguing thoughts.
Generally, while a simple reduction in the human head count appears to provide a solution to AGW (if there were ten times less of us, there would be a tenth the emissions sounds logical enough), folk usually have in mind the burgeoning population of third world countries when they talk of such overpopulation. Of course, these are the very nations who are not really the cause of the AGW problem but who are in the front line when it comes to its impacts. Further, it’s not just the wealthy nations but wealthy communities, indeed wealthy households that really lie at the root of the AGW problem. Or perhaps a more equitable way of reducing emissions would be to be mindful of the impact a person’s age has even on their annual emissions.
The post I responded to specifically referred to albedo in a manner suggestive of how global warming is affected. However, frequently misunderstood is the fact that when retrofitting a house is that it is much more cost effective to put an inexpensive reflective barrier below the roof, in the attic, than to reroof with white roofing. When building a new house the combination of a white roof and the reflective insulation is best, but the gains are pretty small. With understanding, a builder can construct a chimney effect that uses heat gains inside a house plus attic solar heat to help keep a house cool.
Solving the heat island effect, which is not of much importance in the larger scheme of things with white roofs, sounds like the sheep albedo effect to me.
Because you are confused- The elephant in the developing world’s room has to do with the near certainty, if nothing is done, of we all, or our offspring, being able to witness the death of billions from starvation and war over resources (food), live, via satellite. The conceptually simple solution required to stop continuing overproduction of humans is to 1) Empower women, in the poor areas where multiple male offspring or large families are thought to be necessary (often by men), to be able to make the reproductive choices for themselves and their own family; 2) Families (e.g. male heads of family in the parts of the world of importance) need to be provided with a minimal source of income in a manner such that they are able to count on some level of economic stability; And, 3) Methods of contraception should be provided to parents. As I said, such a program would be expensive and would depend upon stable energy supplies for the developed world.
You are correct that it is the developed world that is the source of the CO2 problem, but you need to recognize that it is the developed world that is the only agency that can help the rest of humanity to get through the peak fossil energy/climate heating/ocean acidification/fresh water shortage/desertification/overpopulation crisis. We have to solve our fat cat problems quickly in order to be able to help the rest of the family. Steve
MARodger wrote: “… a simple reduction in the human head count appears to provide a solution to AGW …”
Sure it does — if any reduction in GHG emissions resulting from that “simple reduction in the human head count” will occur within the next five to ten years.
The most aggressive, but still humane, imaginable measures to slow the growth of the human population — such as those you enumerate — certainly won’t achieve that result.
Whereas simple, readily available, cost-effective (and even profitable) measures to reduce fossil fuel consumption by the small minority of “human heads” who populate the industrialized nations could easily do so.
Guys, basically we got a whole herd of fricking elephants jostling for position in the room.
1)There’s the end of fossil fuels, increasing scarcity of other critical resources (e.g. rare earths, helium, Pt group metals, etc.)
2)There is certainly overpopulation.
3)There is overconsumption.
4)There is environmental degradation as we try to cope with 1-3.
5)There is climate change.
6)There is the need to develop and deploy a new energy infrastructure.
7)There is the need to develop sustainable manufacturing.
8)There is the need to develop a sustainable economic model that doesn’t rely on growing consumption or growing population for its sustainability–and which will even work with a shrinking population.
9)There is a need to develop a democratic form of government that works despite the fact that most of the population is too stupid to even understand their own self interest, let alone science or policy.
10)There is the fact that the current global economy is a giant shell game trying to keep us from seeing that the money we thought we had really isn’t there.
Any one of these could sink us. Some could destroy civilization. They will all make each other worse. And that is just off the top of my head