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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 46151 to 46200:

  1. Climate's changed before

    Kristjan, I think it is expected to be more or less constant within a particular range of temperature/states. Ie once all the ice is melted, then the albedo feedback becomes a lot more subtle. Ditto, on an iceball earth, you would expect sensitivity to be high at point where ice melts at tropic.

  2. The science isn't settled

    Good question. As far as know, for ECS you need to know where feedbacks will stabilize. Ie if you perturb CO2, where does T settle when all feedbacks are in equilibrium. Now I think you could say there is a lot of confidence about what the feedbacks are, a lot of confidence about how the feedbacks work, but a lot less confidence about quantifying some of those processes accurately. (eg the complex dance of aerosol, water vapour, temperature and clouds).

  3. The science isn't settled

    @ bob, relax man. I'm not sure why you're so defensive.

  4. The science isn't settled

    so is the uncertainty mainly the result of the lack of theoretical understanding or the lack of more sophisticated technology (e.g. better satellites)? How much of the uncertainty in equilibrium climate sensitivity is from a lack of theoretical understanding?

  5. Climate's changed before

    Is climate sensitivity a constant or dependant on other variables? Meaning, as the earth gets warmer (or cooler) does the climate sensitivity stay the same or increase/decrease (or maybe it's dependant on some other variables as well)?

  6. The science isn't settled

    engineer:

    I will answer the question with more questions.

    1) you are selecting some very simple examples from heat transfer (mixing two different quantities, at two temperatures, of the same fluid) and the properties of materials (a single Hookian spring). They are high-school "engineering", not engineering school engineering. How simple is it to calculate the peak spark plug tip temperature in an F-1 racing engine at the end of a straight-away on the 72nd lap of the race at [pick a course] on a hot summer afternoon - from first principles? Would you consider the design of racing engines to be an area that is not well understood?

    2) I would think that brige-building, slope stability calculations, etc. would be considered well understood engineering areas. Why does standard design practice often  use relatively large (e.g. 2 or greater) factors of safety? Surely any factor of safety greater than one will do? (For those not familar with the term, a design factor of safety of 2 means that the design strength is twice the needed strength.)

    3) a standard physics example of things that are difficult to calculate is the n-body problem. Does this difficulty in calcuating an exact answer mean that our understanding of gravity is not well understood?

    4) If you wish to continue the discussion, would it be better if we did so without rhetorical questions?

  7. The science isn't settled

    Understanding the feedback processes well does not necessarily mean that crucial numbers can be extracted easily. Things like - amount of aerosol, full thermal description of ocean, cloud vapour response etc. The Argo network, better satellite measurement, GRACE and so on eventually allow for more precision.

  8. The science isn't settled

    engineer,

    I think that the problem is that you are trying to compare climate science with the hardest of hard sciences -- engineering sciences, like classical physics.  Many other sciences are not nearly so precise, including quantum physics, biology, neuroscience, medicine and more difficult chemistry (especially the state of chemistry before the development of the electron microscope).

    Would you consider all of these fields to be "not well understood?"

  9. Climate Sensitivity Single Study Syndrome, Nic Lewis Edition

    Albatross,

    I often point out to people ('skeptics', usually) the error of relying on a single study, and most often it is with climate sensitivity estimates. It's good to see that caution explained here. I'm not trying to bait anyone. After reading at several places in the article that one should not lean on a single study, it simply leapt out at me that this had been done to make a point about uncertainty on climate sensitivity estimates from intermediate complexity models. Is it inappropriate to apply the same standard to this question as it is to climate sensitivity estimates?

  10. 2013 SkS News Bulletin #8: Alberta Tar Sands and Keystone XL Pipeline

    @jyushchyshyn:

    If the Keystone XL were to be approved, the refined product would be sold to the highest bidder -- most likely China.

    The primary cause of manmade climate change is the burning of fossil fuels. Keeping the reamaining deposits of fossil fuels in the ground ensures that they will not be burned. 

  11. The science isn't settled

    I have some questions related to this that have been bothering me for a while.

    This article isn't about equilibrium climate sensitivity from double co2, but I'll use that for my point. the IPCC report gives a value of 2 to 4.5 C with a likely value of 3C and confidence level of greater than 66%. Less than 1.5C has a confidence level of less than 10%.

    This is where I'm confused, for very well understood fields, such as heat transfer, equilibrium values can be calculated with a high degree of accuracy. For example, we can calculate the equilibrium temperature that a mixture of 1lb of 80F water and 1lb of 60F water would reach. Or in vibrations, how much a spring would stretch when it reaches rest from a hanging mass.

    Obviously these are simple examples, but the point is that equilibrium values can be calculated with a high degree of accuracy in well understood fields certainly. The 5% not understood in climate looks like it has a pretty significant impact on the calculation of an equilibrium value. So why is the topic of climate considered well understood? Thanks

  12. The science isn't settled

    Thinking on this further - that statement is not "an essential part of AGW theory". It is an outcome of the current theory of climate. Falsifying climate theory is same as for any other theory - the theory must change if predictions derived from the theory do not match observation with both the limits of prediction and limits on observation. One of the problems with claims to  falsify climate theory is that they falsify predictions that climate theory does not make.

  13. 2013 SkS News Bulletin #8: Alberta Tar Sands and Keystone XL Pipeline

    If you have a plan not to use the oil which Keystone would deliver, why do you need Obama to reject it? Why not let the market stop it. Global warming is caused by consumers, not suppliers.

  14. Global Warming: Not Reversible, But Stoppable

    1)Byalko (2012) get the formula from a regression of T and CO2 for last 780Kyr

    2)The reference [19] to Byalko (2010)

    "...climate perturbations increase proportionally to the time derivative of temperature [19] ..." is a very general discussion of basins of stability, and does not convince me yet.

    That said, i do like Byalko (2012) teasing the 40Kyr periodicity out of a simple model.

    sidd


  15. The science isn't settled

    Further to 6 - measure the change in surface radiation or OLR and then find that is inconsistent with calculated change due to increased GHG.

    You could also add - models based on AGW forcing would not reproduce past climate within the errors of model and forcing. You might think from arguments about paleo that this isnt a strong argument, but note that you can use this method to disprove alternative hypotheses like "the sun explains it all". "GHG changes have no effect".

    I think that the easy practical ways to disprove AGW were all tried long ago and failed with explains your problem with find them.

  16. Global Warming: Not Reversible, But Stoppable

    Bill Everett @26 equilibrium temperature "Teq =0.98(C - 280)" must have some elements missed, in life haste possibly. I just readily found "http://www.oocities.org/marie.mitchell@rogers.com/Climate_Notes.html" with a bunch of familiar looking numbers and formulae I recall from Drs. Randall, Trenberth, Hansen & others video lectures the last few weeks like the Watts m**-2 forcing (no feedback) = 5.35*LN(CO2/CO2<base>). I'd suggest searching each of those to find the agreement from expert sources before using, but that site doesn't seem to be pushing an agenda, no diatribes just some related quoting after the numbers.

  17. The science isn't settled

    h-j-m @61, each of the following methods states a condition which has been experimentally tested and is known to be false, but which would falsify the theory if true.

    Method 1:  Warming of land surfaces equal warming of oceans, showing the change in temperature is caused by changes of SST rather than forcing.

    Method 2:  Stratosphere warming as troposphere warm showing the warming to be dominated by changes in solar radiance.

    Method 3:  Meso-sphere and thermosphere increasing in volume (showing that they are warming) as troposphere warms.

    Method 4:  Warming exists even though anthropogenic forcing factors remain constant.

    Method 5:  Known natural forcings are larger than known anthropogenic forcings.

    Method 6:  Width of anthropogenic GHG absorption spectra in outgoing LW radiation  unchanged over time.

    I am sure the list can be extended substantially, particularly once we start applying statistical tests rather than the crude method of simple falsification.  It should be noted that if there were reasonable doubt about the theory, competing natural explanations would not have been falsified (they all have been).

    Now, here is the real challenge.  Find a theory that contradicts the claim that is both falsifiable and has not already been falsified.  It is a challenge "skeptics" seem to avoid like the plague.

  18. Climate Sensitivity Single Study Syndrome, Nic Lewis Edition

    Hi Tom @33,

    Either Dana or I will respond to your post, but I for one would like to investigate this more closely before doing so.  Thanks for your patience.

  19. Climate Sensitivity Single Study Syndrome, Nic Lewis Edition

    Albatross @32, Dana correctly describes Lewis as claiming that the mode (most likely climate sensitivity) of his result is identical to the mode of Aldrin et al, but then incorrectly calls that claim a simple misrepresentation.  It is not a misrepresentation.  The modes of the two studies are identical to the first decimal point.  It is, however, misleading in that it is an apples and oranges comparison.  Given that other studies report the mean, in comparing with other studies the mean should be reported, or it should be made absolutely clear that not only are you reporting the mode, but that the authors you are reporting on reported the mean.

    Dana then engages in his own apples and oranges comparison, stating (correctly) that  Aldrin et al reported a climate sensitivity of 2 C, without stating that it was the mean.  As the preceding paragraph mentioned only modes of the climate sensitivities, contextually that indicates that Aldrin reported the mode, which is false.  It thereby creates a misleading impression.  It further misleads because the requirement to be responsive is ignored.  It appears that Dana is contradicting Lewis, whereas he is merely reporting a different value.  As it is his clear intention to rebut Lewis, readers should be able to reasonably expect that his counter evidence will be responsive.

    Further, the claim that the 1.6 C modal value appears nowhere in the paper is at best an evasion, and at worst directly untrue.  The figures are part of the paper, and the information in the figures therefore appears in the paper.  As such, the modal value of the main analysis, which is easilly identified from the figures, appears in the paper.  Dana is welcome to show that the figure does not show a modal value of 1.6 C if he likes, but simply pretending it is not part of the paper is not appropriate.

    It would be easy to correct the article by removing these flaws.  The discussion could be replaced with an informative discussion of the reason climate sensitivity studies report means (or central estimates) and why reporting only the mode in making those comparisons is misleading.

  20. The science isn't settled

    I take that this sentence

    "anthropogenic greenhouse gases are causing most of the observed global warming"

    is an essential part of AGW theory.

    Can someone please offer a practical method of how to disprove it?

    Unfortunately so far I failed to find one.

  21. Climate Sensitivity Single Study Syndrome, Nic Lewis Edition

    Barry@31,

    Dana might disagree with me, but the following text from Dana's post is correct:

    "Lewis's claimed value of 1.6°C appears nowhere in the paper itself. Rather, Lewis apparently ignored the authors' reported findings in favor of a value he estimated from graphs in the paper" 

    What Lewis did amounts to cherry picking and in turn being deceptive.

    As for your claim that:

    "It seems inconsistent to cite a single paper (Olsen et al 2013) to buttress a point, when citing single studies is repeatedly advised against."

    Nonsense. Please stop trying to bait people, your argument makes no sense in the context of the discussion.

  22. Global Warming: Not Reversible, But Stoppable

    Andy:

    The analogy I use with people is that of the 'climate flywheel', which we have gradually accelerated up over the last 200 years or so -- but particlualrly over the last 50 years at an ever increasing rate. So if we stopped emissions today the flywheeel would keep turning and would only very slowly lose speed over the forthcoming millenia. Only by actively removing greenhouse gasses from the atmosphere could we create a brake and actually begin to slow down that flywheel.

    Of course the real problem is that, as of the moment, we don't show any inclination to even consider reducing the rate of acceleration. 

  23. Climate Sensitivity Single Study Syndrome, Nic Lewis Edition

    It seems inconsistent to cite a single paper (Olsen et al 2013) to buttress a point, when  citing single studies is repeatedly advised against.


    Dana, if Tom Cutrtis is right, and the modal value Lewis gives is consistent with Aldrin, you should update the article. You will need to revise your argument on that.

  24. Global Warming: Not Reversible, But Stoppable

    @Bill Evert #26. The equotation is subtracting ppm (a ratio) from degrees celcius (a measurement of energy) multiplying by an unknown 0.98. That formula can not be correct.  

  25. Global Warming: Not Reversible, But Stoppable

    Bill Everett @26, 0.98*(CO2 concentration - 280) represents a climate sensitivity of 274.4 C per doubling of CO2, a figure which is definitely wrong.  Are you sure you have not misquoted the equation?  If not, I would not be quoting Byalko as a guru on climate change. 

  26. Global Warming: Not Reversible, But Stoppable

    @Killian #11 James Hansen et al (many persons) do say in your reference "scenarios all assume a massive 100 GtC reforestation program, essentially restoring biospheric carbon content to its natural level". That 100 GtC (47 ppmv CO2) is 91% of a Brazilian rain forest (only +8% of the current land biomass so it's possible). 50 ppmv CO2 = 106,631,500,000 t carbon. Brazilian rain forest (10% of the Earth's carbon store) has 110,000,000,000 tC (52 ppmv CO2) on 3,375,413 sq. km. Hansen et al have the 100 GtC being bio-sequestered over 2031-2080. Since the data I've seen shows ~+1 ppmv CO2/yr from land use clearing, just stopping that would be really handy over 67 years. It would be great, and interesting, if we were some other species that might do those things that Hansen et al recommend but I think James Hansen might be confusing us with some superior species (a whole bunch of you maybe). A 2nd Brazilian rain forest or equivalent complex mix on our planet does not seem to mesh well with our actual interests that I see in the daily news.

  27. Global Warming: Not Reversible, But Stoppable

    @ Doug #22, http://www.probos.net/biomassa-upstream/pdf/finalmeetingECN.pdf as an introduction to how biomass is torrefacted. Indeed is used in roating coffee beans but has more links with making charcoal

    BTW used coffee ground is an excellent fuel for gassification.

  28. Global Warming: Not Reversible, But Stoppable

    Shouldn't the "about 340 ppm by 2300, approximately the same level as it was in 1980. In the next 200 years" be the next 287 years ? I'm getting so old I'm losing track of decades so it might be me.

    Moderator Response:

    [AS] Oops. You are not the only one getting old! I changed it to "300 years". Thank you.

  29. Global Warming: Not Reversible, But Stoppable

    I find the preceding comments extremely interesting and important. I looked at this post and the first few comments yesterday, printed the Matthews and Solomon op-ed, and resolved to read that short piece this morning, review any additional comments, collect a few resources, and formulate a comment of my own. I woke at 5:30, it is now 7:49, I have run out of time. I have scanned quickly the last half of the comments. I would like to be in e-mail contact with many of the commenters. Click on the author at http://www.degruyter.com/view/j/integ.2012.12.issue-2/integ.2011.101/integ.2011.101.xml and send me an e-mail if you agree.

    I am not a scientist of any sort. I am not a mathematician. But I think I can understand some science and some mathematics and some other things. It is critical to remove the "violence" (i.e., arguing to get others to adopt your view) from the "violent agreement" (Wyoming@19). That is, we need to convert argument to discussion. The reason is nicely put in two sentences in J.B. Calhoun's 1970 Ekistics paper: "Thus, in the presence of this increased exposure to value conflict, there will be required an augmented awareness of the necessity for others to maintain value sets differing from one's own. Furthermore, realizing one's own functional role requires expenditure of considerable effort in assisting others to fulfill the objectives of their value sets. [pp. 431-432]" This was in the context of describing his predicted conceptual revolution 7 in ~2018 AD (for context, revolution 2 was the Living-Agricultural Revolution of about 8157 BC; revolution 5 was the Scientific-Exploitive Revolution of about 1868 AD).  His simplistic model was originally presented in December 1968  at the AAAS annual meeting in Dallas (Frontiers of Science Lecture III). I can send a pdf format scan of that paper to those who contact me.

    I have some understand of systems dynamics. For example, in the spring of 1971, the local Sierra Club chapter asked me to give a talk on the "Limits to Growth" model. I prepared and gave a two-hour presentation. The first third was a basic introduction to systems dynamics, the second third was a description of Forrester's "World Dynamics" model and results of my study of multiple scenarios, sensitivities of various couplings in that model, etc., and the last third was on the current status of the work in progress in Dennis Meadows group at MIT and what might be expected from it.

    Much of the discussion here is great, but somewhat in the wrong place, in my opinion. This site is a "debunk denialism, explain the consensus science, and maintain an acquaintance with the real ongoing 'debate' about the fine points" forum in the broad sense of "forum." But we do need a serious discussions along the lines of the preceding comments so that we can (metaphorically) find our places in the choir and sing out in harmony sufficiently well and increasing loudly to cause the needed paradigm shifts (William@20; also see Makem & Clancy: A Place In The Choir).

    With regard to the temperature-CO2 equilbrium and temperature change from the pre-industrial temperature, one suggestion is Teq =0.98(C - 280), where Teq is the equilibrium temperature change from the pre-industrial temperature in degrees C and C is the atmospheric CO2 concentration in ppm, from Byalko, Phys. Usp. 55(1) 103-108 (2012). There, the estimated time of relaxation to equilibrium is 650-750 years. I quote the concluding two paragraphs from that paper:

        The practical consequences of the forecasts of the energy sector and the corresponding solutions of the relaxation equations are quite substantial. The main conclusion is as follows: all actions to 'correct' the atmosphere begin to affect the average temperature of the planet with a noticeable delay. Thus, in the radical scenario, the maximum CO2 emission occurs in 2030, but its maximum concentration is attained only in 2042, and the temperature reaches some limit (possibly, a maximum) only by the end of the 21st century.
        The warming leads to one more unpleasant consequence, which is that climate perturbations increase proportionally to the time derivative of temperature [19]. A qualitative conclusion hence follows: weather anomalies will become maximal by the middle of the 21st century, when the CO2 concentration passes its maximum. This statement relates to the radical scenario, while the inertial scenario is completely catastrophic both for temperature and for weather anomalies. The humanitarian consequences of global warming cannot be evaluated in the framework of a physical approach to climate problems.

    I apologize for my comment being somewhat disjointed (had less than three hours of sleep last night and am falling further behind schedule).

    -- Bill

  30. Doug Hutcheson at 10:38 AM on 21 April 2013
    Global Warming: Not Reversible, But Stoppable

    William @ 20, the Guy McPherson essay in turn links to a disgusting article by that doyen of the radical Right, James FishingDelingpole, which concludes;

    "Our culture deserves better than to have the terms of debate dictated by malign, politically motivated, professional offence-takers.

    Let's stop surrendering and start fighting back."

    I couldn't have put it better myself.

    After reading what Delingpole wrote (and subsequently disinfecting my monitor), I am amazed that he is given oxygen. Surely he is smart enough to know he is batting for the wrong side? Still, his rhetoric is so inflammatory, I'm glad he doesn't bat for us: stuff like that from this side would do untold damage to getting the message, about stopping AGW, out in a sane and rational way.

  31. Global Warming: Not Reversible, But Stoppable

    Let's put some figures on Killian @11.

    Between 1850 and 2008, cumulative emissions due to Land Use Change represented 32.8% of all anthropogenic emissions.  Part of that comes from intensive animal husbandary and the expansion of rice paddies rather than deforestation, but we will ignore that.  If follows that complete reforestation to 1850 levels will draw down around 36 ppmv of CO2.  That could be approximately doubled by reforesting to, essentially, tenth century levels, ie, by returning Europe to the once verdant forest it was.

    That is the total of the draw down that could be managed by "sustainable" means.  Counting a switch to permaculture is not an additional draw down.  A permaculture garden stores substantially less carbon per acre than does a forest, so any acreage set aside for permaculture reduces that total draw down.  Never-the-less, it must be considered technically feasible to draw down CO2 as Killian suggests.  The total draw down would reduce the CO2 concentration to approx 310 ppmv, with equilbriation of the partial pressure of CO2 in the ocean over the next two centuries drawing that down further to abotu 285-290 ppmv.  Problem solved!

     

    What is missing from this analysis is how we are going to feed the population once all of the world's arable lands have been returned to forest.

     

    As pointed out by William, permaculture is labour intensive.  So much so that feeding a population by permaculture is not feasible unless every familly has its own permaculture garden.  With the labour hours of all famillies dedicated to just feeding themselves, there is no excess labour for such luxuries as geting an education, publishing books or newpapers, manufacturing any electronic equipment (including radios) having a civic life, and a democratic governance, long distant transport, long distance communications except by courier, or a population of the Earth greater than about 1 billion.

    The great danger of global warming is primarilly that it will create conditions that will result in the collapse of world trade.  Failing that, it may cause deaths in the millions but our civilization will struggle on.  With the collapse of world trade, however, we will face deaths in the billions from war, starvation and disease.

    Killian's solution to that threat is to embrace the threat as the solution.

    My opinion is different.  I think if we are going to be forced back into another dark age; we should at least put up a fight.

  32. Doug Hutcheson at 09:47 AM on 21 April 2013
    Global Warming: Not Reversible, But Stoppable

    Wyoming @ 18, you said:

    If we continue BAU we will have a collapse due to climate change/fuel supply issues, if we don't continue BAU we have collapse because only BAU can supply the food requirements of 7 going on 9 billion people.

    I have never seen our dilemma so succinctly expressed. Everything comes back to the fact that there are simply too many of us.

  33. Doug Hutcheson at 09:23 AM on 21 April 2013
    Global Warming: Not Reversible, But Stoppable

    Ger @ 9, can you clarify what you mean by "torrefact"and "torrefaction"? Google suggests it is from the Spanish "torrefacto", which refers to the roasting of coffee beans. I presume torrefaction is a process for roasting or burning biomass, but I have never encountered the word before.

  34. Record snowfall disproves global warming

    dvaytw - in very general terms, the Clausius–Clapeyron relationship between temperature and water vapour is known from mid-19th C. Issues with precipitation were flagged in Ch 4 of WGII of the IPCC FAR 1990. Beyond the broad picture however, regional climate prediction was not possible then (and remains a considerable challenge now  -see for instance here) and so perhaps you ask the source of the their claim for drier winters? 

  35. Global Warming: Not Reversible, But Stoppable

    Scenario #1 in Limits To Growth, the equivalent of the "no policy" of current MIT prof's, looked to the long-term consequences of "poisoning the planet" and the global population's decline from starvation due to those various poisons in our seas, soils, food water, air and us. Here in Puget Sound we are already seeing those consequences in our shellfish industries, salmon unable to spawn in their natal streams,&  first-born Orca dying from the toxins concentrated in their mother's milk. The continuing leak of radioactivity from the Fukushima Daiichi nuclear power plant crisis hasn't reached us in significant amounts yet, but prognosticaters report it is enroute. How many streams, lakes and rivers are uncontaminated? None around here or other parts of this continent. Folks who live in the Niger River delta have seen their life expectancy rates reduced from 65 to 45. Contaminated breast milk is being reported in subsistence cultures all over the world.  Without our pollution, yes, survival of the species 200 years from now might be possible.  Getting there seems unlikely - unless, of course, you have a mustard seed.

  36. Global Warming: Not Reversible, But Stoppable

    Paradigm changes can occur incredibly rapidly when they get going.  Look at our nearly smoke free indore environment and  the change from horses to cars.  However, to really change the world opinion on the use of fossil fuels to an extent that it will lead to action and will overcome vested interests, it will take a high impact disaster.  Sandy, the disappearance of the Arctic ice and such events are not enough.  We need, for instance, a complete failure of northern hemisphere crops due to a clear, demostrable lurch northward in the climate zones.  Unfortunately (or fortunately, depending on your point of view) it will be too late for many of us.  Massive starvations have occured again and again in the past but they have been localized.  Think Ireland, for instance.   We have had a little hint of  crop failure in Russia in 2010 and the USA in 2012 but they will only be seen as signs in hindsite.  If indeed the modern fertile crescent (Russia, Canada and the USA) fail, starvation will be global.  It will be too late for Most of us.  The following link is interesting.  Guy is pretty far out there but he gives a good list of possible tipping points.

    http://guymcpherson.com/2013/01/climate-change-summary-and-update/

  37. Global Warming: Not Reversible, But Stoppable

    CBD,

    I think we are in violent agreement as they say.  I say the general non-scientific reader will likely misunderstand the structure of the language used by the authors and reach the wrong conclusion.  You say that the " foolish people might reason that we can continue letting the temperature rise and 'just stop emitting when things get bad'."  I think we are talking about the same people, in a slightly different way, and coming to the same conclusion.

  38. Global Warming: Not Reversible, But Stoppable

    Killian,

    I think you have a misunderstanding regarding sustainable agriculture techniques and permaculture in particular. Some background, after I retired from my engineering career I owned and operated an organic farming operation for a number of years. I have spent a lot of time learning about farming, sustainable practices and such particular issues as permaculture and biodynamic practices.

    I have no issues with any of the attempts to develop sustainable farming practices and think it is a worthy goal. However, one has to keep in mind that these techniques are knowledge that we need people to develop and preserve for future needs as they have no fundamental ability to sustain our current population levels and complex civilization. Our extremely complex civilization and some 7 billion plus population is the direct result of our forebear's having obtained access to vast amounts of fossil fuels. One leads to the other and this has been well researched and documented.

    Almost all global food production, in percentage terms, is based upon heavy dependency on fossil fuels, be it from building the machinery used in farming and transporting food, storing food, making fertilizer, pesticides, fungicides and herbicides, etc. This reliance is not limited to 'industrial agriculture' but also applies to almost 100% of organic production as well. The amount of global food production from human/animal only labor food production is very small. And ramping up human/animal production to levels sufficient to support our current population/civilizational complexity is mathematically impossible. This is the dilemma of being in overshoot or past our global carrying capacity. If we continue BAU we will have a collapse due to climate change/fuel supply issues, if we don't continue BAU we have collapse because only BAU can supply the food requirements of 7 going on 9 billion people.

    Take some time to research permaculture production levels per human hour of labor. It will shock you. There is a good reason that before the introduction of industrial farming techniques and access to cheap fossil fuel some 98% of the population were farmers. When only human and animal labor is used it is very difficult for a farmer to reliably grow more food than he, his family and his animals (a plow horse is a tractor that runs on bio-fuel) need for their own use. There is no avoiding having some years when you produce less than you need to consume. This is why starvation was common in older times and is common in places where subsistence farming is still practiced. Now think about trying to supplant our current system of food production and supply for a city like Phoenix, Sao Paulo, Cairo, Moscow, Beijing, Hong Kong, Los Angeles, New York, etc. Pretty hard to solve that problem. And if you are planting vast acreages to forest like you mention it is wise to keep in mind that by definition you are covering arable land in forest that your sustainable farmers will need to be growing crops upon. You will need to be using every square inch of ground while you are trying to maintain the population levels if you are using sustainable techniques.

    There are a host of things we all must do to avert total disaster and there are no simple solutions. We absolutely have to cut GHG emissions, we must become much more efficient in our use of fuels, we must develop alternative energies, we must learn to live more simply and consume less, but most important of all things (and by far the hardest) is that we must find a way to dramatically reduce population levels as fast as possible. If we do not find a way to agree to cut population levels beyond the very slow decline in global growth rates( which indicate a maxing of population near 9 billion around mid-century) there is no possible solution to our above dilemma. We will just run into a brick wall.

  39. Global Warming: Not Reversible, But Stoppable

    Wyoming wrote: "I think that a significant percentage of the readers (not even counting the Deniers,) on initial reading of the post, would come to the conclusion that all we have to do is wait until the rising levels of CO2 have resulted in conditions which are at our limits of tolerance and then we stop emmisions and all is going to be ok."

    Except that the point the article actually makes is that rather than 'everything being ok' in such a scenario, what it would actually mean is that "conditions which are at our limits of tolerance" would then persist for hundreds of years.

    Seems like a bad plan.

  40. Global Warming: Not Reversible, But Stoppable

    Sorry, here are the Seattle Food Forest links:

    http://www.seattle.gov/parks/projects/jefferson/food_forest.htm

    http://www.takepart.com/article/2012/02/21/its-not-fairytale-seattle-build-nations-first-food-forest

  41. Global Warming: Not Reversible, But Stoppable

    Moderator, I stated clearly my awareness of the 30-year lag with regard to the climate system. What I have said flies in the face of nothing, you simply don't know of these exceedingly simple ways to return to pre-industrial levels of GHG's.

    As I said, it is yet a tiny percentage of people who look at the energy, resource and climate issues we have in a fully holistic manner, yet, no discussion of any of these issues is meaningful without discussing all of them. So long as we continue to attempt to discuss them seperately we will continue to fail to make meaningful changes in policies.

    People, seriously, if you think you understand what's going on yet look only at the climate science or tech-based solutions...  egad.

    You can start with Rodale, which is a study that looked at, though they don't use the term, applying permaculture design principles to farming. Basically what most of you might think of as no-till farming.

    Rodale Institute 30-year comparative Study of Farming Methods. 
    Tainter video (1 of 7, the rest are also available.) Diminishing Returns on Complexity 
    Jared Diamond on Choosing to Simplify 
    Hansen, et al. 
    An essay on Hansen's strategies 
    Willie Smits: Rebuild a Rainforest, Grow a Commmunity 
    Food Forest process 
    Seattle Food Forest 
    Yacouba: Stopping The Desert 
    Green deserts?

    Moderator Response:

    [DB] And again, none of what you furnish for support deals with ocean acidification and the basic chemistry of seawater.  If humans manage to somehow initiate the drawdown of atmospheric CO2, the oceans will simply start spitting back out what they have under duress absorbed.  So your goal of returning atmospheric CO2 below 300 ppm target remains an elusive and unrealized goal.

    If you wish to explore that further, take it to the Physical Chemistry of Carbon Dioxide Absorption thread, and the followup Seawater Equilibria thread, where that is more appropriately discussed.

    Further, please note that Youtube videos, while useful, generally do not constitute scientifically reliable evidence in a science-based forum such as this.  Much more credence is given to the primary literature published in peer-reviewed, reputable journals.

  42. Global Warming: Not Reversible, But Stoppable

    I must admit that when I started reading this post my first reaction was 'WHAT!'.  After carefully reading through it 2 times my reaction was "Ok, that, guess, is technically right. But what a way to misstakenly try to accomplish the stated goal of trying to forestall inaction on the part of people because they have the wrong impressions about the answers to the 2 posed questions. 

    I think that a significant percentage of the readers (not even counting the Deniers,) on initial reading of the post, would come to the conclusion that all we have to do is wait until the rising levels of CO2 have resulted in conditions which are at our limits of tolerance and then we stop emmisions and all is going to be ok.  The Deniers of course would twist the language of the post towards their arguments with no trouble at all.

    In frank words, I think the way this post went about explaining the science completely misunderstands how most people comprehend what they sort of read and will result in exactly the opposite of what the authors intended.   They better hope that the general public is not reading this. 

  43. Global Warming: Not Reversible, But Stoppable

    @Killian #11:

    Please provide citations for the numerous claims that you have made. Thank you. 

  44. Global Warming is Accelerating, but it's Still Groundhog Day at the Daily Mail

    @TomCurtis #25:

    the key point is that a confidence bound is a line that the observed value is expected to fall below a certain percentage of the time

    *click*! Yup, that's all I needed. Thanks!

    (BTW, what is up with the stupid edit box on this site, and it's inability to let me copy/paste text into it? Whenever I try, I just get "undefined".)

  45. Global Warming: Not Reversible, But Stoppable

    Agree with comment from CB@2.  As human inertia will not rapidly decline and temps will continue to rise, will not climate inertia pick up on its own with declining albedo and increasing defrosting of the perma frost.

    Thinking beyond zero human GHG emissions, might we also focus on planetary recovery, even in small gradual steps?  

  46. Global Warming: Not Reversible, But Stoppable

    I can't believe people - everyone - gets this so wrong. Of course Climate Change is reversible. At least the process is. While some of th effects will be hard to reverse as bioregions change, if we act quickly enough that the bases of these zones are still intact, these will also revert. To the extent some changes are permanenet, adaptation will be possible.

    The key issue is how longit takes to start reversing and get back to pre-industrial levels of CO2. That will ultimately determine how much ecosystems are impacted before we can cool the planet. It should be obvious to all that returning GHGs to pre-industrial levels will, in fact, cause the planet to cool over time. The approximate 30-year lag is the largest obstacle. It would take, in the absolute best case, 20 years to draw down CO2 to preindustrial levels, but more realistically closer to 50 since, well, human beings are largely idiots. That means we're looking at roughly 20 to  75 years of additional warming before reaching a level where a relative cooling would take place, with relatively less heat retained a GHG levels fall.

    Far too many people still don't understand the full systemic nature of this. Even without AGW we still have to simplify society due to resource constraints and the instabilities that come with that and diminishing returns to complexity. (See J. Tainter.) Once a society has reached a level where the resource base has been overshot there are two essential options: deceiving itself into believing it can overcome Nature with technology and/or bigger mo‘ai and the magical thinking that comes from both. The fact our economy is based on mythology is what has basically gotten us to this point, being based in a non-mathematical realities that do not even consider physical limits. This cannot go on. A resource-based economy, steady-state is not only a good idea for management of resources, it's absolutley necessary to avoid a collapsed society. This is a choice that is unavoidable. (See J. Diamond.)

    Such an economy requires localization based on bio-regional management of resources. Natural systems and resources will become far more a part of the materials we use. Natural building, virtually no cars, mass transit for the far less movement we will be doing, etc. A huge change will be a natural system of localized food production using regenerative methods, which are based in natural organizational principles. (See permaculture, 30-year Rodale study, Alan Savory, etc.) And this is the first leg of our carbon draw down. According to the Rodale study, very large amounts of carbon can be sequestered in soils, which is where it needs to be anyway. This has addtional positive effects such as mitigating flooding, reducing run-off into water systems and eliminating chemical runoff which is the primary cause of eutrophication. We can even green desert regions with this methodolgy and potentially choose to shape the hydrological cycle.

    The second leg of this is reforestation and aforestation. 40% of the dry weight of trees is carbon. Rebuilding lost forest ecosystems alone will draw down huge amounts of carbon based on estimates from Hansen, et al. I don't recal lthe number, but it is a minimum of 50 ppm, potentially double that. Adding to this a key element to a localized and highly resilient food system, Food Forests, would have hte same, but accelerated, effect given Food Forests are actively managed and accumulate carbon faster than a natural process of getting to an apex forest system. Whereas a prairie to forest process can take centuries, or more, reforestation, aforestation and food forests can reach apex in mere decades, and be essentially established within 7 years, particularly a Food Forest.

    These processes alone can get us to negative accumulation with no changes to our economic system. Add in a full shift to a localized, largely de-industrialized economic and social system with "renewable" (renewables are dependent on FFs, so are not truly renewable, yet) energy and we mazimize this even more be reducing the load we are putting into the atmosphere by 80 - 90 percent.


    In other words, those who call AGW irreversible are bdly incorrect and it is extremely dangerous to keep repeating this defeatist mantra. While it is not intentionally defeatist, it may as well be. Designing sysems depends on initial conditions and a needs analysis. This must have a realistic understanding of the resource base. But if you are convinced we will be living in a radically different world because we cannot draws down carbon, your planning will be skewed to adaptation rather than mitigation and will allow massive amounts of current resources to be lost altogether or squandered on trying to survive an avoidable future.


    The only reason to believe AGW is irreversible is to believe only long, slow natural feedbacks will draw it down. This is blatantly incorrect and is somethiung we need to stop repeating. Fast feedback, human-engineered, natural systems can get us back to < 300 ppm CO2 in mere decades.

    Moderator Response:

    [DB] Please provide proof citations for your claims, especially this one:

    Fast feedback, human-engineered, natural systems can get us back to < 300 ppm CO2 in mere decades.

    As that flies in the face of established oceanic chemistry.

  47. Ferran P. Vilar at 00:35 AM on 21 April 2013
    Global Warming: Not Reversible, But Stoppable

    Andy,

    Are you sure the climate system doesn't have any inertia? This is a general feature of  system dynamics. Doesn't the ocean act as an accumulator, as a capacitor in a circuit? What, then, is the meaning of "at equilibrium"?

    After a pulse of CO2, "about 40 percent of the equilibrium response is obtained within five years. This quick response is due to the small effective inertia of continents, but warming over continents is limited by exchange of continental and marine air masses. Even after a century only 60 percent of the equilibrium response has been achieved. Nearly full response requires a millennium." (Hansen, 2008, Earth's Energy Imbalance and Implications). I don't think Hansen refers to the socioeconomic system... I may have some misunderstanding here-

    Could you please clarify this for me?

    Thank you

     

  48. Global Warming: Not Reversible, But Stoppable

    @villalob#3, biochar would reduce or delay emittance for a 42 to 100 years. For USA only (based on 1999 figures) one would to torrefact 13,530,208,333 metric tons to replace the coal fired electricity. Pure biomass residues dry matter weight.

    Slightly more efficient approach is to do the torrefaction of the biomass and gassify an amount to produce high hydrogen containing syngas, helped by solar assisted steam generation (ISCC,IGCC combination). Capture the CO2 during cleaning of syngas and use in controlled (greenhouse) environment to boost plant productivity.

    Even capturing CO2 of coal would help right away and can be executed right away. Of course to use the CO2 in plantgrow stimulation not for enhanced oil recover methods.

    Anyway stop emitting of CO2

  49. Record snowfall disproves global warming

    Deniers I've argued with about this claim that this is a "post prediction" in that scientists were earlier saying we should expect warmer and drier witners.  Can someone provide me articles dis-proving this claim?

  50. Global Warming: Not Reversible, But Stoppable

    Damon Matthew's figure 1c doesn't seem to resemble what I recall seeing with regard to the 1% to 2x CMIP3 ensemble.  IIRC the temperature deceleration after stabilzation is much quicker.  Given that the actual growth has been much slower than a 1% growth, the deceleration should be even flatter.  Shouldn't it?

    Regards, AJ 

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