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Unforced variations: Nov 2011

Filed under: — group @ 31 October 2011

Once more unto the open thread…


341 Responses to “Unforced variations: Nov 2011”

  1. 201
    David B. Benson says:

    John @174 — The length of time series required depends upon the variance to be explained. Records with considerable internal variability require longer records to resolve the underlying trend.

  2. 202

    (#175). So where is Ira Glickstein? …
    Comment by MARodger — 14 Nov 2011 @ 11:08 AM

    Here I am and here is my answer to:

    (# 160). Hi Ira,
    I am just curious how one can look at the aggregate of the evidence and not be very concerned about the likely effects of climate change–particularly in a world that will have ~10 billion people and likely no source of cheap energy, fertilizer or organic chemical feedstock.

    That one can accept that greenhouse gasses are responsible for ~33 degrees C of warming and think you could double CO2 in the atmosphere without significant warming simply defies logic–as well as evidence.
    Comment by Ray Ladbury — 12 Nov 2011 @ 8:02 PM

    OK Ray (and MARodger), I accept the basic science of the Atmospheric “greenhouse effect” and that doubling of CO2 levels will, all else being equal, raise mean temperatures by 2-4.5ºC (IPCC) or 0.5-1ºC (some skeptics).

    According to the Mauna Loa data, CO2 levels have recently gone up by ~2 ppm/yr, so, to double from the current ~390 ppm would take until ~2200. Even if the rate of increase doubled to ~4 ppm/yr, which is highly unlikely, we would not see doubling until the year 2100.

    From the Ice Core record, we know that natural cycles and variations have caused mean temperatures to be much warmer and colder over the past few hundreds of thousands of years. That was prior to the industrial age. It was a period when hominids and early homo-sapiens survived and flourished (along with polar bears and other animal and plant life). Thus, we know that natural cycles and variations not under our control may augment or diminish human-caused warming.

    As you point out, if trends continue, populations will grow and sources of cheap (fossil) energy will deplete. Depletion of fossil fuels will self-limit further atmospheric CO2 increases. We have 100 to 200 years to adapt to carbon-neutral or carbon-free energy, and/or the 0.5º – 4.5ºC rise in mean temperatures we may see in the next century or two.

    Am I concerned about fossil fuels and do I want us to do something about it? YES! Since 2003 my wife and I have shared a single automobile (a hybrid Prius) and an electric golf cart, I do 40-50 miles on my bicycle each week, we have an energy-efficient home with extra insulation and a programmable thermostat, we recycle to the max, etc. But frankly, when it comes to fossil fuels, I am more concerned about our dependence on unstable foreign sources and the blood and treasure we have to spend to assure access than about the long-term dangers of a bit of warming.

    As for government mandates and subsidies, I used to support action on biomass, solar, and other alternative energy. However, I now realize the government is totally incapable of choosing the winners in a responsible way. Ethanol, as we now know, was a give-away of our money to powerful agricultural interests and corn-growing states, and has hardly saved any net CO2 while dropping my Prius MPG substantially. More recently, the half a billion dollar loan guarantee dropped down the Solyndra hole has political overtones.

    That is why I (along with James Hansen :^) have long favored a revenue-neutral carbon tax, charged at the mine, well or port of entry, where it will be efficient to collect and hard to cheat on, with the proceeds returned, on an equal basis, to every legal citizen. That will boost the net cost of energy for those of us who use more than the average, and put money in the pockets of those who use less. High-carbon industries will have to raise prices and thus lose business and profits, which will motivate them to make the most rational choices and use carbon-neutral/free sources when that makes economic sense. Greedy self-interest will pump money into alternative energy research and development more efficently than political payoffs.

    I think that makes more sense than having politically-connected special interests wreck the economy on the quesionable basis of fears of future warming that may or may not occur a century or two from now.

    I hope this answers your valid and thoughtful questions, Ray, and I look forward to further constructive and respectful cross-discussion with you, MARodger, and other members of the RC community.

  3. 203
    Ray Ladbury says:

    Ira, First, the preponderance of estimates–and evidence–favor a sensitivity of 3 degrees per doubling. If this estimate is incorrect, there is far more probability that it is higher than that it is lower. Second, there is the fact that CO2 will not increase linearly, but rather exponentially, increasing at least as quickly as energy consumption, doubling every 30-40 years. What is more, with China now growing rapidly, and India and Brazil not far behind, growth in energy may itself grow.

    I commend you on your life decisions and on your decision to accept the science and propose solutions rather than denying the facts as your buddies at WTFUWT do. I do, however, think that the risks are far higher than you evidently do. I also see little or no progress toward either developing a sustainable energy infrastructure, nor toward energy independence. What I see is a species in denial and a future generation whose future I don’t envy.

  4. 204
    MARodger says:

    For the record, Ira Glickstein @202, I’m with Ray Ladbury on this issue.
    Who are these “some skeptics” whose work you rate as highly as the IPCC? In your original version, these were “other experts” – do these experts also ignore pre-2011 emissions when discussing the doubling of CO2? And you mention that during ice-ages mankind “survived and flourished.” I’m not sure of the relevance. Is this your vision of mankind’s future, to survive and flourish in a returned stone age?
    And if you are minded to reply to this, Ira Glickstein, do remember RealClimate is about climate science which requires a tad more discipline than “reasonable” scepticism.

  5. 205
    SecularAnimist says:

    Ira Glickstein wrote: “More recently, the half a billion dollar loan guarantee dropped down the Solyndra hole has political overtones … political payoffs.”

    Solyndra has “political overtones” only because it has been dishonestly politicized by those who wish to undermine the rapid growth of the solar industry — which is, in fact, the fastest growing industry in America and the fastest growing source of new electricity generation on Earth. There is no evidence of any “political payoffs” in the Solyndra loan guarantee.

    Ira Glickstein wrote: “We have 100 to 200 years to adapt to carbon-neutral or carbon-free energy”

    Not according to the International Energy Agency, whose just released 2011 World Energy Outlook calls for urgent action to reduce GHG emissions within the next FIVE YEARS, which finds that:

    “Without further action, by 2017 all CO2 emissions permitted in the 450 Scenario [ie. limiting peak CO2 levels to 450 ppm, thereby limiting temperature rise to 2C] will be ‘locked-in’ by existing power plants, factories, buildings, etc … If stringent new action is not forthcoming by 2017, the energy-related infrastructure then in place will generate all the CO2 emissions allowed in the 450 Scenario up to 2035, leaving no room for additional power plants, factories and other infrastructure unless they are zero-carbon, which would be extremely costly. Delaying action is a false economy: for every $1 of investment avoided in the power sector before 2020 an additional $4.3 would need to be spent after 2020 to compensate for the increased emissions.”

    The IEA adds:

    “We cannot afford to delay further action to tackle climate change if the long-term target of limiting the global average temperature increase to 2°C, as analysed in the 450 Scenario, is to be achieved at reasonable cost. In the New Policies Scenario, the world is on a trajectory that results in a level of emissions consistent with a long-term average temperature increase of more than 3.5°C. Without these new policies, we are on an even more dangerous track, for a temperature increase of 6°C or more … rising fossil energy use will lead to irreversible and potentially catastrophic climate change.”

    Two additional points:

    First, as others have already pointed out, the claims of extremely low climate sensitivity by “some skeptics” are not credible and are inconsistent with empirical observation.

    Second, in 2010 anthropogenic GHG emissions rose at the highest rate ever recorded, to the highest levels ever recorded, exceeding even the worst-case emissions scenarios contemplated by the IPCC. Without urgent action to reduce emissions, any hope of avoiding the most catastrophic consequences of AGW is rapidly fading.

    The individual energy conservation measures that you describe are all well and good, but they are not sufficient — government and corporate policies to reduce GHG emissions (and indeed to make it easier and more affordable for individuals to take the actions that you describe) are essential, as the IEA makes clear.

  6. 206
    Susan Anderson says:

    This gives the skinny on Solyndragatepocalypse and puts it in proportion, as well as being brief and amusing.
    http://www.markfiore.com/political-cartoons/watch-solyndra-solar-green-tech-obama-stimulus-environment-animated-video-mark-fiore-animation

    Meanwhile, back at the ranch, I see something about an award: is this a new one or the same as mentioned earlier.? Regardless, well deserved and then some!!!!

    “Mann to receive Hans Oeschger Medal from European Geosciences Union”
    http://live.psu.edu/story/56383

  7. 207

    THANKS Susan Anderson (#206), SecularAnimist (#205), MARodger (#204), and Ray Ladbury (#203) for your serious comments and questions. (Sorry for the length of this comment, but I am answering four postings at once.)

    Susan, THANKS! I watched the amusing SolyndraGateApocalypse video and agree that there should be absolutely NO subsidies that amount to government picking winners. As the video points out, the lion’s share always goes to the most established interests with the most lobbyists, namely Big Oil, Big Power, Big Labor, and energy-rich states.

    Solyndra is a nit (if half a billion can be so described) but appears more eggregious because it went down the hole so soon after we taxpayers put money into it. These bad investments of public money (yours and mine) usually have the courtesy to wait till the next administration before going bust.

    So, let us agree to let greedy, self-interested market forces, spurred on by an umbrella over carbon free/neutral energy provided by the Hansen/Krauthammer/WSJ Revenue-Neutral Carbon Tax, rather than letting the government pick winners. And, as I (and Hansen) describe it, it is a redistributive tax, taking from big energy users (usually the rich) and giving to small (usually the poor).

    SecularAnimist, if you don’t see “political overtones” in Solyndra, you must be tone deaf. Just go to CNN for the timeline.

    As for the FIVE YEAR deadline in your IEA links, that is for CO2 to reach 450 ppm, which would require the current +2 ppm/yr CO2 rate to increase by an average over the next few years of +12 ppm/yr, which is physically impossible. Yes, I know they are counting the CO2 in the “pipeline” to get to their doomsday estimates, but I do not put much credence in that.

    My 200 year estimate is based on doubling from 390 to 780, and my 100 year allows for the CO2 rate to double from the current 2 ppm/yr to 4 ppm/yr.

    MARodger: No, I do not want to go back to stone age conditions. My point is that hominids and early homo-sapiens (and polar bears and other animals and plant life) survived and flourished over multiple ~100,000-year cycles of much higher- and lower-than current temperatures and CO2 levels. Given our science and technology, almost totally lacking in ancient times, we will adapt. As the history of the Roman and Medieval warm times, and the Little Ice Age sunspot minima teaches us, environmental changes are adapted to. Some populations gain and others lose, with a net benefit to human civilization.

    Ray Ladbury: In my comment, I allowed a CO2 sensitivity range of 0.5ºC to 4.5ºC (average = 2.5ºC, pretty close to your 3ºC estimate).

    The fact is, that despite continued rapidly rising CO2 levels, natural variability seems (taking the midline of the error bounds) to have reduced the rate of warming over the past decade and a half to very near zero. Of course, it is possible for that to happen with CO2 sensitivity at 3ºC or even 4.5ºC, but quite a bit more likely if the actual sensitivity is on the lower end of the reasonable range.

    The way the IPCC gets above 1ºC sensitivity is to assume that the net feedback effect of clouds (i.e., increased water vapor due to the warming) on temperatures is positive. If it is neutral, the calculations favor 1ºC and if net negative, lower sensitivities. Either side could be right. Time will tell.

    I allowed that CO2 rise might double from the current 2 ppm/yr to 4 ppm/yr, which is how my ~200 year window for doubling got reduced to ~100 years.

    Your most recent comment says that CO2 will grow exponentially “doubling every 30-40 years”. But in a previous comment, you wrote “…particularly in a world that will have ~10 billion people and likely no source of cheap energy, fertilizer or organic chemical feedstock.” [Emphasis added].

    I assume by “cheap energy” you mean fossil carbon. So won’t carbon energy be depleted by the time the world population passes ~10 Billion (several decades at current rates)? Won’t lack of carbon energy sources retard and eventually reverse the growth of CO2 levels in half a century or less? So how can they double more than once, which I allowed for in my 100 year low bound on CO2 doubling? Where did I go wrong on this rather simple math?

    Oh, Ray, I am a Guest Contributor at WUWT – you seem to have made a typographical error on that acronym :^)

  8. 208
    Andrew W says:

    On his WUWT post Ira Glickstein says: “The point of this posting is that, whatever the difficulties, it is possible for skeptics to post over at RC, so long as we are not too blatant about it, and if we are not too sensitive about our words being edited.”

    Well, after pointing out factual errors in claims made by Anthony at WUWT, none of my comments have been posted on that blog for about a year.

  9. 209
    SecularAnimist says:

    Ira Glickstein wrote: “As for the FIVE YEAR deadline in your IEA links, that is for CO2 to reach 450 ppm, which would require the current +2 ppm/yr CO2 rate to increase by an average over the next few years of +12 ppm/yr, which is physically impossible. Yes, I know they are counting the CO2 in the ‘pipeline’ to get to their doomsday estimates, but I do not put much credence in that.”

    Either you did not read the IEA report, or you did not understand it, because your account of it has nothing to do with what the report actually spells out.

    And it is evident from all of your comments that you “put credence in” whatever claims support your predetermined conclusions, no matter how nonsensical or contrary to observed facts those claims may be.

    Ira Glickstein wrote: “if you don’t see ‘political overtones’ in Solyndra, you must be tone deaf. Just go to CNN for the timeline.”

    Yes, I am “deaf” to dishonest politicization of the Solyndra matter. The “timeline”, of course, begins with the Bush administration’s selection of Solyndra to receive a DOE loan guarantee, and the Bush administration’s efforts to push that loan guarantee through before Obama was even sworn in. Which, presumably, the Bush administration did to reward an Obama campaign contributor.

  10. 210
    JCH says:

    5 x 12 = 60
    60+390 = 450

    Lol. Okay, I’m not bright, but good grief Ira, is that really what you thought?

  11. 211
    J Bowers says:

    Major storms could submerge New York City in next decade

    Sea-level rise due to climate change could cripple the city in Irene-like storm scenarios, new climate report claims.
    […]
    The report, commisioned by the New York State Energy Research and Development Authority, said the effects of sea level rise and changing weather patterns would be felt as early as the next decade.

  12. 212

    (# 208). On his WUWT post Ira Glickstein says: “The point of this posting is that, whatever the difficulties, it is possible for skeptics to post over at RC, …”

    Well, after pointing out factual errors in claims made by Anthony at WUWT, none of my comments have been posted on that blog for about a year.

    Comment by Andrew W — 16 Nov 2011 @ 2:35 PM

    Andrew W, I am not a Moderator at WUWT, so I do not know if you were on some sort of no fly list over there. However, just today they posted your comment on my current WUWT topic where you claim WUWT “…simply bans people who can point out factual errors in claims made here.” The WUWT Moderator replies, “[Not sure about that, but I am under no such instruction. I will however snip personal abuse…]”

    OK, your most recent comment was passed and the WUWT Moderator says your future comments will pass if they do not contain “personal abuse” which seems like fair dinkum to me.

    My (unsolicited) advice is to try to post over there again, on topic with a “just the facts ‘mam” demeanor. While I have complained a bit about RC in my postings to WUWT, over here at RC I have scrupulously avoided any reference to those issues, and have been (almost excessively) courteous. If you post in that manner at WUWT, I suspect you will get through. If you think they have blocked any of your postings, please send a copy to me, Ira@techie.com, and I promise to look into it.

    [Response: Discussing comment moderation issues at any blog are extremely tiresome. No more on that please. – gavin]

  13. 213
    SecularAnimist says:

    J Bowers quoted The Guardian: “Sea-level rise due to climate change could cripple the city in Irene-like storm scenarios, new climate report claims.”

    Indeed, some readers will recall that New York city officials ordered the evacuation of 370,000 residents of low-lying areas of the city as Irene approached — and for good reason.

    As it happened, by pure luck, Irene followed a path that spared New York City a massively destructive inundation (Vermont got clobbered instead).

    The streets and buildings of New York City don’t have to be submerged for the place to become uninhabitable. All it takes is for the sewer system to be flooded. Millions of people in one of the most densely populated cities in the world — and all the toilets backing up. Not a pretty picture.

  14. 214
    Hank Roberts says:

    For Ira Glickstein — you said, or suggested, that you’re an engineer (back when you thought ten years was sufficient to determine a trend for annual climate data, see above). You got that straightened out, I think.

    You might want to read something from the engineering side on CO2 amounts over time. This may help. http://www.nap.edu/catalog.php?record_id=10798
    Authors: National Academy of Engineering, National Research Council
    “… a simple quantitative estimate of when the greenhouse problem will become dangerous. It won’t be next year—but when? If we assume the greenhouse problem will become serious when the carbon dioxide (CO2) concentration in the atmosphere reaches twice the preindustrial concentration, it will happen sometime in the second half of this century, if current trends continue. Is doubling … entering the danger zone? Some have proposed a lower figure…”

    As others pointed out above, your understanding of the numbers seem a bit off in this regard as it was on detecting trends in noisy data. There are likely clearer expositions available; possibly even in the FAQ section; someone may have a suggestion.

    (Folks, remember what we know works — don’t quote wrong information — point to correct information sources and encourage the readers to work through the examples, eh?)

  15. 215
    Ray Ladbury says:

    Ira, First, you speak as if all values between 0.5 and 4.5 are equally probable. They are not. The probability that sensitivity is greater than 3 is significantly greater than the probability is less. The probability that sensitivity is less than 2 degrees per doubling is less than 5%, and the probability that it could be as low as 1 degree is nil. It is virtually impossible to get the climate system to look Earthlike if sensitivity is less than 2.

    And no, cloud feedback in the models is not positive because it is assumed to be, but rather because the evidence suggests that it is positive.

    As to your mathematical error, consider this: if the increase in energy consumption is x% per year, and current consumption is A, then the increase in consumption dA=x%Adt, A will increase as exp(xt/100). The data show global energy consumption icreasing at about 4.6-5% per year and so doubling every 14-15 years.

    I’ve done the math, and there is enough coal, oil, natural gas, tar sands, etc. to quadruple the CO2 content of the atmosphere to over 1000 ppmv. This would bring us, with high probability, to ~6 degrees above preindustrial levels–puite possibly this century. This is well into the danger region.

  16. 216
    ccpo says:

    Chris R., There are no solutions at present. None. Merely reducing consumption, as I said, is not a solution, but merely an exercise in buying time. It is by no means certain that we can even find solutions in time to avert severe consequences. The fact that the problem is difficult makes it all the more criminal that fossil fuel interests have successfully prevented society from even acknowledging the problem, let alone working toward solutions.

    Comment by Ray Ladbury — 5 Nov 2011 @ 6:52 PM

    Bah-humbug, Ray. Of course there are solutions. And why is reducing consumption not one of them? You could use some edumacation in regenerative design.

    Hansen says reducing extraction and use of FFs and improving agroforestry and farming to regenerative practices, we can below 350 within decades. (Page 15, section 31. NOTE: I thought I saw a number for forestry in one of his publications not long ago.): http://www.columbia.edu/~jeh1/2010/201010_BluePlanet.pdf

    Rodale study finds carbon farming, aka regenerative farming aka permaculture-based farming can sequester GHGs equal to 40% of current emissions: http://www.ifoam.org/growing_organic/1_arguments_for_oa/environmental_benefits/pdfs/Rodale_Research_Paper_Regenerative_Agriculture.pdf

    We can do this. Principle: natural before technical solutions.

  17. 217
    CM says:

    Ira,

    The way the IPCC gets above 1ºC sensitivity is to assume that the net feedback effect of clouds (i.e., increased water vapor due to the warming) on temperatures is positive. If it is neutral, the calculations favor 1ºC and if net negative, lower sensitivities.

    You’ve got some basic stuff confused here. Cloud is not water vapor, and cloud feedback is not identical with water-vapor feedback. The latter is beyond a doubt positive, as water vapor is a powerful greenhouse gas. Increased water vapor also comes with a negative feedback called the lapse-rate feedback. Scientists have a pretty good handle on their combined effect. What remains uncertain is the magnitude of the cloud feedback.

    You don’t need positive cloud feedback to get sensitivity above 1 °C. Given neutral cloud, the water-vapor (less lapse-rate) and surface albedo feedbacks should get you to 2 °C (AR4, I: 8.6.2.3). And neutral cloud does not appear to be what we’re given.

  18. 218
    Nick Gotts says:

    “From the Ice Core record, we know that natural cycles and variations have caused mean temperatures to be much warmer and colder over the past few hundreds of thousands of years. That was prior to the industrial age.”

    We also know that the periodicity of these natural cycles and variations is in the range 20,000 – 100,000 years.

    “It was a period when hominids and early homo-sapiens survived and flourished (along with polar bears and other animal and plant life).”

    Actually it was a period during which most of the Earth’s megafauna disappeared, although that is in my view probably due mostly to human activity rather than climatic change. But the implication is that climate changes of lesser magnitude are nothing to worry about. This is breathtakingly complacent: global ecosystems are already severely stressed by the presence of seven billion people, likely to grow to at least 9.5 billion, changes in dietary habits toward greatly increased global meat and dairy consumption, and the depletion of crucial resources such as fresh water, soil, fish, available phosphorus and key metals. Moreover, while Homo sapiens as a species flourished, we simply have no way of knowing how much human suffering resulted from climate change; what is clear is that in the modern world, quite small climate changes would threaten the livelihoods of hundreds of millions of people.

  19. 219
    MARodger says:

    As a ballpark figure, recent annual rises in CO2 levels have roughly doubled in the last 40 years, (See a graph of recent CO2 levels rises here) and that is 40 years of big rises in fuel price. Such a doubling every 40 years will result in 800ppm or so by 2100.

  20. 220
    Nick Gotts says:

    “the net feedback effect of clouds (i.e., increased water vapor due to the warming) on temperatures is positive” – Ira Glickstein

    Good grief. Are we expected to take someone who makes such a stunningly elementary error as confusing the feedbacks from water vapour and from clouds seriously?

  21. 221
    MARodger says:

    What to make of the responses of Ira Glickstein @207 to my own questioning @204?
    It seems that climate sensitivity may turn out to be in the range 2.0-4.5 (UN IPCC) or 1.0-0.5 (some unnamed skeptics) but it doesn’t matter. Even if there is a tripling of atmospheric CO2, it doesn’t matter a jot because whatever the climate throws at us mankind will adapt, mankind will survive and flourish. The proof of this is that a tiny ignorant population of cave men survived and flourished in the face of past humongous ice ages despite lacking any modern technology. If that wasn’t enough proof, history teaches us that mankind adapts to climatic changes. Medaevial warm times, Little Ice Ages – easy peasy. Okay there were some losers but such changes brought a net benefit to mankind’s adaptable civilisation.
    Wow! Perhaps, if this is true, we should be adding even more to the climate change so as to reap more of those wonderful ‘net benefits’.
    In summation, Ira Glickstein avoids two seemingly straightforward questions while explaining that manifest destiny will ensure it all works out just fine for us. He forgets that RealClimate is about climate science not his usual brand of “reasonable” skepticism.

  22. 222

    “The proof of this is that a tiny ignorant population of cave men survived and flourished in the face of past humongous ice ages despite lacking any modern technology.”

    Amazing, isn’t it, how ‘modern technology’ supposedly trumps everything, including a full suite of functioning ecological services?

    The writer above evidently believes that ‘past performance IS a guarantee of future results’–provided only that there is some vague similarity somewhere, such as humans being involved.

  23. 223
    Hank Roberts says:

    “For ’tis sport to have the engineer/ Hoist with his own petar …”

  24. 224
    Hank Roberts says:

    So, how, and for how long, has meltwater been getting frozen onto the bottom of the Antarctic ice? http://www.bbc.co.uk/news/science-environment-15749757

    “radar data has indicated the base of the sheet has been severely disrupted by water that has been freshly frozen, layer upon layer, on to the bottom of the ice column. ANTARCTIC GAMBURTSEV PROJECT (AGAP)”

    This is not entirely new, e.g. “Refrozen water, unexpectedly discovered in the EDML (EPICA Dronning Maud Land) borehole, will be analysed for dissolved and particulate trace elements as well as gases to determine the origin and history of the sub-glacial water….” http://www.awi.de/en/research/research_programme/paces_2009_2013/the_changing_arctic_and_antarctic/wp_1_role_of_ice_sheets/

    and

    “UNEXPECTED BASAL CONDITIONS UNDER ANTARCTIC ICE STREAM C DISCOVERED WITH A NEW BOREHOLE VIDEO PROBE

    Barclay Kamb and Hermann Engelhardt (Caltech),
    Frank Carsey, Lonne Lane, and Alberto Behar (JPL)

    In a recent study of Anarcticas Ice Stream C, a joint NSF-NASA research team has discovered a surprising gap between the base of the ice stream and the rock below. The gap is up to 1.4 m (60 inches) wide, and is filled with water at a pressure nearly high enough to lift the ice stream off its bed. The discovery is significant in relation to the mechanism for rapid movement of the ice streams, which are huge, fast-flowing ice currents within the slow-moving ice sheet that covers most of Antarctica. The mechanism for their rapid movement is being intensively studied because of the possibility that rapid ice-stream flow may cause the ice sheet to disintegrate, resulting in a disastrous rise in world-wide sea level….the width of the gap … = 1.5 m (59 inches)…. The horizontal dimensions of the gap were beyond the illumination from the probe’s sideward-shining floodlamp, which is thought to be about 0.5 m under the conditions of the water clarity that prevailed in borehole no.3.

    The discovery of a substantial gap between the base of the ice and the bed is quite surprising. ”
    http://glaciology.caltech.edu/upc/pressrelease.html

    (Aside, it may not be meltwater, pure speculation on my part, but liquid water also turned up in the deepest hole ever drilled, into rock, by the USSR: http://www.damninteresting.com/the-deepest-hole/ )

  25. 225
    Ray Ladbury says:

    ccpo,
    The reason why I am more pessimistic than you is that I define the problem more broadly than simply climate change. In my mind it is a combination of rising population, rising expectations/development and resource depletion, along with the challenges posed by solutions to these issues. It is pretty much inevitable that population will rise to at least 9 billion, and probably closer to 10 billion by around mid century.

    The key to holding it to these levels is increased development, and that will entail increased consumption by the majority of humanity. If their standard of living does not rise dramatically, fertility rates will not fall. High fertility and high poverty will itself pose serious environmental threats–complete deforestation, desertification, depletion and consequent loss of aquifers and other groundwater, growth of ocean dead zones and so on. To avoid these threats, consumption will actually have to rise, but given the lack of renewable energy alternatives, this will worsen climate change, further deplete critical resources and probably decrease overall soil fertility and agricultural productivity.

    Now let us assume that everything goes according to plan. We hold population to 10 billion and it slowly starts to decrease. Then we face all the challenges of an aging and falling population (viz. Japan) but on a global scale. The only way to deal with these issues is increased productivity (per person). This, too will require increased energy consumption (unless we can figure out how to harness Rosenfeld’s law the way we did for Moore’s law).

    Now, of course, all this would be different if we’d started to tackle these problems in the mid ’70s as we should have, rather than another 40 years of “Bidness as usual”, but we didn’t. It is distinctly possible that now we are too late to avoid all but the absolute worst of outcomes.

  26. 226
    Ray Ladbury says:

    Nick,
    Ira is here to be educated–as am I…as are you. Time will tell whether the learning curve of any of us has a positive slope. So far, he at least seems willing to listen.

  27. 227
  28. 228

    Kevin McKinney (#222), MARodger (#221, #219), Nick Gotts (#220, #218), CM (#217), Ray Ladbury (#215), and Hank Roberts (#214) – THANKS for your comments and questions.

    Hank Roberts Statistical significance is a well-established concept that I used during my multi-decade career as a System Engineer and in my System Science PhD work. It was first brought into the RC Times Atlas thread when I paraphrased Phil Jones, former head of the UK CRU. You are correct that, in the case of mean surface temperature, a decade of data is insufficient to determine that the conclusion has less than a 5% chance of being wrong. However, that does not prevent us from looking at the midline of the temperature record error bounds and noticing that the rise seems to have flattened out over the past decade and a half. That could be a mistaken conclusion, but it is still more probable than that the rise remained the same as the previous decade.

    Kevin McKinney: There are no guarantees, but the past is usually something of a guide to the future. We (humanity) will either cut fossil fuel use drastically -or- we will learn to adapt to some rise in mean temperatures -or- we will have another Little Ice Age, or something between those extremes. Given political and economic realities, which do you think is more likely?

    MARodger: I did not say everything will work out fine for all of humanity “easy peasy”. Lots of people starved during the Little Ice Age and lots were killed by the Roman Legions during the Roman Warm period. Do you think humanity will drastically cut fossil fuel use any time soon? If not, we will have to adapt to climate change as we have in the past.

    You are correct that the rate of rise in CO2 has gone from about 1 ppm/yr to about 2 ppm/yr over the past 40 years. If that rate of rise continues (unlikely due to depletion of cheap fossil fuels), it will be 4 ppm/yr in 2050 and 8 ppm/yr in 2090. You conclude that that will result in a CO2 level of up to 800 ppm in 2100. In my original comment, I said CO2 could double from 390 to 780 by 2100, so we are on the same page.

    Nick Gotts: Warming causes relatively more water vapor in the Atmosphere, causing relatively more clouds. Yes, I know when water vapor condenses into clouds it reflects incoming Sunlight, so daytime clouds have net negative feedback, nighttime clouds have positive feedback, and both differ from uncondensed water vapor. There is net negative feedback from precipitation and storm events, and so on. The key issue is that additional water vapor, due to additional warming from rising CO2 levels, has an effect on CO2 sensitivity. Absent the water vapor/clouds/precipitation effects, CO2 sensitivity would be about 1ºC. IPCC assumes net positive feedback and gets 2ºC-4.5ºC. Some skeptics assume net negative feedback and get less than 1ºC.

    You say “…Actually it was a period during which most of the Earth’s megafauna disappeared, although that is in my view probably due mostly to human activity rather than climatic change…” Are you claiming that early homo sapiens, over 100,000 years ago, killed off most of the large animals, and it was not due the cold climate?
    Please explain.

    CM: Estimates of CO2 sensitivity are all over the place, with even the IPCC giving a range of more than two to one. Time will tell.

    Ray Ladbury: You earlier said, given current trends, cheap energy (which I assume means fossil carbon) would not be available when the population reaches ~10 Billion. You now say there is enough to raise CO2 to over 1000 ppm, raising temperatures by ~6ºC over pre-industrial levels this century (before 2100). I think that is a stretch, but time will tell. Sadly you and I will not be around to see it.

    Hank Roberts: In my earlier comment, I did say CO2 levels could double as early as 2100, and you quote a study that says sometime in the second half of this century, which means between 2051 and 2100. Possible, but not likely due to depletion of cheap fossil fuels and consequent development of effective carbon-neutral/free energy in response to market forces. But I could be wrong.

  29. 229

    I am writing a little article about civilization in 2150. At this time, I predict a WW population of abot 500 million, as nothing of substance gets done about CO2 levels until 2050. Comments appreciated — hossradbourne@gmail.com

  30. 230

    #205, 207, 209, 210–

    Specifically, the original quote from SA said:

    “If stringent new action is not forthcoming by 2017, the energy-related infrastructure then in place will generate all the CO2 emissions allowed in the 450 Scenario up to 2035, leaving no room for additional power plants, factories and other infrastructure unless they are zero-carbon, which would be extremely costly.”

    So, change *BY 2017* is needed to avoid 450 ppm *BY 2035.* (Cross-checking, 2 ppm x 24 years gives an increase of 48 ppm over today’s 392, or 440 ppm. Not much acceleration needed, then, to hit 450 by 2035–and 24 years for carbon cycle feedbacks to kick in.) Yeah, you could say that’s “CO2 in the pipeline,” but there is clearly a limit to how fast you can replace massive amounts of expensive (and essential) infrastructure.

    This is the problem in a nutshell–we need to act well BEFORE the consequences are obvious in order to avoid the worst damage.

    (IMO, we’re already too late to avoid significant damage; for instance, I think there’s essentially no chance of preserving September Arctic sea ice at this point. Feedbacks from that eventuality seem not to be well-characterized, as far as I can tell, especially in terms of atmospheric circulation.

    (But, hey, it could be worse than just losing September sea ice. Much worse, actually–6 or even 8 C warming over the planet as a whole, instead of (as at present) just over the mid-Arctic. Doing nothing would be a good way to get there.

    (By the way, a “back of the envelope” question–what, I casually wonder, would be the CO2 feedback effect of, say, warming nearly the entire surface of the Arctic Ocean by (arbitrarily) 5 C for a month, assuming it were nearly all open water?)

  31. 231
    vukcevic says:

    Re: john burgeson says:
    17 Nov 2011 at 10:52 AM
    …….
    Here is something just up your street: The other day I extrapolated the temperature data for Central England region up to 2150. It is based on the currently available CET data, with 0.25C/century rise applied to the oscillation (the average during last 350 years).
    I was surprised by the result:
    http://www.vukcevic.talktalk.net/CET-NVa.htm
    the extrapolation is based on this more detailed graph:
    http://www.vukcevic.talktalk.net/CET-NV.htm
    Natural variability law is derived directly from the CET data and may be applicable to the North Atlantic only.
    The projection is confirmed by my solar formula too, devised some 8 years ago,
    http://www.vukcevic.talktalk.net/NFC7a.htm
    when the NASA was predicting high solar activity for the most recent cycle. To my astonishement this turn out ok. It is based on the little known polar magnetic field data, as shown here:
    http://www.vukcevic.talktalk.net/LFC2.htm
    I have no opinion on any of this; I just apply data and put results on line.
    Fiction? May be, so is your article, I assume.

  32. 232
    CM says:

    Ira (#228, in response to my #217 and Nick’s #220),

    Sorry, you don’t get to go “estimates… are all over the place… even the IPCC… time will tell.” That’s not the point. The point is that you goofed by conflating cloud feedback with water vapor feedback. These are best kept distinct, for various reasons. In particular, the uncertainty of the combined water vapor/lapse rate feedback is not nearly as wide as the cloud uncertainty—as your statement would suggest to the unwary reader that it is.

    Moreover, you goofed when you claimed that only positive cloud feedback accounted for IPCC’s climate sensitivity estimate being over 1 °C. I showed you chapter and verse of the IPCC report where it clearly says otherwise. The IPCC no-feedback point estimate of one degree was good enough for you when you were misrepresenting it, so when your misrepresentation is pointed out, it really will not do to reply that the IPCC gives a range anyway. Besides, the range it gives is clearly stated in the reference I gave you: “…in the absence of cloud feedbacks, current GCMs would predict a climate sensitivity (±1 standard deviation) of roughly 1.9°C ± 0.15°C (ignoring spread from radiative forcing differences).” That range does not support your claim at all.

    C’mon, stop swerving and say it, “I goofed.” You’ll feel better, and we won’t be tempted to impugn your learning ability or, heaven forbid, your honesty.

  33. 233
    MARodger says:

    Ira Glickstein @228. Your position is changing by the day. @202 we had ice age men entering the discussion for reasons that were beyond me. They reappeared @207 along with some Romans and looked to be presented as evidence of man’s ability to adapt to climatic changes. “As the history …… teaches us, environmental changes are adapted to. Some populations gain and others lose, with a net benefit to human civilization.

    Now @228 you are strongly questioning man’s ability to avoid climate change, that humanity will thus be forced to adapt and emphasising that it will not be fine for everyone – no sign of ice age men & no mention of ‘net benefit’ although the walk-on straw man was shot down.

    Perhaps it would be best to concentrate on straightforward things that cause less confusion. What of the “some skeptics” (that you initially termed as “other experts”), those who calculate climate sensitivity at 1.0 to 0.5 deg C – they remain still unnamed although I note you cite these “other experts” again here @228. And are these “other experts” responsible for you’re ignoring pre-2011 emissions when considering doubled CO2? Answers still awaited on these from @204. These are answers that should be easy peasy.

  34. 234

    “We (humanity) will either cut fossil fuel use drastically -or- we will learn to adapt to some rise in mean temperatures -or- we will have another Little Ice Age, or something between those extremes. Given political and economic realities, which do you think is more likely?”

    Well, #3 is unlikely any time soon, I think, so I’ll say that a combination of #1 and #2 is most likely.

    I’m advocating as forcefully as I know how that we do as much of #1 and as little of #2 as possible, since available evidence indicates that this will be most likely to bring about the least deleterious results.

    How about you, since we’re getting all friendly now?

  35. 235
    David B. Benson says:

    john burgeson @229 — Too large by a factor of at least 50.

  36. 236
    JCH says:

    According to this, at the time written, the anthropogenic component of atmospheric CO2 was doubling every 31 years. It’s currently ~110 ppm, so it would reach ~220 ppm by 2042, and ~440 ppm by 2073. Atmospheric levels of ~500 ppm in 2042 and ~720ppm in 2073.

    A lot of people around the net are claiming this is simply impossible. Ray Ladbury indicates it is possible.

    Is there enough FF to do it? I do not think FF will have to be cheap in order to do it.

  37. 237
    wili says:

    It is depressing to come here and find otherwise intelligent people chasing their tails trying to reason with obvious trolls.

    I don’t suppose there is any chance of drawing anyone away from this useless pursuit and into a discussion of this article–

    http://www.newscientist.com/article/mg21228392.300-hyperwarming-climate-could-turn-earths-poles-green.html?full=true

    “Hyperwarming climate could turn Earth’s poles green”

    “…In particular, the release of methane from melting Arctic permafrost has not yet been factored in. Methane is a potent greenhouse gas, but remains in the atmosphere for only 10 years on average before it reacts with hydroxyl radicals in the air to form CO2. However, a large release of methane from melting permafrost could swamp the hydroxyl supply, allowing the methane to linger in the atmosphere for 15 years or more, further amplifying the warming (Global Biogeochemical Cycles, DOI: 10.1029/2010GB003845).

    Some feedbacks never before considered might also come into play. Pearson says that in the future oceans may store less carbon. Normally some atmospheric carbon is lost at sea, buried in the carcasses of tiny marine animals. But sediment from the Eocene contains little carbon, suggesting that this process failed during the last hothouse (Paleoceanography, DOI: 10.1029/2005PA001230).

    To work out why, Pearson looked at fossils of foraminifera, microscopic shelled marine animals. The tiny shells contain a chemical record of the position the animals occupied in the water column when they were alive. He found that Eocene foraminifera lived closer to the ocean surface than they do today, suggesting there was little food to sustain deeper-dwelling species.

    Pearson thinks the warmer temperatures allowed bacteria at the ocean surface to metabolise faster, recycling carbon before it could sink and feed foraminifera living at depth. “If we warm the planet now, we switch on our bacteria,” he said last month at a Royal Society discussion meeting in London.

    A warming climate will also see trees and other large plants spreading north into the Arctic, says Bette Otto-Bliesner of the US National Center for Atmospheric Research in Boulder, Colorado, who also attended last month’s Royal Society event. Plants are darker than snow, so they absorb more of the sun’s radiation. When Otto-Bliesner plugged the effect into a climate model of the Arctic, it got 3 °C warmer.

    Then there’s hyperwarming. Ed Landing of the New York State Museum in Albany coined the term to describe the spiralling temperatures seen during the Cambrian period as a result of rising sea levels.

    Vast areas of the continents were covered with shallow seas during the Cambrian, which began 542 million years ago, because sea levels were sometimes tens of metres higher than today. Sea water absorbs more of the sun’s heat than land, so swamping the continents caused the planet to warm up even more. Sea temperatures reached 40 °C and oxygen levels in the water crashed …”

  38. 238
    Pete Dunkelberg says:

    wili – New scientist article – OK,so New Scientist can go overboard in either direction. I thought their Oct 22 – 28 article was pretty good:
    http://www.newscientist.com/article/dn21049
    http://www.newscientist.com/special/climate-knowns-unknowns

    More form NS:
    http://www.newscientist.com/topic/climate-change

    wili, we don’t know how far this warming will go because we don’t know how soon The Revolt Of The Humans will put an end to Big Carbon’s diabolical desires. Take action to increase the reality oriented community.

  39. 239
    Hank Roberts says:

    > ocean surface, bacteria
    Not news, except in the sense of very bad news already warned of.
    Cassandra file item.

    https://www.google.com/search?q=ocean+bacteria+“Jeremy+jackson”

    You’ll be seeing oceanographers and marine biologists moving away from the seashore a bit sooner than everyone else if he’s right about the rise of slime.

  40. 240
    john byatt says:

    Calibrating the End-Permian Mass Extinction

    Shu-zhong Shen1,*, James L. Crowley2,3, Yue Wang1,*, Samuel A. Bowring2,*, Douglas H. Erwin4,5, Peter M. Sadler6, Chang-qun Cao1, Daniel H. Rothman7, Charles M. Henderson8, Jahandar Ramezani2, Hua Zhang1, Yanan Shen1,9, Xiang-dong Wang1, Wei Wang1, Lin Mu1, Wen-zhong Li1,10, Yue-gang Tang11, Xiao-lei Liu1,12, Lu-jun Liu1, Yong Zeng13, Yao-fa Jiang14, Yu-gan Jin1
    .

    ABSTRACT

    The end-Permian mass extinction was the most severe biodiversity crisis in earth history. To better constrain the timing, and ultimately the causes of this event, we collected a suite of geochronologic, isotopic, and biostratigraphic data on several well-preserved sedimentary sections in South China. High-precision U-Pb dating reveals that the extinction peak occurred just before 252.28 ± 0.08 Ma, following a decline of 2‰ in δ13C over 90,000 years, and coincided with a δ13C excursion of -5‰ that is estimated to have lasted ≤20,000 years. The extinction interval was less than 200,000 years, and synchronous in marine and terrestrial realms; associated charcoal-rich and soot-bearing layers indicate widespread wildfires on land. A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction.

    http://www.sciencemag.org/content/early/2011/11/16/science.1213454

  41. 241
    Richard Simons says:

    john burgeson @229: I claim no particular expertise in that area, but I would not quibble with your estimate of future population size. A concern I have with some of the higher estimates I’ve seen is that they appear to focus on one element e.g. demographic transition, irrigation water) and ignore other, interacting elements (e.g. cost of energy, plastics and N fertilizer, food fish supply, climate change). I would be happy to be put right if anyone knows of a decent attempt to consider all factors when looking at likely sustainable population size.
    How do you envision the population size reducing? Is it by birth control measures, mass regional starvation, global epidemics, civil war or invasion and genocide, or a mixture of all of these? These would drastically alter the attitudes and skill sets of survivors, as well as impacting on the infrastructure.

  42. 242
    Ray Ladbury says:

    Ira, I said there was sufficient carbon to raise CO2 levels above 1000 ppmv. I didn’t say that would be cheap carbon. I don’t expect people to stop burning fossil fuels merely because they become more expensive. In parts of India, they burned wood ’til there were no trees left.

  43. 243

    (#242) Ira, I said there was sufficient carbon to raise CO2 levels above 1000 ppmv. I didn’t say that would be cheap carbon. I don’t expect people to stop burning fossil fuels merely because they become more expensive. In parts of India, they burned wood ’til there were no trees left.

    Comment by Ray Ladbury — 18 Nov 2011 @ 3:17 PM

    As any commodity becomes more expensive (in this case cheap fossil fuels), prices go up and that provides an incentive and market for alternatives (in this case more efficient use, recycling, and carbon free/neutral fuels). So, while I have no doubt, Ray, there is enough carbon in the ground to raise CO2 levels above 1000 ppmv, it is unlikely to ever happen due to the cost. Once the cost of carbon rises above the cost of non-carbon alternatives, market forces will cause the most intelligent consumers and producers to switch. The problem with having government pick the winners is that they always favor established special interests.

    James Hansen and I favor a revenue-neutral carbon tax with all proceeds returned to legal citizens on an equal per-capita basis to speed the effect of these market forces by boosting the cost of carbon fuels and thereby encouraging consumers and industry to improve energy efficiency and expand the market for solar, biomass, water, nuclear, and/or whatever should be the real winners. Does anybody know what the eventual market winners will be? It may be a source you and I never heard of.

    (#203, #204, #233, #234) Ray, MARodger and others ask where I got my lower limit for CO2 sensitivity (0.5ºC to 1ºC) and the related issue of the treatment of cloud feedback in mainstream climate models.

    Here is a .pdf of a 2009 paper by Lindzen and Choi that appeared in GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L16705, doi:10.1029/2009GL039628, 200.

    Richard Lindzen, is an American atmospheric physicist and Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology. Based on Earth Radiation Budget Experiment (ERBE) data, he and Choi conclude that “…ERBE data appear to demonstrate a climate sensitivity of about 0.5ºC which is easily distinguished from sensitivities given by models.”

    An easier to read source for the possibility that CO2 sensitivity has been over-estimated due to how the mainstream models treat cloud feedback is Dr. Roy Spenser’s blog.

    You all may read the paper and the blog and agree or not. I do not have sufficient expertise to judge.
    Happy reading!

    [Response: Your expertise would surely allow you to note that Lindzen and Choi had many errors – even acknowledged by Lindzen – and expounded on by Trenberth et al. Indeed, even Roy Spencer took issue with their claims. – gavin]

  44. 244
    MARodger says:

    Ira Glickstein @243. You present a single paper by “some skeptics” (Lindzen & Choi 2009) to give authority to your assertion that climate sensitivity has been assessed by as being in the range 1.0 to 0.5 deg C (as opposed to the range assessed by the IPCC of 4.5 to 2.0 deg C).

    This initially appears to be progress. Sure Lindzen & Choi 2009 carries very little authority (in comparison with the IPCC) being only preliminary research (which subsequent analysis has found wanting) and that it is only addressing a part of global sensitivity. But it would at least carry some authority.
    Yet when I examine the paper there no mention of your 1.0 to 0.5 deg C sensitivity. You claim Lindzen & Choi 2009 gives authority to your assertion. As the paragraphs are numbered within the paper, could you point to the particular paragraph that is the source of your 1.0 to 0.5 deg C assertion? (Be warned that there is a limit to my “happy reading” of your references.)
    I acknowledge your other reference to Roy Spencer. This is not so happy. Simply pointing at the home page of Spencer’s website is rather discourteous. If you wish to refer us to some of Spencer’s work, you will have to be more specific.

    To demonstrate how easy peasy this providing of references should be, here is UN IPCC FAR providing reference for the 2.0 to 4.5 deg C. You will note the reference also defines climate sensitivity to be “the equilibrium global average warming expected if CO2 concentrations were to be sustained at double their pre-industrial values (about 550 ppm).” I still have no answer as to why you @202 introduce the figure 780ppm (ie 2 x 390ppm) to replace the standard 550ppm, a very significant difference.

  45. 245
    Ray Ladbury says:

    Lindzen and Choi 2009…

    Ooh! Unfortunate choice. They didn’t even use the right definition for sensitivity! I would note that in the past decade or so, every paper that has gotten an estimate for sensitivity less than ~2 degrees per doubling either relied on a time interval that was too short or was subsequently shown to be wrong–or both. I’d count that as evidence against a small value for sensitivity.

    Also, Ira, you ignore the fact that despite rising costs and imperial edict–vast regions of the subcontinent were totally deforested. Demand becomes rather inelastic when survival is at stake.

  46. 246

    Gavin, regarding the CRU cyber-attack two years ago, you said

    [Response: They [hackers] used something to directly access the backend mySQL database (to export the password/user details to file prior to erasing them in the database) and to monitor logins to the ssh account. Neither of these things are standard WordPress functions. I conclude therefore they must have hacked both, though the actual entry point is obscure. – gavin]

    Is there any chance I can get a copy of the malicious code that was doing these things, or at least any further information on the code?

    frank

  47. 247
    Marcus says:

    The discussion of methane here reminds me on a RC post about some work of Susan Solomon 2010, about fluctuations of stratospheric water content and possible links with multiyear or decadal variations on the climate – weather verge

    http://www.realclimate.org/index.php/archives/2010/01/the-wisdom-of-solomon/

    Methane was explained to be a source for stratospheric water due to photolysis.

    The paper ist cited some 90 times, google scholar says

    http://scholar.google.at/scholar?start=10&hl=de&as_sdt=0&sciodt=0&cites=3234929203770138070

    but I cannot figure out something unequivocal from that.

    Is there any convincing explanation available this time where this fluctuations originate from, i.e. 10% loss of H2O from 2000 to 2010?
    So the picture clearer now how important this kind of climate feedback is.

    Marcus

  48. 248

    Thanks MARodger #244 for your comment.

    Ira Glickstein @243. You present a single paper by “some skeptics” (Lindzen & Choi 2009) … As the paragraphs are numbered within the paper, could you point to the particular paragraph that is the source of your 1.0 to 0.5 deg C assertion? …

    Yes, the last sentence of paragraph 17 includes that estimate, based on analysis of the ERBE data.

    … Simply pointing at the home page of Spencer’s website is rather discourteous. If you wish to refer us to some of Spencer’s work, you will have to be more specific. …

    You are right. Here is a specific page Global Warming 101 where Spenser makes the point about CO2 sensitivity and positive/negative feedback issues. About halfway down this relatively short write up, he contends that a doubling of CO2 by itself, would directly yield less than 1ºC of warming, which he says is not a controversial statement.

    He then goes on to add “… clouds, water vapor, and precipitation systems can all be expected to respond to the warming tendency in some way, which could either amplify or reduce the manmade warming. These other changes are called “feedbacks,” and the sum of all the feedbacks in the climate system determines what is called ‘climate sensitivity’. Negative feedbacks (low climate sensitivity) would mean that manmade global warming might not even be measurable, lost in the noise of natural climate variability. But if feedbacks are sufficiently positive (high climate sensitivity), then manmade global warming could be catastrophic. …”

    … I still have no answer as to why you @202 introduce the figure 780ppm (ie 2 x 390ppm) to replace the standard 550ppm, a very significant difference.
    Comment by MARodger — 19 Nov 2011 @ 7:06 AM

    Once you have an estimate of CO2 sensitivity, which is a logarithmic effect, it should apply to any doubling (within some reasonable range). Thus doubling the current CO2 level, 390 to 780 would boost mean temperatures about the same amount as 275 to 550. I choose 390 because that is where we are at now, and I used that to calculate that the next doubling (where temperatures will be up over current levels by 2-4.5ºC using IPCC estimates) will be reached around the year 2200 if they keep rising at about 2 ppm/yr or about 2100 if the rate of rise doubles to about 4 ppm/yr.

    Note that estimates of CO2 sensitivity are uncertain because analysts have quite a bit of what I call “wriggle room” due to the complexity of the climate system, for example a range of 2.5ºC between the IPCC low and high estimates.

    My favorite example of this type of analytic uncertainty is a 2007 email from Dr. Makiko Sato to Dr. James Hansen where she details several analyses of the mean US temperatures for the very hot years of 1934 vs 1998. (Click here, then scroll down about 1/5 of the way to a “Page 1 of 22″. An easier to access copy of that email with data in graphic form appears here.)

    Her refreshingly candid account shows the 1999 analysis with 1934 0.5ºC warmer than 1998. Subsequent re-analysis, between 2001 and 2007, shows the 1934-1998 difference as: 0.12ºC, 0.036ºC, -0.015ºC, and 0.12ºC. This is clear evidence that analysis of the difference between the means of the thousands of thermometer readings taken in various years has “wriggle room” of up to 0.5ºC. And, please note this is analysis by US scientists of US data, which should be more reliable than worldwide data from countries with lower density of thermometer readings. The latest analysis, done after the date of the Sato email, has 1998 0.12ºC warmer than 1934.

  49. 249
    MARodger says:

    Ira Glickstein @248. I note that my lesson in ‘easy peasy referencing’ @244 fell on deaf ears.

    You asserted @202 that “some skeptics” say doubling CO2 would raise global temperatures 1.0 to 0.5 deg C (which you gave apparently equal weight with the UN IPCC’s 4.5 to 2.0 deg C).
    To give authority to your statement, @248 you provide two references.

    Firstly you pluck the value of 0.5 deg C from paragraph 17 of Lindzen & Choi 2009., a value that is plainly not a global value and plainly speculative within a speculative piece of research. Further Lindzen & Choi 2009 is now superseded by Linzden & Choi 2011 which makes no mention of any 0.5 deg C value. (And it would be wrong not to point out that both these papers have been show to be fundamentally flawed.) I see in all this no support for you assertion.

    Secondly you provide quotes from a Roy Spencer reference where again I see no mention of the values you assert. From Spencer you quote a value for direct CO2 sensitivity “… less than 1 deg C …” Spencer qualifies this value “… about 1 deg F …” or 0.55 deg C (Spencer calls this value “not controversial” although I would strongly disagree.).
    Frankly, I am not sure what you are trying to say in this. The origins of your assertion @202 remains a mystery. As this is a confusion that you appear incapable of resolving I can but assume you dreamt your numbers up.

    Your response @248 that double CO2 can be taken as double today’s value (that is nigh on CO2 tripling!) is pure nonsense if it is included in discussion of the timing of that doubling/tripling, which is exactly what you do. Note that even your Spencer link discusses potentially “catastrophic” warming and the warming of the last 100 years that (along with any future warming associated with a pre-2011 45% rise in CO2 levels) you Ira Glickstein appear to feel can be simply & safely ignored. As was stated back @160 “It simply defies logic.”

  50. 250
    MARodger says:

    Some links that failed @pevious post.

    Lindzen & Choi 2009/2011
    http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf

    Critique of Lindzen & Choi 2009/2011
    http://www.skepticalscience.com/Lindzen-Choi-2009-low-climate-sensitivity.htm


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