RealClimate logo


Unforced variations: Nov 2014

Filed under: — group @ 2 November 2014

This month’s open thread. In honour of today’s New York Marathon, we are expecting the fastest of you to read and digest the final IPCC Synthesis report in sub-3 hours. For those who didn’t keep up with the IPCC training regime, the Summary for Policy Makers provides a more accessible target.

Also in the news, follow #ArcticCircle2014 for some great info on the Arctic Circle meeting in Iceland.

410 Responses to “Unforced variations: Nov 2014”

  1. 251
    Notepad says:

    Jon (#240),
    I think you would have to dig deeper into the papers on the EPICA core data to clarify the methods used, but I think there is some confusion here.

    It’s not as if the CO2 samples were extracted at regular 700-year intervals and represent the concentrations at that precise moment — and that therefore one could miss a giant peak between measurement points. My understanding is that, rather, each sample itself spans years, decades or centuries, especially at deeper levels. I would expect that a sample for any period during which a peak manifested and disappeared would reflect that peak by showing a higher concentration than adjacent or overlapping samples.

  2. 252
    Meow says:

    @16 Nov 2014 @ 5:48 PM:

    1. The age of each trapped gas sample listed in the data files (e.g. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-co2-2008.txt ) does not indicate that that sample accumulated entirely in that year. Rather, due to various effects, each sample accumulated over several to many years. I am not sure how the listed ages are chosen, except that those for more recent periods in rapidly-deposited ice can be determined, with some error, by annual layer counting. (If any glaciologist has read this far, please correct and expand upon this question).

    Bender et al, “Gases in ice cores”, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC33751/ discusses how gas becomes trapped in ice, and the processes that cause many years’ accumulation to contribute to each sample. Here’s an important quote: “At Vostok, for example, the bubble closeoff zone is about 8 m thick. A single layer of ice traps bubbles throughout the ≈300 yr it moves through this zone. This process accounts for the largest share of the dispersion of gas ages in a single sample of ice.”

    Thus, we can’t simply say “here are N samples with an average resolution of 700 years; what guarantee do we have that CO2 didn’t surge and subside between the samples”.

    2. All of scientific knowledge is provisional, based upon the best of our knowledge to date. Everything in the record shows that no CO2 excursion similar to the present has occurred in the last ~800ky. Could it have occurred? Yes. Do we have any evidence that it did? No. Do we have substantial evidence that it’s unlikely? Yes, both directly from CO2 readings in core samples, to related readings in core samples (e.g., hydrogen/oxygen isotope ratios), to our understandings of natural factors that might initiate and terminate such an excursion.

  3. 253
  4. 254
  5. 255
    Jon Keller says:

    #244 MARodger:

    Apologies for the lack of clarity. Specifically, the original ‘claim’ I am referencing is that the current levels of CO2 in the atmosphere (in ppm) and the current globally averaged temperature are both unprecedented on a relatively long time period, mostly 800 kyr. Another claim I’m investigating is that the rates of increase of temps/CO2 are unprecedented. Your first link included exactly what I’m talking about for CO2: “The magnitude and rate of the recent increase are almost certainly unprecedented over the last 800,000 years.” My goal is to find out what support exists for these claims beyond the low-resolution ice core data from Dome C.

    Now, you pointed out that actually, the 800 kyr ‘levels claim’ is usually just CO2, and now that I look back I see you are correct. The temperature levels claim only extends back a few thousand years at most, and since we have higher resolution records of that time period, I consider that part of it put to rest, leaving only “CO2 levels in the atmosphere are unprecedented over 800 kyr” for the ‘levels’ claim.

    As far as the ‘rates’ claim goes, as long as we’re on the topic, your last link contains that one for CO2 and NASA has it for temperature. This one is even spottier because when we look at two points 700 years apart and find the rate all we can see is the average rate of change over the 700 years. How can anyone confidently say there wasn’t a 100 year period where temps and/or CO2 increased just as dramatically as now? Like I said earlier, it really doesn’t matter in terms of the science whether or not these claims have a solid basis, but it kind of matters that people are repeating them with such high certainty if, hypothetically, it’s not really that certain.

    #245 Hank Roberts:

    I checked that paper, and there was another high resolution paper released just a few weeks ago. Both of these papers only extend back about 23,000 years, so perhaps the high confidence range should only be “unprecedented in the last 23,000 years”?

    Also: The latter paper describes the West Divide Ice Core as being the highest resolution ice core to date, and it goes back 68 kyr. However the WDC data at NCDC only goes back 1.5 kyr. Anybody know where I can find the WDC data? I didn’t see it in the references in the paper.

    #246 Kevin McKinnney:

    You’re right, I might be overestimating the uncertainty! I just want to find the information that leads to the conclusions that the recent increases really are unprecedented. I thought maybe there was a paper using a composite ice core record that concludes that CO2 changes are unprecedented, but I haven’t found one.

    Overall rates during the PETM may have been less dramatic than today, but my point is that we are comparing a 100 year trend to trends over thousands of years. If, for the sake of argument, our warming leveled off in 200 years, and then we took a data point 1,000 years from now and a data point where we started (which is all we can do with ice core data from the distant past), we would have, say, 4 K / 1100 years = 0.0036 K/year or 0.036 K per decade, which I don’t think would seem so out of the ordinary.

    I don’t know what mechanism would act as an accelerated carbon sink. But did you see the link to Yale Climate Connections I posted earlier? Assuming exponential decay, 20% in 300 years corresponds to ~ 5% in 1000 years.. so if it started with a data point at 250 ppm, then somehow jumped to 400 ppm in 100 years, and then our next data point is 1000 years ahead, it’s back down to 270 by then and it seems totally insignificant. I’m not proposing a mechanism, I’m not saying this is something that happened, I’m just wondering if it’s too soon to say it definitely hasn’t.

    There’s probably something about this the climate scientists know that I don’t, which is why I came to a climate science website to ask!

    Again, thank you all for your thoughtful responses.

  6. 256
    Jon Keller says:

    To add to my previous post, I’ve learned over the years to always check the source when I hear big claims. Climate science is one topic where whenever I encounter some claim, whether it be from the AGW activists or the ‘skeptics’, I check the source, and I’ve found that as long as the source is reputable it virtually always ends up supporting AGW theory. But this one has bugged me for a long time because I can never seem to find a definite source or even a full explanation like the ones found on this site for other topics. The people making the claim always point to the 800 kyr ice core data, but as I pointed out it just doesn’t seem like a fair claim based just on that.

    So we know for a fact that there are no possible mechanisms that could ever increase co2 over a short time span (100 or so years) faster than humans are doing now? We know for a fact that there is no possible way a sudden increase to 400ppm and subsequent decrease is hidden in between points anywhere in the data?

  7. 257
    Chuck Hughes says:

    “We know that CO2 is absorbed by seawater, and taken up by organisms on land and in the sea, but that real sequestration operates largely by the weathering of siliceous rock.” ~ Kevin McKinney

    This is something I really don’t understand. I’ve read about it in comments and seen it referred to but I don’t understand the process of weathering of siliceous rock and how that has an effect on CO2 concentrations. Can someone point me to a link or site that explains this? Thanks

  8. 258
    Chuck Hughes says:

    The longer I look at it, the more it looks like a scythe to me:
    http://img.qz.com/2013/12/temperature_record-wheelchair.png?w=640

    Comment by Hank Roberts

    Serious question for Hank…

    Do you ever panic about this stuff? I’m curious because you’re pretty even keel, never over the top and quite understated about your personal opinions. And sometimes even cryptic in your response to direct questions.

    I have many “Oh Sh*t!” moments while reading and trying to decipher all this information about Climate Change but I may be the only one here that does that. It looks really bad to me but what do I know?

    If you can give me a direct honest answer I’d appreciate it. I’m not too bright so try to keep it simple. Thanks.

  9. 259
    Chuck Hughes says:

    So we know for a fact that there are no possible mechanisms that could ever increase co2 over a short time span (100 or so years) faster than humans are doing now? We know for a fact that there is no possible way a sudden increase to 400ppm and subsequent decrease is hidden in between points anywhere in the data?

    Comment by Jon Keller — 17 Nov 2014

    Jon, I’m not the sharpest tool in the shed but I think you’re looking for a loophole somewhere that somebody missed. If you read the AR5 Report or summary and read down the long list of scientists who put this together and understand their credentials and the fact that they’re being HIGHLY CONSERVATIVE in their estimates, erring on the side of caution before issuing an alarm, then you can start to wrap your head around the situation. Climate Science and the knowledge about CO2 has been around for a long, long time. Sure, there’s always a “chance” that something was overlooked or misunderstood. That’s why there’s such a thing as “peer review”. Is anything fool proof? I doubt it but in this case, people who are “skeptical” about the reality of AGW simply do not understand the science.

    At some point you have to accept the reality of the situation and decide to take action. We’re out of time. My only question is, exactly how out of time are we? If you’re still hoping somebody missed some piece of key evidence I think you’re out of luck.

    Google Dr. Peter Ward. He’s pretty good at explaining the history of the Earth and mass extinctions along with what caused them and what’s causing the current situation we’re in. Professor Stephen Hawking gives us maybe a 50/50 chance of surviving this century and beyond. Others are less optimistic. Everybody on this site has a slightly different take on how bad things are but I think everyone agrees it’s dire. There are no real skeptics on this in the scientific community that I have found and believe me I’ve looked. Dr. Ward has some great videos on TED Talks. Good luck with your research.

  10. 260
    MARodger says:

    Jon Keller @255.
    Let us then put “that part of it [] to rest, leaving only “CO2 levels in the atmosphere are unprecedented over 800 kyr” for the ‘levels’ claim.” In the past I have had long arguments with folk concerning the likelihood of CO2 topping 400ppm(v) in the last 13 million years. Dismissing all possibility of it having happened in the last 800ky should therefore be child’s play.
    Imagine Kevin McKinney’s “pixie dust” to be a big balloon containing 266GtC of CO2. And during one of the interglacials of the last 800ky with CO2 at 275ppm somebody popped the balloon. Ooops!!
    This would be the most efficient means for the pixies to achieve 400ppm (and far more efficient tham human efforts). The pulse would quickly begin to be drawn from the atmosphere and by 1,000 years would have returned to a level of some 300ppm, a level not unprecidented over the last 800ky.
    The question you appear to be asking is if these pixies could get away with their handiwork not leaving a mark on the CO2 record gleaned fron ice cores at 700 year intervals.
    The is “no” and that is because of what is described by Meow @252.1. And there will also be many other ways of checking such a pulse could not have occurred.

    Finally I would add a warning if aspects of “the claim” beyond simple levels of atmospheric CO2 are not “put to rest” but kept up past their bedtime. Warning. Discussing meaningfully rates of increase of a value requires a certain discipline which has so far in this present interplay been noticable by its absence. End Warning.

  11. 261
    Chris Dudley says:

    Hank (#234),

    Don’t fear the reaper. The world’s got a fever, and the only pre- scrip- tion is more cowbell! http://www.hulu.com/watch/536145

  12. 262
    Chris Dudley says:

    Chuck (#257),

    Kevin misspoke. Siliceous rocks are primarily silica, SiO2, and don’t play a direct role in sequestration. Silicate rocks, and those containing calcium and magnesium, provide the metal ions which allow carbonate ions to precipitate out of water or be incorporated in bone or shell which can become solid deposits (think of marble and chalk). Those deposits sequester carbon. Weathering involved breaking down silicate rock minerals through the effects of exposure to hydrogen ions in water.

  13. 263
    tokodave says:

    Chuck, here’s a link:

    http://www.skepticalscience.com/weathering.html

    If you read up on climate history you’ll see Arvid Hogboom, a Swedish geologist, worked with Svante Arrhenius as Arrhenius developed his work. He knew it was important to understand the geologic cycling of CO2 and Hogboom was active in researching the topic.

  14. 264
    Lennart van der Linde says:

    Jon Keller 255,

    Diffenbaugh & Field 2013 say the rate of human-caused warming is/will be at least 10-100 times faster than any natural episode in the past 65 million years:
    http://climate-institute.webstarts.com/uploads/Natural_systems_climate_change_Field_Nature_2013.pdf

    As far as I know this has not been disputed. If so, I’ve missed it.

  15. 265
    Hank Roberts says:

    > Jon Keller
    You aren’t going to get scientists to tell you something is impossible nor that something is proved.

    But it appears you’ve come across the claim that what’s happening now could have happened in the past and that since science hasn’t proved it’s impossible then human activity isn’t the only possible explanation for the current rate of CO2 increase. Do you see the (at least) three bogosities in that claim?

    Sure, CO2 could increase faster than it’s increasing at present. There are, as I recall, only two ways known or imagined: Hit a planet like ours with either an asteroid or an intelligent species. Either event produces a rate of increase in CO2 faster than anything else we know about or have imagined. We know these have happened. Another possibility — not nearly as fast — is a huge increase in vulcanism, one that covers vast areas of the surface with lava to a great depth, releasing CO2 from deep in the Earth. That’s happened, and while slow, it apparently sufficed.

    But nobody’s come up with any notion of how to make such a CO2 spike _disappear_ from the atmosphere and ocean within a few centuries so there would be no evidence in the geological record. Remember you’d have to disappear not only the CO2 but all the evidence of it being changed to something else.

    Huh? That’s fairies in the garden stuff.

    That’s what the folks have to suggest you look for — some kind of magical process that turns gas into plants that become sedimentary layers that become rock to great depths. That’d be some kind of a “Chia pet planet” episode or an “Ice 9” crystallization rate.

    That’s the “God is in the gaps” argument — and it won’t wash.

  16. 266
    Radge Havers says:

    Chuck Hughes,

    Skeptical Science:
    http://www.skepticalscience.com/weathering.html

  17. 267
    Meow says:

    17 Nov 2014 @ 9:34 PM: Science doesn’t deal in certainties, but in probabilities based upon the evidence we have. Here’s an analogy that might help.

    Imagine that you’re a dedicated birder living in south Florida. You have lived in the same house, beside the same next-door neighbor, for 20 years. During that time, both of you have changed jobs and had various schedules. Also during that time, you have seen and heard many birds, but you have never seen or heard a canary from the direction of your neighbor’s house. She has, however, said that she likes parrots much more than canaries, and she has shown you a parrot in a handsome cage. You have also heard that same parrot many times.

    At some point, the police appear at your door and ask whether your neighbor has ever had a canary.

    What do you say?

    1. She had at least one canary for a short period, but it died or she sold it before you could hear it.
    2. She had a mute canary for 10 years.
    3. She kept a canary in a soundproof cage for 10 years.
    4. She definitely didn’t have a canary during your 20 years of co-residence.
    5. She almost certainly didn’t have a canary during your 20 years of co-residence, because you never perceived evidence of one, plus she told you that she much preferred parrots.

  18. 268
    Unsettled Scientist says:

    @Chuck Hughes

    Here is a lecture that explains the CO2 Weathering mechanism and it’s effect on stabilizing the temperature. The lecture is part of a class given at the University of Chicago by one of the contributors to this site: David Archer. It’s part of a larger class, so the lecture deals with a few other concepts before getting into the carbon cycle around minute 21, and into the Urey reaction around minute 23.

    The CO2 Weathering Thermostat: http://www.youtube.com/watch?v=NiAhwi7Qy3g

    For those still trying to wrap their head around the whole of climate science I recommend checking out the full course: http://forecast.uchicago.edu/

  19. 269
    Jim Larsen says:

    255 Jon K quoted, “The magnitude and rate of the recent increase are almost certainly unprecedented over the last 800,000 years.”

    as an example of possible overconfidence, and asked, “How can anyone confidently say there wasn’t a 100 year period where temps and/or CO2 increased just as dramatically as now?”

    I think your example puts the uncertainty just about right. For there to have been such a 100 year period a heretofore unknown super way to remove CO2 naturally must have been in action. The odds of such a huge drawdown in CO2, and the odds of it happening immediately and only after an increase that left no trace…

    and we’re almost certainly getting into “almost certainly” territory, where Denialist Physics and Magic lie.

  20. 270
    Hank Roberts says:

    > ever panic about this stuff?

    I did once or twice back early in the 1970s.

    “One of the penalties of an ecological education is that one lives alone in a world of wounds. Much of the damage inflicted on land is quite invisible to laymen. An ecologist must either harden his shell and make believe that the consequences of science are none of his business, or he must be the doctor who sees the marks of death in a community that believes itself well and does not want to be told otherwise.”
    ― Aldo Leopold, A Sand County Almanac

  21. 271
    Jon Keller says:

    #251 and #252, Notepad and Meow:

    You both had basically the same point, that is, that each data point is not actually a capture of a single moment as I thought but rather is created over hundreds of years. Now we are making progress. So now the question is, what exactly does the co2 value for each sample represent? Is it an average for the period that the sample represents? If anybody is knowledgeable about ice core data retrieval, your input would be very helpful.

    Here is what I have gathered from some brief research. The paper Meow linked states, “A single layer of ice traps bubbles throughout the ≈300 yr it moves through this zone.” By “zone” they mean the bubble closeoff zone for each layer. This page describes the methods of collecting data from ice cores in some detail. In one laboratory, multiple samples are crushed at the same time and then analyzed, so if all of these samples and their bubbles are from a multi-centennial layer of ice, combining them and then analyzing the CO2 levels would result in a rough average of the time period.

    The other lab uses larger samples, i.e. more bubbles per sample, which should yield the same results.

    Did I make any mistakes so far?

    Dating the data points seems a bit complex, I found a paper describing the methods in detail but haven’t had time to dig in yet.

    Meow: For your point #2,

    Could it have occurred? Yes … Do we have substantial evidence that it’s unlikely? Yes

    — that’s exactly the thing though. The argument isn’t being presented as ‘it’s unlikely that this has happened before’ (which I wouldn’t have a problem with), it is being presented as a fact that it hasn’t, which doesn’t seem totally honest to me. However, if it has been established with high certainty then I can’t see any issue with it.

    “Today carbon dioxide is at an “unprecedented” level …”
    “The globe is warming at a faster rate than it ever has before …”

  22. 272
    Meow says:

    On ice cores, further reading seems to indicate that some exchange of gas occurs between the atmosphere and portions of the ice column, and/or between different portions of the ice column, until a bubble is entirely closed off. (See Goujon et al, “Modeling the densification of polar firn including heat diffusion: Application to close-off characteristics and gas isotopic fractionation for Antarctica and Greenland sites” at 1). I still haven’t quite puzzled out the implications for the age PDF of a bubble, but this does seem to imply that the number of years sampled by a given bubble is similar to the bubble-ice age difference (“delta age”).

    Are there any glaciologists reading who’re willing to expand on this discussion?

  23. 273
    Hank Roberts says:

    P.S. for Chuck Hughes, you asked about panic; someone else asked a while back:
    http://www.realclimate.org/?comments_popup=13212#comment-251625

    I’m in despair. Is it justified?

    [Response: No. – gavin]

  24. 274
    Jon Keller says:

    Thanks everyone again for your responses, but before I get to my reply I think some of you are seriously mistaking my motivations. I am not trying to find an alternate explanation for what is happening now. As I have mentioned previously, I know that the isotopic signature (among other things) points to us being responsible for recent CO2 increases in both magnitude and rate. And I am very familiar with the science behind the CO2 warming effect. When I say things like “how do we know…”, I am not trying to cast doubt but am legitimately wanting somebody to answer, “here’s how”. I never doubted that the scientists have a good reason for their high confidence in the unprecedented claim. I simply want to know how they reached it, so I am asking questions. And “take their word for it” is not a very scientific way to reach a conclusion.

    I also know that nothing in science is proven beyond a doubt, so when I said “we know for a fact…” I just meant with high confidence.

    #259 Chuck Hughes:

    I don’t question anything you said in that post except your evaluation of my motives. I’m all for action. Enough said on that point, I think?

    #260 MARodger:

    I am starting to get a better picture of the significance of the ice core data, see my last post #271. I was indeed asking about the ‘pixies’ getting away with their handiwork. Unfortunately, there were no descriptions of these ‘many other ways of checking’ previously in the conversation. In fact, ‘other ways of checking’ are exactly what I have been looking for, evidenced by my last reply to you — “My goal is to find out what support exists for these claims beyond the low-resolution ice core data from Dome C.”

    Please do let me know which discipline I lack in order to have a meaningful discussion on rates of increase of CO2 and temperature.

    #264 Lennart van der Linde:

    Thanks for the link, I glanced over it but won’t have time to read through it fully tonight.

    #265 Hank Roberts:

    I didn’t come across the claim that “what’s happening now could have happened in the past …”. I came across the claim (many times) that “Recent increases in co2 are unprecedented in the past (800kyr)” and also rates of temperatures. I had the EPICA Dome C ice core data for other purposes, I noticed that going back there are hundreds (sometimes >1,000) year gaps between points, so I thought “how do we know?”

    But I’m realizing through this discussion that my understanding of the ice core data is flawed, and if I correct my knowledge it may provide the answer I’m looking for. Also, you and MARodger are alluding to other ways of checking besides the ice cores. I wasn’t aware that we could find other precise geological evidence of CO2 concentrations going back 800 kyr. Now that I am aware of that avenue, I will start looking into it. For instance, this page describes ocean sediments providing a climate record going back millions of years. Does that record operate in any way similar to the ice core data wherein we can extract a time series of values?

    #267 Meow:

    I know that science doesn’t deal in certainties. In your analogy, I would, like any reasonable person, say “5. She almost certainly didn’t have a canary during your 20 years of co-residence, because you never perceived evidence of one, plus she told you that she much preferred parrots”.

    But on the subject which we are discussing, I want to know why scientists are ‘almost certain’. I don’t need absolute 100% confidence. I just need the high confidence the scientists have. I know that my confidence level contrasts with the scientists’ confidence level, and since I do not know as much as they, I am trying to bring my confidence level up by learning some of what they know. I just thought there was more than the ice core data, because based on my original understanding, it didn’t seem like very strong evidence. Now I am trying to understand that data in this new light (#271), while possibly also learning of other ways to determine past climate change.

    #269 Jim Larsen:

    What kind of traces would a past increase leave that we can check for outside of the ice core record? This is an honest question. That sort of ‘trace’ is what I am looking for.

    #272 Meow:

    Okay, so if your understanding is correct, then each bubble approximately represents some time length “delta age”. So how does the measured co2 level of the bubble represent the time period (age) through (age + ‘delta age’)? Would it more heavily reflect the end of that time period right before it gets cut off? Would it favor the period when it formed? Or is the value randomly somewhere in between?

    Thanks all for your time. I will continue reading on this tomorrow.

  25. 275
    Hank Roberts says:

    > it is being presented as a fact that it hasn’t

    Um, no. You’re working your way into a logical trap here, or into a graduate degree in climatology — your choice.

    You’ve hit what Ken Thompson famously wrote about in Reflections on Trusting Trust.

    It’s more generally discussed here, about proving a negative.

    The only way to prove, say, that there is no evidence of unicorns in the fossil record, is by giving an argument to that conclusion. Of course one would then have to prove the premises of that argument by giving further arguments, and then prove the premises of those further arguments, ad infinitum. Which premises we should take on credit and which need payment up front is a matter of long and involved debate among epistemologists. But one thing is certain: if proving things requires that an infinite number of premises get proved first, we’re not going to prove much of anything at all, positive or negative.

    If you’re reasoning your way through this on your own, you’ve hit that problem — to decide at what point you stop questioning each premise, remembering Stein’s Law*.

    But you won’t ever get an absolute proof from science.

    If you’re relying on someone who tells you that “it is being presented as a fact” and you need to check the claim — that’s setting you up. It’s not presented as a fact — except to the extent that any scientific writeup is oversimplifying what the actual researcher concluded in the actual paper.

    Now if you’re reading a university PR department’s press release, or the antithetical press release from Morano et al., yes, you’ll find claims that something’s a fact or not a fact. But that’s puffery.
    ____________
    * “If something cannot go on forever, it will stop.”

  26. 276
    Hank Roberts says:

    P.S.
    > If, for the sake of argument, our warming leveled off in 200 years

    https://www.google.com/search?q=if+we+stop+burning+fossil+fuel+immediately+what+happens%3F

    and click “images” (beware that the image search result has a very high proportion of bogus stuff or misstated captions, choose good sources)

    http://earthobservatory.nasa.gov/blogs/climateqa/files/2010/03/co2_emissions.gif

    and see the references and sources cited at
    http://earthobservatory.nasa.gov/blogs/climateqa/stabilize-gg-emissions-effects/

  27. 277
    Thomas says:

    Jon Keller:
    Just because the individual samples are some rough average over a period as long as 700 years, doesn’t imply that that is the maximum resolution possible. If we knew to high acuracy the functional form of the smearing of the data, and we take measurements more frequently than that, we could in principle deconvolve the data and obtain a curve with resolution much better than seven hundred years. Now I doubt the “smearing” function is all that well known, and its probably not independent of time either. Due to those uncertainties one can likely only improve the resolution somewhat (like maybe a factor of two). So with just the data you are working with you cannot come up with a hard limit of the time resolution.

  28. 278
    wili says:

    “Senate Rejects Keystone XL Pipeline By One Vote”

    http://thinkprogress.org/climate/2014/11/18/3593489/keystone-xl-senate-vote/

  29. 279

    Danny…
    You seem to be on a wrong track. Try this.

    Is the world warming? I think you concluded it is

    Is a hotter world a problem? It is.

    Does CO2 warm the world? It does, as mentioned and experiments confirm the mechanisms of IR transmission.

    (Has CO2 risen? I think you’ve observed it has. Is rather less important, actually.)

    What shall we do about a hotter world which is a problem? Over to you. (You may wish to consider that regardless of all other factors, causes, etc, reducing CO2 will oppose a rise, and if sufficient cause a reduction in how hot the world is.)

    You mentioned healthcare. I invite you to compare the tobacco company funded efforts to confuse the very clear conclusions of Doll, Black etc and have people carry on smoking and also the anti vaccination fringe with the tactics of oil and coal suppliers and their interested parties on climate.

    There’s my simplistic understanding, and my effort to tailor a path to pragmatic conclusions for you.

    None if this is hard to find though.

  30. 280

    #262–Yes, Chris is right, I ‘misspoke’. I meant silicate rock, as in this description:

    Significantly, via the calcium carbonate-generating part of the chemical process, there is a net loss of readily-mobile carbon: we start with twice as much as we end up with. That’s why weathering of silicates is so important. The missing carbon is locked up in the calcium carbonate in the following way: as shelled creatures die and their remains accumulate, we get a carbonate-rich sediment. As the sediments continue to accumulate, our carbonate-rich layer will be progressively buried under new layers of sediment and in time it will turn into solid rock – limestone. Globally, limestones are very common and often occur in great thicknesses (think of the White Cliffs of Dover, for example). That carbon is thereby locked away and immobilised for a very long time. The overall process may be expressed as follows:

    CO2 + CaSiO3 = CaCO3 + SiO2

    I’d written “silica-ceous” (without the hyphen) but spell-check altered that to “siliceous”–the former, apparently, is not a standard word in English, though I’m not the first to use the coinage. (Or at least, to *try* to use the coinage!) And the latter, as Chris points out, doesn’t mean just any old rock with significant silicon content, but applies to substances containing SiO2, silicon dioxide. And, about those siliceous rocks:

    Rainwater containing carbonic acid is able to react with most minerals at varying rates according to their chemical stability. Now, some naturally-occurring minerals are extremely stable. Think about gold, eroded mechanically from ore deposits and then recovered by prospectors, maybe hundreds of thousands of years later, from river-gravels by panning. Or quartz (silicon dioxide), found as hard, white pebbles on beaches. They’re both pretty bomb-proof.

    http://www.skepticalscience.com/weathering.html

  31. 281

    #263–Yes. Arrhenius got his Nobel basically for leading a bruising and extended scientific battle to recognized the phenomenon of ionic dissociation, which–if you read the SkS link Dave (and later, I) supplied–you’ll see is involved in silicate weathering. Who knows? Maybe that could even be part of a chain of association by which Arrhenius became interested in the atmospheric-CO2-and-climate problem. I wrote about Arrhenius (and more, including a brief mention of Hogbom) here:

    http://hubpages.com/hub/Global-Warming-Science-And-The-Dawn-Of-Flight

    I’ve always liked the Arrhenius-as-“Ionist” croquet cartoon a little way into the article.

  32. 282
    MartinJB says:

    Meow et. al. Neven’s sea-ice blog has glaciologists in the comment threads. Might want to see if any of them cab shed light on the ice core questions.

  33. 283
    MARodger says:

    Meow @272.
    I have certainly read from such sources as Glaciologists that the period of gases being mixed spans decades rather than centuries. And the sort of results they obtain also suggest such a period is obtained for at least some ice cores. There is a graph of such mixing in this slide-show (Page 4 of the PDF) but the firn can be much deeper than this example with, in some instances, thousands of years before bubble closure.

  34. 284
    Chris Dudley says:

    China has asked India to control greenhouse gas emissions. http://zeenews.india.com/news/sci-tech/china-asks-developing-countries-to-cut-greenhouse-gas-emissions_1500409.html

    As WTO members, once China’s regulations on greenhouse gas emissions are in place, China could impose GATT Article XX tariffs on imports from India as an aid in persuasion. Perhaps China’s leverage will do the job.

    Canada should probably be next on the list after India.

  35. 285
    Hank Roberts says:

    > Jon Keller
    You linked to http://www.geolsoc.org.uk/~/media/shared/documents/policy/Climate%20Change%20Statement%20final%20-%20new%20format.ashx

    where you find

    “… There is some evidence that the rate of increase in CO2 in the atmosphere during the abrupt global warming 183 million years ago (Early Jurassic), and perhaps also 55 million years ago (the PETM), was broadly similar to today’s rate/34.”

    So that, as of 2010, addresses your original question. That cites in
    footnote 34:
    Cohen, A.S., Coe, A.L. and Kemp, D.B., 2007, The Late Palaeocene Early Eocene and Toarcian (Early Jurassic) carbon isotope excursions: a comparison of their time scales, associated environmental changes, causes and consequences.
    Journal of the Geological Society 164, 1093-1108.

    That’s:
    doi: 10.1144/0016-76492006-123 December 2007
    http://jgs.lyellcollection.org/content/164/6/1093.abstract?cited-by=yes&legid=jgs;164/6/1093#cited-by

    (That paper, I recall, is one of the links fairly often mentioned by the methane emergency folks, but if you read it — it’s paywalled, requiring a librarian to borrow it for you — the events, amounts and timing are not directly comparable to the fossil fuel CO2 over the past hundred years. Close enough for interesting study.)

    The two links in the right sidebar on that page (Web of Science, and Google Scholar) find citing articles. Since 2006, that’s quite a few papers.

    Like I said above about trust — at some point, those of us without expertise in the subject have to decide where to stop. And any scientist, outside of his or her own specific field, has the same challenge understanding this stuff.

    I’ve observed elsewhere that science doesn’t grow like the mighty oak, from a single deep taproot on which all else depends. Scientific work grows like kudzu, thriving wherever there’s material good enough to raise interesting questions. That’s why people saying “Darwin was wrong” aren’t overthrowing evolution. Of course Darwin was wrong. But he was interesting and useful and later work improved on what we know.

    Same is true for any scientist’s work.

  36. 286
    MARodger says:

    John Keller @274.
    Concerning “other ways of checking” I had nothing particular in mind.
    As this is pixie CO2 under consideration, obtaining evidence of its source from isotope data would be awkward to argue. But although the pixies supply the CO2, they have to stand aside with the consequences. There would be a significant warm century or two with back-of-fag-packet temperatures of perhaps +0.85ºC which could perhaps then feature in the ice core temperature record. And the CO2 would very quickly turn the oceans more acid than today with the level taking tens of thousands of years to recover. I’d be surprised if that didn’t show up. The pH decrease would, what, be about the same amount as the glacial/interglacial decrease (or perhaps a little more)? This would result as the CO2 would initially enter both ocean & ecosphere but then be pulled out of the ecosphere and all into the oceans as the CO2 levels drop down towards the 300ppm over that first millennium.

    As for the “certain discipline” I spoke of, I was talking of discipline in a general sense. That is, I mean a “level of precision” in your assertions. It is easy to fall foul of the argument when both that “precision” is missing and it is rates of change that are being discussed.

  37. 287
    Meow says:

    @19 Nov 2014 @ 1:02 PM: Also the pixie CO2 would have to be produced by oxidizing some source of carbon. This would deposit evidence, in ice and ocean-bed cores, in addition to that you’ve listed. This would probably include various isotope data, changes in sulfate/mercury/arsenic levels (particularly if the source was coal or volcanism), changes in iridium levels (if the source was extraterrestrial), changes in the amount of biogenic carbon deposited (due to changes in primary production), changes in the amount and type of dust deposited (due to changes in precipitation amounts and patterns), etc.

    Critically, the rate at which these markers are deposited onto snow/ocean and are incorporated into ice/bed cores vary (due to the differing weights and reactivities of the different markers), which would have the effect of smearing out the evidence among bubbles having different age PDFs. This, in turn, would make it less likely that all such markers would evade detection.

    That said, the OP should delve further into glaciological and other paleo-evidence papers for further information.

  38. 288
    wili says:

    (I see we’re back to full-bore tail-chasing mode here.)

    Meanwhile: http://thinkprogress.org/climate/2014/11/19/3593567/china-climate-target-peak-coal-2020/
    “China To Cap Coal Use By 2020 To Meet Game-Changing Climate, Air Pollution Targets”

    Realistic?

  39. 289
    CM says:

    Jon Keller @255 wrote:

    But did you see the link to Yale Climate Connections I posted earlier? Assuming exponential decay, 20% in 300 years corresponds to ~ 5% in 1000 years.. so if it started with a data point at 250 ppm, then somehow jumped to 400 ppm in 100 years, and then our next data point is 1000 years ahead, it’s back down to 270 by then and it seems totally insignificant.

    Jon, you may want to check your arithmetic. But it’s more important that you go back and read your link again. The point it makes is precisely that we could get back down to ~20% of the CO2 slug in a few centuries, but then things slow down, and it could take another 10,000 years to get down down to a 10% airborne fraction.

    You cannot assume a simple exponential decay, because there are several different physical processes removing CO2 from the atmosphere over different time scales.

  40. 290
    Hank Roberts says:

    Several interesting papers in Geophysical Abstracts, some full text access.

    http://onlinelibrary.wiley.com/doi/10.1002/2014GL061881/abstract
    Cheng, L., and J. Zhu (2014), Artifacts in variations of ocean heat content induced by the observation system changes, Geophys. Res. Lett., 41, 7276–7283, doi:10.1002/2014GL061881.

    new methods to assess long-term trends in the OHC (0–700 m) are proposed that suggest the presence of a continuous upper ocean warming (0.36 ± 0.08 W m−2) since 1966.

    Peltier, W. R., and G. Vettoretti (2014), Dansgaard-Oeschger oscillations predicted in a comprehensive model of glacial climate: A “kicked” salt oscillator in the Atlantic, Geophys. Res. Lett., 41, 7306–7313, doi:10.1002/2014GL061413.

  41. 291
    Tony says:

    Wili,

    I don’t think it’s realistic. But Climate Progress are ever the optimists.

  42. 292

    #284–“Canada should probably be next on the list after India.”

    Well, as Diane Sawyer pointed out in the Globe and Mail:

    Canada has made strong and continuous assertions that we are harmonizing GHG policy with the United States. Indeed, our 2020 target is identical to the U.S. target, while we have harmonized a range of vehicle GHG regulations.

    We’ll find out how sincere that stance was now, won’t we? Ms. Sawyer seems to have her doubts:

    Canada’s hiding in the U.S. shadow on climate policy has proved a good strategy to justify inaction. No longer will this be the case. With a bilateral China-U.S. agreement on controlling long-term GHG, pressure will mount for Canada to not only announce new long-term GHG targets, but to prove it is taking action.

    All that said, though, how about Russia as “next on the list?” Emissions are roughly 3x the Canadian case–5.18% of the global total, against Canada’s 1.48%. (Though I must admit that much as I detest Harper & co. politically, Putin et al. would probably be a couple of orders of magnitude less amenable still.)

    And before you get to Canada, after Russia there’s Japan (3.48%), Iran (!) (1.7%), and South Korea (1.69% and surely rising faster than Iran)… and after Canada, there’s 6 more non-EU nations before you get down below 1%.

    Maybe it would be better just to get a good agreement in Paris?

    Data–a little dated, but sortable, which is nice:

    http://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions

  43. 293

    #288–wili–

    I suspect that China’s goal on coal (cha-ching!) is indeed realistic. The piece you link gives some reasons why that is likely to be the case.

    I’ll only add one additional one, which is that they’ve smashed every renewable energy goal that they have set in the past. Admittedly past performance is not a guarantee, etc., etc., but what precedent does exist suggests that optimism is warranted.

  44. 294
    Chris Dudley says:

    President Obama’s veto threat for the Keystone vote was correct. There is a process going on already. However that process is compromised. It is being conducted by the State Department and has already suffered from the failure to conduct a proper environmental impact study, initially going with an industry greenwash.

    President Obama is obliged to appoint an administrator for the Economic Regulatory Administration which has authority on cross boarder oil pipelines. This is a part of the Department of Energy, which does know something about environmental impact studies for large projects. http://www.law.cornell.edu/uscode/text/42/7136

    Secretary of State Kerry should recommend that President Obama restart the process using the correct federal authority rather than the State Department.

  45. 295
    sidd says:

    The Chinese announcements are significant. Standing Committee announced the deal with USA. This new announcement was made by the State Council, (these guys are the bureaucracy, of course very tightly interlocked with the Standing Committee.) This tells me that both the Standing Committee and the State Council have the unity and confidence to set markers on both peak coal use and, more important, timing of peak coal use.

    The People’s Daily has this to say:

    ” Installed nuclear power capacity will reach 58 gigawatts and that under construction will top 30 gigawatts by 2020.

    Installed capacity of hydro-, wind and solar power is expected to stand at 350 gigawatts, 200 gigawatts and 100 gigawatts, respectively.”

    Bear in mind that China has repeatedly smashed wind and solar targets in the past.

    They got smart people. They will go after load management next, turn up a hundred million thermostats at a time by half a degree in summer peaking load, and they can do it too. Too juicy a target not to.

    sidd

  46. 296
    Jim Larsen says:

    274 Jon k asked, “What kind of traces would a past increase leave that we can check for outside of the ice core record?”

    So if the impossible happened, what trace would it leave? I’m not sure, but one poster already stated that celestial impact and sentient beings are the only two things big and fast enough for your scenario. Both leave tons of evidence.

  47. 297
    Hank Roberts says:

    For Jon K., this may be the sort of thing you’re looking for:
    http://www-odp.tamu.edu/publications/tnotes/tn27/index.html

    There ought to be a detectable layer of different fossils for the event you’re looking for, since you’d expect an “explosive growth” of different species while the atmosphere was so different:
    http://earthobservatory.nasa.gov/Features/Phytoplankton/

    Now, nobody’s found that yet. Opportunities remain for fame and fortune in biostratigraphy, for someone willing to put in the time and attention.

    As they say, the devil is in the details. This is never so true as it is for studying thin sedimentary layers in deep core samples.

  48. 298
    Chris Dudley says:

    A group of Harvard students, frustrated by the university’s refusal to shed fossil fuel stocks from its investment portfolios, is looking beyond protests and resolutions to a new form of pressure: the courts.

    The seven law students and undergraduates filed a lawsuit on Wednesday in Suffolk County Superior Court in Massachusetts against the president and fellows of Harvard College, among others, for what they call “mismanagement of charitable funds.” The 11-page complaint, with 167 pages of supporting exhibits, asks the court to compel divestment on behalf of the students and “future generations.” http://www.nytimes.com/2014/11/20/us/harvard-students-move-fossil-fuel-divestment-fight-to-court.html

  49. 299
    Hank Roberts says:

    Seriously, in case you thought I was joking — this is the sort of thing you’re looking for — single year layers:
    http://scholar.google.com/scholar?q=biostratigraphy+annual+varve

  50. 300
    Hank Roberts says:

    A “lessons learned from failure” article by Google engineers, after the failure of Google’s big efficiency experiment:

    http://spectrum.ieee.org/energy/renewables/what-it-would-really-take-to-reverse-climate-change

    Trying to combat climate change exclusively with today’s renewable energy technologies simply won’t work; we need a fundamentally different approach. So we’re issuing a call to action. There’s hope to avert disaster if our society takes a hard look at the true scale of the problem and uses that reckoning to shape its priorities.