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Tom Curtis at 23:23 PM on 13 January 2014Real Skepticism About the New Marcott 'Hockey Stick'
Michael Sweet @95, it is likely that the realization with that single spike I drew attention to lies near the mean either shortly before or after the spike, giving it an amplitude of 0.7 C, large enough to be a candidate "unicorn spike". Potentially it is even larger. Of course, we do not know that that is the case. But nor do we know that the realization in question had values above the mean for several centuries before or after the visible spike.
With respect to your MWP analogy, here are two of the Marcott proxies and their mean over the period 7950-8990 BP:
Clearly both show temperature fluctuations significantly greater than 1 C over periods of a centurly or less. GISP2 likewise shows very large short term temperature fluctuations, although it was not used by Marcot.
However, your assumption of the existence of proxies which show excursions higher than the actual signal is not warranted. Most of Marcott et al's proxies have a low resolution. So much so that the mean resolution of all 73 proxies is 160 years, despite the existence of several annually resolved proxies. Marcott et al made the reconstruction by taking the existing values of the proxies, and linearly interpolating them into 20 year bins. Such linearly interpolated will not show the full spike. Using the mean resolution, even if by chance (1 in 10) one data point happens to coincide with the peak of a "unicorn spike", the proxy will show a peak of the same magnitude, but with a 320 year period rather than a 200 year period. Most proxies will show much smaller peaks, with half showing peak magnitudes 50% or less of the "unicorn spike" magnitude. This graph gives an idea of the effect:
Note, I have used a small number of proxies, all but one of which show 50% or greater magnitude the "unicorn spike". Consequently the "reconstruction" shows a much greater magnitude (less smoothing) then a full array of 73 proxies would show. Further the initial random temporal displacement due to dating error, plus the temporal displacement from the monte carlo reconstruction will further reduce the magnitude of the reconstruction.
The important point here, however, is that the areas of above average temperatures during a "unicorn spike" need not coincide with regions that provided high resolution proxies; so a "unicorn spike" can exist and have no proxies showing temperatures greater than the peak temperature of the spike.
Finally, I do not claim that high local spikes in fact exist. I suspect, in fact, that they do not. What I claim is that nobody has shown we have sufficient information from Marcott et al to show they do not exist. Given that Marcott et al certainly do not claim they have shown they do not exist, and caution against claiming that they do not exist; anybody wanting to claim otherwise requires a very rigorous proof. Both Tamino and KR have neglected an essential aspect of that proof (using their respective methods), which is a shame because in other respects their approaches are both interesting and informative.
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michael sweet at 21:06 PM on 13 January 2014Real Skepticism About the New Marcott 'Hockey Stick'
Tom,
The single realization you point to is smaller than the 0.9C spike you suggest so it does not seem to me to be an appropriate example.
When we look at the MWP it is easy to find single proxy records that show an increase in temperature much greater than the average across the globe. If your hyothesized spike in temperature existed, there should be many individual proxies that are higher i.e. 1-2C higher for 200 years. Can any such proxies be found? How can the hypothesis that a global spike of 0.9C might have happened when no local spikes have been identified be supported? Almost by defination, if there was a global spike, local spikes must have been higher.
I see your claim as that high local spikes exist and have been poorly dated so that they cancel out. Can you provide examples of these local spikes ( I have not seen examples in the past)? If the local spikes do not exist, it is a moot point wether they were properly dated. If they exist we can look at the individual data to see how reliable the dating is for those proxies.
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barry1487 at 20:54 PM on 13 January 20142013 was Australia's Hottest Year, Warm for Much of the World
DMarshall, I'm guessing the BOM use the same baseline period as HadCRUt due to their collaboration over the years. HadCRUt reason for using this baseline is here.
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barry1487 at 20:06 PM on 13 January 20142014 SkS Weekly News Roundup #2
Great news for the Australian economy, bad news for environmentalism.
$20 trillion shale oil find surrounding Coober Pedy 'can fuel Australia'
Brisbane company Linc Energy yesterday released two reports, based on drilling and seismic exploration, estimating the amount of oil in the as yet untapped Arckaringa Basin surrounding Coober Pedy ranging from 3.5 billion to 233 billion barrels of oil.
At the higher end, this would be "several times bigger than all of the oil in Australia", Linc managing director Peter Bond said.
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Dikran Marsupial at 19:36 PM on 13 January 201416 ^ more years of global warming
Earthling, by talking of the "faithfull" you give the impression of being a troll, here only to provoke an intemperate response, without being interested in the scientific response to the point you have raised. If that is not your intention, I suggest that you avoid such inflamatory terms in future posts. If it it your intention, I suggest you find another blog where such behaviour is appreciated.
The point of controlling for the effects of volcanic eruptions, solar activity and ENSO is to undestand what has cause changes in GMST in the past, not to be able to predict it in the future. The point is to discover what part of the observed changes cannot be explained by volcanic eruptions, solar activity and ENSO.
We know that there will be short term warming and cooling influences in the future, but if they do not have a long term secular trend, they will not be the cause of a long term trend in GMSTs, which is what climatologists are primarily interested in.
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pheidius at 16:48 PM on 13 January 2014Climate's changed before
Hi,
Sorry about the delay but, yes, the papers are available. I would have included them at the onset but I was confused by the insert and source tabs. The Mclean paper is available on this page http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/studentv.html as a pdf on a link called McLean (1994)The second paper I referenced is here
I have mulled over the discrepancy because its magnitude is glaring. The pertinent facts, as I see them, are that while both camps seem to agree that a ppmv of 2000-2300 marked the bitter (acidic) end of the line at the KT boundary E.G. dead oceans, they clearly disagree on the ppmv preceding the heat sink's 10, 000 year collapse. Mclean's numbers would indicate a millennium long sharply punctuated yet steady uptick where the second author(s) see a steady 350-500 ppmv for the Ma and only then see a massive jump in the final 10,000 years.
I think I see a possible way to explain this difference. In doing further research, I am seeing some current rump climatology research, which undermines a critical assumption that Mclean may have used. The current working assumption, in most climatology models, is that the Earth reabsorbs around 50% of the Co2 emitted and that the remainder is added to the heap, as it were, thus causing an ever increasing ppmv. This may be a key assumption that Mclean did not question and used in the exposition of his model. The other authors used a more direct measurement of ppmv for the Ma(the size of leaf stomata). This would support the rump research, which postulates that the Earth’s sinks absorbs Co2 regardless of the amount emitted, keeping the ppmv in the 300-500 ranges.
I am trying to ground my take on this on the older and longer data sets. In comparing the two sides, one used an assumption to approximate ppmv for the Ma in question while the other used a form of indirect measurement that has wide acceptance in the field of geology. This brings me back to the salient question with which I began. The Ma preceding the KT boundary extinction event saw 10-25 % higher co2 levels annually yet the ppmv fluctuated between 350-500. I understand the risks involved in a 90 percent annual increase yet I am struck by the fact that the second set of author(s) paper required the instantaneous release of 4600 Gt on top of 1,000,000 years of a 25 % increase before the sinks failed catastrophically over a period of 10, 000 additional years. In terms of percentages, the 90 Gt number which you described, as a 90 % increase over baseline constitutes only a .019 % annual increase relative to the near instantaneous increase wrought by 4600 gt.(not to mention the other colossal atmospheric effects of a bolide collision).
I am, by no means, taking a hard and fast position here. I do see another unquestioned assumption as well as other implied and, as of yet, unexamined data sets and models in the position taken by the second paper for the need for an additional 4600 Gt to precipitate disaster. I will have to reread this paper carefully and look closely for the source(s) of this modeling.
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Tom Curtis at 11:14 AM on 13 January 2014Real Skepticism About the New Marcott 'Hockey Stick'
Michael Sweet @91, here are Marcott's reconstruction plus all thousand "realizations" created by perturbing the proxies:
If you look at about 5.8 kyr BP, you will see a purple spike that rises about 0.2 C above the mass of realizations, and about 0.7 C above the mean. It is certainly possible that this is a "unicorn spike" similar to, of slightly smaller in magnitude to those of which KR speaks. It is impossible to tell for sure, as once the realization falls back into the mass, it is impossible to track. All that spike, and similar spikes above and below the mass, show is that very rapid changes in global temperature are possible given the Marcott data. It does not show the potential magnitude of such changes, nor their potential duration, other than that the magnitude cannot be greater than about 1.2 C (the width of the mass of realizations).
One thing the individual spikes do not show is that their is a reasonable probability of such spikes above the mass. Given that there are 1000 realizations, over circa 10,000 years of relatively stable temperatures, those few visible spikes are significantly less than 5% of occurences. Whether or not there are high magnitude spikes, we can be reasonably certain global temperatures over the last 12 thousand years are constrained within the mass of realizations except on the shortest of time scales.
The one thing that is required to close the argument is an analysis of all 100 year trends within all one thousand realizations to determine what percentage have a 100 year trend close to 0.1 C per decade. I in fact requested the data on his realizations from Marcott at the original time of those discussions, but he replied that he was too busy at the time, and I have not renewed the request.
Finally, with regard to KR's response to you @92, clearly we disagree about what is at issue (100 year trends, vs unicorn spikes). I also disagree with his characterization of my position. I am not arguing that such high 100 year trends are possible, given Marcott; but only that it has not yet been shown that they are not possible given Marcott. Finally, I consider his insistence on seeing the math as bluster. My argument is that he has not shown me the relevant math to support his position. The relevance of the maths he has shown can be shown without bringing in more maths.
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Tom Curtis at 10:27 AM on 13 January 2014Real Skepticism About the New Marcott 'Hockey Stick'
KR @90, I believe that you have misinterpreted the quoted passage. Following the passage through in detail, we see that:
1) They generate 73 identical pseudo proxies;
2) Each proxy is perturbed 100 times to generate 100 pseudo-proxy stacks;
3) The power spectra of the stacks is examined, and compared to the power spectra of the white noise proxies to determine the resolution of the technique.
Now, by your interpretation, the generation of the 100 pseudo-proxies for each proxy perturbation of the signal by error in the proxies. In that case, however, there is no additional step corresponding to the monte carlo method using 1000 pseudo-proxy stacks generated by perturbing the actual proxies. On that interpretation, it follows that Marcott et al never got around to testing the resolution of their procedure.
Alternatively, the 100 perturbations are the analog of the perturbations of the proxies in the full Marcott proceedure. On that interpretation, however, the test of resolution starts with 73 identical proxies. That differs from the real life situation where regional proxies will vary due to regional differences (the result of which being that limited proxy numbers can enhance variability in the record); and in which proxies records contain noise, both with regard to dating and signal strength, both of which tend to smooth the record.
That is, either my criticism is valid (on my interpretation of the quote), or the test does not even test the effect of Marcott's proceedure on resolution (on yours).
While discussing your method, I will further note that the original issue was whether or not, consistent with Marcott's reconstruction, there could have been periods of 100 years or more with global temperature trends equivalent to those over the twentieth century (0.1 C per decade). There is no basis to assume that such trends would be part of a single spike. They could have been part of a rise to a plateau, or a short sine pulse (ie, a spike followed by a trough of similar magnitude and duration). Therefore your test, although based on Marcott's estimate of resolution, does not properly test the original hypothesis, but only a subset of instances of that hypothesis.
I have more to add in direct response to Michael Sweet, but that response may be delayed untill this afternoon (about 5 hours).
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Real Skepticism About the New Marcott 'Hockey Stick'
michael sweet - As the Marcott et al authors themselves stated, their Monte Carlo method, including perturbation of proxy dating and temperature value, will blur high frequency (fast) changes. With a cut-off around 300 years, a signal that varied at <300 years won't come through at all.
However, a single unphysical 0.9Cx200yr 'unicorn' spike such as hypothesized by skeptics is a complex signal, from the 0.9x100yr addition to the average, to the very fast changes at the inflection points of the spike - and much of the <300yr signal survives the Marcott processing leaving a diminished but noticeable 600yr peak. Tom Curtis and I disagree on the possibility of Marcott style processing being able to detect such a short spike - but the frequency space math I've run, as well as Tamino's Monte Carlo tests, indicate that it shows clearly. A point that I will insist upon until I see math indicating otherwise.
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michael sweet at 09:52 AM on 13 January 2014Real Skepticism About the New Marcott 'Hockey Stick'
Tom
It seems to me that your proposal is that there might be a short, 0.9C spike in the indiviudal records but they cancel out because of dating errors. Can you provide two proxies that show such a spike? If none of the individual proxies show such a spike, it follows that the sum of the proxies cannot have an undetected spike in it.
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Hockey sticks to huge methane burps: Five papers that shaped climate science in 2013
Tom Curtis - I strongly disagree, and have responded in detail on the appropriate thread.
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Real Skepticism About the New Marcott 'Hockey Stick'
Tom Curtis - "...neither Tamino nor your tests allow for the innate smoothing implicit in any reconstruction from the fact that the measured age of each proxy will differ from the actual age of the proxy by some random amount"
I would wholly disagree, as they tested that effect as well. From the Marcott et al supplemental:
We modeled each of the 73 proxy records as an identical annually-resolved white noise time series spanning the Holocene (i.e., the true signal), and then subsampled each synthetic record at 120-year resolution (the median of the proxy records) and perturbed it according to the temperature and age model uncertainties of the proxy record it represents in 100 Monte Carlo simulations. (emphasis added)
As they stated, their 'white-noise' test explicitly includes the random uncertainties in proxy age you are concerned with. As per the prior discussion on this thread, I feel that their frequency response fully characterizes the effects of their analysis, and that correspondingly a 200-year duration 0.9C spike would be reduced and blurred by a factor of roughly three - leaving a signal that would be clearly visible in the Marcott reconstruction. Tamino found results consistent with mine by performing the Monte Carlo analysis himself, which again indicates that a 'spike' of that nature would be visible in the Marcott analysis - evidence that such a spike did not in fact occur.
For such a signal to be missed, for the frequency response to have far less of a high frequency response, would require that Marcott et al significantly underestimated proxy age uncertainties - that they mischaracterized their proxies. I believe the burden of proof for such a claim would rest with the claimant.
As to my characterization of such spikes, I consider them fantastical unicorns because there has been _no_ postulation of _any_ physically plausible mechanism for such a short-lived global temperature excursion. It is my personal opinion that at least some of the emphasis on 'spikes' (such as the many many posts on the subject at WUWT, ClimateAudit, and the like) has been for the purpose of rhetorically downplaying the Marcott et al paper and its evidence of the unusual nature of current climate change, an extended claim of it's not us. I would take the entire matter far more seriously if there was _any_ physical possibility involved.
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scaddenp at 08:12 AM on 13 January 2014Newcomers, Start Here
The accusation probably tells you more about the mind-set of the accuser than climate scientists. Presumably they would happily do biased research for the money.
There are several erroneous assumptions involved. 1/ some think that grant money goes to the scientist - a gravy train for them - whereas reality is that funding usually goes to employer and they draw their salary. 2/ The commonest assumption is the belief than funding is tied to AGW. A look at, say, NSF grants would show funding goes to find out things that arent already known and funder doesnt care which way the results fall. 3/ It is also often thought that if AGW was shown to be false/irrelevant, then all these people would lose jobs. In practise, scientists move the next interesting problem.
You might ask, if climate science is biased, why FF companies spend money on misinformation rather than using their considerable research infrastructure to show alternative results. Answer would be that their own scientists would tell them its more effective to use PR because on the whole they find the science of AGW convincing. (I work in petroleum research).
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Mal Adapted at 07:46 AM on 13 January 2014Newcomers, Start Here
ZincKidd, I've wished for a more effective counter to the "funding bias" arguments of the deniers myself. Pithy retorts along the lines of "If scientists were in it for the gold, they'd be working for the fossil fuel corporations" only carry so much weight. Try this SkS discussion from a while back for some ideas.
A response from a scientist who depends on grant money is Scott Mandia's "Taking the Money for Grant(ed)".
More recently, there have been some damning studies of where deniers get their funding. It might help convince your "friend" that the accusations of funding bias are coming from people who are paid to make them.You should keep in mind that it takes money to make money. The people who stand to lose the most if fossil fuel use is curtailed are willing to pay top dollar for skillful propaganda, to convince the public that AGW is all a hoax. Scientists, however, are ethically (and financially) constrained from adopting that strategy. It's kind of a lop-sided struggle.
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DSL at 07:33 AM on 13 January 2014Newcomers, Start Here
ZincKidd, your friend has a basic misunderstanding about climate science. This is probably due to not having read any of it. Have him show you work that undermines the basic physics involved.
Still, it's one of the silliest arguments there is. The basic claim is that scientists are fudging studies in order to toe the line. In other words, climate science is a hoax. Since the basic theory is well over 100 years old, that means that at least five generations of scientists working in climate-related areas are part of the hoax. It also means that decades' worth of graduate students in atmospheric science and physics are also part of the hoax. And all the editors of all the journals. All of these people have been publishing fictions. That takes talent. Think about it. A working scientist must get together with his team and design a study that undetectably perpetuates the fiction. Since climate science is progressive and interdisciplinary, it's like a giant house of cards. Every study published is a potential weak link in the house.
Yet no one has been able to locate the hoax. Upwards of a million people involved (all living and dying with the secret), and no one has ever figured out the fictional element of physics upon which the entire house is based.
Heck, even the Earth is involved in the hoax. Arctic sea ice volume at summer minimum is at roughly 20-25% of its 1979 minimum. Have your friend do the math to figure out how many joules it has taken to manage that. I guess all of the polar scientists and engineers (and Inuit!) could be in on the hoax as well.
That's what your friend wants you to believe. That's what he thinks is reality. Weigh the probability of that reality against the probability that, in fact, the science is actually describing physical reality. Show me where the lie is. That's what I'd ask. It's one thing to claim that scientists are motivated to lie for money; it's another thing to actually show evidence of a lie. Invite your friend to SkS to present his case. If there's solid evidence, I'll change my mind.
I've often found that that type of "skepticism" comes from people who haven't actually sat down and read a published paper or talked one-on-one with a scientist. They're more than happy to make broad claims about "libtard scientists" as long as they're never forced to humanize those scientists by looking them in the eye.
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grindupBaker at 07:19 AM on 13 January 20142014 SkS Weekly News Roundup #2
Climate scientist Arctic & Antarctic specialist Dr. Dan Lubin has a lecture on video on the web "Global Warming and the Polar Regions: Signs of Human Impact" at University of California Television discussing the Polar Night Jet and some changes of last few decades. I forget whether it has close relevance to this "Polar Vortex" but likely yes.
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martin3818 at 04:24 AM on 13 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
@12 Tom Curtis
Thanks Tom for your explanation. I’m certainly less confused now, although I will probably still have to draw what you said as I’m more visually oriented.
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citizenschallenge at 01:55 AM on 13 January 2014Richard Alley's Air Force Ostrich
Excuse the dog piling but it's January 2014
Justin has had plenty of time to think about and list his "cogent arguments."
But, he has posted nothing.
I would suggest that indicates that after some serious thought he realized he had no argument and rather than admitting to it, he silently exits the discussion. Typical of the behavior of your committed climate science denialist type.
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Composer99 at 18:44 PM on 12 January 2014CO2 was higher in the past
roscoe:
Your point being?
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Poster9662 at 17:57 PM on 12 January 20142014 SkS Weekly News Roundup #2
This might not be such a calamity as it might have been before the US became determined to become energy independent via atural gas and shale oil. As a result of this push it is claimed US CO2 emissions have fallen 3.8% from 2011 to 2012, are 11% below the 2007 peak, are at the lowest levl since 1994 and. have declined in five of the last eight years (http://tinyurl.com/cwgnsop)
Moderator Response:[JH] On Jan 13, 2014, the US Energy Information Adminsitration posted the following: U.S. energy-related CO2 emissions in 2013 expected to be 2% higher than in 2012
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roscoe at 17:29 PM on 12 January 2014CO2 was higher in the past
There is a man who lives close to me who is in the Guiness Book of Records for growing the world's largest vegetables.
He pumps CO2 into his greenhouse.Moderator Response:[TD] Please read the post "CO2 is Plant Food," and comment there, not here.
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ZincKidd at 17:19 PM on 12 January 2014Newcomers, Start Here
Hey gang, great site. I've recently discovered an old aquaintance of mine, to my surprise, is a rabid climate "skeptic.". He's used arguments that seem pretty obviously bogus, but I don't always have my ducks in a row to counter them. For myself, the eye opener for me was the Jerry Mitrovica video on sea level. But that was not convincing to the skeptic who thinks it was biased by funding. That's a good catch-all for anything you disagree with. He's also claimed that to insist on peer-review is cherry picking, "there's a lot of articles out there that disagree, the idea that in the last year only 1 was published that was contrarian is false". His aruments seem to hinge on that catch-all, funding bias.
One claim of his is that the reason there is apparent consensus is that all of the scientists accept grant money that influences them to find in favor of AGW. This seems to me to be rather a vague claim, as a quick look reveals grants coming from many institutions, such as the NSF, NASA, Naval Research, NOAA, many Universities, etc. I think the "skeptic" respose would be all of these are biased. I know a few working scientists, and grant money seems often hard to come by, but none of the scientists I know are climatologists. I also don't see this argument addressed directly as one of the numbered favorites-- any idea where I could find out more? Better info on the grant processes in general? My gut tells me the claim doesn't hold water, but I don't really have any relevant details...
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Glenn Tamblyn at 15:58 PM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
DMarshall
The standard definition of Climate as defined by the World Meteorological Organisation is weather averaged over 30 years. Additionally the WMO defines preferred periods to use as reference baselines when looking at climate - 1901-1930, 1931-1960 and 1961-1990. So the baseline fits the WMO standard. And the more different datasets there are that use the common baseline the easier it is for people to work with different datasets doing intercomparisons etc. If the base lines kept being altered then there would be a need to do continual rebasing to allow datasets to be compared.
For some data series there may be operational reasons why a different period is used but they still use 30 years when possible.There is no actual need to adjust a baseline since all the data points are anomalies relative to a base line. The important fact about the dataseries is the relationship between the data points, not what theyt are baselined.to
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Tom Curtis at 14:10 PM on 12 January 2014Hockey sticks to huge methane burps: Five papers that shaped climate science in 2013
KR @19, as I contributed in a small way to the 'dust-up', I should probably feel insulted that you have included me among the 'skeptics'. As I have noted elsewhere, neither Tamino nor your tests allow for the innate smoothing implicit in any reconstruction from the fact that the measured age of each proxy will differ from the actual age of the proxy by some random amount. I have discussed this in detail here, where interested readers can find your response, and my response to your response. My argument was, of course, not that the Marcott et al algorithm would not show rapid changes in temperature occuring over a short period, but that neither you nor Tamino had shown that it would.
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DMarshall at 09:32 AM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
Why is 1961-1990 still the baseline and not 1971-2000?
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grindupBaker at 05:28 AM on 12 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
davidsanger #18 Prof. Richard Muller Berkeley Earth web site has an analysis of land-only measurements from 36,000 temperature stations 1750-2000 showing +1.5C (+0.9C over the past 50 years) with a graph of a fit to measurements that's a near-perfect smooth exponential curve punctuated only by a dozen or so very sharp downward spikes of which the 7 largest are volcano-named on the graph Laki, Tambora, Cosiguina, Krakatoa, Agung, Chichon & Pinatubo. Land MST is slightly depressed following each spike, proportional to the spike height, then moves back to the original land MST curve. Data & fitting software are available for download and they invite comment on both.
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Joel_Huberman at 05:08 AM on 12 January 2014Talking Trash on Emissions
Scaddenp@11 and Tom Curtis@12: Thanks for your very helpful, informative replies. Now I know much more than I had ever imagined I would know about CO2 emissions per capita, and I've found every additional detail to be fascinating.
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grindupBaker at 05:06 AM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
PluviAL #3 It starts "Compared to the Arctic,". There has been a much larger change in Arctic sea-ice extent (a reduction) over the last few decades than the change in Antarctic sea-ice extent so the statement in the posting is correct (and rather obvious). I think Antarctica is the opposite of a driving force in weather and so climate, I think it's a deadening force. For example, there's no heat transport from the equator southward in the Atlantic to the Antarctic but there's a large heat transport from the equator northward in the Atlantic to the Arctic.
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william5331 at 04:39 AM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
It should be a fun year the next time we have an El Nino
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wili at 04:38 AM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
Speaking of Australia and temperature increase, there is an excellent group from Australia that puts out good overviews of CC research. Here's a chapter from their report from September 2013 "Is CC Already Dangerous?" on "Danger from implied temperature increase": http://www.climatecodered.org/2013/09/is-climate-change-already-dangerous-3.html
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Earthling at 04:33 AM on 12 January 201416 ^ more years of global warming
I'm not sure whether this is good or bad news for the faithful, but there will always be "short-term warming and cooling influences of volcanic eruptions, solar activity, and El Niño and La Niña events" so removing them is pointless.
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PluviAL at 03:44 AM on 12 January 20142013 was Australia's Hottest Year, Warm for Much of the World
Antarctica is a driving force in weather and so climate. (And, I postulate plate tectonics too; if anyone has info olong those lines.) It reacts in proportion to the energy in the atmosphere just like any other region. Sea ice extent, and characteristics are just the way Antarctica reacts to the energy and its particular dynamics. It does not seem right to say "Antarctic sea-ice extent is not as strongly influenced by recent global warming." I don't know how else to phrase it but it does not seem correct.
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macoles at 22:34 PM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
Thanks Bob, I hadn't concidered that the ocean soaking up the better part of that 45% CO2 would require ongoing acidification. I foolishly just assumed that if the ppm reached a manner of equalibrium then its effects would too.
Thanks aswell to both Toms for the links and explanations.
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Philippe Chantreau at 18:10 PM on 11 January 20142013 was Australia's Hottest Year, Warm for Much of the World
It's also worth adding that this is not just one year, i.e. random weather, as one poster suggested. The increasing frequency and severity of heat waves in Australia can be seen happening over a number of years, of which this last one is the culmination. The frequency and severity of fires seems to follow a similar pattern. I'll add that this is provably unusual, since it is causing well adapted native animals to die by the thousands, like the bats that have been falling on the ground and dying recently, despite their desperate attempts to cool themselves with their own urine. Joeys are found passed out on the ground from heat exhaustio;, if there is one animal that is heat resistant, it should be that one but nothing lives well in the 50 deg Celsiusneighborhood...
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davidsanger at 17:59 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
thanks KR@20 that's as I suspected, so the end result would just be delayed for a short-term then.
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grindupBaker at 17:25 PM on 11 January 2014Oceans heating up faster now than in the past 10,000 years, says new study
Chris @ #6 "the current rate (about 0.18degree per century)" (10zj/yr I seem to recall that's current IPCC) or more likely 0.25C per century, based on latest decade, because I believe Balmaseda, Trenberth & Kallen ORAS4 is the more accurate because onwards & upwards is the way it's been going. I think we can expect IPCC to be lagging a bit.
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grindupBaker at 16:20 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
Agnostic@12 Graph at SKS "Sun & climate: moving in opposite directions" linked above shows solar forcing increase of 0.75/4=0.19 Wm**-2 1880-1979. It requires a surface temperature increase of +0.063 Celsius to balance that, so surface temperature should have increased that much 1880-1979, but it actually increased ~+0.39 Celsius, which is 6 times as much as it should have. So, not only is there no hysteresis from the increased insolation 1880-1979 pertaining to the following decades, but some mysterious unknown factor has caused an extra 5 times the warming during 1880-1979, after which it even accelerates. Now that I've discovered this (I should get Nobel Prize) it only remains for scientists to plod away and identify this mysterious warming agent. ** Used Dr. Randall 0.6 Earth bulk emissivity.
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Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
davidsanger - There would be a short-term dip in forcings until the stratospheric aerosols came down, much as we saw with the 1991 Pinatubo eruption - see the stratospheric aerosols below:
After that warming would simply resume. At most warming might be delayed 5-10 years, resuming on much the same track after that. And no, no permanent amelioration, just a short delay reaching radiative balance at the same temperature we would reach without such a volcano.
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Glenn Tamblyn at 16:12 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
davidsanger
Generally speaking the cooling impact of volcanic aerosols will dissipate within a few years. Then the full warming effect of the CO2 emerges. As long as the CO2 concentrations remain the same no persistent amelioration can occur. The only remotely conceivable way that amelioration could occur is if it resulted in increased carbon sequestration somewhere, pulling it out of the atmosphere. If volcanic cooling persisted for a long time then it might lower ocean temperatures and allow greater uptake of CO2 by the ocean. However when the volcanic cooling ended the system rewarms and the oceans outgas the CO2 again and result is zip.
The only type of volcanic impact I can imagine have a long term effect would require continuous vulcanism for centuries to millenia, long enough for the increased uptake of CO2 into the ocean to be transferred down to the depths and possibly deposited on the sea floor. If the extra CO2 absorbed is still near the surface when the volcanic cooling ends it will outgas again; it needs to be removed from contact with the surface for any long term impact.
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Hockey sticks to huge methane burps: Five papers that shaped climate science in 2013
Hank_Stoney - Regarding Marcott et al 2013, Tamino tested a theoretic 0.9 spike (100 years up, 100 years down) against their Monte Carlo testing, and found they were clearly visible in the resulting analysis. I personally repeated that with a separate technique, using the frequency transform Marcott et al described in their supplemental data, and found that such a spike would leave a 0.2-0.3C spike in the final data.
No such spike appears anywhere in the Holocene data Marcott et al analyzed. And that doesn't even include the physics indicating a CO2-driven spike of the kind we are currently experiencing cannot just vanish over 100 years - rather, 1-10Ky would be required (Archer et al 2008); there is just no physical mechanism for such a spike.
The entire 'dust-up' you mention arose from fantasy hypotheticals created by 'skeptics', hypotheticals which simply do not hold up under analysis. Hypotheticals, I'll note, which are certainly not peer-reviewed...
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chriskoz at 15:43 PM on 11 January 20142013 was Australia's Hottest Year, Warm for Much of the World
It's worth adding that last year's rainfall anomaly in the East (coastal floods on QLD & NSW due to Oswald while extreme drought inland) happens to be consistent with the CSIRO model predictions in this part of the world due to climate change: the East Coast will become generally wetter and inland drier and rain will be falling in more sporadic and more intense events.
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davidsanger at 15:28 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
A question on volcanoes: Hypothetically, if there were to be a major volcano in the near future, and a subsequent increase in aerosols and reduction in temperature for a while, and at the same time CO2 levels continued to follow the same pattern as before, would the net result centuries later be the same or would some of the effects of the increased CO2 levels be permanently ameliorated?
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Hank_Stoney at 15:10 PM on 11 January 2014Hockey sticks to huge methane burps: Five papers that shaped climate science in 2013
Not trying to be make any waves but wasn't there a big dust-up at the time of publication regarding statements similar to the following (quoted from above):
1. What hockey stick graphs tell us about recent climate change
. . . Shaun Marcott and colleagues showed global temperature rose faster in the past century than it has since the end of the last ice age, more than 11,000 years ago. . .
And the actual language in the paper that was expanded upon in the FAQ at realclimate.org (my emphasis):
Q: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?
A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century. Other factors also contribute to smoothing the proxy temperature signals contained in many of the records we used, such as organisms burrowing through deep-sea mud, and chronological uncertainties in the proxy records that tend to smooth the signals when compositing them into a globally averaged reconstruction. We showed that no temperature variability is preserved in our reconstruction at cycles shorter than 300 years, 50% is preserved at 1000-year time scales, and nearly all is preserved at 2000-year periods and longer. Our Monte-Carlo analysis accounts for these sources of uncertainty to yield a robust (albeit smoothed) global record. Any small “upticks” or “downticks” in temperature that last less than several hundred years in our compilation of paleoclimate data are probably not robust, as stated in the paper. (link)
In my mind, that's a pretty clear contradiction. Maybe others disagree?
If not, I think we should offer proper caveats about the results of the study rather than open ourselves up to such easy criticisms.
Just my $.02.
P.S. I know that Tamino made a blog post defending those types of claims so maybe reference that as well even though it was neither peer-reviewed nor included in the Marcott analysis.
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Bob Lacatena at 14:55 PM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
Macoles, 24,
Your understanding is incorrect. The "natural carbon cycle" is just that, a cycle, not a reservoir. About half of human emissions go into the ocean, causing acidification which may turn out to be as or more dangerous than climate change. A big chunk goes into the atmosphere. Most of the rest goes into expanded vegetation.
It can't and doesn't just disappear. It took nature hundreds of millions of years to bury it in the ground. That won't happen easily, or quickly. There are some mechanisms by which carbon will be deposited in the deep oceans, but that will happen very slowly.
worse yet, we can't even count on it continuing to go into either the ocean or vegetation. As the ocean warms, it's capacity to absorb CO2 is reduced. Eventually, if it warms enough, it may release some of that absorbed CO2 -- a positive feedback. The same goes for vegetation. While for a while, it may show more growth due to mildly warmer temperatures, increased precipitation, and higher CO2 levels, that's hardly a permanent trajectory. Eventually, expansion of the deserts and droughts, especially if it happens too quickly, will reverse some or much of that growth (worst case would be, for example, the transition of major parts of the Amazon to savanna). The subsequent release of carbon is yet another positive feedback.
If we reduce emissions, there is no reason to think one particular sink (atmosphere, ocean, vegetation) to absorb more than another, and as the planet will continue to warm until it reaches a new equilibrium temperature, any of those positive feedbacks listed above could still come into play.
Interestingly, even if we found a magical, technological way to suck CO2 out of the atmosphere, the ocean would still replace some of it, and those positive feedbacks might still kick in. It's a very dangerous game that we're playing... Carbon Roulette.
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Tom Curtis at 13:35 PM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
As an addendum to my @28, and Chriskoz's @27, increasing background emission rates by 1.51 x 10^12 mol per year (2.4% of the current increase of emissons over background levels) with a 0 Gt C spike results in a CO2 concentration of 400 ppmv after 1 million years. That is an excess emissions rate of 0.02 Gt C, and represents a reasonable estimate of the maximum safe emissions in the very long term. For all intents and purposes, that means we need to target 0 net emissions in the long run. An intermediate target less than 5 - 9% of current emissions will be necessary to ensure we avoid the full ECS response to increased CO2. I am sure Chriskoz and I will agree that above that is madness, and the closer to 0 net emissions the better.
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Tom Curtis at 13:21 PM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
chriskoz @27, I quite agree, and am happy to see your expansion on my point that:
"On the other hand, it does considerably better than that (and worse for us) at 1000 GtC, the level of emissions we notionally should not exceed to keep the global temperatures increase below 2 C."
My original point was that for any reasonable estimate of cumulative emissions by 2100, ongoing emissions after 2100 of just 9% of current emissions will be sufficient to prevent CO2 levels from falling. I did not claim they would not rise. As also noted @22, that level is sufficient for an effectively indefinite rise in CO2 levels in the very long term (by human time scales).
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chriskoz at 12:59 PM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
Tom Curtis@22,
You modelled your scenario in GEOCARB model a little bit inaccurately. Originally, you said @13:
if we cease all emissions, then temperatures will not rise much above the TCR to the peak CO2 concentration - but will not fall much below it for thousands of years either. However, if we retain emissions at just 9% of current levels, CO2 concentrations will not fall
(emphasis yours)
It mean that your scenario is to cease the CO2 emissions now but keep the 9% residue of CO2 emissions (70E12 mol/yr as "degassing simulation") forever. Such scenario translates to the Transition CO2 Spike of sth like 500GtC (cumulative emissions to 2011) in GEOCARB. Yours 5000GtC input is unrealistic.So, with 500GtC spike input and degassing simulation of 70E12 mol/yr, the GEOCARB output is 505ppm CO2 spike (obviouly higher than today's real value because of shorter timeframe - 50y - of release in GEOCARB) but the minimum CO2 reached is 455ppm (in 400y), therefore somr than 50ppm higher than today. So I think, according to your argument, the residual degasing rate does not need to be as high as 9% of the current rate, so that CO2 concentrations "will not fall". In fact, I modified the degassing simulation of 40E12 mol/yr (5% of current levels) and I got the minimum CO2 of 398ppm in 700y, which is incidentally the current level.
So I argue that CO2 degasing of just 5% of current levels, if kept indefinitely, will ensure that the current 400ppm "will not fall". Further, please note that this 40E12 mol/yr degassing includes the volcano output (7.5E12 mol/yr spinup parameter) estimated from the current geo configuration. Therefore, the "human C residual outpout" in this scenario is only 32E12 mol/yr, or 4% of current levels.
For those who want to understand how the numbers are spun by GEOCARB on a shorte and long timescale, check out the rock weathering simulation by choosing "Silicate Thermostat" as an output graph. Before the simulation (years -100 to -50), the silicate weathering rate (WeatS) is in balance with volcano degassing (Degas), which is equal to the spinup value of 7.5. That equilibrium results in 272ppmCO2. If you show "Silicate Thermostat" for 1 million years, you sea that WeatS still would not catch up with Degas (33.7 vs. 40 in my simulation), therefore CO2 in the A would still be rising causing T rise and slowly speeding up WeatS. Such scenario (CO2 degassing at 5 times the natural level for 1My) has nothing to do with AGW and I'm not a geologist to judge how likely it is (i.e. if enough C and the mechanisms of its elevated level of release) exist in the system. It is just to show how miniscule CCycle changes are in the long-term natural system, as opposed to the "disaster-like", abrupt anthropo disturbance.
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Tom Curtis at 12:39 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
chriskoz @15, the situation he implies is implicit in the fact that the temperature response lags the forcing. Because of that, the temperature response can be below the equilibrium temperature response for a value less than the peak insolation long after the peak insolation has passed. So long as the decline in insolation has not fallen below that lower value, temperatures will continue to rise, albeit at a slower and slower rate. I discuss this @10.
As mentioned @16, this situation occurs annually. In fact, the peak insolation annually is in December, coinciding with the peak SH insolation. The peak SH temperature, however, lags the peak SH insolation by about a month, and occurs in January. Likewise the peak NH insolation is in July, but the peak NH temperature is in August. Because air over land heats faster than air over sea, the NH has a larger response to changes in insolation than the SH, resulting in the peak global temperature also occuring in August.
Indeed, this situation also occurs daily on a local level, with peak insolation at noon, but peak temperatures around 1 or 2 pm.
It is, however, important to note that this situation can only occur when there is a lag in the temperature response to forcing. Absent that lag, peak temperature will always occur at the time of peak forcing.
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Tom Curtis at 12:30 PM on 11 January 2014Global warming is being caused by humans, not the sun, and is highly sensitive to CO2, new research shows
Climate Agnostic @12, if your point is the very narrow and technical point that it is theoretically possible that global temperatures could continue to rise after the forcing that caused that rise had started to fall, then I have already conceded that point. As it happens, that happens every year when the seasonal peak temperature occurs in August though the relevant forcing (NH summer insolation) peaks in July, and falls thereafter.
However, as I have pointed out @10, the merely theoretical possibility that the increase in insolation to 1950 was the cause of the increase in temperature to 2014 is inconsistent with observations. As a candidate scientific theory, it has been falsified. Therefore that merely theoretical, but in fact falsified possibility is irrelevant to this discussion. At most your point is that the statement:
"we know the sun can't be causing the current global warming because solar activity has declined slightly over the past 50 years"
represents a contingent (inductive) argument ie, one that is not guaranteed to be valid under all circumstances. But unless you wish to argue that all inductive arguments should be avoided, that is irrelevant. The number of circumstances under which the argument is valid far exceeds those under which it is invalid, including the current circumstances as shown @10. Therefore the only 'flaw' in the argument is that it provides less certainty than can be obtained by a more detailed argument.
Now, either you know that the Sun is not the cause of the continuing increase in global warming after approx 1960, in which case you are arguing a mere technicality; or you do not, in which case you are massively confused. The later appears likely in that you appear to think the possibility of ongoing warming from a declining forcing is independent of the lag in the forcing. That is false. If there is no lag, then the increase in temperature at any time will exactly correspond to the increase in forcing, so that at the peak of forcing, you will also be at the peak in temperature.
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tcflood at 11:32 AM on 11 January 2014New Study Suggests Future Global Warming at the Higher End of Estimates: 4°C Possible by 2100
Tom Curtis @ 13
If nearly all of the ECS response is attained at a couple hundred years, then one could use the TCS and ECS pretty much interchangeably. This was the impression that I had because of the apparent lack of distinction in common use in discussions.
But the reason I focused on the hydrosphere @ 8 is because of the “pause” in SAT over the last 15 years being explained by supposing that periodic oscillations in ocean-atmosphere thermal coupling can lead to faster than usual heat transfer from the lower troposphere into the oceans below 700 m or so.
Does periodic slowing of SAT increase by periodically enhanced AO coupling imply that those models that don’t do the AO coupling especially well could significantly overestimate the rate of SAT increase over, say, a 50-100 year period? So could the TCS in fact be significantly smaller than the ECS? Could this have led to an over-estimation of likely rate of SAT heating in the 21st century?
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