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Comments 42651 to 42700:

  1. The Beginners Guide to Representative Concentration Pathways - Part 3

    I don't think it is fair to say that CCS is not working, at least at a technical level, the few pilot projects that are running seem to be working OK. The problems with CCS are economic, scalability and regulatory. 

    The economic problem could be solved with a hefty carbon tax, which is easier said than done, of course. 

    The scalability problem is much more problematic, since the mass of CO2 that has to be stored is about three times the mass of the fossil fuels that produced it. Establishing a new global industry much bigger than the current oil, gas and coal industries in a matter of decades is not feasible. Note that in all of the RCPs, the absolute amounts of fossil fuels consumed increases by 2100. The scalability problem is not so much a question of the size of the potential reservoirs, but our ability to build the infrastructure to put the CO2 there.  

    The regulatory problem is a major stumbling block in my opinion. Geological CCS has all of the problems of unconventional gas development and more and, if it is to be a climate-relevant solution, it will have to be implemented in sedimentary basins everywhere. The potential hazards of CCS are real and include leakage, earthquakes, industrialization of the landscape and groundwater contamination. The regulatory and public acceptance problems will make CCS more expensive, slower to implement and more limited in scope. 

    rustneversleeps and I wrote a long piece on CCS recently that covered some of these points in more detail. 

  2. Global warming...still happening

    Global warming is produced by an energy imbalance at TOA, an imbalance which is evidenced most clearly in accumulating ocean heat content.  I would suggest that you use the latest NOAA values for OHC (http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html)  which show, through the first quarter of 2013, an unabated rise in heat accumulation on earth (as oceans absorb ~93% of that imbalance).  The atmospheric temperatures, due to the far, far lower heat capacity of the atmosphere relative to the oceans, and driven by the current set of ocean-atmosphere heat transfer mechanisms (ENSO, PDO, AMO, thermohaline circulation, etc), provide the least reliable assessment of an energy imbalance at TOA is derived from atmospheric temperatures.  A ton of statistics on a poor indicator is not particularly helpful.

  3. The Beginners Guide to Representative Concentration Pathways - Part 3

    Perhaps I am behind the times, but my understanding is that none of the CCS schemes is working.  Does anyone have a link to an up to date summary of the status of CCS?  If CCS does not yet work, it will be difficult to implement in a timely fashion.

    On the other hand, wind and solar continue their amazing drop in cost.  Wind is already the cheapest new source of energy and will soon be cheapest even compared to coal plants that are paid for.  Solar is economic for home installation in areas with expensive electricity and will soon be economic everywhere.  I have started to look at how to install solar at my home in Florida even though Florida has no incentives.

  4. It's El Niño

    dvaytw - it's not strictly true that El Nino and La Nina simply move heat around. But over time, in a stable climate, they would balance out to zero. The only reason the climate system is gaining energy in the long-term is because the increased Greenhouse Effect is trapping more heat in the surface ocean.

    That's why global temperature, and therefore subsurface ocean temperature, tracks atmospheric CO2 so well in the ice core records over the last 800,000 years.

    I don't consider it a worthwhile exercise spending time on crank ideas from Bob Tisdale.   

  5. CO2 lags temperature

    tcflood - the abstract is here: Abe-Ouchi et al (2013) - Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume.

    Sounds interesting. Note that it relates to the 100,000-year cycle - as stated in the abstract:

    "Carbon dioxide is involved, but is not determinative, in the evolution of the 100,000-year glacial cycles."

    Your comment omits this crucial bit of information.

  6. CO2 lags temperature

    Sorry.  For completeness, the authors on that Nature paper are Ayako Abe-Ouchi, Fuyuki Saito, Kenji Kawamura, Maureen E. Raymo, Jun’ichi Okuno, Kunio Takahashi, and Heinz Blatter.

  7. CO2 lags temperature

    I have always been bothered by the lack of a detailed and convincing explanation for the 100 ky periodicity of the last four ice ages when the periodicity of northern temperate zone insolation intensities from Milankovich cycles (my understanding is that this is the important component of these cycles) is close to 20 ky.  A recent paper in Nature (Vol 500, August 8, 2013, page 190) presents an explicit explanation and also describes how CO2 has a role but is not determinative in ice age/interglacial cycles. What do you people at SkS think about this paper?   

  8. It's El Niño

    Thanks for the info, Rob, but what do you think of my characterization of the problem with his hypothesis?  I'm trying to sum it up in a way that is hospitable to people like myself without a solid science background.

  9. Global warming...still happening

    I'm imaging the climastrology reponse to Dan Bailey's repost of the excellent Climate Central graphic-

     

    begin simulation exercise

    'Ya see...we had 4 steps up and a plateau from 1900-1940, so we've had 4 steps up now, so we're due for another plateau!!!  If only climate scientist could count with the fingers on one hand'

    (end simulation exercise).

  10. The Beginners Guide to Representative Concentration Pathways - Part 3

    I tend to agree with chriskoz that the level of CCS envisaged in all but one (RCP8.5) of the pathways seems unrealistically high. Also, the amount of solar/wind/geothermal generation seems very low; this category is the smallest (or nearly so) in all four pathways in Figure 14 above.

    This triangular diagram from van Vuuren et al is interesting. In all four pathways, fossil fuels (with or without CCS) make up greater than 50% of energy technologies by 2100, and it is only in the final few decades that the fossil fuel share drops below 62.5% and only in two of the pathways (3PD and 4). Considering that absolute levels of fossil fuel consumption rise in all four cases (Fig 14) and that much of the CCS activity, especially geological storage, will likely be handled by future versions of the big oil companies, the demise of Exxon et al may not be a foregone conclusion.

    I know, these are not forecasts, just projections, but it is surprising that none of the pathways models the kind of energy transition (i.e.,renewables-dominant, with little fossil fuel and CCS) that many green-minded people envisage.

  11. 2013 SkS Weekly News Roundup #35B

    Link for second article is missing. Here it is: http://grist.org/climate-energy/carbon-targets-carbon-taxes-and-the-search-for-archimedes-lever

    Moderator Response:

    [JH] Missing link inserted. Thanks for bringing this to our attention. 

  12. Global warming...still happening

    I still don't understand why this argument hasn't already been put to bed. I've seen several news articles and papers in recent months talking about the pause in warming being linked ot the enso cycle, as if this was news? Surely this was patently apparent ever since this chart was first circulated:

    http://skepticalscience.com/graphics.php?g=67

    All trends continue upward, it's just we're still in the la nina and neutral territory of the spectrum.

    It seems obvious to me that the next El Nino is gonna prove decisively what this chart already shows.

  13. Global warming...still happening

    Thanks, Daniel (#16), for the very nice graph from Climate Central. One from NASA that conveys a similar lesson can be found here. In the NASA graph, small differences can be seen among the four datasets/interpretations. The dataset/interpretation from the Japanese Meteorological Society shows 1998 as the warmest year on record, but the datasets/interpretations from the other three sources show 2005 and 2010 as being slightly warmer. Consistent with the graph from Climate Central, the graph from NASA clearly shows (by simple eyeballing) that, regardless of dataset/interpretation, the decade 2001-2011 was warmer than any preceding decade.

  14. Global warming...still happening

    Joel, depending on the datasets used, 2005 and/or 2010 each equalled 1998 as the warmest year for the surface temperature record.  However, when viewed as decadal averages, the most recent decade has been the warmest, by far:

    Dacades of Warming

    Source

  15. empirical_bayes at 03:05 AM on 1 September 2013
    Global warming...still happening

    @VeryTallGuy for #2, @Ari Jokimäki for #7,

    I am not familiar in depth with the Santer et al (2011) calculations, but a quick look at their Appendix and their Equation (A1) and runup to that suggests these a pretty ad hoc.  They themselves say, in their paragraph numbered "68":

    While non‐independence of samples is an important
    issue in formal statistical significance testing, it is not a
    serious concern here. This is because our pc(i)′ and pf (i)′
    values are not used as a basis for formal statistical tests.
    Instead, they simply provide useful information on whether
    observed TLT trends are unusually large relative to modelbased
    estimates of unforced trends, or unusually small relative
    to model estimates of externally‐forced trends.

    I can't comment on what they are trying to do here, but it's fair to say this is no conventional kind of statistical significance being calculated.  Worse, statistical "significance" cannot be properly used in the way VeryTallGuy seeks to do so, and as many do.  "Significance" has a specific technical meaning, and I would strongly recommend reviewing that, e.g., at http://en.wikipedia.org/wiki/Statistical_hypothesis_testing#Interpretation See also http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1756718/

    The problems classical significance testing or hypothesis testing has in complicated situations is one of many reasons why modern statistical inference is couched in the Bayesian view. See the text, J. Kruschke, Doing Bayesian Data Analysis for a great introduction. Alternatively, check out http://hypergeometric.wordpress.com/2013/08/22/soon-you-will-be-one-of-us/

  16. Global warming...still happening

    Thanks to both Ari and the moderator (DB) for the explanation. I hadn't realized that the data shown in the Berkeley Earth summary graph had been corrected in the same way that the red line in Ari's graph had been corrected. The explanatory legend at the Berkeley Earth site didn't make that clear. But it makes sense, because the red line in Ari's graph resembles all four lines in the Berkeley Earth summary graph. I conclude that the uncorrected global temperature in 1998 has not yet been exceeded by any subsequent uncorrected annual average global temperature.

  17. Global warming...still happening

    Joel, the caption of the figure in question mentions the data-source for the pink line: "one year running mean averaged from all surface temperature analyses". Further details are available in Rahmstorf et al. paper to which there's a link in the references section.

  18. Global warming...still happening

    Very nice article, but there's one thing I don't understand. The pink line in the second figure suggests that the uncorrected global temperature in 1998 was higher than for any succeeding year. In contrast, other global temperature measurements, such as the four measurements graphed on the "Berkeley Earth" summary page suggest temperatures higher than 1998 in several of the succeeding years. My guess is that a different global temperature data set was used to generate the pink line, different from the data sets used to create the lines in the Berkeley Earth summary graph (NASA GISS, NOAA/NCDC, Hadley/CRU, and Berkeley Earth). Am I right? In any case, it would always be a good idea to provide the source of any data set used to make graphs.

    Moderator Response:

    [DB] The paragraph immediately following the legend for that graphic fully explains the corrections done:

    As we can see from the graph, surface temperature changes shown in pink sometimes go outside the projections. This is because some factors are not included in IPCC projections. Such factors are solar activity changes and eruptions of volcanoes. Additionally, the variation of El Niño/La Niña is random and therefore it doesn't change in simulations at the same time it does in real life. IPCC projections are combined results from many simulations, so the El Niño/La Niña variations of different simulations tend to cancel out when simulation results are combined. This means that the projections don't actually include El Niño/La Niña variation either. It should be noted that even if surface temperature shown in pink doesn't stay within limits of projections, it does stay within limits of all individual simulations (not shown in the Figure above).

    Once these exogenous and transitory factors are removed, the underlying trend emerges, shown in red.

    The BEST version, using a similar accounting:

    BEST

  19. 2013 SkS Weekly News Roundup #35B

    Several things in the livescience article "Cooler Pacific Ocean May Explain Climate Change Paradox" disturbed me.

    1. The Pacific Ocean (as a whole ocean) is warmer, not cooler. The equatorial surface has been cooler, which is what happens when we have a turnover of warmed surface water going down and cold deep water coming up. "Cooler Pacific Surface" would be more accurate.

    2. What "Climate Change Paradox"? Deniers claiming "global warming has stopped" doesn't create any climate change paradox, let alone a paradox that needs to be explained.

    3. The picture caption "A thermometer in the Earth shows increasing global climate sensitivity" is absurd.

    The actual article isn't so bad, although I wish that a little more clarity had distinguished the difference between the surface and the ocean, making it clear that we can have a cool-warm surface alternation with a cool or cooling ocean or with a warm or warming ocean, and that we currently have the surface alternation with a seriously warming ocean (bad news). The packaging of the story (not likely the fault of the writer) shows a level of scientific understanding that I would expect to see on a denier site.

  20. Global warming...still happening

    Solomon isn't seeing any recent increase in stratospheric water vapor, and Chapman's contribution spectrogram seems to confirm this.  Over a longer period then we need to look to Dessler (2010) for long term water vapor feedbacks.  You can just bet that some of the denierrati will jump on this to argue that there are no positive feedbacks, that we're limited to forcing from increased CO2 only, ECS is about 1C and thus all is right with the world.

  21. It's El Niño

    Actually SkS has been writing about this oscillation for years, a.k.a the Interdecadal Pacific Oscillation (IPO). For the latest discussion see this recent(ish) SkS post: A Looming Climate Shift: Will Ocean Heat Come Back to Haunt us?.

    The oceans are warming due to the increased (enhanced) Greenhouse Effect (this is the upward slope in the 2nd graphic below), but the wind-driven ocean circulation moves back-and-forth between intense and sluggish phases, which results in the 'hiatus' and 'accelerated warming' decades. The net effect is illustrated in the graphics below:

        

       

    SkS will have upcoming posts/rebuttals explaining this in some more detail. You'll see how the observations by Kosaka & Xie (2013) tie in nicely with the wind-driven ocean circulation.

    Good to see Bob is slowly coming around to our way of thinking though. He still has a looooong way to go.

  22. It's El Niño

    Hey guys: Bob Tisdale’s crowing about the recent studies attributing slowed surface warming to La Nina:

    “Anyone with a little common sense who’s reading the abstract and the hype around the blogosphere and the Meehl et al papers will logically now be asking: if La Niña events can stop global warming, then how much do El Niño events contribute? 50%? The climate science community is actually hurting itself when they fail to answer the obvious questions.

    And what about the Atlantic Multidecadal Oscillation (AMO)? What happens to global surface temperatures when the AMO also peaks and no longer contributes to the warming?

    The climate science community skirts the common-sense questions, so no one takes them seriously."

    http://wattsupwiththat.com/2013/08/28/another-paper-blames-enso-for-the-warming-hiatus/#more-92630

    How’s this for a summary argument against the Tisdalian hypothesis (if it constitutes one):

    Tisdale and his crowd at WUWT seem to think temperature is just a number that just moves up and down somewhat arbitrarily, like a stock price.  They don't conceptualize things properly in terms of heat energy, which can't be created or destroyed.  

    ENSO doesn’t generate, absorb or destroy heat. So when Tisdale says La Nina “stops” global warming and El Nino “contributes”, he’s got it totally wrong. Nothing is being stopped – the heat energy is simply being moved around.  That's why we use the term "oscillation".  

    And the proper question to ask Tisdale is simply, Where is the heat coming from?

     

    I'm probably getting it all mucked up, as I have little science background, but I'm trying to put it in easy terms for non-sciencish people like myself.

    Also, what do you think of this graphic from Hotwhopper:

    ENSO without AGW:
    ENSO without AGW

    ENSO without AGW:
    ENSO with AGW

  23. CO2 was higher in the late Ordovician

    @Tom:

    Wait!  They may not be unrelated!  I just read a paper suggesting roots increase weathering.

    <a href = "http://www.pnas.org/content/98/8/4290.full.pdf">Falkowski and Rosenthal</a>


    If the late Ordovician was the first time land rhizomes evolved, it would suggest to me it could have caused a pulse of calcium which pulled down atmospheric carbon in the sea, not necessarily in freshwater bogs through the land plants themselves.

  24. Greenhouse Effect Basics: Warm Earth, Cold Atmosphere

    Molecular visualizations of CO2 from the GIF's (from Timothy Chase's website):

    Ground State Mode

    Ground State

     

    Pure Symmetric Stretching Mode

    The pure symmetric stretching mode v1 of CO2. While this is a mode that may gain and lose energy collisionally it is not infrared (IR) active as there is no transient electric dipole.

    Symmetric

     

    Bending Mode V2

    The bending mode v2 of CO2, responsible for the 15.00 μm (wavenumber 667 cm-1) band -- the mode dominating the enhanced greenhouse effect and that primarily used by AIRS. This is infrared (IR) active due to a transient dipole: bending results in charge being asymmetrically distributed with net positive near the carbon atom and negative near the two oxygen atoms.

    Bending

    And

    Bending

     

    Asymmetic Stretching Mode V3

    The asymmetric stretching mode v3 of CO2 is responsible for the 4.26 μm (wavenumber of 2349 cm-1) band. The asymmetic stretch result in a net positive charge near the carbon atom and a net negative charge with the isolated oxygen atom, creating an electric dipole and making it infrared (IR) active. Given the range of atmospheric temperatures and concentrations of CO2 the bending mode v2 plays a greater role in climate change.

    Asymmetric

  25. Greenhouse Effect Basics: Warm Earth, Cold Atmosphere

    It might be helpful to visualize the various vibrational modes of CO2 with these animated GIFs:

    Asymmetric  Asymmetric

    Bending  Bending 

    Symmetric  Symmetric

  26. Greenhouse Effect Basics: Warm Earth, Cold Atmosphere

    MThompson @81. I think you are both right and wrong. The asymmetric stretch is stronger than the bend, however the important fact you are missing is the distribution of IR radiation emitted by planet Earth. This is a (near) black body distribution, and the peak (at 288K) almost co-incides with the CO2 bend. Thus the bend plays a more important role simply because there is more radiation in the Earths emission spectrum to absorb.

  27. Greenhouse Effect Basics: Warm Earth, Cold Atmosphere

    Many thanks to Phil and KR for educating me on this topic. Naturally I have done considerable reading online, but many times the explanations are not clear to me because of the misapplication of concepts and poor analogies.


    From my reading it seems that asymmetric stretch is the primary vibrational mode for CO2 and is some 13x more intense than the two bending modes combined. So in my understanding from this discussion and other reading is that CO2 is capturing the blackbody radiation of the earth at these wavelengths. Additionally there is some broadening of the lines that allows more than just the two primary “peaks” to be absorbed, and that broadening increases the total energy stored in vibrational modes of C02.


    Please let me know if I have a good mental image of the process.

  28. Global warming...still happening

    For me, it is pretty obvious that the graph of Chapman et al (2013) will become a classic to illustrate the greenhouse gaz effect.

  29. NASA GISS adjustments introduce warming bias

    Apparently so. I've commented on the subject here. 

  30. Watts' New Paper - Analysis and Critique

    Continuing from an unfinished page here:

    As I pointed out on a WUWT thread that claimed adjustments were distorting the data, 

    It could be argued that it’s better to look at raw temperature data than data with these various adjustments for known biases. It could also be argued that it’s worth not cleaning the dust and oil off the lenses of your telescope when looking at the stars. I consider these statements roughly equivalent, and (IMO) would have to disagree.

    Various replies (arguments from authority, etc) followed, mostly ignoring the rather copious literature on time of observation bias. 

  31. Where SkS-Material gets used - Coursera's Climate Literacy Course

    Richard Alley's course I mentioned above has been postponed until January 6, 2014:

    Energy, the Environment and Our Future - Penn. State University
    "Get Rich and Save the Earth…Or Else! Learn about the past, present, and possible futures of human energy use."

    This suits me just fine as I won't have to juggle two courses running in parallel (I'm currently enrolled in University of Melbourne's "Climate Change")!

  32. NASA GISS adjustments introduce warming bias

    I'm assuming this page is under construction?  I'm asking because I've just been hit with this line in a debate.

  33. Global warming...still happening

    Tamino gave an even better summary later in the thread:

    If you flip a coin 10 times and all 10 flips give "heads" then you've got strong evidence the coin is biased. If you flip a coin 10 times and record the result, then repeat that process 1000 times, and one of the "flip sets" is 10 heads, you do NOT have evidence of a biased coin. If you then report the single set of 10 which gave 10 heads, without mentioning the 999 sets of 10 which didn't, you're dishonest (maybe to yourself). Does that make it clear?

  34. Global warming...still happening

    Regarding Santer et al and time required for trend significance, Tamino posted something very interesting a few years ago:

    Cherry Snow - It turns out that if you cherry-pick an extrema starting point for your trend identification (as opposed to the more frequent values near the trend), the t-value needed to establish trend significance almost doubles. 

    In other words, if you select a trend point such as the 1998 El Nino as your start, as done over and over by 'skeptics', it distorts the statistics such that the trend over that period is less significant, so that what would be reasonable (say, 17 years) is insufficient due to that cherry-pick. 

    Cherry-picking extrema end points weakens trend significance, making the oft-repeated "16 year" claims even less meaningful - they have the least trend significance of any possible data selection of that length. 

  35. Global warming...still happening

    VeryTallGuy #2: I think your interpretation of Santer et al. makes sense, but I'm not a statistics expert.

    Chriskoz #5: Sorry, the vertical axis is indeed insufficiently labeled (but it's like that already in the Chapman et al. paper). The vertical axis shows Brightness Temperature.

    I don't think I said anything about total outgoing IR, but only the "characteristic absorption frequencies of greenhouse gases". The study of Chapman et al. shows that the IR absorption of said greenhouse gases has increased over the ten year study period.

  36. One Planet Only Forever at 23:51 PM on 30 August 2013
    Global warming...still happening

    The indepth presentation is interesting and infromative. However, I prefer a simpler statement.

    The warming since 1998 can best be evaluated after the next signifcant El Nino of the magnitude that occurred in 1998 occurs. There are other variable factors influencing the surface temperature, but the global average surface temperature history shows very strong "bumps" in the global averages when significant El Ninos are acting.

    So the implication that a specific minimum number of years of data is required to establish statistical significance is not correct. The major variable influencing factors need to recur in the data being evaluated, whatever time that takes.

  37. Abraham et al. (2013) explore the known unknowns in the oceans and global warming

    Ranyl in (1): The reason that researchers don't make these available in open access journals is because that there is a cost of about 2000 dollars to make them open access. Someone has to pay for the residual cost (after volunteer reviews, etc.) of editing, formatting, posting, and maintaining the journal archive.

    If I charge the 2000 dollars to a grant, then I must either cut back the pay to myself or my students, or I must cut back the number of analyses that are done. There is no free lunch.

  38. Global warming...still happening

    Ari,

    Last figure is unreadable, especially the axis legends.

    At least I can imagine on horizontal axis the values of spectral numbers where known CO2 and H2O absorption bands are. But I have no clue what is on vertical axis.

    And how do you read from said figure that total outgoing IR in the spectrum shown has decreased over last decade as implied by the caption?

  39. The Beginners Guide to Representative Concentration Pathways - Part 3
    Sorry, I meant to add that it's really not so much reserves that matter but the likely rate of production, as fossil fuels get tougher and tougher to extract (e.g. oil sands might be an enormous reserve but they won't be produced at anything like the rate of conventional oil from similar sized reserves).
  40. The Beginners Guide to Representative Concentration Pathways - Part 3
    It's not clear to me that any consideration has been taken of energy reserves in these pathways. For example, oil use in RCP8.5 is shown rising to double what it is today? That seems unreasonable, given that even though a peak of all liquids has not been experienced, the energy content of what is produced is not substantially different from 8 years ago. It may not be possible to increase the energy from oil much in the future. If this is true, then any pathway that projects much increase would be unusable. The same applies for coal use, given that the data on coal reserves is poor but some analyses I've seen suggest energy produced from coal could well peak before mid-century, even within a decade or two. Ditto natural gas, despite the hype of fracking (US dry gas production has stalled for the last 18 months, for example).Do the RCPs take account of plausible reserve scenarios at all? I think they need to
  41. Abraham et al. (2013) explore the known unknowns in the oceans and global warming

    The paper in question seems to be available here.

    Many a time you can google these by putting the title of the paper in quotes, and then adding the filetype:pdf definition.

  42. Global warming...still happening

    Let's then look at the trends recently.

    I used GISS, and by my reckoning, there are *no* years in the past 33 where the trend is negative.

    This applies whether the trend is defined as end – to – end, or least squares best fit.

    Going for the least squares best fit approach, which seems more reliable, the last time there was a 17 year negative trend was 1976, and there are only 3 in the past 50 years (’67, ’68, ’76)

    On that basis, there is nothing unusual whatever about the current “pause”, indeed it is expected and could even be argued as overdue.

  43. Global warming...still happening

    Thanks, Shoyemore. I think that there might be a separate article on that paper in SkS in near future.

  44. Global warming...still happening

    I think the meaning of statistical significance has been misapplied to the current hiatus/pause.

    As I understand Santer (please correct me if I'm wrong) defines statistical significance as a 95% probability of a positive trend over 17 years. As applied to a "pause" in surface temperatures during a period of rising Co2, let's define that as

    "During a period when CO2 rises at 1.5ppm per year, we expect, for any given year, a 5% probability that the trend across the preceeding 17 years will display a zero or negative value"

    Let's define modern warming as being over the past 50 years (during which time Co2 has risen at ca 1.5ppm/year)

    We then *expect* one in twenty of the past 33 years (those where we can measure the previous 17) to show a negative or zero trend for the preceeding 17.

    Our prediction is then that roughly one or two years of the past 33 will have a negative trend.

    Feedback on if this is a correct interpretation of the science would be much appreciated.

  45. Global warming...still happening

    Ari,

    This paper is causing some current stir ... it may be one you would like to comment on in the light of this excellent review of papers & perhaps add to your list.

    Recent global-warming hiatus tied to equatorial Pacific surface cooling

    Thanks.

     

  46. Human CO2 is a tiny % of CO2 emissions

    YubeDude @252, I am not aware of any use of O18 as a marker of CO2 of organic origin.  Of course, I am not expert in the field, so that only means it has not made it into popular presentations (or the IPCC reports).  Further, searching google scholar does not readilly turn up studies using O18 as a marker for the organic origin of CO2. 

    I suspect it is possible in principle.  However, fractionation of O18 in respiration is a confounding factor, and likely to be stronger.  Further, atmospheric O18/O16 ratios will vary more with time than than C13/C12 ratios due to the fractionation of O18 in water by evaporation and condensation.  No doubt there are other complexities of which I am not aware as well.

    Sorry I can't help anymore.

  47. Human CO2 is a tiny % of CO2 emissions

    TY Tom for the reply. I understand about the carbon ratio and the meaning what I am interested in is if CO2 also caries the O-18 marker that would link that particular molecule of  CO2 directly to combustion and not just a sink release or another anthropogenic use of older carbon sources such as chemical manufacturing that is petro-chemically based.

    I am wondering if O-18 has any merit whitin the topic as I see no mention or research that attempts to link or associate its presence with A-CO2.

     

    No quibble on my part as to the evidence rather just a currisoity in regards to this darn O-18. Thanks in advace for any light you may be able to shed.

  48. Abraham et al. (2013) explore the known unknowns in the oceans and global warming

    ranyl @1 Sometimes they are free, like the Trenberth paper referenced at the end (Balmaseda et al.).  

    The journals probably can't afford to make every important paper free.  But the amazing thing is the wealth of knowledge that you can get right here for free, thanks to so many highly qualified people who, as I understand it, donate their time in writing these posts, and who also frequently engage questions and criticisms down here in the comments section.  

  49. How much will sea levels rise in the 21st Century?

    in the link you posted the authors cite the A2r scenario, updated with current developing country projections: "

    "The RCP8.5 is based on the A2r scenario (Riahi et al. 2007), which provides an updated and revised quantification of the original IPCC A2 SRES scenario storyline (Nakicenovic et al. 2000). With a few exceptions, including an updated base year calibration (to 2005) and a revised representation of short-term energy trends, especially in developing countries, the RCP8.5 builds thus upon the socio-economic and demographic background, resource assumptions and technological base of the A2r scenario."

    if you look at the final values of CH4 and CO2 atmospheric concentrations in 2100 you will see that the A2 scenario is approximately 15% below the RCP 8.5 high error margin estimation.   You will also find that the A1Fl concentrations match that value much more closely.

     

    2.  This is the limitation of science, in a non-linear environment.  PIOMAS has been verified by Cryosat-2.  This has not been utilized in the AR5.  The non-linear response of multiple coupled systems to the loss of arctic sea ice will produce traumatic shifts that are unforetolled by the AR5.  The paper I quoted is published in 2008, this is not a "new" paper. 

    3.  Your estimates of climate sensitivity are based primarily on paleoclimate data.  However, you do not have a statistically signficant number of sample points for the current climate regime.  So, you throw out the anomalous data that indicates that there is a much higher climate sensitivity during interglacials.  You justify this because you do not understand why a runaway warming did not occur if sensitivities were actually that much higher during the interglacials. 

    In addition, the issues that I have brought up are not uncertainties, they are unknowns.  The difference is that the unknowns are not contained in the current models.  The body of evidence indicates that these unknowns (defined as proesses with impacts that are determined to be real, potentially catastrophic, but currently undefined and so not included in the model) will have effect, and that the potential effects of their cumulative impacts will surpass even the worst case scenarios. 

    The 3,425 ZJ cumulative energy deposition is your value not mine.  I assume a current TOA imbalance of .75 W/m^2 and a 2100 TOA imbalance value of 3.5 W/m^2 (linear and proportional to RCP 8.5).  Yeilding an average TOA imbalance of 2.125 W/m^2 between now and 2100, producing the cumulative energy deposition of 2,939 ZJ.  I used RCP 8.5 for continuity of discussion, I do believe that RCP 10.0 is more likely given the albedo and carbon cycle feedbacks (as well as emission scenarios) posited in @16.

    6.  The .44 TOA came from your post@ 43 when you said, "That formula predicts a current TOA energy imbalance of 0.44 W/m^2, and a 2100 imbalance of 1.76" 

    you did not show your math so I reproduce it here:

    1.  TOA imbalace will be have constant proportionality to RF between now and 2100 (you say this is conservative)
    2.  Current TOA is .63, RF is 1.635(to pre-industrial)  Ratio is 35.8/100
    3.  you then used RCP 6.5 for your calculation, I used RCP 8.5
    4.  8.5 * 35.8/100 = 3.27 W/m^2
    5.  If I use a starting TOA of .75 then my values are slightly higher for TOA in 2100 = ~3.5

    7.  The rate of warming from the last interglacial is approximately 200X slower than current warming rates.  This is an undeniable truth.  The ice will necessarily melt more slowly.  The Milankovich cycles are not GHG driven events.  I am sure you know this.

    I would ask that future discussions by AR5 reviewers list clearly and succinctly whether or not the following unknowns are contained within their models.

    1.  The cessation of Anthropogenic SOx emissions in 2070
    2.  The reduction of the OTC by 80% in 2060 and its effects on North Atlantic carbon sink.
    3.  The effect of drought on the Amazonian basin by year 2050 on natural carbon sequestration
    4.  The potential for boreal peat carbon emissions in a +4C environment
    5.  The step-change in annual surface temperatures produced in the arctic for an ice-free state in the summer.
    6.  The total emission potential from the ESAS under a regime of consistent +10C water temperatures in late summer.
    7.  The localized ocean warming effect on the West Antarctic Ice Shelf under a regime of 80% reduction of the OTC.
    8.  The projections of Western United states drought under a regime of a summer ice-free arctic in 2030.
    9.  Accelerated Permafrost emissions due to an ice free summer state in 2030.
    10.  The effects of these non-analyzed carbon cycle and albedo feedback scenarios within an environment where Carbon Capture and Sequestration is NOT utilized by developing countries and ECS for 2XCO2 is actually 4.5C.

    The above would be a very useful study.  It would also provide a reasonable basis for the collective mea culpa due to the human race (and the Nobel Committee) when the arctic ice DOES disappear in 2030 and catastrophic warming events begin to reveal these unknowns to be real and disasterous.

  50. Abraham et al. (2013) explore the known unknowns in the oceans and global warming

    In abstract, states that sea level rise is at 3 mm/yr.  This sounds low compared to other estimates I have read.  see http://www.nap.edu/openbook.php?record_id=12782&page=244

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