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Thoughts on 2014 and ongoing temperature trends

Filed under: — gavin @ 22 January 2015

Last Friday, NASA GISS and NOAA NCDC had a press conference and jointly announced the end-of-year analysis for the 2014 global surface temperature anomaly which, in both analyses, came out top. As you may have noticed, this got much more press attention than their joint announcement in 2013 (which wasn’t a record year).

In press briefings and interviews I contributed to, I mostly focused on two issues – that 2014 was indeed the warmest year in those records (though by a small amount), and the continuing long-term trends in temperature which, since they are predominantly driven by increases in greenhouse gases, are going to continue and hence produce (on a fairly regular basis) continuing record years. Response to these points has been mainly straightforward, which is good (if sometimes a little surprising), but there have been some interesting issues raised as well…



Records are bigger stories than trends

This was a huge media story (even my parents noticed!). This is despite (or perhaps because?) the headline statement had been heavily trailed since at least September and cannot have been much of a surprise. In November, WMO put out a preliminary analysis suggesting that 2014 would be a record year. Earlier this month, the Japanese Meteorological Agency (JMA) produced their analysis, also showing a record. Estimates based on independent emulations of the GISTEMP analysis also predicted that the record would be broken (Moyhu, ClearClimateCode).

This is also despite the fact that differences of a few hundredths of a degree are simply not that important to any key questions or issues that might be of some policy relevance. A record year doesn’t appreciably affect attribution of past trends, nor the projection of future ones. It doesn’t re-calibrate estimated impacts or affect assessments of regional vulnerabilities. Records are obviously more expected in the presence of an underlying trend, but whether they occur in 2005, 2010 and 2014, as opposed to 2003, 2007 and 2015 is pretty much irrelevant.

But collectively we do seem to have an apparent fondness for arbitrary thresholds (like New Years Eve, 10 year anniversaries, commemorative holidays etc.) before we take stock of something. It isn’t a particularly rational thing – (what was the real importance of Usain Bolt’s breaking the record for the 100m by 0.02 hundredths of a second in 2008?), but people seem to be naturally more interested in the record holder than in the also-rans. Given then that 2014 was a record year, interest was inevitably going to be high. Along those lines, Andy Revkin has written about records as ‘front page thoughts’ that is also worth reading.

El Niños, La Niñas, Pauses and Hiatuses

There is a strong correlation between annual mean temperatures (in the satellite tropospheric records and surface analyses) and the state of ENSO at the end of the previous year. Maximum correlations of the short-term interannual fluctuations are usually with prior year SON, OND or NDJ ENSO indices. For instance, 1998, 2005, and 2010 were all preceded by an declared El Niño event at the end of the previous year. The El Niño of 1997/8 was exceptionally strong and this undoubtedly influenced the stand-out temperatures in 1998. 2014 was unusual in that there was no event at the beginning of the year (though neither did the then-record years of 1997, 1990, 1981 or 1980 either).



So what would the trends look like if you adjust for the ENSO phase? Are separate datasets differently sensitive to ENSO? Given the importance of the ENSO phasing for the ‘pause’ (see Schmidt et al (2014), this can help assess the underlying long-term trend and whether there is any evidence that it has changed in the recent decade or so.

For instance, the regression of the short-term variations in annual MSU TLT data to ENSO is 2.5 times larger than it is to GISTEMP. Since ENSO is the dominant mode of interannual variability, this variance relative to the expected trend due to long-term rises in greenhouse gases implies a lower signal to noise ratio in the satellite data. Interestingly, if you make a correction for ENSO phase, the UAH record would also have had 2014 as a record year (though barely). The impact on the RSS data is less. For GISTEMP, removing the impact of ENSO makes 2014 an even stronger record year relative to previous ones (0.07ºC above 2005, 2006 and 2013), supporting the notion that the underlying long-term trend has not changed appreciably over the last decade or so. (Tamino has a good post on this as well).



Odds and statistics, and odd statistics

Analyses of global temperatures are of course based on a statistical model that ingests imperfect data and has uncertainties due to spatial sampling, inhomogeneities of records (for multiple reasons), errors in transcription etc. Monthly and annual values are therefore subject to some (non-trivial) uncertainty. The HadCRUT4 dataset has, I think, the best treatment of the uncertainties (creating multiple estimates based on a Monte Carlo treatment of input data uncertainties and methodological choices). The Berkeley Earth project also estimates a structural uncertainty based on non-overlapping subsets of raw data. These both suggest that current uncertainties on the annual mean data point are around ±0.05ºC (1 sigma) [Update: the Berkeley Earth estimate is actually half that]. Using those estimates, and assuming that the uncertainties are uncorrelated for year to year (not strictly valid for spatial undersampling, but this gives a conservative estimate), one can estimate the odds of 2014 being a record year, or of beating 2010 – the previous record. This was done by both NOAA and NASA and presented at the press briefing (see slide 5).



In both analyses, the values for 2014 are the warmest, but are statistically close to that of 2010 and 2005. In NOAA analysis, 2014 is a record by about 0.04ºC, while the difference in the GISTEMP record was 0.02ºC. Given the uncertainties, we can estimated the likelihood that this means 2014 was in fact the planet’s warmest year since 1880. Intuitively, the highest ranked year will be the most likely individual year to be the record (in horse racing terms, that would be the favorite) and indeed, we estimated that 2014 is about 1.5 to ~3 times more likely than 2010 to have been the record. In absolute probability terms, NOAA calculated that 2014 was ~48% likely to be the record versus all other years, while for GISTEMP (because of the smaller margin), there is a higher change of uncertainties changing the ranking (~38%). (Contrary to some press reports, this was indeed fully discussed during the briefing). The data released by Berkeley Earth is similar (with 2014 at ~35%~46% (see comment below)). These numbers are also fragile though and may change with upcoming updates to data sources (including better corrections for non-climatic influences in the ocean temperatures). An alternative formulation is to describe these results as being ‘statistical ties’, but to me that implies that each of the top years is equally likely to be the record, and I don’t think that is an accurate summary of the calculation.

Another set of statistical questions relate to a counterfactual – what are the odds of such a record or series of hot years in the absence of human influences on climate? This question demands a statistical model of the climate system which, of course, has to have multiple sets of assumptions built in. Some of the confusion about these odds as they were reported are related to exactly what those assumptions are.

For instance, the very simplest statistical model might assume that the current natural state of climate would be roughly stable at mid-century values and that annual variations are Gaussian, and uncorrelated from one year to another. Since interannual variations are around 0.07ºC (1 sigma), an anomaly of 0.68ºC is exceptionally unlikely (over 9 sigma, or a probability of ~2×10-19). This is mind-bogglingly unlikely, and is a function of the overly-simple model rather than a statement about the impact of human activity.

Two similar statistical analyses were published last week: AP reported that the odds of nine of the 10 hottest years occurring since 2000 were about 650 million to 1, while Climate Central suggested that a similar calculation (13 of the last 15 years) gave odds of 27 million to 1. These calculations are made assuming that each year’s temperature is an independent draw from a stable distribution, and so their extreme unlikelihood is more of a statement about the model used, rather than the natural vs. anthropogenic question. To see that, think about a situation where there was a trend due to natural factors, this would greater reduce the odds of a hot streak towards the end (as a function of the size of the trend relative to the interannual variability) without it having anything to do with human impacts. Similar effects would be seen if interannual internal variability was strongly autocorrelated (i.e. if excursions in neighbouring years were related). Whether this is the case in the real world is an active research question (though climate models suggest it is not a large effect).

Better statistical models thus might take into account the correlation of interannual variations, or have explicit account of natural drivers (the sun and volcanoes), but will quickly run into difficulties in defining these additional aspects from the single real world data set we have (which includes human impacts).

A more coherent calculation would be to look at the difference between climate model simulations with and without anthropogenic forcing. The difference seen in IPCC AR5 Fig 10.1 between those cases in the 21st Century is about 0.8ºC, with an SD of ~0.15 C for interannual variability in the simulations. If we accept that as a null hypothesis, the odds of seeing a 0.8ºC difference in the absence of human effects is over 5 sigma, with odds (at minimum) of 1 in 1.7 million.

None of these estimates however take into account how likely any of these models are to capture the true behaviour of the system, and that should really be a part of any assessment. The values from a model with unrealistic assumptions is highly unlikely to be a good match to reality and it’s results should be downweighted, while ones that are better should count for more. This is of course subjective – I might feel that coupled GCMs are adequate for this purpose, but it would be easy to find someone who disagreed or who thought that internal decadal variations were being underestimated. An increase of decadal variance, would increase the sigma for the models by a little, reducing the unlikelihood of observed anomaly. Of course, this would need to be justified by some analysis, which itself would be subject to some structural uncertainty… and so on. It is therefore an almost impossible to do a fully objective calculation of these odds. The most one can do is make clear the assumptions being made and allow others to assess whether that makes sense to them.

Of course, whether the odds are 1.7, 27 or 650 million to 1 or less, that is still pretty unlikely, and it’s hard to see any reasonable model giving you a value that would put the basic conclusion in doubt. This is also seen in a related calculation (again using the GCMs) for the attribution of recent warming.

Conclusion

The excitement (and backlash) over these annual numbers provides a window into some of problems in the public discourse on climate. A lot of energy and attention is focused on issues with little relevance to actual decision-making and with no particular implications for deeper understanding of the climate system. In my opinion, the long-term trends or the expected sequence of records are far more important than whether any single year is a record or not. Nonetheless, the records were topped this year, and the interest this generated is something worth writing about.

References

  1. G.A. Schmidt, D.T. Shindell, and K. Tsigaridis, "Reconciling warming trends", Nature Geoscience, vol. 7, pp. 158-160, 2014. http://dx.doi.org/10.1038/ngeo2105

308 Responses to “Thoughts on 2014 and ongoing temperature trends”

  1. 151

    [Ray]: What have you got against physics?

    [Alan]: Nothing. I think we are in a warming trend and CO2 is the cause. However, i don’t believe that the Earth has a positive feedback to this if there is any feedback it is far more likely to be negative based on the long term stability of the Earth’s climate.

    – See more at: http://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/comment-page-3/#comment-624216

    (Ray replies @ 149, pointing out that positive feedbacks do not necessarily imply long-term instability. One could add that we also know that there’s a big old hairy negative one in the form of good old Planck.)

    I’d point out out we have observational evidence of feedback mechanisms in play:

    As reported in AR4, observations from radiosonde and GPS measurements
    over land, and satellite measurements over ocean indicate
    increases in tropospheric water vapour at near-global spatial scales
    which are consistent with the observed increase in atmospheric temperature
    over the last several decades. Tropospheric water vapour
    plays an important role in regulating the energy balance of the surface
    and TOA, provides a key feedback mechanism and is essential to the
    formation of clouds and precipitation.

    (“Water vapor feedback”)

    And:

    Observations show that the cryosphere has been in transition during
    the last few decades and that the strong and significant changes
    reported in AR4 have continued, and in many cases accelerated. The
    number of in situ and satellite observations of cryospheric parameters
    has increased considerably since AR4 and the use of the new data
    in trend analyses, and also in process studies, has enabled increased
    confidence in the quantification of most of the changes… They reveal a
    general decline in all components of the cryosphere…

  2. 152

    My #151–Got rushed there at the end. Of course, the second quote shows the “albedo feedback” in play. Another quote:

    …reduced sea ice extent has altered, and in the future may
    continue to alter, ocean circulation, ocean productivity and regional
    climate and will have direct impacts on shipping and mineral and oil
    exploration (see WGII, Chapter 28). Furthermore, decline in snow cover
    and sea ice will tend to amplify regional warming through snow and
    ice-albedo feedback effects (see Glossary and Chapter 9).

    And I neglected to mention the source of the two quotes; both come from AR5:

    http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter02_FINAL.pdf

    http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter04_FINAL.pdf

    Going forward to Chapter 9, one finds that:

    Analysis of observed declines in sea ice and snow coverage from 1979
    to 2008 suggests that the NH albedo feedback is between 0.3 and 1.1
    W m–2 °C–1 (Flanner et al., 2011). This range is substantially above the
    global feedback of 0.3 ± 0.1 W m–2 °C–1 of the CMIP5 models analysed
    in Table 9.5. One possible explanation is that the CMIP5 models
    underestimate the strength of the feedback as did the CMIP3 models
    based upon the systematic errors in simulated sea ice coverage decline
    relative to observed rates (Boe et al., 2009b).

    http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter09_FINAL.pdf

  3. 153
    Hank Roberts says:

    > I don’t believe …

    Computation could help you triumph over your beliefs.

    http://www.aip.org/history/climate/xwiring.htm

  4. 154
    Jim Eager says:

    Victor wrote @144: “Hey, why not use a 30 year average? That way all you’d have is a sudden leap, with no “trend” at all.”

    You didn’t read the Robert Grumbine post I pointed you to that explains why 30 years is used for determining the underlying trend in climate, did you?

    If you had you would have learned that 30 years is not at all an arbitrary choice, but is in fact determined by the data set itself, a property common to all time series data sets.

    But then it’s quite clear that “learning” is not at all your goal here.

  5. 155
    Steve Fish says:

    Re- Comment by Victor — 27 Jan 2015 @ 10:44 PM, ~#144

    Well Victor, I know, I know how hard it is when simply presented data contradicts ones bias. Time to see an optometrist about them blinkers!

    Steve

  6. 156
    KeefeAndAmanda says:

    In reply to Victor at #144,

    You continue to commit what I at comment #120 exposed:

    You argue that this “slowdown” is evidence against the truth that an increased greenhouse gas effect slows down the rate of heat flowing out of the planetary system and thus increases the total heat in the system. But your argument commits a typical serious and amateurish category mistake with respect to cause and effect – this mistake is the denial of the truth that cause and effect relationships can and many times do produce real world data that express as nonmonotonic functions. (An example of a graph of a nonmonotonic function would be one showing cyclic behavior around an upward accelerating underlying trend curve.) It’s simply false that cause and effect relationships must form perfect one-to-one correlations between cause and effect, between the function’s input and output.

    In addition, these arguments based on these denials give no explanation as to where all this heat came from since the late 1800s. There are only two ways to increase the heat in a system – increase the rate of flow of heat into the system or decrease the rate of flow out of the system. You seem to hold to those arguments that all this heat increase in the total system since the late 1800s has come at least mostly from a never-ending increase of heat into the system via either a posited increased output from the sun or a posited decreased albedo. But the entire professional peer reviewed literature in its ongoing aggregate on the subject says that it is beyond all reasonable doubt that a posited increase in the rate of flow of heat into the system cannot account for almost all the heat increase since the late 1800s. Therefore, by the process of elimination, we have a confirmation of what the physics says, which is that this heat increase in the whole system since the late 1800s is all or almost all due to a decrease in the rate of flow of heat out of the system.

    Your whole argument denies the logic and mathematics of causality and it denies essentially the entire professional peer reviewed literature in its ongoing aggregate on the subject as to where all this heat came from since the late 1800s.

  7. 157
    Victor says:

    #146 MARodger: “If this hiatus of yours is established science, climatologists will be debating it within scientific papers.”

    Yes, and in fact there are many. It’s been estimated that somewhere around 50 different “explanations” for the hiatus have been offered, most in peer reviewed papers, yes. If these scientists felt it could be explained away by some sort of statistical sleight of hand they would not have bothered.

    “the odd scientist responding to the myth of a hiatus spread by people like you, responding by saying it isn’t the hiatus you say it is.”

    No. In every case their remarks imply that they accept it. Not one points to anything close to the statistical interpretations offered by Gavin and Tamino. In just about every case they feel confident they can account for it by pointing to a steady rise in Oceanic warming, which for them means that the Earth is still “heating up” regardless of what’s happening in and around the surface.

    I dealt with that issue in an earlier post (#104). Given the necessity for some sort of delay during any heat transfer from the atmosphere to the oceans, the current state of the oceans can’t possibly be used to explain the current state of the atmosphere. From examining the evidence it looks to me like there could be something like a 21 year lag from the latter to the former. Thus, if one wants to embrace the notion that heat is being transferred from the atmosphere to the oceans, the heating we see now in the oceans is most likely a reflection of the heating we saw in the atmosphere back during the period 1979-1998. Unless the oceanic heating has some other cause. If that were the case then I can’t see how CO2 emissions can be blamed.

    In sum: 1. a significant number of climate scientists acknowledge the hiatus in surface warming, though they feel confident it can be explained; 2. almost all such explanations are based on assumptions regarding the transfer of atmospheric heating to the oceans — assumptions that can’t be maintained due to the necessary delay required by any such mechanism, as elucidated above.

  8. 158
    Victor says:

    #150 jgnfld

    OK, first of all I’d like to correct my error. I meant 2000, not 2002. Though 2002 works also, as would 2001, 1999 or, for that matter, 1997.

    Secondly, I’d like to comment a bit on this business of 1998 being an “extreme El Nino year” and thus somehow misleading when assessing trends. For skeptics like myself, most of the warming being observed is due to natural events, not CO2 forcing. El Nino is one of these natural events. As is La Nina. So from my perspective I see no reason to discount or compensate for either when assessing warming trends.

    I find it interesting that “warmists” pay attention to such natural events only as needed to explain away anomalies in their theories, but never to account for data that suits them.

    Thirdly, my claim is that the change in trend is evident regardless of whether or not one chooses 1998 as the pivot year. This is the opposite of cherry picking. Sorry if I confused you. I’m claiming that the picture changes at some point in or around that year, that’s all. No cherry picking needed.

    Fourthly: “ridiculousness” is not a word. Not really. “Absurdity” would be preferable.

  9. 159
    Alan Millar says:

    Kevin McKinney says:
    28 Jan 2015 at 8:22 AM

    ” See more at: http://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/comment-page-3/#comment-624216

    (Ray replies @ 149, pointing out that positive feedbacks do not necessarily imply long-term instability. One could add that we also know that there’s a big old hairy negative one in the form of good old Planck.)”

    Of course there are both positive and negative feedbacks possible in the Earth’s climate system. It is the net overall feedback to increased radiative forcing that is important and we are way way short of understanding how these operate.

    We know for instance that the Earth has received greatly increased forcing in the last 400 million years but has cooled from 22c to 14c. We haven’t got proof of why this should be.

    We know that the glacial cycles in the current ice age are highly correlated with cycles in the Earth’s orbit, however we have not proven the exact mechanism behind them.

    The Planck feedback is not a negative feedback in the true sense and I don’t know why great play is made of this in preventing constantly increasing heating.

    It would be better described as the bleeding obvious feedback. Of course emissions rise as forcing increases this is to achieve equilibrium. However, equilibrium is always achieved at a higher overall temperature. Planck feedback does not allow you to equalise at the same or lower temperatures prior to the increase in forcing.

    Therefore, if you keep increasing forcing, yes the ‘Planck emissions’ will also keep increasing but always ending in higher overall temperatures. Planck feedback will not stabilise the temperatures at a particular point if forcings are constantly increasing a la the proposed water vapour feedback to increased temperatures. You need some other negative feedback mechanism to do that.

    Alan

  10. 160
    gmb92 says:

    MARodger@125 and Victor (various),

    MARodger: “Kosaka & Xie for some reason do have a rather strange statement within their abstract: “…challenging the prevailing view that anthropogenic forcing causes climate warming”. I remember it at the time because it doesn’t seem to square in any way with the rest of the paper.”

    Considering the context of the rest of the paper, they could be referring to political realms that are making the argument, which the study basically refutes.

    In Meehl et al., which Victor selectively quotes from, they have a similar statement.

    “…has been touted as a failure of any model to simulate what actually occurred in the early-2000s.”

    In the footnotes is reference to an article titled “White House Climate Action Plan Hotly Debated in Senate Hearing”.

    What is apparent is Victor is not independently reading these studies, but is being presented with them from dubious sources, with quotes selected to fit narrative. If Victor had bothered to read past the first line of the Meehl et al abstract…

    “However, a number of individual ensemble members from that set of models successfully simulate the early-2000s hiatus…”

    Decadal trends aren’t supposed to match multi-model averages, as individual runs vary between cooling and warming over 10-year periods, some longer periods of cooling or flat trends. Thus the notion of a pause isn’t particularly meaningful in the context of what models project, but studying decadal attribution is still very useful, as it might ultimately narrow the ranges of decadal projections. What deniers want to do is skip all that, misrepresent the models by claiming they predict steady warming (conflate multi-model ensemble means with individual model runs), and conclude the physics is wrong and CO2 causes less warming.

  11. 161
    John E Pearson says:

    143 Hank Roberts googled for me.

    Be that as it may there are lots of good scientists who claim the trend for the last decade and a half has slowed and they have written papers attributing it to SO2, Gavin, I think, to vulcanism, and Mann to SO2 from Chinese power plants. My point was simply that the most recent decade and a half trend is virtually identical to the previous one so one ought not to be declaring it rare.

  12. 162
    Hank Roberts says:

    > V. … discourse on “Ocean heat content.” (see #104)

    “discourse” –> “doesn’t know, didn’t look it up”

    For any young reader who lacks access to a library, you can paste questions like V.’s into Google Scholar and find relevant information.

    This, for instance, sums up the information he didn’t find:

    http://www.met.reading.ac.uk/~sgs02rpa/MISC/England2014.png

    That’s from: http://www.met.reading.ac.uk/~sgs02rpa/latest.html

  13. 163
    John E Pearson says:

    MarRodgers at 146: Victor may well be a troll but I assure you I am not. There are lots of climate scientists that are using terms like “hiatus”. Santer et al https://www.llnl.gov/news/small-volcanic-eruptions-explain-warming-hiatus use the phrase “”hiatus”” (and they do put quotes around it) in their recent paper: http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014GL062366/ . I believe Gavin also has at least one paper on SO2 and increased vulcanism accounting for the alleged “hiatus.” I believe that Mann has a 2008 paper attributing the “slow down” to SO2 from Chinese coal-fired power plants. This isn’t trolling. This is simply science playing out the way it does. I think it is counter-productive to pretend that these conversations have not been taking place.

  14. 164
    JCH says:

    The Oceanic Heat Budget

    About half the solar energy reaching Earth is absorbed by the ocean and land, where it is temporarily stored near the surface. Only about a fifth of the available solar energy is directly absorbed by the atmosphere. Of the energy absorbed by the ocean, most is released locally to the atmosphere, mostly by evaporation and infrared radiation…

    Victor – show us the part where there is significant warming of the oceans by the atmosphere.

    That the climate system could switch quickly to a state where slightly less warming of the atmosphere is taking place and more energy is being retained in the oceans makes perfect sense. You can literally watch it happen in images of the surface of the Eastern Pacific Ocean.

  15. 165
    Jim Lovejoy says:

    @alan millar comment 139
    “if there is any feedback it is far more likely to be negative based on the long term stability of the Earth’s climate.”

    That’s a relief. Without the stability of the Earth’s climate, we might have had multiple swings of more than 5C over the last million years, which could have resulted in repeated glaciations. I’m glad you’ve determined that is impossible.

  16. 166
    3000 Quads says:

    Frequent commenter Hank Roberts has been awarded the 2014 Climate Commenter of the Year. As Gavin Schmidt was awarded Blogger of the Year a couple of years ago and Roberts frequently comments here, I hope you will forgive the intrusion for this announcement. Congratulations Mr. Roberts.

  17. 167
    tamino says:

    Re: #158 (Victor)

    You said:


    For skeptics like myself, most of the warming being observed is due to natural events, not CO2 forcing.

    How odd that you call yourself a “skeptic” but you’ve already made up your mind (that “warming is due to natural events”). Judging by the comments you’ve made, your belief is NOT based on knowledge or analysis (in fact, you have actively disdained rigorous analysis).

    You’re not a skeptic. You’re a fake.

  18. 168
    MARodger says:

    Surely the pantomime season is over.
    “Oh no it’s not!”
    “Oh yes it is!!!”

    Victor the Troll @157.
    I say to you “If this hiatus of yours is established science, climatologists will be debating it within scientific papers.” (My added emphasis) and you reply that indeed climatologists are doing so.
    No they are not!! Science is investigating a flat global temperature record 2007-to-date. They are not about your hiatus that began in 1998 and that apparently disproves AGW. All these quotes you threw in @115 & @134, not one of them is a scientific analysis of the causes of any hiatus that dates so early.
    I doubt this situation can be explained more simply. I keep it simple because you obviously have problems in that department. Sadly your deficient understanding of the mechanisms of ΔOHC cannot be corrected so simply. Suffice to say that SST has very very little to do with ΔOHC.

  19. 169
    MARodger says:

    gmb92 @160.
    I would agree that they were very likely addressing politics with that sentence but that the message probably got a bit mangled in editing.

  20. 170
    MARodger says:

    John E Pearson @163.
    Climatology does not ignore a “hiatus”. The problem is that the term “hiatus” is used for may different things. There is the Daily Mail hiatus that can be 20 years long, and counting. If a certain month had a temperature anomaly the same as one back in 1995, there cannot have been any global warming in 20 years, can there. Then there’s the Lindzen hiatus. There has been no statistically significant warming in the last 17 years. There’s the Andrew Neal hiatus which fits something like a rolling 5-year average temperature (usually with great imprecision) and declares the hiatus started in the year dot. A precise version would show a flatish temperature profile about 8 or 9 years long, and counting.

    An analysis of GISS global tempertures shows an increase of the linear rate of warming since 1980 up to 2007 (see red trace on graphic here – usually 2 clicks to download your attachment) which strongly suggests a global slowdown cannot have begin before that time.
    Climatology will examine phenomenon prior to 2007 as there was a short preceeding acceleration (which is why the linear regression 1980-1999 still fits 1980-2014) and the process resulting in the ending of that acceleration will have begun eariler that 2007.
    That makes my position clear for normal folk.

  21. 171
    Marcus says:

    Re #158

    “For skeptics like myself, most of the warming being observed is due to natural events, not CO2 forcing. El Nino is one of these natural events.”

    For anyone capable of true skeptikal thinking it is quite obvious that ENSO is an not a trend generator at all, but an oscillation that overlays trend lines, no matter whether you “believe”/understand CO2 forcing.

    The observed warming occurs since the industrial revolution, ENSO has a frequeny of once per a couple of years

    http://de.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillation

  22. 172
    Jim Eager says:

    Victor wrote @158: “For skeptics like myself, most of the warming being observed is due to natural events, not CO2 forcing. El Nino is one of these natural events.

    Unfortunately for “skeptics” like Victor, ENSO does not generate heat, it only moves heat around, which is the reason the 1998 spike above the trend line was so short lived.

    Another natural fact that Victor seems to be ignorant of, and unfortunately, people like Victor mistake their ignorance for skepticism.

  23. 173
    Jon Keller says:

    #163 John E. Pearson,

    There are lots of climate scientists that are using terms like “hiatus” … I think it is counter-productive to pretend that these conversations have not been taking place.

    I think some of the confusion here arises from different definitions of “hiatus” being used. As I noted in #98 there is a “hiatus”, but it may not be the hiatus that you are talking about.

    For instance, as I pointed out, when looking at global warming as a whole there is absolutely no hiatus of any kind as the total heat content of Earth has increased with no pause or appreciable slowdown.

    Even if you restrict the definition of “hiatus” to air temperatures, there are few datasets that actually demonstrate a trend of 0 since circa 2000. But there has been a slow-down, numerically speaking. I don’t think anybody here is pretending that this slow-down does not exist, we are only saying that it isn’t an actual change in trend as it is being presented by contrarians. Statistically speaking, the “hiatus” could easily be part of a continuing upward trend similar to the one from 1970-2000.

    So to sum, have the years since 2000 seen a slower rate of net warming in the air than 1970-2000? Yes. That definition of “hiatus” is true. But has the overall warming trend changed? I haven’t seen evidence that it has, only evidence that it hasn’t (see Gavin, Tamino, etc).

    Hope that clears it up.

  24. 174
    Robin Levett says:

    @Victor #158 28 January 2015 at 12:49pm:

    “Secondly, I’d like to comment a bit on this business of 1998 being an “extreme El Nino year” and thus somehow misleading when assessing trends. For skeptics like myself, most of the warming being observed is due to natural events, not CO2 forcing. El Nino is one of these natural events. As is La Nina. So from my perspective I see no reason to discount or compensate for either when assessing warming trends.”

    So you’d see no need to “compensate”, when assessing warming trends, for seasonal differences in temperature readings? You’d be happy with using summer temperatures for one half of the period you are assessing, and winter temperatures for the other?

  25. 175
    Dan says:

    Re: 163.
    I would add the prevalence of La Ninas over the past decade or so as a significant dampening influence on the global temperature warming trend. I believe there is some info on this in the July 2014 vol. 95, no.7, “Special Supplement to the Bulletin of the American Meteorological Society” (“State of the Climate in 2013”).

  26. 176
    Ray Ladbury says:

    Alan Millar,
    Care to explain how you get 33 degrees of warming without a significant net positive feedback?

  27. 177

    “Of course there are both positive and negative feedbacks possible in the Earth’s climate system. It is the net overall feedback to increased radiative forcing that is important and we are way way short of understanding how these operate.”
    – See more at: http://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/comment-page-4/#comment-624273

    Then how can you be so sure that there is not a ‘net positive’ feedback? And why do you think [as you seem to, since there can’t be a single ‘net’ number otherwise] that feedbacks aren’t dynamic with changes in temperature?

    I’m glad at least that you concede that positive feedbacks do indeed exist.

    “Planck feedback will not stabilise the temperatures at a particular point if forcings are constantly increasing a la the proposed water vapour feedback to increased temperatures. You need some other negative feedback mechanism to do that.”

    But they won’t be “constantly increasing.” As Ray has pointed out, the series will converge. And for a guy who ‘relies on the physics’, it seems a bit bizarre to characterize the water vapor mechanism as merely “proposed.” After all, we know that water vapor is ‘the most important greenhouse gas,’ right? And we know that it is increasing consistently with observed warming, right? OK, detailed study of the resultant forcing might be needed to ‘nail it down’ conclusively. But I think we’re well past the ‘proposed’ stage here.

    “We know for instance that the Earth has received greatly increased forcing in the last 400 million years but has cooled from 22c to 14c.”

    Presumably, you are referring to the ‘faint sun’ paradox, as solar forcing is the only one that is known to have “greatly increased”. One proposed solution, and likely to be at least part of the answer, is that the CO2 content of the atmosphere has decreased roughly in proportion. But the data are not good enough so far in the past, as I understand it, to allow us to verify or disprove that hypothesis.

    All in all, your #159 is doing a good job of refuting the sort of “long term stability” that you touted in your #139. Or at least characterizing it better; apparently, your “long term stability” allows of 8 C swings. (And actually, more; the mid-Cretaceous ‘super-Greenhouse’ is evidence by sea-surface anomalies of up to 9 C. Not sure what just what GMST anomaly would be implied by that, but I’m guessing it would be significantly higher. See linked abstract below.)

    http://adsabs.harvard.edu/abs/2006AGUFMPP33C..04F

    I’d remind you that while humans have survived more than a full glacial cycle, we didn’t yet exist as a species when temperatures last hit 3 C above our pre-Industrial levels, back in the Pliocene. Neither, of course, did any of our staple foods, many of which are known to be highly sensitive to maximum temperatures, with productivity dropping quite rapidly with prolonged or repeated excursions above 30C. Yet “business as usual”–which still approximates fairly well to AR5’s RCP 8.5–is projected to lead to a GMST anomaly in the range of 2.6 to 4.8 C by 2100.

    Now, I don’t know that that will be “catastrophic”, to get back to your comment at #139. But I sure don’t think it’s a very smart idea to run that particular experiment, other than virtually. Especially without a ‘control Earth’ available.

  28. 178

    > has been awarded

    By some guy writing a “lukewarmist” blog that hypes the conspiracy theories, phrased in passive tense, spun by mentioning Gavin, to suggest it’s anything like the real award made to a real climate scientist by a real group.

    Distraction. Eschew.

  29. 179
    swood1000 says:

    …supporting the notion that the underlying long-term trend has not changed appreciably over the last decade or so. (Tamino has a good post on this as well).

    I become somewhat confused by the different opinions as to whether or not there has been a pause. For example, if you look at page 92 of the APS Climate Change Statement Review Workshop, http://www.aps.org/policy/statements/upload/climate-seminar-transcript.pdf, you will see this statement by Dr. William Collins, head of the Climate Sciences Department, and director of the Center at LBNL for Integrative Modeling of the Earth System (CLIMES) at the Lawrence Berkeley National laboratory (LBNL), as well as lead author on the Fourth and Fifth Assessment of the IPCC:

    “Now, I am hedging a bet because, to be honest with you, if the hiatus is still going on as of the sixth IPCC report, that report is going to have a large burden on its shoulders walking in the door, because recent literature has shown that the chances of having a hiatus of 18 of 20 years are vanishingly small.”

    Dr. Collins said that there has been a pause which, if it continues, will be difficult to explain at the time of the sixth IPCC report. Is he wrong?

  30. 180

    *sigh*

    I miss the talk here. Wish I could come back. How about if I promise never to bring up my drought study unless it gets published in a peer-reviewed journal? Would that satisfy Bouldin-sama?

  31. 181
    Matthew R Marler says:

    166, 3000quads: Frequent commenter Hank Roberts has been awarded the 2014 Climate Commenter of the Year – See more at: http://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/comment-page-4/#comment-624325

    Congratulations to Hank Roberts, but awarded by whom?

  32. 182
    Victor says:

    Meanwhile I can’t help but notice that no one has of yet engaged with my comments regarding time delays with respect to oceanic heating. (See #104, as I recall.)

    I’m not a climate scientist so I have no problem admitting I could be wrong. But I’m still waiting for someone to set me straight. How can the current temperatures of the oceans (both shallow and deep) be used to account for a warming hiatus at the surface, if we need to account for the time it takes for heat to be transferred from one to the other? And if one wants to argue that CO2 emissions are responsible for most of the warming, then obviously these emissions are being emitted into the atmosphere, right? Not directly into the ocean. So if you want to attribute ocean heating to AGW, you need to account for the necessary delay. Unless the heating is due to some other factor, currently unknown.

    Since so many explanations of the hiatus (however you want to define it) hinge on what’s happening in the oceans, I’d think this would be an issue climate scientist would need to deal with.

  33. 183
    SecularAnimist says:

    Victor wrote: “For skeptics like myself …”

    You are not a “skeptic”.

  34. 184

    Hank, you are concisely excellent, which is not diminished by a sales endorsement from the Fuller Brush Man.

  35. 185
    jgnfld says:

    @158 victor the troll…

    Your knowledge of English is every bit as good as your knowledge of stats and science.

    OED entry (you’ll need research library access, but then so do you need such for science articles):

    The state or quality of being ridiculous; absurdity.
    1573 J. Bridges Supremacie Christian Princes 413 With almost so manie blasphemies as there bee lines, besides the ridiculousnesse of the whole tale…[3 centuries of entries deleted]…
    1941 Ethics 52 81 As for masculine heroism in the Battle of the Ballot, Charlotte Perkins Gilman has touched it to its proper glory in a rhyme just rolicksome enough to befit its ridiculousness.
    2003 Marie Claire Dec. 97/3 She is as possessed by limitless sarcasm and an awareness of the innate ridiculousness of Internet dating as I am.

    As for your stats comments, others have dealt with your problems in great detail. They are myriad.

  36. 186
    Victor says:

    #164 “Victor – show us the part where there is significant warming of the oceans by the atmosphere.”

    Sorry, but I thought that was your point, not mine. If there is no such process, then how does warming from CO2 emissions get into the ocean in the first place?

  37. 187
    Victor says:

    #167 Tamino: “You’re not a skeptic. You’re a fake.”

    No, I can’t be a fake, since I make no claims to expertise. My comments are based on logic and common sense, with no appeal whatsoever to any personal authority on my part. I could, of course, be wrong. But to prove me wrong you’ll need to engage with what I’ve written. All your personal attack says is that you’re miffed. (Can’t blame you, actually.)

  38. 188
    Jim Baird says:

    Jon Keller, 173. “have the years since 2000 seen a slower rate of net warming in the air than 1970-2000? Yes. That definition of “hiatus” is true.”

    That being the case, is it not rationale to try to ascertain the cause of that reduced rate of warming? If that cause can be determined and then replicated with man made effort we have a climate solution. In an article published at theEnergyCollective today I suggest that that solution can also be the lowest cost, carbon-free, source of energy.

  39. 189
    Jon Keller says:

    #188 Jim Baird,

    … is it not rationale to try to ascertain the cause of that reduced rate of warming?

    Absolutely. I think the goal for science in general is always to know more. On this topic specifically, more knowledge about the specifics of climactic variability such as what we’ve seen since 2000 would naturally lead to better predictions of warming on yearly timescales, among other things.

    I’m not a climate scientist nor do I know much about mitigation, but it seems to me that if this slowdown is the result of heat moving around within the system and not reduced intake from the sun, even if it were possible to replicate it it wouldn’t do any good in the long run. If, however, it is a result of aerosols or some such thing actually preventing heat from entering the system, then we may have options, though again I’m not an expert and I don’t know how plausible they might be.

    It seems the safest thing to do right now is to get behind initiatives to cut back on emissions.

  40. 190
    Victor says:

    The ridiculousness of the word “ridiculousness” becomes apparent when you try to form the plural: “ridiculousnesses.” Now every noun in English has a plural, but I’ve never seen that one. No doubt someone here can find it for me. Mr. Rodger, care to give it a shot? (Even my spell checker chokes on it.)

    Of course one could use “ridiculousities,” but that sounds even worse. As far as I’m concerned all such ridiculousnesses just exemplifes the ridiculousity of the word “ridiculousness.”

  41. 191

    “Given the necessity for some sort of delay during any heat transfer from the atmosphere to the oceans…”

    What ‘necessity’?

    “From examining the evidence it looks to me like there could be something like a 21 year lag from the latter to the former.”

    What ‘evidence’?

    – See more at: http://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/comment-page-4/#comments

  42. 192
    Marcus says:

    Re #182

    re #182:
    “Meanwhile I can’t help but notice that no one has of yet engaged with my comments regarding time delays with respect to oceanic heating.”

    I do not agree that your points have not been sufficiently addressed yet.

    “104
    Victor says:
    26 Jan 2015 at 11:55 AM
    […]

    Well, for one thing, it’s very difficult to understand how a warming process dependent on airborne greenhouse gases could suddenly, over a period of a year or two, shift heat from the atmosphere to the oceans. Here again, various theories have been produced as to how this could happen, but they seem extremely speculative at best”

    This is not the case, the climate system is a dynamic equilibrium. Each sub-system of it, be it atmosphere layers or ocean layers, has an energy throughput, which is in/out balanced for a sufficiently short given period.
    When that dynamic equilibrium is disturbed because a mechanism emerges that changes the game (be it transient or not), the equilibrium temperature changes with that throughput. For example a strengthening of wind over some oceanic region

    http://web.science.unsw.edu.au/~matthew/nclimate2106-incl-SI.pdf

    then would increase the heat flow atmosphere -> ocean, leading to lower (dynamic) equilibrium temperature in the atmosphere which of course occurs very fast, as the thermal mass of the atmosphere is very low compared to the net energy throughput. There is no need to imagine huge amounts of energy to be shifted to and fro, it suffices to keep in mind that the thermal mass of the oceans is big and that of the atmosphere comparatively negligible

  43. 193
    Tony Weddle says:

    Victor,

    If you really wanted to find out what’s going on with OHC, try this post from ReaClimate, which you could have easily found, yourself. The fact that you don’t understand the mechanisms of how increased CO2 warms the oceans is irrelevant, since the heat content of the oceans is increasing (and, thus, the planet, as a whole has continued warming despite your “hiatus”). Perhaps you could provide an alternative explanation for why the oceans continue to warm and then look for research evidence for your hypothesis?

  44. 194
    MS says:

    #180
    Barton – please come back.
    As a long time reader I miss your energy and knowledge in the comment-threads.

  45. 195
    MARodger says:

    Victor the Troll, asks @186 of “significant warming of the oceans by the atmosphere” saying

    “If there is no such process, then how does warming from CO2 emissions get into the ocean in the first place?”

    Up-thread he has wedded himself to the childish idea that it is the increase in atmospheric temperatures (complete with “hiatus”) that is responsible for increases in OHC.

    So here is a problem. How would somebody go about explaining the mechanisms that result in ΔOHC to a denialst as stupid as our Victor? They are complex mechanisma. They are not individually measurable in any helpful way.

    If Victor wasn’t so stupid & trollish I would suggest Rob Painting’s “How Increasing Carbon Dioxide Heats The Ocean” over on SkS and, by way of preparation, the added quote from IPCC AR5 WG1 3.4.1 “The net air–sea heat flux is the sum of two turbulent (latent and sensible) and two radiative (shortwave and longwave) components.”

    Anybody else got any constructive suggestions?

  46. 196
    Ray Ladbury says:

    Oh FFS. Yes, there is a change in the trend-line slope over a way-too-short-to-be-significant period. This so-called “hiatus” is interesting to actual climate scientists because it tells us something about energy transport. It generates papers because it tells us about ocean-atmospheric couplings, not because there is anything to “explain away”. The anti-science imbeciles think climate science is all about anthropogenic warming. It isn’t. It’s about understanding the climate, and anthropogenic warming is just an inevitable consequence of that understanding.

  47. 197
    JCH says:

    MARodger, read this link and these.

    Science of Doom – Does Back Radiation “Heat” the Ocean? – Part 4

    Especially helpful are comments by Stu N.

    RealClimate article by Peter Minnett

    Look at the combination responses by Gavin and Stefan.

    Nick Stokes article

  48. 198
    jgnfld says:

    Re. all English words having plurals or at least you cannot think of any that don’t…

    You think what you say is a rightness, but I in actuality your thinking shows wrongness.

  49. 199
    Hank Roberts says:

    Victor says: … My comments are based on logic and common sense

    Medieval thinking, lacking Bacon and computation.

  50. 200
    tokodave says:

    195 MARodger. “Anybody else got any constructive suggestions?”

    I think several people have put forward suggestions that would certainly be considered scientifically “constructive suggestions”.

    I found this quote from guess who…Gavin, that might be equally relevant:

    “Trying to teach chess to someone whose only interest is tipping the board over is a waste of time.”

    [Response: Not my quote! I was quoting from a comment here from Radge Havers – with some tightening for twitter. – gavin]