The Hansen forecasts 30 years later

From Dr. Judith Curry’s site, a discussion of Hansen’s original forecasts as seen below:

by Ross McKitrick and John Christy

How accurate were James Hansen’s 1988 testimony and subsequent JGR article forecasts of global warming? According to a laudatory article by AP’s Seth Borenstein, they “pretty much” came true, with other scientists claiming their accuracy was “astounding” and “incredible.”  Pat Michaels and Ryan Maue in the Wall Street Journal, and Calvin Beisner in the Daily Caller, disputed this.

The whole debate has focused on comparisons of the 1988 and 2017 endpoints. Skeptical Science waived away the differences by arguing that if one adjusts for an overestimation in the rise of greenhouse gas (GHG) forcing, Hansen’s 2017 Scenario B prediction was not far off reality.

There are two problems with the debate as it has played out. First using 2017 as the comparison date is misleading because of mismatches between observed and assumed El Nino and volcanic events that artificially pinched the observations and scenarios together at the end of the sample. What really matters is the trend over the forecast interval, and this is where the problems become visible. Second, applying a post-hoc bias correction to the forcing ignores the fact that converting GHG increases into forcing is an essential part of the modeling. If a correction were needed for the CO2 concentration forecast that would be fair, but this aspect of the forecast turned out to be quite close to observations.

Let’s go through it all carefully, beginning with the CO2 forecasts. Hansen didn’t graph his CO2 concentration projections, but he described the algorithm behind them in his Appendix B. He followed observed CO2 levels from 1958 to 1981 and extrapolated from there. That means his forecast interval begins in 1982, not 1988, although he included observed stratospheric aerosols up to 1985.

From his extrapolation formulas, we can compute that his projected 2017 CO2 concentrations were: Scenario A 410 ppm; Scenario B 403 ppm; and Scenario C 368 ppm. (The latter value is confirmed in the text of Appendix B). The Mauna Loa record for 2017 was 407 ppm, halfway between Scenarios A and B. Note that Scenarios A and B also represent upper and lower bounds for non-CO2 forcing as well, since Scenario A contains all trace gas effects and Scenario B contains none. So, we can treat these two scenarios as representing upper and lower bounds on a warming forecast range that contains within it the observed post-1980 increases in greenhouse gases. Consequently, there is no justification for a post-hoc dialling down of the greenhouse gas levels; nor should we dial down the associated forcing, since that is part of the model computation.

Now note that Hansen did not include any effects due to El Nino events. In 2015 and 2016 there was a very strong El Nino that pushed global average temperatures up by about half a degree C, a change that is now receding as the oceans cool. Had Hansen included this El Nino spike in his scenarios, he would have overestimated 2017 temperatures by a wide margin in Scenarios A and B.

Hansen added in an Agung-strength volcanic event in Scenarios B and C in 2015, which caused the temperatures to drop well below trend, with the effect persisting into 2017. This was not a forecast, it was just an arbitrary guess, and no such volcano occurred.

Thus, to make an apples-to-apples comparison, we should remove the 2015 volcanic cooling from Scenarios B and C, and add the 2015/16 El Nino warming to all three Scenarios. If we do that, there would be a large mismatch as of 2017 in both A and B.

The main forecast in Hansen’s paper was a trend, not a particular temperature level. To assess his forecasts properly we need to compare his predicted trends against subsequent observations. To do this we digitized the annual data from his Figure 3. We focus on the period from 1982 to 2017 which covers the entire CO2 forecast interval.

The 1982 to 2017 warming trends in Hansen’s forecasts, in degrees C per decade, were:

  • Scenario A: 0.34 +/- 0.08,
  • Scenario B: 0.29 +/- 0.06, and
  • Scenario C: 0.18 +/- 0.11.

Compare these trends against NASA’s GISTEMP series (referred to as the Goddard Institute of Space Studies, or GISS, record), and the UAH/RSS mean MSU series from weather satellites for the lower troposphere.

  • GISTEMP: 0.19 +/- 0.04 C/decade
  • MSU: 0.17 +/- 0.05 C/decade.

(The confidence intervals are autocorrelation-robust using the Vogelsang-Franses method.)

So, the scenario that matches the observations most closely over the post-1980 interval is C.

Read the entire post here: https://judithcurry.com/2018/07/03/the-hansen-forecasts-30-years-later/

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102 thoughts on “The Hansen forecasts 30 years later

  1. The rate of warming since circa 1850 has been fairly steady (albiet with the natural decadal cycles). ie a quasi sine wave.

    If Hansens prediction was spot on, real temps would be spliting the middle of the sine wave instead of reaching Hansen’s prediction only on the crest of the observed sine wave.

  2. There is actually a 65-70 year climate cycle to consider as well. Very unfortunate that climate is defined as 30 years of weather averaged, because of those cycles. It should havce been 70 years. We came out of a cold cycle in the late 70’s and entered a warming cycle. That cycle would take about 35 years from bottom to top. We have that now. If the past holds, the climate will cycle into a cooling phase for the next 35-40 years. THEN what will all the CO2 nannies say? CO2 may continue to increase (or maybe not) but temp will be dropping. I see that as an absolute certainty.

    • I very much doubt that the 30 year choice was an accident. There is no real reason for that choice if climate has been “stable” without non-natural forcings of any meaningful size. Why not use the longest record we have? And since climate scientists are fond of using all sorts of methods to get the record right (shall we say), then why not use back to 1900, or even earlier?

      • “I very much doubt that the 30 year choice was an accident.”
        The main reason was that computations, in those days, were extremely slow. It would have taken months or years longer to do a century run for all scenarios. Anyway there’s no use haggling about time period now. We do have 30 years of prediction to review, and that is all.

        • “. . . computations, in those days, . . . ”

          The 30 year “normal” thing started before modern computers so “those days” = mid-1930s.
          The IBM System/360 was well advanced by the late 1970s so I think the real issue was getting the old records into a format that was readable. From experience with old census reports I know how time consuming and error prone this can be. I’ll guess old temperature records are a lot more difficult than the census. I’ve only “looked” at old temperature records. They are enough to give one the shakes!

      • The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind.
        The 70 year cycle was not known when that was defined. That definition MEANS that slightly 1/2 of one full climate cycle will be used to represent the climate for the last 30 years. And no one knows or cares which half it is. If it’s the colder half, they whine about global cooling. If it’s the warmer half, well, we are seeing that now.

      • Since the origin of the use of climate normals in the US goes back to about the 1930’s I doubt the purpose was nefarious.

        • D J Hawkins :
          How CAN you doubt that it was NEFARIOUS when you can see the
          agendas that have been CONSTRUCTED around that “PREDICTION” ?
          It is the entire BASIS for AGW , ‘Carbon Dioxide is pollution’ , CAGW
          eventually morphing into CACC ( Catastrophic Anthropogenic
          Climate Change ) and all the thoroughly wasteful activity that
          it has produced.
          The unleashing of “self loathing and hatred’ for WESTERN
          CIVILISATION and CULTURE from within it by the reprehensible
          Post-modernist Neo-Marxist Fascist Left Wing is bad enough !
          The UN Agenda 21 and similar punitive measures and “TAXES”
          and the futile pursuit of “sustainability” , “green anything ! ”
          “renewable energy ” and the like has WASTED BILLIONS of
          DOLLARS and the TALENTS of a great many gifted ( but
          ultimately distracted and therefore , stupid ! ) people .
          ALL THAT EFFORT could have been PROPERLY USED to
          benefit mankind and it has been LOST and WASTED
          and EVEN WORSE , it has caused MUCH HARM to
          the concept of “science” itself.
          Scientists have , in many cases , been traduced to
          the level of political-tools and used-car salesmen .
          AND FOR WHAT ?
          As others have commented , and it seems likely ,
          EVEN IF THE EARTH RE-ENTERS A COOLING PHASE
          and the CACC PREDICTIONS FAIL , and CO2 is exonerated ,
          no PhD’s or Nobel Prizes will be “WITHDRAWN” and
          NO BOOK ROYALTIES or LECTURE TOUR PROFITS
          will be “returned to the believers ” and even WORSE ,
          NO DISGRACE will attach to those “who acted on the
          available evidence at the time ” , even though they
          CONCOCTED IT THEMSELVES !
          About the only outcome will be a degree of smugness
          and the chance to say ” I told you so ! ” especially
          by shallow vindictive people with LONG memories
          like me !

          • @Trevor;
            Deconstruction, or applying the knowledge, assumptions, and prejudices of the present to historical events is a pernicious practice, to be eschewed at all times. Do you seriously intend to claim that when the use of climate normals was instituted in 1930 or thereabouts that there was a hidden agenda EVEN THEN to use such to perpetrate a climate scam 50 or so years later? Your tin foil hat is on too tight.

          • The more caps you use in your post, the less likely anyone is going to read it. It’s like walking past someone who is standing on a soapbox and screaming. That type of behavior calls out “I’m a nut job, don’t listen to me!”

          • Chris,
            Some folk s i m p l y must emphasise
            I suggest that the use of upper case [‘shouting’] is not necessary, even without mastery of bold, or italic, or, indeed, underlining. [Which mastery, I lack]
            T h e r e a r e other ways.

            And, yes, I skipped Trevor’s [possibly brilliant] shout-out.

            Auto

          • Right on, Chris. I’ve been telling him that for some time now, but he shouts so much he apparently can’t “hear”.

    • The ‘longest instrumental’ temperature record shows that the temperature was slowly rising since late 1600’s early 1700’s (link ) as the up-slope of the quasi-‘millennial’ cycle, modulated by the shorter 60-70 year North Atlantic oscillation.
      The bold blue line is derived from the CET’s three most prominent spectral components.

  3. Once a person dismisses (as absurd) the concept of a global temperature anomaly having any meaning in such a small range as a couple of degrees, then all this hair splitting over statistical procedures can slide right off into the who-cares bin.

    I suspect that Ross McKitrick and John Christy probably see it this way too, but they just have fun playing with the alarmists, using the alarmists’ game pieces to reveal how badly the game has been played.

    • ROBERT KERNODLE :
      “Once a person dismisses (as absurd) the concept of a global temperature anomaly having any meaning in such a small range as a couple of degrees, then all this hair splitting over statistical procedures can slide right off into the ……………..who-cares bin.”
      REALLY ????
      HOW ABOUT LOOKING AT ALL THE MONEY WASTED and THE DEATHS
      THAT WILL OCCUR BECAUSE OF THE FAILURE TO HAVE ACCESS TO
      CHEAP ENERGY and so on ……………..Aaarrgghh !
      PLEASE …….JUST READ MY COMMENTS ABOVE !

      • Trevor, I was NOT talking about the consequences of caring about a false paradigm. I was talking about believing in a false paradigm.

        If nitpicky analyses about a couple of degrees were in the who-cares garbage can, then all the bad consequences of caring would NOT occur, as a result of falsely believing that those couple degrees of a statistical construct mattered.

        In the who-cares bin, there is nothing to act on, you see — it’s trash.

  4. “…if one adjusts for an overestimation in the rise of greenhouse gas (GHG) forcing,”

    …is really “if one adjusts for the obvious mistake, then there’s no obvious mistake.”

  5. I just don’t get how we can be warmer or similar to 1989. That was a hot year in the Midwest.

    • That’s the problem with global averages. They doesn’t say diddly for what’s happening in your neck of the woods.

  6. 2 El Ninos went above his “C”…..but somehow this one counts
    The past temp history he used has been adjusted down…if he had used today’s temp history..he would have been off the charts
    Even if you count this El Nino…he totally missed the pause

  7. Well, we’ve been through all this a few times at WUWT now. But this is a strange one:

    ” Note that Scenarios A and B also represent upper and lower bounds for non-CO2 forcing as well, since Scenario A contains all trace gas effects and Scenario B contains none. So, we can treat these two scenarios as representing upper and lower bounds on a warming forecast range that contains within it the observed post-1980 increases in greenhouse gases. Consequently, there is no justification for a post-hoc dialling down of the greenhouse gas levels; nor should we dial down the associated forcing, since that is part of the model computation.”

    If I understand that correctly, it is just wrong. Scenario B contained lots of trace gas effects, as did C. And the conclusion is completely wrong.

    I have written a detailed analysis of the scenarios here, with links to sources and details. A quick summary of main sources:

    1. Although Hansen didn’t graph the scenarios, we do have a file with the numbers, here. It is actually a file for a 1989 paper, but there is every indication the scenarios A,B,C are the same.

    2. There are detailed discussions with graphs, from Gavin Schmidt recently, and from Steve McIntyre in 2008 (who got much more right than this article). I won’t give all the links here, because I will probably be sent to spam, but they are in my post linked above. SM also recalculated the scenarios from Hansen’s description; he gives numbers and plots.

    In fact, the main reason Hansen’s result came between B and C was that methane and CFC’s were overestimated in B and even C. Here is the RC plot of the scenarios and outcomes (click to enlarge):

    https://s3-us-west-1.amazonaws.com/www.moyhu.org/2018/06/gavin1.png

    Gavin also gives the combined forcings, which quantifies the placing of the outcome between B and C.

    My calculation of the trends in the actual 30 yr prediction period 1988 to 2017 were
    A: 0.302 B: 0.284 C: 0.123 with observed generally about 0.18
    It doesn’t make sense to give error ranges, since the predictions don’t contain randomness.

  8. The only way to claim that Hansen’s “projections” were accurate is to pretend that the recent El Nino was first caused by CO2, and affect of it won’t fade over time.

    In other words, to lie.

    • Why only El Nino? The quick summary of recent history is that two big La Nina’s (2008 and 2011/2) took temperature down from the predictions, and the El Nino brought it back.

      • There is one of two possibilities.
        1) Nick did not actually bother to read what I wrote.
        2) Nick doesn’t speak English.

        Just to recap Nick, I mentioned only the most recent El Nino. There hasn’t been a corresponding La Nina for that one, at least not yet.

        Do you care to address my comment, or are you going to continue trying to change the subject?

        • “There hasn’t been a corresponding La Nina for that one, at least not yet.”
          So why wasn’t 2011/2 the corresponding La Nina? Or what corresponded to 2011/2? In fact, ENSO is a cycle. Which came first? The chicken or the egg?

          • The 2011/12 La Nina was the completion of the 2010 El Nino ENSO cycle.

            There has not been a full blown La Nina following the 2015/16 very strong El Nino (which was possibly stronger than the super El Nino of 1997/98), although it has come very close on a couple of occasions to full blown La Nina conditions..

            For all we know, since we cannot predict these things with any certainty, we might see a double El Nino, with 2018/19 turning into an El Nino year.

          • “The 2011/12 La Nina was the completion of the 2010 El Nino ENSO cycle”
            Where do you get that from? Who rings the bell to say the cycle is complete?

          • Nick

            According to BOM (which organisation I understand that you trust), since 1987/88 (the date of Hansen’s predictions), there have been the following ENSO events:

            El Nino 87/88, La Nina 88/89 , El Nino 91/92, El Nino 93/94, El Nino 94/95, El Nino 97/98, La Nina 98/01, El Nino 02/03, El Nino 06/07, La Nina 07/08, La Nina 08/09, El Nino 09/10, La Nina 10/12, El Nino 15/16.

            You will note that during this period there has been many more El Ninos than La Ninas. There have been 9 El Ninos, and just 5 La Ninas. Almost two to one.

            Accordingly, as from the time when Hansen made his predictions, we have therefore been in a warming ENSO period/phase, and no one could reasonably argue that during this period ENSO has been neutral. It has been anything but, especially as several of the El Ninos were particularly strong, and only one of the La Ninas was considered to be strong.

            It would have been easier to have judged his predictions if there had been equal number of both, but given that there has been far more El Ninos than La Ninas, it is obvious that the present ENSO cycle following the very strong 2015/16 has yet to complete with a La Nina.

            Presently, conditions are tracking towards El Nino, and BOM say that it is 50/50 for an El Nino early next year. So we might actually have (yet again) a double El Nino.

            See generally:
            El Nino: http://www.bom.gov.au/climate/enso/enlist/index.shtml

            La Nina:
            http://www.bom.gov.au/climate/enso/lnlist/index.shtml

          • Richard Verney: It’s not just the number of El Ninos versus La Ninas, it’s their strengths and durations. Look at the ONI graph that Anthony Banton posted. Sum the areas under the curves. Pretty much balanced. The El Nino – La Nina labels are merely categorizations of a continuum. You must look at the underlying continuum to properly ascertain the net effect. That is done by the multivariate regression based removal of ENSO from the temperature record as Gavin Schmidt and Tamino (see the links in my response to Hugs).

            But even without analyzing that fine grained detail, relying on the grosser categorization, you can see that the underlying warming trend exists independent of ENSO, by simply looking at the trends of all El Nino years, all La Nina years, and all neutral years. (See the links I gave in that same response to Hugs.)

            Your claim has no factual basis. I’m amazed that you are clinging to that obviously false claim.

          • I am well aware that the relative strengths is a factor, and I even mentioned that in my comment above, but of course, there are number of material factors.

            First, the satellite data is much more influenced by El Ninos. It appears far less sensitive to La Ninas. I have not seen much discussion on this, but I suspect that it has something to do with conduction and convection with greater amounts of warm air rising to higher altitudes. When the ocean is warm, it powers convection taking warm air up to height, and up to the altitude where it is measured by the satellite. Conversely, when the ocean is cool, there is less convection and cold air is not taken up to the height where the satellite takes its measurements, so the temperature measurement is not so greatly impacted.

            In the short term, a warmer ocean has more impact on temperatures than does a cool ocean. Of course, these differing conditions impact upon cloudiness which is not well understood or measured, and of course on winds both at low and high altitude.

            Second, if ENSO and volcanoes are detrended from the satellite data, then there is no statistically significant warming over the entirety of the satellite data, ie., there appears, outside just those two natural events, to be no warming for nearly 40 years!

            But at the end of the day, there are so many processes involved which are not well understood, and the data is of questionable quality that we simply do not know what is going on, still less why.

          • Richard, you just invented your claim that the satellite data is much more influenced by El Ninos than by La Ninas. That’s why you don’t see “much” discussion of it–it’s not true.

            Your claim of lack of statistically signifcant warming in the satellite data after removing ENSO and volcanoes is false, which you knew, but since you shamelessly are just making up your own “facts” there is no point in trying to converse with you.

          • But I would argue that the excess of Ninos over Ninas is possibly just the way the world warms. Whereas volcanoes are clearly sporadic separate events, Ninos and Ninas are an integral part of the climate system. On that basis I think you’d be on very shaky grounds indeed trying to subtract them out of the data. The way to deal with the variability they introduce is not to try to subtract them but simply to look at trends over a longer period.

          • No, Ian H, there is no excess of El Ninos over La Ninas, as actual, real, concrete, specific, observations show. And even if there were such an excess (there’s not!), the result would not be warming of the world, because El Ninos merely shift the allocation of where the increasing energy from greenhouse gases goes, they do not increase the total energy in the world. You are just denying all the straightforward evidence that has been presented to you.

          • As usual, Nick’s only reaction to being caught out, is to continue digging.
            I’m talking about the 2015/6 El Nino and only that one.

          • “I’m talking about the 2015/6 El Nino and only that one.”
            Of course, and that is my point. You don’t want to talk about the La Nina’s that made the slowdown that preceded the Nino. ENSO creates both ups and downs, and in the last decade we have had more downs than ups.

          • “…and in the last decade we have had more downs than ups.” You had previously said that they tend to cancel out and don’t need to be explicitly modeled. How long does it take for them to cancel?

          • Well, Clyde, 30 years seems sufficient. Coincidentally that is the WMO’s approximate definition of “climate.”

          • Why is 30 years sufficient? Why not 100, or 1,000? It is just arbitrary not supported by any sound reasoning.

            Would you say that 3 spins of a roulette wheel is sufficient to see whether it is biased? Given that the climate has been going on for approximately 4 billion years, 30 years is not even a blink of an eyelid.

            Even if one merely wishes to consider what climate should look like in the current glacial epoch (the Pleistocene), or the short lived inter-glacial (the Holocene) that we are currently enjoying, 30 years is a ridiculously short period of time to make an assessment.

            One problem we have is that our own life span is so short that we have trouble in seeing things in their proper perspective. –

          • Could you tell us why the 2015/16 EN did not complete the cycle of the 10/11 LN?

            https://www.thegwpf.com/content/uploads/2017/10/Screenshot-2017-10-04-17.58.36-1024×384.png

            Not withstanding that the PDO was overwhelmingly -ve between the 98 and 15 Nino’s.

            https://www.carbonbrief.org/wp-content/uploads/2016/06/NOAA-PDO-Index.png

            You do agree that a -ve PDO has a cooling effect on GMTs?
            That the answer is obviously yes – where are we in the completion of the PDO cycle chicken/egg stakes eh?

          • Nick, ever heard of Bjerknes feedback? That is clearly a case where La Nina is a feedback to El Nino. There doesn’t appear to be anything equivalent going the other way.

            I do think it is hysterical that you want to blame an event starting in late 2014 on something in 2011 as if time stood still.

        • Supporting Nick’s point, ENSO is not a “cycle” though it is an “oscillation,” because cycles by definition are guaranteed to “cycle” back around every time. The 11-year solar cycle is an example. In contrast, ENSO does not come in El Nino – La Nina pairs. Over the long term (e.g., 30 years) the temperature changes from the El Ninos tend to counterbalance the temperature changes from the La Ninas, but there is no predicting the exact sequences, sizes, nor numbers of those two phenomena within that longer period. Therefore it makes no sense to claim that there has been, is, or ever will be, “the” La Nina (or even several La Ninas) that complements a particular El Nino to “complete” that one cycle. There is no such one cycle.

          • A point well made. There is zero justification in picking a start or end date. The longer the time period the greater chance for “oscillations” to cancel out.

          • Tom,
            You said, ” Therefore it makes no sense to claim that there has been, is, or ever will be, “the” La Nina (or even several La Ninas) that complements a particular El Nino to “complete” that one cycle. There is no such one cycle.” In other words, we can’t expect them to cancel out as Nick claims?

          • Clyde, paired cycles are not needed for oscillations to average out to zero. Cycle is a subset of oscillation. Oscillations, both cyclic and not, cancel out over to yield net zero change—by definition.

          • Question: Do we know all there is to know about all oscillations taking place in all the oceans? Do we know all there is to know about all the oceans currents? Or are we still shooting in the dark?

          • Tom

            Even if what you say has merit, the fundamental point is that you should not take a high (EL Nino), or a low (La Nina) to trend a time series since the trend will be significantly impacted by the per chance end point.

      • Nick, you just ignored the 2007 and 2010 El Nino events. The La Nina events you mentioned were in response to those El Nino events. I do get a chuckle out of your blatant bias.

      • Source: SkS kidz?

        I love the graph. It has a certain smell. As if its author was trying to improve his/her point.

        I’m sure that we will all convert because you preach so well. Now how much of that 0.8C you think was detected ‘that year’, and how much was adjusted later on?

        • Hugs, that graph is a a simple way to remove the effects of ENSO–calculating global temperature trends separately for El Nino years, La Nina years, and neutral years, as John Nielsen-Gammon first did in 2012. Those three nearly identical trends reveal the long term global warming independent of ENSO. Dana Nuccitelli calculated those same trends but using a different index of ENSO to decide which were El Nino, neutral, and La Nina years, and got nearly identical results to John Nielsen-Gammon. The key plot with an explanation, and updated through 2015, is available elsewhere, and that plot updated through 2016 is available as a YouTube video. It looks like the graph posted by Anthony Banton might have been updated through 2017.

          But you need not trust any of those sources, because you easily can create a similar graph yourself. So please do that and post your version here, if you find it to differ from any of those.

          A more sophisticated approach to remove the ENSO influence is to use multivariate regression, as Gavin Schmidt did up through 2017 (reposted at Open Mind). In that same Open Mind post, Tamino showed the trend after removing the influences of not only ENSO, but also volcanoes and solar variations; later, Tamino plotted the rates of those trends for easier comprehension.

          • From Tom Dayton “Hugs, that graph is a a simple way to remove the effects of ENSO–calculating global temperature trends separately for El Nino years, La Nina years, and neutral years,”

            It also shows why Hansens projection is not nearly as great as the warmists claim. First, the observed temps only hit hansens projection in the El nino year, which he did not factor in the scenario and Second, the observed temps only hit Hansens projection when he the cooling effect of volcanic activity, something that was pure guestimate. Remove those two factors and his Scenario B is not even close (he did get the general trend correct which started circa late 1800’s)

        • “As if its author was trying to improve his/her point.”
          The “point” is that ENSO is an oscillation overlying a warming trend.
          Simples.

      • Never mind the ENSOs, what is the source of the “global surface temperature change” in that graph? It doesn’t look at all familiar to me. It doesn’t look like Hansen 1988 even.

      • If El Nino left a permanent warming increment then your chart is exactly what one would expect. You knew that, right?

        • Richard M: No, El Ninos cannot leave a “permanent warming mark,” because El Ninos and La Ninas are mere internal variation within the climate system, temporarily redistributing energy between surface and deeper oceans, and thereby between atmosphere and oceans. ENSO does not add or remove energy from the climate system. That is shown by the graphs of all El Nino years, all La Nina years, and all neutral years all having nearly identical, warming, trends. Your assertion is exactly what those graphs show to be completely false. Instead, as Anthony Banton wrote, those graphs show that net-neutral ENSO variation overlaid on a chronic warming trend.

    • MarkW
      You need to move on from the El Nino thing. Long term it has nothing to do with the cause of the warming… any more than the tide is the cause of the sea level rise.

      • That we do not know, and could be correct of one climate as being say the average of 60 years or 120 years rather than the short 30 year period which is presently being used, but the temperature trend does not appear linear, and more closely follows a step change with each successive strong El Nino. Coincidence may be,

        But then again if in any 30 year period there are more El Ninos than La Nina, one would expect to see a warming trend as heat energy is released from the oceans and into the atmosphere.

      • El Nino’s have everything to do with warming, especially since you guys insist on using the most recent El Nino to create the only warming in the last 20 years.
        Absent the recent El Nino, the pause would now be over 20 years long and growing.

        • MarkW
          Leave the El ninos in = there’s warming. Take them out = there’s warming. But you can’t do what your suggesting and leave some in and take others out. That’s called being dishonest(or stupid).

          • Quite.

            When they are all left out, and the data is detrended for ENSO and volcanoes, the satellite data shows no statistically significant warming over the entirety of its record, ie., for nearly 40 years.

      • Simon, there is zero evidence to back your claim. All of the recent warming could have been due to ENSO. While it’s not what I believe, you cannot dismiss the possibility by assertion. Face::palm.

        • Richard M, the evidence is those graphs of all El Nino years, all La Nina years, and all neutral years, all having the same warming trend. That shows it is impossible for that common warming trend to be caused by El Ninos. Literally, impossible.

  9. “Thus, to make an apples-to-apples comparison, we should remove the 2015 volcanic cooling from Scenarios B and C, and add the 2015/16 El Nino warming to all three Scenarios. If we do that, there would be a large mismatch as of 2017 in both A and B.”

    But apparently forget about La Ninas

    • There hasn’t been a La Nina following the 2015/16 El Nino? Only warmunists specialize in remove data that isn’t there.

      • So if you remove the 2016 El Nino, do you remove the 2011/2 La Nina? Where do you stop, and why?

        • If your scientific belief requires you to count our current trend, including the massive 2015-2016 El nino, as proof, then I respectfully submitted to you that you are ignoring that which you don’t want to see. It’s plain silly to argue that the spike in temps the last several years due to El nino are evidienc in favor of CO2 forced climate change. To distract with specious arguments about how to deal with la Nina’s, is just that, a distraction.

          Sure, let’s treat them both the same…and that means not taking a trend at, or near, the peak of one and using it to justify whatever it is we want to believe.

          rip

        • You stop when you have clean data.
          Using an abnormal event to anchor one side of your data trend is dishonest.

          • Why is an El Nino abnormal? They come along quite regularly, and as toneb says, the Nino was two years ago now. Why are Nino’s abnormal, and Nina’s not? When would you ever get “clean data”? Suppose you stopped in 2014. That would be less than two years after a big La Nina.

          • Nick, skeptics were making the same dopey argument that you’re making a decade ago with the ’08 la nina. Wait for the transient event to come & (completely) go and then see what happens. That’ll give us a better picture of where things are headed and a better picture of just how well hansen did, too. So, kick back, relax and smoke a doobie. (’cause not a one of us is going anywhere for a while)…

          • “Nick, skeptics were making the same dopey argument”
            Of course, all the noise about the “pause” was just about a couple of La Nina’s. But I don’t recall any scientists claiming that they weren’t somehow part of the record. The fact is that Hansen predicted based on trace gas forcings. Any such prediction was always going to get knocked around by ENSO events. It looked too warm with the La Ninas, and the El Nino made it look right again. No doubt something else will happen (the forecast runs to 2019).

          • Ahhh, yes, Salvatore who has been consistently predicting global cooling since 2011 and been proven wrong every single time.

          • Using an abnormal event to anchor one side of your data trend is dishonest.
            Isn’t that what Monckton did to come up with his ‘Pause’?

    • Since the last year has been ENSO neutral there shouldn’t be anything to add and since the effect of the volcanoes was less than 2 years nothing to remove.

  10. So exvept for Hasen being an alarmist kook, and like alarmists throughout history wrong, it eas not so bad.

    Alarmist:
    “a·larm·ist
    əˈlärməst/
    noun
    1. someone who is considered to be exaggerating a danger and so causing needless worry or panic.”
    ie, see “climate consensus, esp. James Hansen

  11. This all hypothesises a causal rather than effect relationship between CO2 and temperature, with no actual proof, and can only be wangled to correlate by a model which amplifies small possible CO2 effect using the larger water vapour effect to increase the overall system’s “sensitivity” to CO2, per his and IPCC assumptions.

    The fact of the natural record suggests clouds are the planet’s principal Gaia and what ends the relatively dramatic ice age end of interglacial temperature rises of several degrees in only 7Ka, with increased cloud formation removing heat from the planet’s surface with cloud and precipitation, and reducing incoming solar heating of the surface by reflection/albedo.

    If the models were correct the in the largest and mots recent perturbations we have natural data on, the interglacial events, interglacial warmings would become runaway catastrophes as CO2 is released from the warming oceans a few hundred years AFTER warming starts, by whatever actually causes interglacial ocean warming. And Earth would boil dry. as Venus 2.0. Yje opposite happens, 180 degree opposite.

    In fact the interglacial warming consistently ends suddenly, while atmospheric CO2 is still increasing. The assumptions of IPCC regarding water vapour feedback to somehow amplify the effect of CO2 appear to be 180 degrees out of phase and are clearly denied by natural fact of the temperature and CO2 records, probably in the form of clouds that reduce warming due to oceanic evaporation.

    I would suggest the primary stabilising Gaia effect is clouds from the dominant heat sink of the oceans, a smart lagging system which sets limits of a few degrees between which the system oscillates, between warm interglacials and longer cold ice ages, repeatedly and consistently in amplitude and period.

    A very dominant and self evident control of such a complex system within c.300 degrees Kelvin range, I suggest.

    Our oceanic and atmospheric smart lagging has proven well up to the job of planetary control under significant perturbation, CO2 appears to play very small part in this and any significant warming effect is in fact in a negative feedback relationship with water vapour, so humans can have little to no effect upon these dominant natural cycles with increased CO2 at least. I suggest CO2 is self evidently innocent of causing significant or catastrophic warming of the atmosphere, and the clouds have our backs, on the hard and very significant evidence of interglacial events. .Discuss.

  12. Hansen is close but for the wrong reason. It was natural factors in my opinion that have caused the warming and these same natural factors which caused the warming at least to the end of 2005 have turned and the climatic trends from 2018 on should be down.

    The only way El NINO,VOLCANIC ACTIVITY become relative is if they are tied to the underlying theory. For example if HANSEN said he expected more EL NINO’S and less VOLCANIC activity tied into his AGW theory then they would be relevant.

    Now however we have a simple but telling climate test which is low solar (cooling) versus increasing CO2 (warming).

    I say very low solar(moderated by the geo magnetic field) will result in lower overall sea surface temperatures (which is the trend for the last year in particularly the North Atlantic) and a slight uptick in albedo due to increasing major volcanic activity ,increasing global cloud /snow coverage.

    I also say now – over the next few years will show which thoughts about the climate are correct and which ones are not. The data will lead the way. I go by data to see what may be or not be correct..

  13. Did President Eisenhower forecast the current problem with climate science. from his fairwell address:

    Akin to, and largely responsible for the sweeping changes in our industrial-military posture, has been the technological revolution during recent decades.

    In this revolution, research has become central, it also becomes more formalized, complex, and costly. A steadily increasing share is conducted for, by, or at the direction of, the Federal government.

    The prospect of domination of the nation’s scholars by Federal employment, project allocation, and the power of money is ever present and is gravely to be regarded.

    Yet in holding scientific discovery in respect, as we should, we must also be alert to the equal and opposite danger that public policy could itself become the captive of a scientific-technological elite.

  14. Note that Scenarios A and B also represent upper and lower bounds for non-CO2 forcing as well, since Scenario A contains all trace gas effects and Scenario B contains none.

    This is not true the authors need to reread the original paper they have misunderstood the scenarios.

    • Nick pointed out the error that McKitrick and Christie made and they have updated the original post at Curry’s site accordingly. They still haven’t got it quite right and haven’t changed their subsequent comments but isn’t as egregiously wrong as it was before.
      MODS: In light of this shouldn’t a change be made to the extract in the head post?

      • Revision to McK and C post
        Note: this is a revised version to correct the statement about CFCs and methane in Scenario B.

        Note that Scenarios A and B also differ in their inclusion of non-CO2 forcing as well. Scenario A contains all non-CO2 trace gas effects and Scenario B contains only CFCs and methane, both of which were overestimated. Consequently, there is no justification for a post-hoc dialling down of the CO2 gas levels; nor should we dial down the associated forcing, since that is part of the model computation. To the extent the warming trend mismatch is attributed entirely to the overestimated levels of CFC and methane, that will imply that they are very influential in the model.

        While an improvement on their original statement, which as Nick and I pointed out was incorrect, it still indicates they don’t understand the paper (or didn’t read it). A includes some more trace gases, B and C include N2O as well. The CFCs and methane (and N2O) were not just ‘overestimated’ they followed scenario C, in that they underwent a ‘drastic curtailment’. Nick has shown their trajectories above.
        The statement that the results ‘imply’ that the other trace gases ‘are very influential in the model’, ‘implies’ that the authors hadn’t read the paper because Hansen’s forcing graph ‘explicitly’ shows that!

        Hansen added in an Agung-strength volcanic event in Scenarios B and C in 2015, which caused the temperatures to drop well below trend, with the effect persisting into 2017. This was not a forecast, it was just an arbitrary guess, and no such volcano occurred.

        Hansen added three such volcanoes in B & C to match the active period from 63-88 (95, 15 & 25), no mention of Pinatubo in 91 by McK & C.
        They appear not to have understood the reasoning behind the inclusion (and omission in A).

        Thus, to make an apples-to-apples comparison, we should remove the 2015 volcanic cooling from Scenarios B and C and add the 2015/16 El Nino warming to all three Scenarios. If we do that, there would be a large mismatch as of 2017 in both A and B.

        Since the volcanic eruption effects only lasted 2 years and the forcing in B & C had returned to normal there would be nothing to remove in 2017 and by 2017 we were ENSO neutral so nothing to add.

        The main forecast in Hansen’s paper was a trend, not a particular temperature level. To assess his forecasts properly we need to compare his predicted trends against subsequent observations. To do this we digitized the annual data from his Figure 3. We focus on the period from 1982 to 2017 which covers the entire CO2 forecast interval.

        So, the scenario that matches the observations most closely over the post-1980 interval is C. Hypothesis testing (using the VF method) shows that Scenarios A and B significantly over-predict the warming trend (even ignoring the El Nino and volcano effects). Emphasising the point here: Scenario A overstates CO2 and other greenhouse gas growth and rejects against the observations; Scenario B slightly understates CO2 growth, overstates methane and CFCs and zeroes-out other greenhouse gas growth, and it too significantly overstates the warming.

        The trend in Scenario C does not reject against the observed data, in fact the two are about equal. But this is the one that left out the rise of all greenhouse gases after 2000. The observed CO2 level reached 368 ppm in 1999 and continued going up thereafter to 407 ppm in 2017. The Scenario C CO2 level reached 368 ppm in 2000 but remained fixed thereafter. Yet this scenario ended up with a warming trend most like the real world.

        Because as indicated in Hansen the ‘other trace gases’ contributed about half the forcing and since they actually followed scenario C and CO2 was slightly above B the expectation would be that the trend would fall between B & C, which it did. Scenario B does not “zero-out other greenhouse gas growth”, they seem to be mixing up B & C. McK & C’s bias to only consider CO2 leads them to completely misunderstand the results. This was actually realized by McIntyre about 10 years ago.

  15. https://www.skepticalscience.com/30-years-later-deniers-lying-hansen-88.html#commenthead

    Over at Skeptical Science –
    “30 years later, deniers are still lying about Hansen’s amazing global warming prediction”
    “Scenario B from Hansen’s 1988 paper, with the trend reduced by 27% to reflect the actual radiative forcing from 1984 to 2017, compared to global surface temperature data from Cowtan & Way”

    Summary – Skeptical Science states that if Scenario B was reduced by 27% , then Hansen’s scenario B is spot on.

    If we change the prediction to what actually happened, then the prediction is prefect.

    Climate Science – The last frontier

    • Joe: Those scenarios were not predictions. They were projections.

      Hansen’s goal was to create a model of the climate system’s responses to the forcings of climate (human caused forcings and natural forcings). His purpose was to provide a tool for people to explore the consequences of making choices that affect greenhouse gas concentrations in the atmosphere.

      An analogy of Hansen’s climate model is the computerized navigation tool you use–let’s say Google Maps. Google Maps is a model of transit. That model is a tool for you to explore the consequences of making choices that affect your arrival time at your destination. Google Maps does not predict when you will depart. Instead, Google Maps takes your departure time as input to its model, similarly to Hansen’s climate model taking greenhouse gas concentrations at a given time as inputs. Google Maps uses that input of your departure time to estimate your arrival time, similar to Hansen’s climate model using those inputs of greenhouse gas concentrations to estimate temperature at that time.

      If you are unsure when you want to depart, you input possible departure times to Google Maps and see what the resulting arrival time estimates are. Let’s say you are interested in departing sometime within a two hour window, because you don’t yet know when your traveling companions will be ready to depart, and they are notoriously unreliable. You’re not going to spend the time to run Google Maps separately for each individual possible departure minute. Instead you will input just a few departure times, spanning that two-hour window. Each of your input departure times is a “scenario” of your departure and travel.

      Hansen’s challenge was far worse; it was physically impossible to run his model for every possible set of greenhouse gas concentrations at every moment of time, plus every possible set of volcanic eruptions, solar intensities, and other natural forcings. So Hansen input just three sets of gas concentrations, volcanic eruptions, and so on, spanning what seemed to be a reasonably possible range.

      Suppose you departed within your two hour window, but not at any of the exact times you input to Google Maps, because your traveling companions were not ready to depart when they agreed to. You don’t blame Google Maps for failing to “predict” your departure time, because Google Maps is not a model of your decision of when to depart; Google Maps merely “predicts” your arrival time under the assumption of your departure time–an assumption you explicitly made. Google Maps produced not “predictions” of your arrival time, but “projections” based on assumptions that you knew were uncertain. It makes no sense to blame yourself either, because your knowledge of your companions’ readiness to depart was unavoidably uncertain. You could evaluate Google Maps’s projection skill by inputting your actual departure time and seeing how well the output matched your actual arrival time. But since Google does not let you enter departure times in the past, you could instead mathematically estimate in between the bracketing scenarios you did input.

      Similarly, greenhouse gas concentrations did not exactly match the ones Hansen input to his model. It makes no sense to blame Hansen’s model for failing to “predict” greenhouse gas concentrations, because those were mere inputs to the model. It makes no sense to blame Hansen either, because his knowledge of future greenhouse gas emissions, volcanic eruptions, and so on was unavoidably uncertain. You could evaluate Hansen’s model’s skill by rerunning it with inputs of the forcings that actually occurred in the world. His model’s code has been publicly available for many years, but nobody has rerun it with those inputs, because it’s not worth the effort when it’s much much easier and nearly as accurate to mathematically rescale the outputs.

      Google Maps was useful to you despite the arrival times it projected differing from your actual arrival time. That’s because the scenarios you input to Google Maps bracketed the actual scenario that occurred, so you knew that as long as you left within your two hour window you would arrive before the restaurant closed. If instead Google Maps told you that the restaurant would be closed before your arrival unless you left within the first 15 minutes of your two hour departure window, you could have used that projection to decide to go without your dining companion, or heat up leftovers at home.

      Similarly, Hansen’s model was useful despite the temperatures it projected differing from the actual temperatures. That’s because the scenarios Hansen input to his model bracketed the actual scenario that occurred. That information was, and is, useful by informing us of the consequences of a range of decisions we make.

      • prediction – projection – granted I used the terms generically – that being said, Skeptical science adjusted scenario B downward 27% so that it would match the real temps, and then it only matched the real temps because of the 2016 el nino spurt. Not so much of a match so far in 2018 as the el nino spurt has mellowed.

        • Joe, you either did not read my explanation to you, or you did not understand it. Neither Skeptical Science nor anyone else adjusted Scenario B. Instead, a number of people have calculated the actual forcing scenario that really occurred, and which differed from all three of Hansen’s scenarios. That is the equivalent of entering your actual departure time into Google Maps. Then those people calculated the temperature output that Hansen’s model would have produced from that actual scenario, and discovered that it is a close match to the actual temperatures that really happened. That is the equivalent of running Google Maps with your actual departure time to see the output arrival time.

          As for your claim about the 2016 El Nino, see the multiple comments above, including mine, explaining why you are completely wrong.

          • yes I did read your explanation – They adjusted the projection based on various forcings. The primary difference in A B & C was the forcing from GHG’s, which A most closely resembles actual, They then adjusted the less dominant forcings (to imply that those were the more dominant forcings) in B down 27% to get a match.

            “As for your claim about the 2016 El Nino, see the multiple comments above, including mine, explaining why you are completely wrong.”

            Not So – We agree that cycle/oscillation of the el nino and la nino should somewhat cancel each other out such that the general warming trend should flow through the middle that oscillation. However, the crest of the el nino’s are what is matching the projection in scenario B.

        • No, the reduction was in the forcing caused by the GHGs to allow for the fact that all but CO2 (which followed B) followed C. Then using that forcing which corresponded to the actual GHG which resulted recalculate the temperature.

  16. Hansen should be prosecuted for the false prophecy disguised as a science.
    As a hardcore environmental activist he has foregone his objectivity and credibility as a scientist.

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