Prev  1  2  3  

Comments 101 to 112 out of 112:

101. Albatross at 13:01 PM on 20 May, 2011
     Michael @100, Re aerosols, yes, that is why it is so very unfortunate that the the Glory satellite did not make it into orbit a few months ago. That would have been an invaluable mission.
     0 0
102. Daniel Bailey at 13:32 PM on 20 May, 2011
     @ Albatross Hansen has a great deal to say about aerosols as a negative forcing in his book Storms of My Grandchildren (Pgs. 98-99). Without aerosols, net forcing is about 3 watts (W m²). Aerosols have a forcing of 0 to -3 watts, with a most likely value of -1 watt, thus reducing net forcing to 2 watts. Thus, aerosol cooling might be masking about one-third the greenhouse forcing. But if aerosol forcing is -2 watts, reducing the net forcing to 1 watt, then aerosols have been masking most of the warming. Further cleaning up the air would then result in a doubling of the net climate forcing from what we've been observing. Hence his labeling of our GHG/aerosol emissions as a "Faustian Bargain".
     0 0
103. angusmac at 15:53 PM on 20 May, 2011
     @97 to 99, I am aware that Scenario C emissions have been significantly lower than real-world emissions since 2000. Therefore, Scenario C temperature projections should be below observed temperatures but this is obviously not the case. Real-world temperatures track Scenario C very closely from 1958 to present. Coincidence? Perhaps.

     Dana addressed this problem with his 2.7°C sensitivity Scenario D and achieved good results. However, this change is not "minor". It has resulted in the 2019 temperature projections plummeting from 1.57°C/1.10°C in Hansen (1988) to 0.69°C in Dana (2011).

     This is a dramatic drop of either 0.88°C or 0.41°C depending on which version of Hansen 1988 you prefer.

     0 0
104. angusmac at 15:54 PM on 20 May, 2011
     @100 to 102, I do agree that aerosols could turn out to be a "Faustian Bargain". I also agree that they would probably be a temporary blip similar to Schmidt's 1940s aerosol blip.

     The use of aerosols was my suggestion for getting Scenario B to work if you wished to use a sensitivity greater than the 2.7°C used in Dana's Scenario D.

     0 0
105. Albatross at 02:09 AM on 21 May, 2011
     Angus @103, "Therefore, Scenario C temperature projections should be below observed temperatures but this is obviously not the case. " For crying out loud Angus, the reason for this has been explained to you ad nauseum. One really has to wonder if you are being deliberately obtuse on this point, or repeatedly repeating a falsehood in the hopes that is becomes true. Scenario C is relatively close to observations (for now at least) because of because of two errors: too low emissions run used as input into a climate model with too high a sensitivity (~4.2 C for doubling CO2). Instead of accepting the fact that Lindzen's hypothesis is woefully wrong and cannot explain the observed warming (the point of the post), you seem to be doing everything you can to convince yourself that equilibrium sensitivity is not near +3 C for doubling CO2. Two quotes for you to think about: "Beware those who deride predictive science in its entirety, for they are also making a prediction: that we have nothing to worry about. And above all, do not shoot the messenger, for this is the coward’s way out of openly and honestly confronting the problem" [Dr. Kerry Emmanuel] "Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence." [John Adams]
     0 0
106. angusmac at 16:43 PM on 21 May, 2011
     Albatross@104, I totally agree with your quotations, especially John Adams regarding facts.

     Regarding your statement that I am trying to convince myself that "equilibrium sensitivity in not near +3°C." This is patently untrue. I stated @81 and @103 that Dana's Scenario D with a sensitivity of 2.7°C gives good results.

     I fully understand your "ad nauseum" reasoning that two errors may be cancelling each other out to give the correct answers in Scenario C. This is why I suggested Hansen's aerosol strategy to correct Scenario B. I am willing to wait for a few years (but not ad infinitum) to determine if real-world temperatures will start to follow real-world emissions again or if they will continue to bump along the commitment trajectory. The date of 2015 suggested by Hansen (2006) seems as good a time as any to determine which trajectory real-world emissions are following.

     You may wish to consider Sir Arthur Conan Doyle, "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."

     0 0
107. Michael Hauber at 09:07 AM on 23 May, 2011
     Thinking some more about the possibility that we are following scenario C due to an aerosol boom, I note that land temperatures have continued to rise in the last 10 years, and the gap between land and ocean temps has also increased. This suggests that even over the last 5 or so years external forcing is still firmly in warming mode, and that ocean variability has led to the current short term pause. And it would appear that Co2 forcing is high enough to completely offset any aerosol cooling due to any impact by China, and the solar minimum.
     0 0
108. Kevin C at 21:09 PM on 18 October, 2011
     Well, I read the links to see if Charlie A was right in this thread or not. This paragraph seems to be the relevant:

     Nor, he said, was the temperature data collected in a very systematic and uniform way prior to 1880, so comparisons often begin with temperatures around 1880. "The trouble is that the earlier data suggest that one is starting at what probably was an anomalous minimum near 1880. The entire record would more likely be saying that the rise is 0.1 degree plus or minus 0.3 degree."

     If I read that correctly, Lindzen is claiming that the reason the ITR shows warming from 1880 is that 1880 was a local minima. 'The entire record' seems to refer to a fictitious but accurate temperature record going back rather further. His suggestion is therefore that the early 19th C temperatures were rather warmer, and that warming relative to the long term average is therefore rather smaller. My reading may be wrong, but it does look to me as though Charlie has a point: The reconstruction of Lindzen does not reflect what Lindzen is actually saying. Lindzen's claims may be confused and bizarre, they certainly contradict multiple sources of data, but I don't think he is claiming what the graph shows. (Sorry)
     0 0
109. Bob Lacatena at 23:12 PM on 18 October, 2011
     Kevin, the text I find describing Lindzen's 1989 presentation goes on to say, after your quoted lines:

     He referred to MIT Professor Reginald Newell's work that suggests that between the 19th century and the present there appears to be no change in ocean surface temperatures. Moreover, the record for the 48 contiguous states shows no evidence for warming over the past century. "As far as the data goes, I would argue that we really don't have the basis for saying it's a half degree plus or minus 0.2. That is false use of science. What we have is data that says that maybe it occurs, but it's within the noise."

     Lindzen is clearly saying, here, that there has been no warming to speak of this century, and so his own baseline starts well below the actual warming we've seen, which is where Dana put it. It's Lindzen's prediction and Lindzen's interpretation of the observations that is being used. That Lindzen was so wildly in denial back in 1989 is his own fault and no one else's. Now some may consider this unfair, because Lindzen is being hit with a double whammy in his prediction, by both choosing a starting point far below reality (because he refused to believe there even was any warming) as well as choosing a climate sensitivity that precludes virtually any warming at all and in fact constrains everything within a very narrow range. So what Charlie A is really asking is that we excuse Lindzen's refusal in 1989 to accept the temperature record, and so now to let him hindcast himself back into reality... and then let his bad prediction go on from there, from a more accurate starting point (but one that was not a part of his very wrong 1989 view of the climate). As an aside, a discussion of Linzen's presentation from 1989 is a true Gish Gallop of unbelievable denial tripe. He was already laying the groundwork (a true climate pioneer!) of the denial arguments we see today. It's fun to see them in their early, less polished form. And it's overall pretty comical to read now, in 2011, knowing where things have gone, and what has and has not come to fruition since then.
     0 0
110. Kevin C at 00:52 AM on 19 October, 2011
     Oh yes, I see your point. (And I think you can also see how Charlie and I reached our conclusion?) Given the Lindzen's counterfactual picture of the temperature record, I guess Dana's line is as good as any. Sadly that's not a very satisfying criteria. I suppose presenting an ensemble of possible lines with Lindzen's gradient on the whole record might be more realistic, but that's ugly and arguably misleading too (and wouldn't fit on the graph for the new article). OK, I give up.
     0 0
111. JME at 04:26 AM on 8 May, 2017

     I clicked on the links to try to find Lindzen's temperature predictions shown in the figures, but they just led to some notes from a Mallove talk - no charts or data. Are those predictions published anywhere? If so, I think it would be very helpful. Thanks.

     0 0
112. Tom Curtis at 12:43 PM on 8 May, 2017

     JME @111, the relevant quotes are:

     1)

     "I personally feel that the likelihood over the next century of
     greenhouse warming reaching magnitudes comparable to natural variability seems small," he said. "And I certainly feel that there is time and need for research before making major policy decisions."

     2)

     "What does the temperature record already show about global
     warming? Do the data conclusively indicate about one-half degree centigrade (plus or minus 0.2 degree) global warming over the last century, as some proponents suggest? No, contends Professor Lindzen."

     3)

     "The trouble with many of these records," he said, "is that the
     corrections are of the order of the effects, and most of us know that when we're in that boat we need a long series and great care to derive a meaningful signal."

     4)

     "Nor, he said, was the temperature data collected in a very
     systematic and uniform way prior to 1880, so comparisons often begin with temperatures around 1880. "The trouble is that the earlier data suggest that one is starting at what probably was an anomalous minimum near 1880. The entire record would more likely be saying that the rise is 0.1 degree plus or minus 0.3 degree."

     From (4) you can project Lindzen's estimated trend temperature increase since about 1850.  Strictly for comparison purposes, this requires that you use either HadCRUTv4 of the Berkely Earth LOTI both of which extend back to 1850.  The GISTEMP LOTI only extends back to 1880, a time of which Lindzen says "... probably was an anomalous minimum ...".  Using a GISTEMP decadal or multidecadal average starting in 1880 to establish the baseline for Lindzen's predictions would underestimate his predicted temperature.  It also, however, overestimates his trend in that the 0.1 C rise is taken to be over a 30 year shorter interval.

     Further, for Lindzen to consider there to be an "anomalous minimum", he obviously considers there to be more natural variability (see (1)) than that generated by the ENSO cycle, plus volcanism and other short term effects.  That, however, is what is portrayed in the OP above.  Ergo, arguably the graph understates the prediction for global warming.

     To see to what extent this is true, I made a comparison between the Lindzen prediction and the BEST LOTI:

     

     Comparing this graph to those above, it appears that the errors made worked in Lindzen's favour.  That is primarilly because 1880 was not "...an anomalous minimum..." relative to 1850, contrary to Lindzen's claim.  Consequently the increased trend generated by using an 1880 start date brings the Lindzen prediction closer to observations than do the graphs above.  The only thing better for Lindzen in this more accurate comparison is the better fit with long term variability.  On the other hand, the complete failure to capture the continuation of the temperature trend from the 1970s to late 1980s by Lindzen makes his prediction absurd, if the overall under prediction of temperatures throughout the 20th century had not already.

     Lindzen commented on the observational record, saying:

     "Professor Lindzen cited many problems with the temperature
     records, an example being the representation of the Atlantic Ocean with only four island measurement sites. Urbanization also creates problems in interpreting the temperature record, he said. There is the problem of making corrections for the greater inherent warming over cities--in moving weather stations from a city to an outlying airport, for example."

     These were fair comments in 1989, when the GISS temperature record was based on meteorological stations only.  Now, however, the GISS LOTI and BEST LOTI include ship and bouy data for Sea Surface Temperatures.  What is more, BEST does not adjust for station moves, but rather treats any such move as resulting in a different station.  BEST also relies on far more meteorological stations than GISS even now, and certainly in comparison to the GISS product of 1989.

     Further, rather than "the corrections [being] of the order of the effects", as claimed by Lindzen in 1989, in the modern LOTI temperature series, the corrections reduce the effects:

     

     (See here)

     There is, therefore, no reason to doubt the essential accuracy of the modern observations.  Ergo, Lindzen was wrong - calamatously wrong, in his implied prediction of 1989.

     (Small note:  Lindzen predicts future warming as being small in terms of natural variability.  I took that to mean less than half of a standard deviation of the 1850-1950 temperature data, taken for the excercise as being entirely natural or nearly so.  That exagerates Lindzen's natural variability as anthropogenic forcing was a significant factor over that period.  Base on that yardstick, Lindzen's prediction for the trend from 1990-2100 is a trend of 0.008 C/decade, or 111% of his retrodiction of the observed trend from 1850-1989.  That is, his predicted trend rises by only 11% from his retrodicted trend.)

     0 0

Prev  1  2  3  

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.