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Cherrypicking to Deny Continued Ocean and Global Warming

Posted on 6 March 2013 by dana1981

Cherrypicking global surface air temperatures is one of the most common errors associated with global warming.  In reality, a very small percentage of overall global warming goes into heating surface air temperatures, while approxiately 90% is absorbed by the world's oceans (in totality, at all depths).  Because many other factors influence surface air temperatures on short timescales, the data are noisy, and as a result it's easy to cherrypick temporary flat periods to wrongly claim that global warming has stopped (Figure 1).


Figure 1: Average of NASA GISS, NOAA NCDC, and HadCRUT4 monthly global surface temperature anomalies from January 1970 through November 2012 (green) with linear trends applied to the timeframes Jan '70 - Oct '77, Apr '77 - Dec '86, Sep '87 - Nov '96, Jun '97 - Dec '02, and Nov '02 - Nov '12.

However, climate contrarians are now more frequently shifting their cherrypicks to the relatively shallow layer of the oceans (the upper 700 meters).  The average depth of the world's ocean is nearly 4,000 meters, but the deeper the ocean layer, the more difficult it is to measure its temperature and heat accumulation. 

Fortunately most ocean heat accumulation occurs close to the surface, but accounting for less of the deep ocean layers also means missing more global warming.  The best ocean heat measurements are for the 0–700 meter layer, which accounts for over 60% of overall global warming.  However, only considering ocean heat accumulation to 700 meters also means neglecting 30–40% of overall global warming.

Similar to surface air temperatures, the warming of the 0–700 meter oceans has slowed in recent years (since about 2003), which has made them a ripe candidate for cherrypicking.  This was one of the key findings of Nuccitelli et al. (2012), in which we noted that while heat accumulation in the 0–700 meter oceans has slowed in recent years, at the same time it has accelerated in the 700–2,000 meter oceans. 

Overall, there is no sign that the warming of the 0–2,000 meter oceans has slowed; in fact, they have accumulated more heat in the past 15 years than during the previous 15 years (Figure 2).


Figure 2: Comparison of Ocean Heat Content 0–700 meter layer vs. 0–2,000 meters layer, from the National Oceanographic Data Center.

It should be no surprise that climate contrarians constantly ignore the accelerated warming of the 700–2,000 meter oceans, pretending that they simply don't exist.  In one recent example, a denialist blog disputed the results of Nuccitelli et al. (2012) by showing Figure 3 below (also discussed in this post by Tamino at the Open Mind blog).

Watts OHC denial cherries

Figure 3: 0–700 meter ocean heat accumulation from NOAA PMEL using the methodology described in Lyman et al. (2010), with an arbitrary yellow line drawn in an effort to indicate slowed ocean warming.

The ocean heat content data used in Nuccitelli et al. (2012) and Figure 2 above are from the National Oceanic and Atmospheric Administration (NOAA) National Oceanographic Data Center (NODC) using the methodology described by Levitus et al. (2012), whereas the data in Figure 3 are from the NOAA Pacific Marine Environmental Laboratory (PMEL) using the methodology described in Lyman et al. (2010).

The Levitus methodology fills data gaps with the averaged value of the available data, which has the tendency to underestimate any anomalies.  The Lyman methodology infills the data gaps with anomalies from nearby grids.  The end result is that Levitus is likely to underestimate any warming trend, as discussed in Lyman (2008).  As a result, the data plotted on the denialist blog actually shows more 0–700 meter ocean warming than the data plotted in Nuccitelli et al. (2012).  This is illustrated in Figure 4.

OHC cherries

Figure 4: 0–700 meter ocean heat content data from NOAA NODC (Levitus) and NOAA PMEL (Lyman) using the same baseline.  The yellow arbitrary denialist line is shown, followed by the linear trends for 2003–2012 and 1993–2012 in red.  Standard error bars are also shown.

Despite showing a larger ocean warming trend than Levitus, climate contrarians likely prefer the Lyman data because it does not include the ocean layers below 700 meters.  However, even if we cherrypick this shallow ocean data and cherrypick 2003 as the starting point, the 0–700 meter ocean heat accumulation for 2003–2012 in the Lyman PMEL data is equivalent to 1.2 Hiroshima atomic bomb detonations per second over the past decade.  For 1993–2012, this rate increases to the equivalent of 3.7 detonations per second, and when including global heat accumulation in Nuccitelli et al. (2012) including the 0–2,000 meter oceans, the Earth has accumulated the equivalent of 4 Hiroshima atomic bomb detonations per second over the past decade.

When we consider all the available data, it becomes quite clear that ocean and global warming continue unabated at a rapid rate.  Cherrypicking cannot change that reality.

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Comments 101 to 109 out of 109:

  1. scaddenp'

    Thanks, Fig. 1 in Levitus makes it clear.

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  2. Every time I try to review information on  this site, I always come away with the sad feeling that 100% of the data interpretations that might lead to some conclusion other than anthropogenic CO2 caused Global warming are wrong. That can't be.

    Both sides do have legitimate scientists on them (more on the CO2-is-the-ogre side), but there is no legitimate way that every statement that either side makes can be wrong.  (-snip-).

    When it comes to the escalator effect, different data sets show somewhat different effect.  The GISS data that I have seen seems to show a steady average Global T from 1970 to the early 1990's,  a substantial step from the early 90's to the early 2000's and a relatively steady average from then until now.

    No question we are hotter now than in the 1970's (when climatologists were predicting a coming ice age), but the monotonic correlation with CO2 does not correlate, except over a long term. 

    If we assume that the CO2 driver is the main driver in the background, where is the analysis of all other factors that cause no net temperature climb over these relatively flat periods with step changes when the sub-drivers stop neutralizing the CO2 effect. (-snip-).

    Have any of the models predicted this stair-step climb of temperature?  If none do, then maybe they are missing a driver or incorrectly including it.

    Is there any Experimernt, or any observation, that could occur that might lead the "settled science" folks to say, "We should look at that. We might be wrong".  If there is nothing that can ever prove that your theory is wrong, than it is not a scientific theory. it is just a belief.

    Some day I would like to see a fair and balanced discussion on data linking CO2 to warming and on alternative potential drivers to global warming, rather than this constant barrage of why the other guys are 100% wrong?

    David J Matz, PH.D

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    Moderator Response:

    [DB] In order to make best usage of what this site has to offer, you need to use the Taxonomic listing of arguments and the Search Function (located in the UL section of every page).  Discussions of the intricacies you express interest in are best conducted on those specific threads.

    For example, your claims about data interpretations might be answered by reviewing the Big Picture article and following the links as needed from there.

    Discussions of the Escalator and its permutations are best done here.

    For CO2:temperature correlations, see here.

    CO2 is not the only driver of climate

    Models are not necessarily as unreliable as you think

    As for your theory vs belief, I will place a separate comment about that, as a proper response lies outside the aegis of this function.

    Off-topic/sloganeering snipped.

  3. matzdj, are you saddened by the overwhelming evidence that gravity exists?  I don't know what field your PhD is in, but in science part of the definition of "progress" is that intentionally varied evidence converges on a picture of reality, because reality constrains the evidence.  Scientists are motivated to show that all other scientists are wrong--that the consensus is incorrect--because that path leads to fame and personal pride and a feeling of accomplishment and contribution.  So scientists leap on evidence that appears to contradict the consensus.  But reality always eventually wins, as apparently contradictory evidence is refined until it reveals the truth.

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  4. matzdj: The point of this site is that there is a huge amount of misinformation concerning climate.

    While to a casual observer it may look as though there are two balanced sides both arguing that the other is wrong, if you spend a little time comparing secondary sources against primary sources, I think you will very quickly spot a pattern and be able to draw some conclusions about what is going on. As a starting point, let me pick a couple of examples from your post:

    No question we are hotter now than in the 1970's (when climatologists were predicting a coming ice age)

    What is the basis for your belief that climatologists were predicting an ice age in theh 70's? Is there documentary evidence? Was it a widespread view?

    but the monotonic correlation with CO2 does not correlate, except over a long term.

    Does climate science predict a correlation with CO2 over the short term, or are the other factors which can affect short term trends? Do we know what these are?

    Have any of the models predicted this stair-step climb of temperature? If none do, then maybe they are missing a driver or incorrectly including it.

    Good question. Have you attempted to answer it? ('Hiatus decade' may be a useful search term if you are stuck.)

    Is there any Experimernt, or any observation, that could occur that might lead the "settled science" folks to say, "We should look at that. We might be wrong".

    Plenty. Here's just one to start with: If the Earth's IR spectrum as observed from space did not show CO2 absorbtion lines which broaden as we increase the CO2 concentration in the atmosphere, we would throw out climate science straight away.

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  5. Occasionally, scientific ideas (such as biological evolution) are written off with the putdown "it's just a theory." This slur is misleading and conflates two separate meanings of the word theory: in common usage, the word theory means just a hunch, but in science, a theory is a powerful explanation for a broad set of observations. To be accepted by the scientific community, a theory (in the scientific sense of the word) must be strongly supported by many different lines of evidence. So biological evolution is a theory (it is a well-supported, widely accepted, and powerful explanation for the diversity of life on Earth), but it is not "just" a theory.

    Words with both technical and everyday meanings often cause confusion. Even scientists sometimes use the word theory when they really mean hypothesis or even just a hunch. Many technical fields have similar vocabulary problems — for example, both the terms work in physics and ego in psychology have specific meanings in their technical fields that differ from their common uses. However, context and a little background knowledge are usually sufficient to figure out which meaning is intended.

    Below is a generalized sequence of steps taken to establish a scientific theory:

    1. Choose and define the natural phenomenon that you want to figure out and explain.
    2. Collect information (data) about this phenomena by going where the phenomena occur and making observations. Or, try to replicate this phenomena by means of a test (experiment) under controlled conditions (usually in a laboratory) that eliminates interference's from environmental conditions.
    3. After collecting a lot of data, look for patterns in the data. Attempt to explain these patterns by making a provisional explanation, called a hypothesis.
    4. Test the hypothesis by collecting more data to see if the hypothesis continues to show the assumed pattern. If the data does not support the hypothesis, it must be changed, or rejected in favor of a better one. In collecting data, one must NOT ignore data that contradicts the hypothesis in favor of only supportive data. (That is called "cherry-picking" and is commonly used by pseudo-scientists attempting to scam people unfamiliar with the scientific method. A good example of this fraud is shown by the so-called "creationists," who start out with a pre-conceived conclusion - a geologically young, 6,000 year old earth, and then cherry-pick only evidence that supports their views, while ignoring or rejecting overwhelming evidence of a much older earth.)
    5. If a refined hypothesis survives all attacks on it and is the best existing explanation for a particular phenomenon, it is then elevated to the status of a theory.
    6. A theory is subject to modification and even rejection if there is overwhelming evidence that disproves it and/or supports another, better theory. Therefore, a theory is not an eternal or perpetual truth.

    For a good discussion of science terminology (especially for the "Evidence, not Proof" bit), see here:

    And speaking of NASA again:

    Which brings us full-circle to matzdj's comment sparking this line of discussion: anthropogenic climate change (ACC)/anthropogenic global warming (AGW) is indeed a theory. In reality, the National Academies of Science refer to it as "settled fact" instead of a scientific theory.

    Per the National Academies of Science, in their 2010 publication Advancing The Science Of Climate Change (pp 44-45):

    "Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small.

    Such conclusions and theories are then regarded as settled facts.

    This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities."

    And note that the above National Academies paper is available for free download after a free registration. No purchase necessary. And the quote is from pages 44 & 45.


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  6. @ matzdj

    About that 1970s ice age prediction:

    This meme stems originally from a 1971 Rasool and Schneider study, which was predicated on a quadrupling of aerosol emissions; this possible pathway never happened.

    Emissions actually went the opposite trajectory due to the establishment of the EPA and the Clean Water Act in 1970, the Vienna Convention on the Protection of the Ozone Layer of 1985, the The Montreal Protocol on Substances that Deplete the Ozone Layer of 1987 and the Clean Air Act of 1990.

    The meme originates with a 1974 Time article and a 1975 Newsweek report.

    However, those are media articles, not scientific studies. A survey of peer reviewed scientific papers from 1965 to 1979 show that few papers predicted global cooling (7 in total). Significantly more papers (42 in total) predicted global warming (Peterson 2008). The large majority of climate research in the 1970s predicted the Earth would warm as a consequence of CO2. Rather than 1970s scientists predicting cooling, the opposite is the case.

    So only the alarmists still perpetuate the "70s Ice Age" meme, FYI.

    Please do a better job of staying on-topic in this thread; thanks.

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  7. matzdj wrote: "Both sides do have legitimate scientists on them (more on the CO2-is-the-ogre side), but there is no legitimate way that every statement that either side makes can be wrong."

    Actually, I am not aware of any "legitimate scientists" who disagree that a doubling of atmospheric CO2 levels would (by itself without feedbacks) cause a little over 1 C of warming. The evidence on that became overwhelming decades ago. Rather, the handful of 'skeptics' claim that undefined negative feedback effects will reduce this warming (and the known positive feedbacks) and that the observations of warming in line with rising CO2 over the past century must therefor have been caused by some other undefined factor. That's getting sufficiently implausible to start straining the "legitimate" scientist label on its own, but that is the extent of current disagreement. No one disputes the CO2 greenhouse effect except non-scientists whose views have no foundation in reality... and which therefor can indeed 'always be wrong'.

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  8. CBDunkerson @107.

    You appear to be setting far higher standards for a "legitimate scientists" label than I would accept. Consider a scientist like say Lindzen who genuinely believes in his unorthodox scientific position despite the overwhelming evidence supporting the orthodox position. He will not balk at challenging that evidence, would not think twice at throwing light into dark corners that other scientists who accepts the veracity of the available evidence would never dream to disturb. While those dark corners continue to exist, the likes of Lindzen continue to do science a service, of sorts.
    For instance, take Spencer & Bradwell 2008. Is this not legitimate science produced by a contrarian?

    The problem with the likes of Lindzen & Spencer is not the science. It is their behavour ouside the science that is unacceptable, things like Lindzen's presentations to non-scientific audiences in which he makes assertions he would never get away with within the science. The same goes with Spencer's book.
    This extra-scientific comment from contrarians is part of the fuel for opinions like that presented by matzdj @102. 100% of the evidence supports AGW? "That can't be," writes matzdj.
    Well surely, if AGW is the correct theory, bar the science misinterpreting evidence (available evidence won't always and unfailingly point in exactly the correct direction), I say, "It can be. Indeed, it must be!"

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  9. MA Rodger,

    I don't think Lindzen and Spencer disagree that "a doubling of atmospheric CO2 levels would (by itself without feedbacks) cause a little over 1 C of warming". Spencer has even posted articles trying to "educate" the less-informed "skeptics" on the reality of the greenhouse effect. As CBDunkerson said, they rely on "undefined negative feedbacks" to support their beliefs in a low CS.

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