Special Important Note:
Some of the analyses below were done specifically for this comment and thus have not had time for submission to the literature or would simply not be of interest due to the simple nature of the analysis. However, the key point regarding evidence that is used throughout the real world is simply “reproducibility” and so if the readers of this comment desire, I will be happy to submit the underlying time series so they can verify the comments I am making. In other words, I will be happy to informally follow the legal rules of “discovery” so that nothing mysterious is being offered (see next).
The temptation for some NCA authors is to dismiss evidence that directly contradicts the views presented here on human-causation by falling back on claims made by assessments such as the IPCC and/or restricting information to “peer-reviewed” literature of their own selection. I realize there is a range of views among the lead authors, but that range is narrow compared with the actual community and compared with what is offered by a critical look at the evidence. It is important to know that material in the NCA will be cross-examined by the informed public, by congressional investigations, by credentialed climate scientists, and very likely by professional legal experts.
In legal venues, the notion of “peer-review” (which the IPCC is not since Lead Authors were their own reviewers) is only a feature of a piece of information and does not accord it special rights or even the category of “admissible evidence.” In such venues, information presented that has known provenance and is reproducible and verifiable, counts as “admissible evidence” (which basically eliminates climate model output since there have been no engineering-level verifications of their veracity – i.e. vague statements of “fairly good agreement” don’t qualify.) The notion that because a finding appears in the IPCC should give it some gravitas, as some scientists believe, is not true if its conclusions can be contradicted by simple evidence. The information presented in my comments fits the description of admissible evidence (and actually has been presented in legal venues) and thus it behooves the NCA to address them directly in the text (and similar comments from others) or risk being found unresponsive to “admissible evidence” that contradicts the fundamental opinions presented in the NCA. Demonstrating that the NCA suppresses clear and reproducible evidence that contradicts its draft “Findings” is a quick way to destroy any default credibility one might have believed should be ascribed to the document. It will be interesting to see if the NCA has the fortitude to embrace and promote evidence that contradicts the assertions conceived in the IPCC.
That the global climate is “changing” is a simple statement of fact since as a non-linear dynamical system the “climate” (defined by any number of response variables) never reaches static equilibrium. Thus, each of its variables (i.e. temperature, precipitation, etc.) is constantly fluctuating over all time scales. This first claim is trivial being neither remarkable nor falsifiable (i.e. one can’t prove the climate is not changing in some way).
The next assertion, i.e. that in the past 50 years the change is due “primarily” to human activities, has not been proven. In other words the simple question, “Has natural variability been ruled out as the primary source of the change?” has nowhere been demonstrated by rigorous methods. The supporting statement regarding U.S. temperatures does not qualify as “proof” for two basic reasons among many others, (a) the statistical population size is woefully too small and (b) the reliance on climate model simulations is improper as these are shown to be significantly different from observations over the recent few decades – the very same decades being claimed as responding to human activities. [Note: Chapter 2 claims that “much” of the change of the last 50 years is due to humans, not “primarily” as in “Report Findings”. These two statements are not consistent with each other, nor has either been proven.]
For (a), a temporal population size of U.S. temperatures that begins in 1895 constitutes only a tiny portion of the history of climate of our nation. To make claims based on these specific 118 years of data (which suffer from issues discussed later) as representing a population large enough to make the further claim that a 50-year sample is somewhat outside of natural variability is not supported by standard statistical analyses nor by the evidence from larger populations.
Simply put, to make claims of unusual behavior, standard statistical techniques indicate one should have a population size of 30 independent values (or in this case: 30 50-year periods). For this claim therefore, the NCA requires 30x50, or 1500 years, not 118. The statistical statement in Point 1 (regarding U.S. temperatures) is analogous to flipping a coin, observing “heads”, then flipping it again and observing “tails” and claiming that the latter result is outside of the system’s natural capability. One can only make that claim if approximately 30 consecutive flips were “heads” with the final one being “tails” – in this case “tails” is statistically outside of the system’s natural simulations.
Fortunately, there are some fairly robust samples of useful variables that extend over 1000 years in the U.S. that bring to bear the appropriate statistical evidence that demonstrates current variations are within natural variability and therefore provide evidence that the “primarily” descriptor in Point 1 is ill-conceived, and indeed falsified.
Then too, reconstructions of the Mississippi Valley show similar, naturally-forced, megadroughts (Cook et al. 2010). Also in the early second millennium C.E. drought was so severe and protracted that the western plains were classified as a migrating-sand-dune ecosystem (i.e. a desert: Muhs 1985, Muhs and Holiday 1995, Schmeisser 2009). Summer heat accompanies such droughts, as demonstrated by the 1930s in the U.S., which would enhance desertification as documented in soil horizons containing aeolian sand in this region deposited during the most recent millennium.
What is demonstrated by this brief discussion is that the U.S. climate has been drier and hotter in the past (as shown by an appropriate statistical population) due to unforced natural variability during which time enhanced greenhouse gas forcing was non-existent. Such a span of time is the appropriate temporal population from which to test the variability of a sample element that is 50 years in length. Thus, without putting the recent 50 years in the context of the last 1000 or so years, the assertion of human causation cannot be statistically sustained, and indeed the evidence shows our current climate fits within the population’s parameters and is therefore not significant at all.
As to part (b) much of the “evidence” related to assertions presented in Point 1 is derived from the belief that climate model simulations are accurate enough to reproduce the current (and future) climate. This belief depends especially on the past 35 years during which the impact of increasing greenhouse gas emissions should be clearly evident in response variables such as atmospheric temperature. Since Point 1 begins with the generic “global climate” there is much that could be examined here, but I shall be brief.
The latest CMIP-5 climate model runs are now open to examination. Early studies, such as Santer et al. 2012 using 20 models, show that since 1979 the bulk atmosphere has warmed much less than models indicate. They found that for the global lower troposphere, the models on average warmed the Earth 1.9 times that of observations and for the mid-troposphere by a factor of 2.5. Through 2012, a larger set of CMIP-5 rcp8.5 models show an average global lower-tropospheric (mid-tropospheric) trend of +0.27 (+0.22) °C/decade warming due, primarily, to greenhouse gases. Observations indicate trends of +0.14 (+0.06) °C/decade (see my Figure 1 and upcoming BAMS State of the Climate), being considerably below the model simulations. [Note: because the comparison with observations ends in 2011 or 2012 the choice of rcp scenario (i.e. rcp4.5, rcp6.0, rcp8.5) is of no consequence as the differences in model simulations of these rcp scenarios occurs later in the 21st century.] These model vs. observation differences are significant and indicate models are likely too sensitive to greenhouse forcing and therefore are not particularly useful at ascribing the reason for recent changes – mainly because the models can’t reproduce the recent changes.
So, the conclusion here is that reliance on climate model simulations (which are shown here and elsewhere to be significantly different than observations) over the past third of a century in the most fundamental response variable (temperature) is improper. The model results have been falsified in terms of the large-scale, main response variable.
Report Finding Point 2: Some extreme weather and climate events have increased in recent decades, and there is new and stronger evidence that many of these increases are related to human activities.
A parenthetical comment is needed here. I realize the authors of this assessment are to varying degrees wedded to the notion that the second statement of Point 1 is correct even though it has not been proven to be so. Since it is relatively easy to demonstrate that Point 1 is unsupportable by objective tests, it is no surprise that some authors then seek to selectively discover “evidence” that can be fashioned to support the assertions without a rigorous and critical eye on the methodologies applied (i.e. conformational bias). This is an unfortunate consequence of the manner by which authors are selected for such assessments (by the government with its own vested political interest) and by the process in which the lead authors are anointed with overwhelming “review authority”, giving them the conflicted-position of judging comments contradictory to their own views.
What could possibly go wrong? This is where the policymakers desperately need a sanctioned “red-team” of credentialed scientists who have a different view, one grounded in hard-core data analysis, regarding the potential dangers and the clearly-evident benefits resulting from greenhouse gas emissions.
To continue, Point 2 is an assertion that rests on essentially little concrete evidence. “Some” events have increased. What does this mean – “most” have not increased? The time frame is further cherry-picked “in recent decades.” What does that mean? (evidently, it means only 50 years as I read the sub-point finding – for Pete’s sake, my own body is way older than that.) The evidence indicates that had the full length of the time series of the extreme events been examined, there would be no significant changes (i.e. floods, droughts, tornadoes, hurricanes – for example, Fig. 2.23 is completely dishonest by starting ~1970 and ending ~2005, etc.), and that for others, even in the “recent decades” there has been no change.
I shall repeat the statement that a sample size of 50 years is wholly inadequate to define changes in extremes. By their nature, extremes are rare, thus a short time series will obviously have a trend of one sign or the other. Think of it this way. With only 50 years of record and dealing with rare “extreme” events, simply by chance, half will have an upward trend and half a downward trend (though significance will likely be low for all.) So, one should have expected about half (i.e. “some”) of the extreme metrics to have risen for natural reasons only. Or, look at it this way. The 20th century produced a set of record values for any specific metric of interest. Simply by statistical properties we should expect about half of those records to be broken in the 21st century (a good number should already have been broken by now - 2013). In other words, the climate realizations of the 20th century in no way encompass all possible solutions to the potential outcomes of a non-linear climate system. We should expect, therefore, extreme events, unseen in our currently-small population of events, simply out of the natural chaos of the climate system. Extreme events have happened, are happening and will continue to happen. A rigorous testing of the frequency and intensity of extremes will yield no alarm (see next).
The inappropriate idea of cherry-picking short periods (i.e. order 50 years) for high and low temperature extremes was put to the test in my recent congressional testimony (un- rebutted) regarding the number of record high temperatures experienced in the central U.S. (AR, IL, IN, IA, KS, MO, NE, and OK) during the terrible drought of 2012. This testimony also exposed the disingenuousness of Meehl et al. 2009 (cited in the NCA many times) who conveniently began their time series after the heat waves of the 1930s. If the uninformed person were discussing the heat and dryness, but started the record only 50 years ago (i.e. 1962 or as Meehl et al. 2009 in 1951), then indeed 2012 was the worst (i.e. driest and hottest) in this region. However, by selecting stations with the longest period-of-record (at least 80 years) I demonstrated the folly of Meehl et al. showing that the number of record high temperatures in 2012 in these most-affected states was exceeded a number of times just since 1895. Thus 2012 was hot and dry in the central U.S., but not the worst and definitely not part of a trend. A similar study of west coast states (CA, OR and WA) indicated a noticeable lull in record high temperatures in recent decades.
The basic idea of my comment here is that a careful and methodical look at extremes indicates the extremes that people really care about are not increasing, but still happening. Figure 2.18 which seeks to support Point 2 misinforms the reader because all it says is the number of low temperature records has gone down faster than the number of high temperature records which has also declined. This is a good example of creating a plot to confirm a bias. In my Figure 4 one can see why the data, when presented properly, do not support Point 2. The number of TMax records in the decade 2001-10 ranks only 7th out of the 11 decades examined, i.e. hottest days are not becoming more frequent. However, when convoluting the message by choosing the metric of “ratio” as in Fig. 2.18, the very low number of record cold TMins is clearly what is driving the last decade with its small denominator. The divergence between record hi TMax and record lo TMin is not a signature of the enhanced greenhouse effect. Indeed, TMin is measured largely in a decoupled, shallow nocturnal boundary layer and thus does not represent the deep layer of the atmosphere, where greenhouse forcing is detected, as well as TMax.
This is an issue that has been largely unappreciated in the NCA. Minimum temperatures have clearly risen in the past 100 years (no argument there), and thus the number of low temperature records has decreased. Observational, theoretical and modeling studies however have demonstrated that changes in the surface and nocturnal boundary layer characteristics by human development will lead to warmer nighttime temperatures (e.g. Christy et al. 2009, McNider et al. 2012, and many others). Though not perfect, the daily maximum temperature is at least a better metric for capturing deep-layer atmospheric changes that may be related to enhanced greenhouse gas forcing. The use of minimum temperatures is therefore improper in attributing changes to greenhouse forcing and should not be used in assessments of this type without clearly stating the science about why these minima are rising. Thus Fig. 2.18 says more about the character of the human- altered surface than of the deep atmospheric response to greenhouse gases and hides a more interesting and honest picture about what is changing and why. As such, a phrase extending the current Point 2 would be “... human activities such as surface development.”
Report Finding Point 3 Human-induced climate change is projected to continue and accelerate significantly if emissions of heat-trapping gases continue to increase.
Point 3 relies entirely on the faith one has in climate model output. These models have been shown here and elsewhere to be inadequate for characterizing the real climate trajectory because they overwarm the atmosphere. Thus, this “Finding” is “true” in the “model world”, but cannot be assumed for the real world. The statement would be truer and much more informative for the nation if it was stated as “Human-induced climate change is projected by models shown to be critically deficient in characterizing the current climate to continue and accelerate significantly if emissions of heat-trapping gases continue to increase.” This is one way to be honest and transparent.
Report Finding Point 4 Impacts related to climate change are already evident in many sectors and are expected to become increasingly challenging across the nation throughout the century and beyond.
This is a bait-and-switch type of statement. That climate change occurs and has impact on society is a trivial truth. Climate will always be changing and therefore will always be impacting society. We know that the negative impacts of weather have been significantly reduced in the past century (in the face of alleged human-induced climate change) in essentially every pertinent metric, i.e. food availability and harvests, longevity, economic output, loss of life to weather disasters, etc. The vague statement “to become increasingly challenging” is meaningless.
Humans generate energy and emit CO2 because of the unquestioned and overwhelming benefits provided. Humans are not evil for doing so, they are actively reducing the effects of poverty, hunger, exposure, diseases, etc. by utilizing the almost miraculous characteristics of energy to fight these age-old enemies. Reduction of these human- killing effects is why carbon-based energy is sought and prized. This report is therefore appallingly incomplete without a direct assessment of the basic analysis of the profound benefits to human life, health and welfare that carbon-based energy provides the citizens of the U.S., i.e. answering the question, “What have we as a society gained through our CO2 emissions?” The answer includes a doubling of longevity, massive reduction in childhood mortality, enough food for everyone to afford, advances in medical care, etc. (not to mention an invigorated biosphere.) Quite remarkable when you think about it.
Associated with this question is the other side, “What are the human consequences from increased energy prices?” If energy costs rise, so does the price of everything. Answers include restricted energy availability, degraded human health and welfare, higher food, shelter and transportation costs, and other profoundly negative results. It is almost obvious that the “increasing challenges” of human existence will arise from making energy less affordable and less available, not from climate change. This is a first-order issue to address if this report seeks to understand the human dimension.
Since the remainder of the “Report Findings” assumes Point 1 is fact, there is no need to address the other points. My comments above regarding Points 1-4 are sufficient to treat the others as sub-points based on an ill-conceived assumption at the start. However, I will briefly address Table 1.1 for the Southeast.
Table 1.1 Southeast Decreased water availability, exacerbated by population growth and land-use change, is causing increased competition for water; risks associated with extreme events like hurricanes are increasing.
This statement is a classic case of trying to create the impression of alarm when there is nothing to say about climate change in the Southeast. The water provided by the climate of the SE is not decreasing and the number and intensity of hurricanes is not increasing. Thus, regarding the climate response to enhanced greenhouse gases, as the Table’s title claims “Observations of Climate Change”, there are no claims to be made. This statement merely says the population is growing and the normal impacts of that growth are being seen, (a) that water needs are increasing (though the SE consumes only about 2.5 percent of its available surface water while cities consume less water than forests) and (b) that more infrastructure is being built to get in the way of hurricanes. The Table’s claim in the box says nothing about the Table’s heading “Regional Observations of Climate Change.” Had the box addressed the actual truth of the matter the “Observations of Climate Change” would simply say, “nothing seems to be changing outside of the variations seen in the past century.” This is how to be honest and transparent.
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