President “Trump thinks scientists are split on climate change”… He’s right, Dana Nuccitelli is wrong

From Watts Up With That:

Guest rebuttal by David Middleton

Trump thinks scientists are split on climate change. So do most Americans

There’s a 97% expert consensus on human-caused global warming, but most Americans are unaware

Dana Nuccitelli

Mon 22 Oct 2018 06.00 EDT


The Guardian

Back around 2009, I “crossed swords” with Mr. Nuccitelli a few times in the Yahoo! Answers forum.  Dana is a smart guy and strikes me as a very decent person.  The last think I want is for him to be able to copy one or two words from my post and run whining to  the the New York Times and complain about civility; so I will make a concerted effort to not insult him in this post… But I just can’t resist this…


Dana… Mr. Data is laughing at you.

Scientists are very divided on climate change

Much of my rebuttal was put together from prior WUWT posts on this subject, there’s at least one new addition to the vast evidence of scientific division (Stenhouse et al., 2017).

Stenhouse et al., 2014   told us that atmospheric scientists are very divided on climate change over the past 150 years.

89% × 59% = 52%… A far cry from the oft claimed 97% consensus.

When self-described “climate scientists” and meteorologists/atmospheric scientists are segregated the results become even more interesting…

Only 45% of meteorologists and atmospheric scientists endorse the so-called consensus.  Even self-described climate scientists only reach 78%.

Maibach et al., 2016 told us that atmospheric scientists were very divided about climate change since 1950.

“Climate change is real”

Page 8 from AMS_Member_Survey_Report_2016-4


Pages_11_12 from AMS_Member_Survey_Report_2016_Page_1

“And dangerous”

Page 20 from AMS_Member_Survey_Report_2016-2

Page 22 from AMS_Member_Survey_Report_2016-3

“And today, there’s no greater threat to our planet than climate change.”

 So climate change can no longer be denied – or ignored. The world is looking to the United States – to us – to lead. 

–Thankfully former President Barack Hussein Obama, April 18, 2015


Pages_11_12 from AMS_Member_Survey_Report_2016_Page_2

Climate Change…

Survey Says.png

Conflict within the AMS

Stenhouse et al., 2017 tells us that there is conflict within the American Meteorological Society on the subject of climate change.

This article analyzes open-ended survey responses to understand how members of the American Meteorological Society (AMS) perceive conflict within the AMS over global warming. Of all survey respondents, 53% agreed that there was conflict within the AMS; of these individuals who perceived conflict, 62% saw it as having at least some productive aspects, and 53% saw at least some unproductive aspects. Among members who saw a productive side to the conflict, most agreed as to why it was productive: debate and diverse perspectives enhance science. However, among members who saw an unproductive side, there was considerable disagreement as to why. Members who are convinced of largely human-caused climate change expressed that debate over global warming sends an unclear message to the public. Conversely, members who are unconvinced of human-caused climate change often felt that their peers were closed-minded and suppressing unpopular views. These two groups converged, however, on one point: politics was seen as an overwhelmingly negative influence on the debate. This suggests that scientific organizations faced with similar conflict should understand that there may be a contradiction between legitimizing all members’ views and sending a clear message to the public about the weight of the evidence. The findings also reinforce the conclusion that attempts by scientific societies to directly address differences in political views may be met with strong resistance by many scientists.

So… Where does this 97% number originate?

Second hand opinions of abstracts of papers. The authors’ tabulate their opinions regarding whether or not the abstracts support the AGW paradigm.  One of the earliest examples was Anderegg et al., 2010.   The most recent and oft-cited is Cook et al., 2013 (Mr. Nuccitelli was a coauthor).

As Legates et al., 2013 pointed out, Cook defined the consensus as “most warming since 1950 is anthropogenic.” Cook then relied on three different levels of “endorsement” of that consensus and excluded 67% of the abstracts reviewed because they neither endorsed nor rejected the consensus.

The largest endorsement group was categorized as “implicitly endorses AGW without minimizing it.” They provided this example of an implied endorsement:

‘…carbon sequestration in soil is important for mitigating global climate change’

Carbon sequestration in soil, lime muds, trees, seawater, marine calcifiers and a whole lot of other things have always been important for mitigating a wide range of natural processes. I have no doubt that I have implicitly endorsed the so-called consensus based on this example.

The second largest endorsement group was categorized as “implicitly endorses but does not quantify or minimize.” Pardon my obtuseness, but how in the heck can one explicitly endorse the notion that “most warming since 1950 is anthropogenic” without quantification? This is the example Cook provided:

‘Emissions of a broad range of greenhouse gases of varying lifetimes contribute to global climate change’

By this subjective standard, I have probably explicitly endorsed the AGW “consensus” in many of my WUWT posts.

By Cook’s standards, I have implicitly endorsed AGW without minimizing it and implicitly endorsed but did not quantify or minimize.  While I am a luke-warmer, I am 100% certain that I have never explicitly or implicitly endorsed the consensus.

No Schist, Sherlock.

One of the most frequent refrains is the assertion that “climate scientists” endorse the so-called consensus more than other disciplines and that the level of endorsement is proportional to the volume of publications by those climate scientists. Well… No schist, Sherlock! I would bet a good bottle of wine that the most voluminous publishers on UFO’s are disproportionately more likely to endorse Close Encounters of the Third Kind as a documentary. A cursory search for “abiogenic hydrocarbons” in AAPG’s Datapages could lead me to conclude that there is a higher level of endorsement of abiogenic oil among those who publish on the subject than among non-publishing petroleum geologists.  This doesn’t elevate their hypothesis to a scientific consensus.

These exercises in expertise cherry-picking are quite common. A classic example was Doran and Kendall Zimmerman, 2009. This survey sample was limited to academic and government Earth Scientists. It excluded all Earth Scientists working in private sector businesses. The two key questions were:

1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?

2. Do you think human activity is a significant contributing factor in changing mean global temperatures?

I would answer risen to #1 and my answer to #2 would depend on the meaning of “human activity is a significant contributing factor.” If I realized it was a “push poll,” I would answer “no.”

Interestingly, economic geologists and meteorologists were the most likely to answer “no” to question #2…

The two areas of expertise in the survey with the smallest percentage of participants answering yes to question 2 were economic geology with 47% (48 of 103) and meteorology with 64% (23 of 36).

The survey was limited to government and academic scientists.  Had the survey included economic geologists in the mining and oil & gas industries, only about 30% would have answered “yes” to question #2.

The authors then derisively dismissed the opinions of geologists and meteorologists…

It seems that the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes.

No discipline has a better understanding the “nuances” than meteorologists and no discipline has a better understanding of the “scientific basis of long-term climate processes” than geologists.  I could run through numerous surveys of geoscientists that demonstrate strong disagreement with the so-called consensus.

The authors close with a “no schist, Sherlock” bar chart:

The most recent example of expertise cherry-picking was Stenhouse et al., 2014.

The 52% consensus among the membership of the American Meteorological Society explained away as being due to “perceived scientific consensus,” “political ideology,” and a lack of “expertise” among non-publishing meteorologists and atmospheric scientists…

While we found that higher expertise was associated with a greater likelihood of viewing global warming as real and harmful, this relationship was less strong than for political ideology and perceived consensus. At least for the measure of expertise that we used, climate science expertise may be a less important influence on global warming views than political ideology or social consensus norms. More than any other result of the study, this would be strong evidence against the idea that expert scientists’ views on politically controversial topics can be completely objective.

Finally, we found that perceiving conflict at AMS was associated with lower certainty of global warming views, lower likelihood of viewing global warming as human caused, and lower ratings of predicted harm caused by global warming.

So… Clearly, 97% of AMS membership would endorse the so-called consensus if they were more liberal, more accepting of unanimity and published more papers defending failed climate models.  No schist, Sherlock!

What, exactly, is a “climate scientist”?

35 years ago climatology was a branch of physical geography. Today’s climate scientists can be anything from atmospheric physicists & chemists, mathematicians, computer scientists, astronomers, astrophysicists, oceanographers, biologists, environmental scientists, ecologists, meteorologists, geologists, geophysicists, geochemists to economists, agronomists, sociologists and/or public policy-ologists.

NASA’s top climate scientist for most of the past 35 years, James Hansen, is an astronomer. The current one, Gavin Schmidt, is a mathematician.

It seems to me that climate science is currently dominated by computer modelers, with little comprehension of the natural climate cycles which have driven climate change throughout the Holocene.

Climate scientist seems to be as nebulous as Cook’s definition of consensus.

Closing Note

I wrote this without actually reading beyond the headline of Mr. Nuccitelli’s article.  Did I miss anything?

OK… I glanced at it… Nope, I didn’t miss anything.


Anderegg, W. R. L., Prall, J. W., Harold, J., & Schneider, S. H. (2010). Expert credibility in climate change. Proceedings of the National Academy of Science, 107, 12107–12109.

Cook, J., Nuccitelli, D., Green, S. A., Richardson, M., Winkler, B., Painting, R., et al. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters, 8, 024024.

Doran, P., & Zimmerman, M. (2009). Examining the scientific consensus on climate change. EOS. Transactions of the American Geophysical Union, 99, 22–23.

Legates DR, Soon WW-H, Briggs WM et al. (2013) Climate consensus and “misinformation”: a rejoinder to “agnotology, scientific consensus, and the teaching and learning of climate change”. Sci Educ. doi:10.1007/s11191-013-9647-9.

Maibach, E., Perkins, D., Francis, Z., Myers, T., Englbom, A., et al. (2016). A 2016 National
Survey of American Meteorological Society Member Views on Climate Change: Initial Findings. George Mason University, Fairfax, VA: Center for Climate Change Communication.

Stenhouse, N., and Coauthors, 2014Meteorologists’ views about global warming: A survey of American Meteorological Society professional membersBull. Amer. Meteor. Soc.9510291040, doi:

What is the Meaningful 97% in the Climate Debate?

From Watts Up With That:

Guest opinion: Dr. Tim Ball

For a brief period, the New York Times added a column to their best-seller book list. It identified the percentage of people who finished reading the book. As I recall, the outright winner for lowest percentage was Umberto Eco’s Name of the Rose with only 6%. It is an excellent and fascinating book if you understand the Catholic church, its theological disputes, know much about medieval mythology, understand Catholic religious orders, and are familiar with the history of Italy in the Middle Ages. As one reviewer wrote, “I won’t lie to you. It is absolutely a slog at times.” This phrase struck me because it is exactly what a lawyer told me after reading my book “The Deliberate Corruption of Climate Science.”

I told him it was a slog to research because it required reading all the Reports of the Intergovernmental Panel on Climate Change (IPCC), a task that few, certainly fewer than 6%, ever achieve, including most of the people involved with the production. This is the tragedy. There are so many people with such strong, definitive views, including among skeptics and the general science community who have never read the Reports at all. The challenge is made more difficult by the deliberate attempt to separate truth and reality from propaganda and the political agenda.

In media interviews or discussions with the public, the most frequent opening challenge is; “But don’t 97% of scientists agree?” It is usually said obliquely to imply that you know a lot, and I don’t understand, but I assume you are wrong because you are in the minority. I don’t attempt to refute the statistics. Instead, I explain the difference in definitions between science and society. Then I point out that the critical 97% figure is that at least 97% of scientists have never read the claims of the IPCC Reports. How many people reading this article have read all the IPCC Reports, or even just one of them? If you have, it is probably the deliberately deceptive Summary for Policymakers (SPM). Even fewer will have read the Report of Working Group I: The Physical Science Basis. Naively, people, especially other scientists, assume scientists would not falsify, mislead, misrepresent, or withhold information. It is worse, because the IPCC deliberately created the false claim of consensus.

I wrote earlier about the problem of communications between groups and the general public because of the different definition of terms. Among the most damaging, especially in the public debate, is the word consensus. Exploitation of the confusion was deliberate. On 22 December 2004, RealClimate, the website created to manipulate the global warming story, provided this insight;

We’ve used the term “consensus” here a bit recently without ever really defining what we mean by it. In normal practice, there is no great need to define it – no science depends on it. But it’s useful to record the core that most scientists agree on, for public presentation. The consensus that exists is that of the IPCC reports, in particular the working group I report (there are three WG’s. By “IPCC”, people tend to mean WG I).

In other words, it is what the creators of the Reports consider a consensus. This is classic groupthink on display. One characteristic of which says they have,

“…a culture of uniformity where individuals censor themselves and others so that the facade of group unanimity is maintained.”

The source of the 97% claim in the public arena came from John Cook et al., and was published in 2013 in Environmental Research Letters. It was titled “Quantifying the consensus on anthropogenic global warming in the scientific literature.” I acknowledge to people some of the brilliant dissections of this claim, such as Lord Monckton’s comment, “0.3% consensus, not 97.1%.” If I have time, I explain how the plan to exploit the idea of consensus was developed by the same people and corrupted science exposed in the emails leaked from the Climatic Research Unit (CRU) in November 2009.

Harvard graduate, medical doctor, and world-famous science fiction writer, Michael Crichton provides an excellent riposte.

“I want to pause here and talk about this notion of consensus, and the rise of what has been called consensus science. I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you’re being had.

Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus.”

The attempt to deceive and divert was built into the structure, format, and procedures of the IPCC. Few people know that a major part of the deception is to identify all the problems with the science but only identify them in the Report of Working Group I: The Physical Science Basis. They know most won’t read or understand it and can easily marginalize the few who do. In 2012 I created a list of several of these acknowledgments, but only one is sufficient here to destroy the certainty of their claims about future climates. Section 14.2.2. of the Scientific Section of Third IPCC Assessment Report, (2001) titled “Predictability in a Chaotic System” says:

“The climate system is particularly challenging since it is known that components in the system are inherently chaotic; there are feedbacks that could potentially switch sign, and there are central processes that affect the system in a complicated, non-linear manner. These complex, chaotic, non-linear dynamics are an inherent aspect of the climate system.”

“In sum, a strategy must recognise what is possible. In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible” (My emphasis).

This is not reported in the Summary for Policymakers (SPM) that is deliberately different. David Wojick, an IPCC expert reviewer, explained,

“What is systematically omitted from the SPM are precisely the uncertainties and positive counter evidence that might negate the human interference theory. Instead of assessing these objections, the Summary confidently asserts just those findings that support its case. In short, this is advocacy, not assessment.”

He should add, it is deliberate advocacy, as the RealClimate quote shows.

The SPM receives scant attention from the media and the public, except for the temperature predictions and then only the most extreme figure is selected. The Science Report receives even less attention, but that is by instruction because it is released months later. All of this is why I quoted German physicist and meteorologist Klaus Eckart Puls (English translation version) on the cover of both my books.

“Ten years ago, I simply parroted what the IPCC told us. One day I started checking the facts and data – first I started with a sense of doubt but then I became outraged when I discovered that much of what the IPCC and the media were telling us was sheer nonsense and was not even supported by any scientific facts and measurements. To this day I still feel shame that as a scientist I made presentations of their science without first checking it.” “Scientifically it is sheer absurdity to think we can get a nice climate by turning a CO2 adjustment knob.”

Cook wrong on Consensus: Monckton

From The Australian Climate Sceptics Blog:

0.3% Consensus, Not 97.1%

‘Quantifying the consensus on global warming in the literature’: a comment

by Christopher Monckton of Brenchley

Science and Public Policy Institute

5501 Merchants’ View Square, #209, Haymarket, VA 20169


The latest paper apparently showing 97% endorsement of a consensus that more than half of recent global warming was anthropogenic really shows only 0.3% endorsement of that now-dwindling consensus.


Cook et al. (2013) stated that abstracts of nearly all papers expressing an opinion on climate change endorsed consensus, which, however, traditionally has no scientific role; used three imprecise definitions of consensus interchangeably; analyzed abstracts only; excluded 67% expressing no opinion; omitted some key results; misstated others; and thus concluded that 97.1% endorsed the hypothesis as defined in their introduction, namely that the “scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)”. The authors’ own data file categorized 64 abstracts, or only 0.5% of the sample, as endorsing the consensus hypothesis as thus defined. Inspection shows only 41 of the 64, or 0.3% of the entire sample, actually endorsed their hypothesis. Criteria for peer review of papers quantifying scientific consensus are discussed.

Introduction: no role for consensus in science

Though Cook et al. (2013) reviewed abstracts of 11,944 papers on climate change and concluded that 97.1% of those expressing an opinion supported consensus, the philosophy of science allows no role for head-count. Aristotle, in his Sophistical Refutations, (c. 350 B.C.E.), identified the argument from consensus as one of the dozen commonest logical fallacies in human discourse.

Al-Haytham, the astronomer and philosopher of science in 11th-century Iraq who is recognized as the father of the scientific method, wrote that “the seeker after truth” – his phrase for the scientist – does not place his faith in any mere consensus, however venerable. Instead, he checks. “The road to the truth,” said al-Haytham, “is long and hard, but that is the road we must follow.”

In 1860 T.H. Huxley said: “The improver of natural knowledge absolutely refuses to acknowledge authority, as such. For him, skepticism is the highest of duties: blind faith the one unpardonable sin.”

Albert Einstein, when told that 100 Nazi scientists had published a book rejecting his theory of special relativity, responded that a single paper would have sufficed to refute his hypothesis. His own single paper of 1905 on the electrodynamics of moving objects had demonstrated why Newton’s laws, till then universally accepted as true, incompletely described the motion of celestial objects.

Popper (1934) formalized the scientific method as an iterative algorithm starting with a general problem (GP0), to address which a scientist proposed a falsifiable hypothesis or tentative theory (TT0). Thereupon others would either demonstrate during the error-elimination phase (EE0) that the hypothesis was false, in which event it was rejected, or, more rarely, demonstrate that it was true.

By far the commonest outcome, however, especially in the physical sciences, is that error elimination will fall short of demonstrating the hypothesis but will fail to disprove it, in which event it gains some credibility. The statement of the general problem may then be modified accordingly (GP1), and a new tentative theory (TT1) may later be advanced to address the modified problem; and so on. Pedetemptim, and if necessary ad infinitum, science iteratively converges upon the truth (Fig. 1). Consensus adds no value to this process.

In the scientific method, then, there is no place for mere consensus. A hypothesis that is demonstrated – such as Pythagoras’ theorem – needs no consensus, for it is objectively true. A hypothesis that is disproven needs no consensus, for it is objectively false. A hypothesis that is neither demonstrated nor disproven gains credibility, and not because a dozen or even 12,000 papers endorse it but because – and to the extent that – it has not been demonstrated to be false. Science is not a belief system. A priori, then, head-counts are inappropriate tests of scientific results.

Problems in defining the climate consensus

Al-Haytham’s scientific method required observing nature, stating a problem precisely, formulating a hypothesis to address it, testing the hypothesis, analyzing the results, drawing conclusions, and publishing the findings. It is essential to the scientific method that a tentative theory be stated in rigorously precise terms.

In particular, the definition of the hypothesis should be expressed quantitatively. An imprecisely defined hypothesis, especially if it is not quantitative, may be insufficiently rigorous to be testable. If it be untestable, then, stricto sensu, it is not of interest to science. It is a mere curiosity. Yet Cook et al. do not confine themselves to a single definition of the hypothesis to which their consensus is said to adhere. Three definitions of climate consensus coexist in the paper –

Definition (1): “the consensus position that humans are causing global warming” (abstract);

Definition (2): the “scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)” (introduction);

Definition (3): that our enhancement of the greenhouse effect will be dangerous enough to be “catastrophic”; (implicit in the introduction, in discussion of the need to raise awareness of scientific consensus to justify a “climate policy”, and explicit in Table 2 of Cook et al., citing a paper opposing “the catastrophic view of the greenhouse effect”).

President Obama was among those who thought Cook et al. had shown a consensus endorsing definition (3). The following tweet was posted in his name:

“Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous.” [Emphasis added]

Definitions (1, 3) fall short of the criteria for definition of a Popper-falsifiable hypothesis, and definition (2) could have been clearer. Not only do Cook et al. adopt the definitions interchangeably, but each definition is imprecise and insufficiently quantified to allow rigorous Popper-falsification. None of the definitions specifies the period to which it applies, or how much global warming was observed over that period, or whether the warming is continuing, or, if so, at what rate, or whether that rate is considered dangerous, or what rate if any is considered dangerous.

Additionally, definitions (1) and (3) do not specify what fraction of warming was considered anthropogenic, and definition (2) assigns no quantitative value to the term “very likely”. Such imprecisions render the hypotheses unfalsifiable and hence beyond the realm of legitimate scientific inquiry.

Definition (2) is akin to, but less precise than, that of the Intergovernmental Panel on Climate Change (IPCC, 2007, p. 665):

“Greenhouse gas forcing has very likely [90% confidence] caused most of the observed global warming over the last 50 years.”

Definition (3) is implicit in the opening words of Cook et al.:

“An accurate perception of the degree of scientific consensus is an essential element to public support for climate policy (Ding et al., 2011). Communicating the scientific consensus also increases people’s acceptance that climate change is happening (Lewandowsky et al., 2012).”

The implication is that the authors of all abstracts endorsing definitions (1) and (2) also endorse the catastrophist definition (3). However, a hypothesis to the effect that humans cause some warming, or even that most current global warming is very likely to be anthropogenic, is not – and need not imply – a hypothesis that current warming, if continued, might prove sufficiently damaging to justify a climate policy. It is by this unwarranted extension that President Obama’s Twitterer erroneously assumed that the survey indicated 97% endorsement of catastrophic global warming.

The use of multiple imprecise and ill-quantified definitions of climate consensus has some precedents in the literature. Cook et al. cite two instances:

“Surveys of climate scientists have found strong agreement (97-98%) regarding AGW amongst publishing climate experts (Doran & Zimmerman, 2009; Anderegg et al., 2010).”

Doran and Zimmerman (2009)

The two authors sent a 2-minute online survey to 10,257 earth scientists at universities and government research agencies. Only 5% of the 3,146 respondents identified themselves as climate scientists; 90% believed mean global temperatures had generally risen compared with pre-1800s levels; and 82% believed human activity was a significant contributing factor in changing mean global temperatures. Only 79 of the respondents listed climate science as their area of expertise and had also published more than half of their recent peer-reviewed papers on climate change. Of these, 98% believed human activity was a significant contributing factor in changing mean global temperatures. However, the sample size was insufficient to deliver a statistically reliable result, and the respondents were not asked whether they believed the anthropogenic influence on temperature might become sufficiently damaging to require a “climate policy”.

Anderegg et al. (2010)

From publication and citation data, the authors selected 908 of 1372 climate researchers, defined as people who had published at least 20 climate papers and had either signed petitions opposing or supporting the IPCC’s positions or had co-authored IPCC reports. Of these, 97-98% believed that “anthropogenic greenhouse gases have been responsible for ‘most’ of the ‘unequivocal’ warming of the Earth’s average global temperature over the second half of the 20th century”. The definition of the consensus in Anderegg et al. is less imprecise than definition (2) in Cook et al. Yet, like Cook et al., Anderegg et al. did not seek to determine how many researchers considered global warming to be actually or potentially damaging enough to require a climate policy. Nevertheless, the two surveys are often cited as demonstrating a near-unanimous scientific consensus in favor of a climate policy, when in fact, like Cook et al., neither survey had asked any question either about whether and to what extent the anthropogenic component in recent warming might be dangerous or about whether a “climate policy” should be adopted in attempted mitigation of future warming.

In Cook et al., the definition of consensus hypothesis that comes closest to those of the IPCC and of other head-count papers is definition (2). Table 1 lists some of these definitions.

Source Quantitative definition of climate consensus
IPCC (2001),

Ch. 12 (attribution),

p. 699

“… most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.”
Oreskes (2004) As IPCC (2001), supra.
IPCC (2007),

Ch. 9 (attribution),


“Greenhouse gas forcing has very likely [90% confidence] caused most of the observed global warming over the last 50 years.”
Schulte (2008) As IPCC (2001), supra.
Doran & Zimmerman (2009) “… human activity is a significant contributing factor in changing mean global temperatures.”
Anderegg et al. (2010) “… anthropogenic greenhouse gases have been responsible for ‘most’ of the ‘unequivocal’ warming of the Earth’s average global temperature over the second half of the 20th century.”
Cook et al. (2013),

definition (2)

“…scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW).”

Table 1. Successive quantitative definitions of a climate consensus.

Incomplete statement of the survey results

None of the seven “levels of endorsement” by which Cook et al. categorize their selected abstracts provides evidence that any of the 11,944 abstracts encompasses the catastrophist definition (3):

1               “Explicitly states that humans are the primary cause of global warming”

2              “Explicit endorsement without quantification”

3              “Implicit endorsement”

4              “No opinion, or uncertain”

5              “Implicit rejection”

6              “Explicit rejection without quantification”

7              “Explicit rejection with quantification”

The first endorsement level, “Explicitly states that humans are the primary cause of global warming”, reflects definition (2) and is akin to the other definitions in Table 1. The second and third levels, “Explicit endorsement without quantification” and “Implicit endorsement”, reflect definition (1) in that, like it, they are not quantitative. Yet the first three levels of endorsement are treated as one in the results:

“To simplify the analysis, ratings were consolidated into three groups: endorsements (including implicit and explicit: categories 1-3) …”.

Results of an inspection of the Cook et al. data file

It is not possible to discern either from the paper or from the supplementary information what fraction of all abstracts endorse definition (2). A file of raw data was supplied, though it was only posted online some weeks after publication. This comma-delimited text file was dowloaded and the abstracts allocated by Cook et al. to each level of endorsement were counted. Results are given in Table 2:

E.Level 1 2 3 4 5 6 7 Total





















Papers 64 922 2910 7970 54 15 9 11,944
% all 0.5% 7.7% 24.4% 66.7% 0.5% 0.1% 0.1% 100%
% opin 1.6% 23.0% 72.5% 1.3% 0.4% 0.2% 99%

Table 2. Abstracts in the seven levels of endorsement specified in Cook et al. (2013). Only 64 abstracts, according to the authors’ data file, explicitly endorsed definition (2), the quantitative hypothesis. NB: “+quant” indicates “with quantification”; “–quant” indicates “without quantification”; “% all” indicates the percentage of all 11,944 abstracts that fell in each level of endorsement; “% opin” indicates the percentages of all 4014 abstracts, excluding the 7930 that expressed no opinion but including the 40 that expressed uncertainty (1% of all papers). These 40 are not shown separately in the datafile or in the table. Therefore, the percentages of papers expressing an opinion sum to 99%, not 100%.

Definition (1): The count confirmed the authors’ count that 3896 of the 11,944 abstracts (i.e., 32.6%) fell in their endorsement levels 1-3, indicating that fewer than one-third of all abstracts indicate implicit or explicit support even for the limited definition (1) hypothesis that humans cause some warming. It was only by excluding those 7930 endorsement-level-4 abstracts that expressed no opinion (but retaining the 40 level-4 abstracts expressing uncertainty) that Cook et al. were able to conclude that 97.1% endorsed consensus.

Definition (2): The count, in line with an earlier result published by Friends of Science in Canada, showed only 64 papers, or just 0.5% of the sample, explicitly endorsing the quantitative hypothesis to the effect that humans are the primary cause of current warming. This value was independently verified by a separate inspection of the data file to identify occurrences of the search term “,1” at the end of each data record using the search facility in Microsoft Notepad, whereupon 64 such occurrences were indeed found. However, of the 64 abstracts to which Cook et al. assigned an endorsement level of 1 (“explicit endorsement with quantification”: Annex 1), 23 do not in fact endorse definition (2). Only 41 papers (0.3% of the sample: Annex 2) endorse definition (2).

The conclusion of Cook et al., as expressed in their abstract, is as follows:

“Among [4014] abstracts expressing a position on AGW, 97.1% endorsed the conssensus position that humans are causing global warming.”

A 97% consensus is also asserted in the closing words of the paper:

“Among [4014] papers expressing a position on AGW, an overwhelming percentage (97.2% based on self-ratings, 97.1% based on abstract ratings) endorses the scientific consensus on AGW.”

In the introduction. Cook et al. define “AGW” as the “scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)”. However, the authors’ own analysis shows that only 0.5% of all 11,944 abstracts, and 1.6% of the 4014 abstracts expressing a position, endorsed “AGW” as they had defined it. Taking into account that more than one-third of the 64 abstracts do not in fact endorse the quantitative hypothesis in Cook et al., the true percentages endorsing that hypothesis are 0.3% and 1.0% respectively.

Evidence that the climate consensus is declining

Oreskes (2004) published an essay in Science alleging that not one of 928 abstracts she had reviewed had disagreed with the consensus as defined in IPCC (2001): “Most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. Her adopted definition of consensus, then, was similar to but more precise than definition (2) in Cook et al. It, too, falls well short of stating that manmade warming may prove catastrophic.

Her essay concluded that three-quarters of her sample endorsed the “consensus” either explicitly or, by evaluating impacts or proposing mitigation, implicitly. A quarter took no view. None, she said, disagreed with the consensus as defined in IPCC (2001). Yet the fact that a paper evaluates impacts or proposes mitigation does not necessarily imply that the authors endorse the notion that more than half of the past 50 years’ global warming was anthropogenic.

Schulte (2008) reviewed 539 papers published in the three years following the period studied by Oreskes, using the same search term and the same IPCC definition of consensus. He found that “the proportion of papers that now explicitly or implicitly endorse the consensus has fallen from 75% to 45%.” Only 2% of the papers reviewed “offer new field data or observations directly relevant to the question whether anthropogenic warming has prevailed over natural variability in the past half-century”. Only one paper mentioned the possibility of catastrophic climate change, but without providing any evidence for it. No paper provided quantitative evidence for the consensus hypothesis. Schulte concluded: “There appears to be little basis in the peer-reviewed literature for the degree of alarm on the issue of man-made climate change which is being expressed in the media and by politicians.”

The 75% consensus reported by Oreskes in 2004 exceeds the 45% found by Schulte in 2008, which in turn exceeds the 0.5-1.6% (0.3-1.0% after correction) found but not reported by Cook et al. in 2013.

Accordingly, the undisclosed results in Cook et al. indicate either that earlier head-count papers had not (as Cook et al. in their published results had not) drawn any distinction between quantified and unquantified consensus, or that over the past decade the consensus has dwindled.

Has there been any ‘current’ warming?

Figure 2. No global warming for 12 years 6 months, according to the HadCRUt4 dataset.

Cook et al.’s definition (1) is that “humans are causing global warming”. Definition (2) is that humans are the chief cause of “the current warming”. Though the least-squares linear-regression trend on the monthly HadCRUt4 dataset (Morice et al., 2012) shows surface warming over the half-century 1956-2005 at a rate equivalent to 1.2 Cº/century, trends on the same dataset over shorter periods show no warming exceeding the upper bound of the published measurement uncertainties for more than 17 years, no warming at all over the 12 years 6 months November 2000 to May 2013 (Fig. 2), and cooling at 0.5 Cº/century over the decade May 2003-April 2013.

In the usual sense of the word “current”, then, global warming is not currently occurring, rendering definitions (1) and (2) untestable: for no scientist could legitimately endorse a consensus to the effect that global warming is currently occurring when, currently, it is not.


The defects identified in the surveys of climate consensus by Cook et al. and by the authors of some of the papers they cite follow a pattern to whose existence peer-reviewers should be alert. First, any argument from consensus on a question such as the extent to which anthropogenic global warming may prove dangerous is defective a priori and ought really to be rejected without further review.

Secondly, no survey of opinion for or against a consensus hypothesis ought to be regarded as scientific where it is not made clear which hypothesis is under test, or where the hypothesis under test is not clearly and precisely formulated. A fortiori, a survey paper that exhibits multiple definitions of the consensus hypothesis and fails to state clearly the identity and definition of the hypothesis on the basis of which the survey was actually conducted should surely be rejected.

Thirdly, the consensus hypothesis under test ought to be expressed in quantitative terms. Mere qualitative definitions of any scientific hypothesis run the risk of appearing more political than scientific in their formulation, and papers based on such definitions may also prove more political than scientific in their effect.

Fourthly, if several “levels of endorsement” are specified, then the number of abstracts, papers, or scientists considered to have supported each level of endorsement ought to be explicitly stated in the paper under review. Cook et al. specified three levels of endorsement that supported the notion of anthropogenic warming (however defined); yet, on the stated ground of simplifying the analysis, the number of papers allocated to each of the three levels of endorsement – a key result on any view – was not stated. The analysis would indeed have been simpler if one endorsement level supporting one definition of climate consensus had been adopted.

Fifthly, all data files and programs should be archived at the time of submission to the journal and included at the time of publication as part of the supplementary material. Reviewers should ask for the datafiles and programs if they are not available.


The non-disclosure in Cook et al. of the number of abstracts supporting each specified level of endorsement had the effect of not making available the fact that only 41 papers – 0.3% of all 11,944 abstracts or 1.0% of the 4014 expressing an opinion, and not 97.1% – had been found to endorse the quantitative hypothesis, stated in the introduction to Cook et al. and akin to similar definitions in the literature, that “human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)”.



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Annex 1

The 41 papers endorsing the quantitative consensus

Relevant extracts from those 41 of 64 abstracts listed by Cook et al. as endorsing their quantitative definition of the consensus hypothesis that actually endorse it are below. The remaining 23, in Annex 2, do not endorse it.

The data entries have been edited for clarity, particularly by including a space after each delimiting comma; decapitalizing abstract titles; abbreviating and italicizing journal names; removing a “|” mark that appeared after each author’s name; capitalizing all authors’ initials; and correcting some typographical errors.

1: 1992, Implications for global warming of intercycle solar irradiance variations, Nature, Schlesinger M.E.; Ramankutty N, 2, 1

“… we find that since the nineteenth century, greenhouse gases, not solar irradiance variations, have been the dominant contributor to the observed temperature changes.”

4: 1994, Greenhouse statistics – Time-series analysis 2, Theor. & Appl. Climatol., Tol RSJ, 4, 1

“… the hypothesis that the anthropogenically enhanced greenhouse effect is not responsible for the observed global warming during the last century is rejected with a 99% confidence, is reconfirmed.”

6: 1997, Assessments of the global anthropogenic greenhouse and sulfate signal using different types of simplified climate models, Theor. & Appl. Climatol., Schonwiese CD; Denhard M; Grieser J; Walter A, 2, 1

“Our statistical assessments, based on the 1866–1994 period, lead to a GHG signal of 0.8–1.3 K and a combined GHG-SU signal of 0.5–0.8 K detectable in observations. This is close to GCM simulations and clearly larger than the volcanic, solar and ENSO (El Niño/southern oscillation) signals also considered.”

11: 2000, Recent warming in a 500-year palaeotemperature record from varved sediments; Upper Soper Lake; Baffin Island; Canada, Holocene, Hughen KA; Overpeck JT; Anderson RF, 5, 1

“Comparisons of Upper Soper Lake and Arctic average palaeotemperature to proxy-records of hypothesized forcing mechanisms suggest that the recent warming trend is mostly due to anthropogenic emissions of atmospheric greenhouse gases.”

14: 2002, Global Warming 2001, J. de Physique IV, Berger A, 4, 1

“In its Third Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) states clearly that “an increasing body of observations give a collective picture of a warming world and other changes in the climate system” and that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities”.

16: 2003, Do models underestimate the solar contribution to recent climate change?, J. Clim., Stott PA; Jones GS; Mitchell JFB, 4, 1

“… the results confirm previous analyses showing that greenhouse gas increases explain most of the global warming observed in the second half of the twentieth century.”

17: 2003, Modern global climate change, Science, Karl TR; Trenberth KE, 2, 1

“Modern climate change is dominated by human influences, which are now large enough to exceed the bounds of natural variability. The main source of global climate change is human-induced changes in atmospheric composition.”

19: 2004, Numerical simulation of global temperature change during the 20th century with the IAP/LASG GOALS model, Advances In Atmos. Sci., Ma XY; Guo YF; Shi GY; Yu YQ, 2, 1

“The global warming during the 20th century is caused mainly by increasing greenhouse gas concentration especially since the late 1980s.”

20: 2004, Soot climate forcing via snow and ice albedos, PNAS, Hansen J; Nazarenko L, 4, 1

“… soot contributions to climate change do not alter the conclusion that anthropogenic greenhouse gases have been the main cause of recent global warming and will be the predominant climate forcing in the future.”

22: 2005, Mid-late Holocene monsoon climate retrieved from seasonal Sr/Ca and δ18O records of porites lutea corals at Leizhou Peninsula; northern coast of South China Sea, Global & Planetary Change, Yu KF; Zhao JX; Wei GJ; Cheng XR; Wang PX, 5, 1

“… the increase in the concentration of anthropogenic greenhouse gases played a dominant role in recent global warming, …”

23: 2006, Assessment of 20th-century regional surface temperature trends using the GFDL CM2 coupled models, J. Clim., Knutson TR; Delworth TL; Dixon KW; Held IM; Lu J; Ramaswamy V; Schwarzkopf MD; Stenchikov G; Stouffer RJ, 4, 1

“The simulations support previous findings that twentieth-century global warming has resulted from a combination of natural and anthropogenic forcing, with anthropogenic forcing being the dominant cause of the pronounced late-twentieth-century warming.”

25: 2006, Phenomenological solar contribution to the 1900-2000 global surface warming, GRL, Scafetta N; West BJ, 4, 1

“We estimate that the sun contributed as much as 45–50% of the 1900–2000 global warming, and 25–35% of the 1980–2000 global warming. These results, while confirming that anthropogenic-added climate forcing might have progressively played a dominant role in climate change during the last century, also suggest that the solar impact on climate change during the same period is significantly stronger than what some theoretical models have predicted.”

27: 2006, Study on CO2 recovery system from flue gas by honeycomb type adsorbent I – results of tests and simulation), Kagaku Kogaku Ronbunshu, Matsukuma Y; Matsushita Y; Kakigami H; Inoue G; Minemoto M; Yasutake A; Oka N, 3, 1

“Carbon dioxide (CO2) included in the exhaust gas from heat power plants is the chief cause of global warming.”

29: 2007, A model for the CO2 capture potential, Int. J. GHG Control, Stanyeland A, 3, 1

“Global warming is a result of increasing anthropogenic CO2 emissions, and the consequences will be dramatic climate changes if no action is taken.”

30: 2007, Avoiding self-organized extinction: toward a co-evolutionary economics of sustainability, Int. J. Sustain. Devel. & World Ecol., Gowdy J, 2, 1

“There is a a near-universal consensus that global warming is human-caused and that its effects are now accelerating.”

31: 2007, CO2 emissions from road transport and selected parts in the Kosice City, Acta Montanistica Slovaca, Carach V; Muller G; Janoskova K, 4, 1

“Nowadays it is clear that the climatic unstability is mostly caused by human activities.”

32: 2007, Global climate change and children’s health, Pediatrics, Shannon MW; Best D; Binns HJ; Forman JA; Johnson CL; Karr CJ; Kim JJ; Mazur LJ; Roberts JR; Shea KM, 2, 1

There is a broad scientific consensus that the global climate is warming, the process is accelerating, and that human activities are very likely (>90% probability) the main cause.”

33: 2007, Global warming is driven by anthropogenic emissions: a time series analysis approach, Phys. Rev. Lett., Verdes PF, 2, 1

“Here we show, using two independent driving force reconstruction techniques, that the combined effect of greenhouse gases and aerosol emissions has been the main external driver of global climate during the past decades.”

35: 2008, Carbonation of alkaline paper mill waste to reduce co2 greenhouse gas emissions into the atmosphere, Appl. Geochem., Perez-Lopez R; Montes-Hernandez G; Nieto JM; Renard F; Charlet L, 3, 1

“The global warming of Earth’s near-surface, air and oceans in recent decades is a direct consequence of anthropogenic emission of greenhouse gases into the atmosphere such as CO2, CH4, N2O and CFCs. The CO2 emissions contribute approximately 60% to this climate change.”

36: 2008, Climate policy architectures for the post-Kyoto world, Environment, Aldy JE; Stavins RN, 3, 1

“The Intergovernmental Panel on Climate Change has determined earlier that most of the increase in global average temperatures is very likely due to the adverse increase in anthropogenic greenhouse gas concentrations.”

37: 2008, Cycle analysis of low and high H2 utilization SOFCS/gas turbine combined cycle for CO2 recovery, Electronics & Comms. in Japan, Taniuchi T; Sunakawa D; Nagahama M; Araki T; Onda K; Kato T, 3, 1

“Global warming is mainly caused by CO2 emission from thermal power plants, which burn fossil fuel with air.”

38: 2008, Energy sources and global climate change: the Brazilian case, Energy Sources A, Simoes AF; La Rovere EL, 3, 1

“Fossil fuels consumption is the primary cause of global warming.”

41: 2008, Leaf carbon assimilation in a water-limited world, Plant Biosys., Loreto F; Centritto M, 2, 1

“Over the past 150 years the amount of CO2 in the atmosphere has been increasing, largely as a result of land-use change and anthropogenic emissions from the burning of fossil fuels.”

42: 2008, On avoiding dangerous anthropogenic interference with the climate system: formidable challenges ahead, PNAS, Ramanathan V; Feng Y, 2, 1

IPCC models suggest that ≈25% (0.6°C) of the committed warming has been realized as of now.

43: 2008, The potential of water power in the fight against global warming in the US, Energy Policy, Kosnik L, 3, 1

“The leading cause of climate change today is the burning of fossil fuels related to energy production.”

45: 2009, Climate changes and the actions of the European Union for environmental protection, Metalurgia Int., Brezoi AG; Tharin M, 4, 1

“According to the meetings of the experts … the human origin of present-day climate changes is estimated at 90%.”

47: 2010, A novel formulation of carbon emissions costs for optimal design configuration of system transmission planning, Renewable Energy, Sadegheih A, 3, 1

“Global warming, which is mainly caused by the emissions of Green House Gases (GHGs), is said to be a serious part of these environmental problems.”

48: 2010, Analysis of the global warming dynamics from temperature time series, Ecol. Modelling, Viola FM; Paiva SLD; Savi MA, 4, 1

“Global warming is the observed increase of the average temperature of the Earth. The primary cause of this phenomenon is the release of the greenhouse gases by burning of fossil fuels, land cleaning, agriculture, among others, leading to the increase of the so-called greenhouse effect.”

50: 2010, Conceptual design and simulation analysis of thermal behaviors of TGR blast furnace and oxygen blast furnace, Science China – Technol., Zhang H; Li HQ; Tang Q; Bao WJ, 3, 1

“Extensive use of carbon based fuel is the main inducement for global warming and more extreme weather.”

51: 2010, Consumption-based accounting of CO2 emissions, PNAS, Davis SJ; Caldeira K, 4, 1

“CO2 emissions from the burning of fossil fuels are the primary cause of global warming.”

52: 2010, Dynamic competition under cap and trade programs, Infor, Jeev K; Campos-Nanez E, 3, 1

“Greenhouse gases (GHG), like carbon dioxide (CO2), which are released in the atmosphere due to anthropogenic activities like power production, are now accepted as the main culprits for global warming.”

53: 2010, Short-term effects of controlling fossil-fuel soot; biofuel soot and gases; and methane on climate; arctic ice; air pollution; and health, JGR Atmos., Jacobson MZ, 3, 1

“… net global warming (0.7–0.8 K) is due mostly to gross pollutant warming from fossil-fuel greenhouse gases (2–2.4 K), …”

56: 2011, Early onset of significant local warming in low latitude countries, Env. Res. Lett., Mahlstein I; Knutti R; Solomon S; Portmann RW, 2, 1

“… most of the global warming of the past half-century can very likely be attributed to human influence.”

57: 2011, Earth’s energy imbalance and implications, Atmos. Chem. & Phys., Hansen J; Sato M; Kharecha P; Von Schuckmann K, 4, 1

“The inferred planetary energy imbalance, 0.58 ± 0.15 W m−2 during the 6-yr period 2005–2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change.”

58: 2011, Emergent dynamics of the climate-economy system in the anthropocene, Philos. Trans. Royal Soc. A, Kellie-Smith O; Cox PM, 4, 1

59: 2011, Insights on global warming, Aiche J., Seinfeld JH, 4, 1

“The global temperature increase over the last century and a half (∼ 0.8°C), and the last three decades in particular, is well outside of that which can be attributed to natural climate fluctuations. The increase of atmospheric CO2 over this period has been conclusively demonstrated to be a result largely of fossil fuel burning. … That the Earth has warmed and that GHGs are responsible is unequivocal.”

60: 2011, isolation and application of SOx– and NOx-resistant microalgae in biofixation of CO2 from thermo-electricity plants, Energy Conversion And Management, Radmann EM; Camerini FV; Santos TD; Costa JAV, 3, 1

“Microalgae have been studied for their potential use in foodstuffs, agriculture, in the treatment of wastewater and, in particular, in the reduction of atmospheric carbon dioxide, the main cause of global warming.”

61: 2011,On the time-varying trend in global-mean surface temperature, Clim. Dynam.,Wu ZH; Huang NE; Wallace JM; Smoliak BV; Chen XY, 4, 1

“… we estimate that up to one third of the late twentieth century warming could have been a consequence of natural variability.”

62: 2011, Performance of amine-multilayered solid sorbents for CO2 removal: effect of fabrication variables, Int. J. GHG Control, Jiang BB; Kish V; Fauth D; Gray ML; Pennline HW; Li BY, 3, 1

“The emission of fossil fuel carbon dioxide (CO2) to the atmosphere is implicated as the predominant cause of global climate change.”

63: 2011, Sensitivity of the attribution of near surface temperature warming to the choice of observational dataset, GRL, Jones GS; Stott PA, 4, 1

“Our results show that the dominant contributor to global warming over the last 50 years of the 20th century is that due to greenhouse gases.”

64: 2011, The relative contribution of waste heat from power plants to global warming, Energy, Zevenhoven R; Beyene A, 4, 1

“Evidence on global climate change, being caused primarily by rising levels of greenhouse gases in the atmosphere, is perceived as fairly conclusive.”

Annex 2

The 23 papers not endorsing the quantitative consensus

Relevant extracts from those 23 of the 64 abstracts listed by Cook et al. as endorsing their quantitative definition of the consensus hypothesis that do not endorse it are below, with reasons why they do not endorse it. The remaining 41 abstracts, in Annex 1, endorse it.

The data entries have been edited for clarity, particularly by including a space after each delimiting comma; decapitalizing abstract titles; abbreviating and italicizing journal names; removing a “|” mark that appeared after each author’s name; capitalizing all authors’ initials; and correcting some typographical errors.

2: 1992, Past; present and future levels of greenhouse gases in the atmosphere and model projections of related climatic changes, J. Experim. Botany, Roeckner E, 2, 1

“The more recent increase in greenhouse gases since pre-industrial times can be related to human activities.”

Reason for rejection: The increase “can be related to human activities”, but the abstract falls short of saying that most of the increase is attributable to human activities.

3: 1993, How sensitive is the world’s climate?, Research & Explor., Hansen J; Lacis A; Ruedy R; Sato M; Wilson H, 4, 1

“Observed global warming of approximately 0.5 C° in the past 140 years is consistent with anthropogenic greenhouse gases being the dominant climate forcing in that period.”

Reason for rejection: “… is consistent with” is not the same thing as “is likely to have been”.

5: 1995, Climate response to increasing levels of greenhouse gases and sulfate aerosols, Nature, Mitchell JFB; Johns TC; Gregory JM; Tett SFB, 4, 1

“CLIMATE models suggest that increases in greenhouse-gas concentrations in the atmosphere should have produced a larger global mean warming than has been observed in recent decades, unless the climate is less sensitive than is predicted by the present generation of coupled general circulation models.”

Reason for rejection: The abstract qualifies its first statement by saying that the climate may be less sensitive than models predict.

7: 1998, A Bayesian statistical analysis of the enhanced greenhouse effect, Clim. Change, Tol RSJ; De Vos AF, 4, 1

“… there is a robust statistical relationship between the records of the global mean surface air temperature and the atmospheric concentration of carbon dioxide over the period 1870–1991. As such, the enhanced greenhouse effect is a plausible explanation for the observed global warming.”

Reason for rejection: The greenhouse effect is a “plausible explanation”, but it is not definite, and there is no quantification.

8: 1999, CFC and halon replacements in the environment, J. Fluor. Chem., McCulloch A, 3, 1

“Substitute fluorocarbons may have direct environmental impact, for example as greenhouse gases … The growth in hydrofluorocarbons (HFCs) amounts to about 10% of the fall in CFCs. It is likely that the impact of new fluorocarbons on climate change will be a very small fraction of the total impact, which comes mainly from the accumulation of carbon dioxide in the atmosphere.”

Reason for rejection: The “total impact” mentioned in the abstract is the impact of Man, not that of Man and nature combined. Man’s impact does come mainly from the accumulation of CO2 in the air, but that falls short of saying that Man’s impact has caused more than half of recent warming.

9: 2000, Causes of climate change over the past 1000 years, Science, Crowley TJ, 5, 1

“The combination of a unique level of temperature increase in the late 20th century and improved constraints on the role of natural variability provides further evidence that the greenhouse effect has already established itself above the level of natural variability in the climate system.”

Reason for rejection: The greenhouse effect may (or may not) have added to the warming that may have arisen from natural variability, but there is no quantification of how much it has added to natural warming.

10: 2000, Radiative forcings and global warming potentials of 39 greenhouse gases, JGR Atmos., Jain AK; Briegleb BP; Minschwaner K; Wuebbles DJ, 4, 1

“Our total radiative forcing due to increase in major greenhouse gas concentrations for the period 1765–1992 is 2.32 Wm−2, only 2% higher than other recent estimates; however, the differences for individual gases are as large as 23%.”

Reason for rejection: Stating the magnitude of a radiative forcing falls short of stating the magnitude of the warming the forcing may be thought to have engendered.

12: 2000, Response of the NCAR climate system model to increased co2 and the role of physical processes, J. Clim., Meehl GA; Collins WD; Boville BA; Kiehl JT; Wigley TML; Arblaster JM, 4, 1

“Another process that contributes to climate response to increasing CO2 is sea-ice changes, which are estimated to enhance global warming by roughly 20% in the CSM and 37% in the DOE model. Sea-ice retreat with increasing CO2 in the CSM is less than in the DOE model in spite of identical sea-ice formulations.”

Reason for rejection: The fact that global warming in the future may be enhanced by sea-ice retreat tells us nothing about whether global warming in the past has chiefly been manmade.

13: 2001, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature, Jacobson MZ, 4, 1

“The magnitude of the direct radiative forcing from black carbon itself exceeds that due to CH4, suggesting that black carbon may be the second most important component of global warming after CO2 in terms of direct forcing.”

Reason for rejection: The abstract is talking of the manmade component, not including the natural component. So there is no quantification of the relative magnitudes of the two: nor is any period specified.

15: 2002, Modeling future climate changes: certainties and uncertainties, Houille Blanche Revue Internationale de l’Eau, Le Treut H, 4, 1

“Present projections indicate, in all cases, a significant change, with a global surface warming in 2100 between 2 C° and 6 C°.”

Reason for rejection: Projections are one thing; observations another. The fact that global warming is projected tells us nothing about what fraction of it in the observed past is attributable to Man.

18: 2003, Utilization of carbon dioxide as soft oxidant in the dehydrogenation of ethylbenzene over supported vanadium-antimony oxide catalystst, Green Chemistry, Chang JS; Vislovskiy VP; Park MS; Hong DY; Yoo JS; Park SE, 3, 1

“This work shows that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene over alumina-supported vanadium oxide catalysts.”

Reason for rejection: “A main contributor” is not the same as “the main contributor”.

21: 2005, Is the Sonoran Desert losing its cool?, Global Change Biol., Weiss JL; Overpeck JT, 2, 1

“Minimum temperature variability in the Sonoran Desert does, however, correspond to global temperature variability attributed to human-dominated global warming.”

Reason for rejection: A correspondence between regional and global patterns of temperature variability attributed to Man is not the same as an assertion that most recent warming is manmade.

24: 2006, Observational constraints on past attributable warming and predictions of future global warming, J. Clim., Stott PA; Mitchell JFB; Allen MR; Delworth TL; Gregory JM; Meehl GA; Santer BD, 4, 1

“… the spatial and temporal nature of observed twentieth-century temperature change constrains the component of past warming attributable to anthropogenic greenhouse gases to be significantly greater (at the 5% level) than the observed warming over the twentieth century.”

Reason for rejection: A 5% confidence level is too low to be reliable.

26: 2006, Positive feedback between global warming and atmospheric CO2 concentration inferred from past climate change, GRL, Scheffer M; Brovkin V; Cox PM, 5, 1

“There is good evidence that higher global temperatures will promote a rise of greenhouse gas levels, implying a positive feedback which will increase the effect of anthropogenic emissions on global temperatures. However, the magnitude of this effect predicted by the available models remains highly uncertain, due to the accumulation of uncertainties in the processes thought to be involved.”

Reason for rejection: The abstract tells us nothing of what has happened. It merely predicts what will happen.

28: 2006, Transient climate simulations with the HADGEM1 climate model: causes of past warming and future climate change, J. Clim., Stott PA; Jones GS; Lowe JA; Thorne P; Durman C; Johns TC; Thelen JC, 4, 1

“The ability of climate models to simulate large-scale temperature changes during the twentieth century when they include both anthropogenic and natural forcings and their inability to account for warming over the last 50 yr when they exclude increasing greenhouse gas concentrations has been used as evidence for an anthropogenic influence on global warming. … new simulations support previous work by showing that there was a significant anthropogenic influence on near-surface temperature change over the last century.”

Reason for rejection: “A significant anthropogenic influence” does not necessarily mean “more than 50%”.

34: 2008, Banagrass vs. eucalyptus wood as feedstocks for metallurgical biocarbon production, Indust. & Eng. Chem. Res., Yoshida T; Turn SQ; Yost RS; Antal MJ, 3, 1

“Excessive emissions of fossil CO2 are known to be a primary cause of global climate change.”

Reason for rejection: “A primary cause” is not the same as “the primary cause”.

39: 2008, Implications of “peak oil” for atmospheric CO2 and climate, Global Biogeochem. Cycles, Kharecha PA; Hansen JE, 3, 1

“Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming.”

Reason for rejection: The dominant cause of anthropogenic warming, but not necessarily the dominant cause of all global warming.

40: 2008, Industrialization; fossil fuels; and the transformation of land use, J. Indust. Ecol., Erb KH; Gingrich S; Krausmann F; Haberl H, 4, 1

“Human-induced changes in global stocks and flows of carbon are major drivers of global climate change.”

Reason for rejection: “Major drivers”, but not “the major drivers”.

44: 2009, Climate change and drying of agricultural products, Drying Technol., Piacentini RD; Mujumdar AS, 3, 1

“Global warming is affecting the world and will continue to affect humans and the ecosystem in the future.”

Reason for rejection: Global warming may or may not be “affecting the world”, but there is nothing in the abstract to tell us that more of it is anthropogenic than natural.

46: 2009, Cost-benefit analysis of climate change dynamics: uncertainties and the value of information, Clim. Change, Rabl A; Van Der Zwaan B, 4, 1

“We analyze climate change in a cost–benefit framework, using the emission and concentration profiles of Wigley et al. (Nature 379(6562):240–243, 1996). They present five scenarios that cover the period 1990–2300 and are designed to reach stabilized concentration levels of 350, 450, 550, 650 and 750 ppmv, respectively.”

Reason for rejection: The abstract concerns itself with projections, and – other than referring to Wigley’s scenarios starting in 1900 – makes no reference to past warming at all, let alone saying that most of it was manmade.

49: 2010, Assessing the climatic benefits of black carbon mitigation, PNAS, Kopp RE; Mauzerall DL, 3, 1

“To limit mean global warming to 2 °C, a goal supported by more than 100 countries, it will likely be necessary to reduce emissions not only of greenhouse gases but also of air pollutants with high radiative forcing (RF), particularly black carbon (BC).”

Reason for rejection: The statement of a target for future emissions is not equivalent to a statement that most recent warming was caused by past emissions.

54: 2010, The Copenhagen accord for limiting global warming: criteria; constraints; and available avenues, PNAS, Ramanathan V; Xu YY, 3, 1

“At last, all the major emitters of greenhouse gases (GHGs) have agreed under the Copenhagen Accord that global average temperature increase should be kept below 2 °C.”

Reason for rejection: The adoption of a target for future emissions is not equivalent to a statement that most recent warming was caused by past emissions.

55: 2011, Coupled climate-society modeling of a realistic scenario to achieve a sustainable earth, J. Oceanog.,Ikeda M, 4, 1

“The surface air temperature (SAT) rises due to the atmospheric carbon, which is partially absorbed by the terrestrial ecosystem and the ocean. These absorption rates are reduced by the rising SAT.”

Reason for rejection: There is no statement here that the surface air temperature rises solely or chiefly owing to the atmospheric CO2.

“Ninety-seven percent of scientists agree: climate change is real, man-made and dangerous”… Survey Says: NOT!

From Watts Up With That:

David Middleton /

Guest dredging up the past by David Middleton

As a geologist, I spend my work days dredging up the past, mostly from the Upper Miocene to the Lower Pleistocene.  My earlier post today about Dr. Will Happer joining the Trump administration led me to dredging up a 2016 survey of the American Meteorological Society (Maibach et al., 2016)… And that led me to dredging up this 2013 Tweet from thankfully former President Barack Hussein Obama…


In light of CNN’s proclamation that Dr. Happer’s “public stance on climate change is in opposition to near universally accepted science,” as outlined in thankfully former President Barack Hussein Obama’s Tweet, I decided to proverbially put 2 + 2 together and see if I get 97%.

“Climate change is real”

Page 8 from AMS_Member_Survey_Report_2016-4


Pages_11_12 from AMS_Member_Survey_Report_2016_Page_1

“And dangerous”

Page 20 from AMS_Member_Survey_Report_2016-2

Page 22 from AMS_Member_Survey_Report_2016-3

“And today, there’s no greater threat to our planet than climate change.”

 So climate change can no longer be denied – or ignored. The world is looking to the United States – to us – to lead. 

–Thankfully former President Barack Hussein Obama, April 18, 2015


Pages_11_12 from AMS_Member_Survey_Report_2016_Page_2

Climate Change…

Survey Says.png


Maibach, E., Perkins, D., Francis, Z., Myers, T., Englbom, A., et al. (2016). A 2016 National
Survey of American Meteorological Society Member Views on Climate Change: Initial Findings. George Mason University, Fairfax, VA: Center for Climate Change Communication.

The Great Climate Change Debate: William Happer v. David Karoly, Part B

From Watts Up With That:

By Andy May

In Part A of the Great Debate series (see here) we discussed Dr. David Karoly’s and Dr. William Happer’s arguments regarding how unusual the recent global warming is and how we know the recent observed increase in CO2 is due to human activities. In Part B we will examine their thoughts on questions three and four.

3. How do we know that the increase in CO2 and other greenhouse gases in the atmosphere have caused most of the recent global warming?

4. Climate models have been used to compute the amount of warming caused by human activities, how accurate are they?

For an introduction to the debate and links to the original documents see Part A.

3. How do we know that the increase in CO2 and other greenhouse gases in the atmosphere have caused most of the recent global warming?

Karoly’s first argument is an appeal to the “consensus.”

“Nevertheless, an overwhelming consensus of climate scientists agree that human-caused climate change is happening, and that global warming will continue throughout the current century, with many adverse impacts on human and natural systems.” From the Karoly statement.

Happer’s detailed response contains his view of “consensus science.”

“Truth has never been determined by “an overwhelming consensus,” and in fact, consensuses have often been completely wrong.” From Happer’s detailed response.

In Karoly’s statement, he goes straight into a discussion of how we know much of the increase in CO2 concentration in the atmosphere is from humans (see previous question in Part A, note Happer agrees the increase in CO2 is due to human activities) but provides no more evidence that CO2 and other greenhouse gases have caused most of the recent warming. For the calculation of the greenhouse gas contribution, he turns to climate models.

How computer models are used to separate natural warming from human-caused warming:

“… climate model simulations have been used to assess the relative importance of different forcing factors on the climate system and how well they explain the observed global warming. The simulations are driven by natural forcing factors, such as changes in solar radiation and volcanic aerosols, as well as human-caused changes in greenhouse gases and human activity-related climate forcing factors, including industrial aerosols and land use change.” From the Karoly statement.

Karoly refers to a whisker plot from the IPCC AR5 report (Figure 3) which shows the impact of human and natural “climate forcings” as computed by the climate models from 1951-2010.

Figure 3. The assumed temperature changes due to GHG (greenhouse gases), ANT (anthropogenic), OA (other anthropogenic), NAT (natural forces), and INT (internal climate variablity) from 1951 to 2010. Source Figure 10.5 from (IPCC 2013) page 884.


Karoly also provides the following illustration of the reasons we “know” humans are causing global warming (Figure 4).

Figure 4. Reasons that we know humans are causing [some] global warming. Source


Most of the reasons given are related to human CO2 emissions, which both Happer and Karoly agree are the main cause of the rising CO2 concentration in the atmosphere and oceans. The principal disagreement between them is how much warming is caused by CO2. The tropopause rises as the surface warms, this is not controversial. Karoly believes that since winter is warming more than summer and nights more than days, this excludes solar variability as a cause of the warming, perhaps this is so. But, none of the reasons given exclude internal variability (mainly ocean cycles).

The cooling upper atmosphere (stratosphere) could be due to more CO2, since CO2 radiates a lot of infrared radiation (IR) to space from the stratosphere. It could also be due to increased shielding of thermal radiation from below due to additional IR absorption in the troposphere. But, regardless of the cause, there is a noticeable correlation between the observed tropospheric warming and the stratospheric cooling in the atmosphere. For a discussion of the significance of the correlation, displays of the data and additional references see Munshi, 2018 (Munshi 2018). Thus, the essence of the debate is not if CO2 warms the lower atmosphere, the argument is about how much warming is due to CO2 and other greenhouse gases. More detail on Figure 4 and references can be seen at this link by John Cook.

Happer points out at the beginning of his statement that CO2 levels today are much lower than during almost any time in the history of life on Earth. Figure 5 shows the history of CO2 levels for the past 550 million years.

Figure 5. History of CO2 levels for the past 550 million years. Source: (Berner and Kothavala 2001).


Happer writes this about Figure 5:

“The important message of Fig. [5] is that CO2 concentrations have been much higher than present values over most of the history of life. Even though CO2 concentrations were measured in thousands of parts per million by volume (ppm) over most of the Phanerozoic, not the few hundred ppm of today, life flourished in the oceans and on the land. Average pH values in the ocean surface were as low as pH = 7.7, a bit lower than the pH = 8.1 today. But this was still far from acidic, pH < 7, because of the enormous natural alkalinity of seawater. The mean global temperature was sometimes higher and sometimes lower than today’s. But the temperature did not correlate very well with CO2 levels. For example, there were ice ages in the Ordovician, some 450 million years ago, when the CO2levels were several thousand ppm.” (Berner and Kothavala 2001) and (Quinton and MacLeod 2014) From Happer’s statement.

Tamblyn writes the following about the same graph and a separate, but similar one in his detailed response:

“Lest we wonder how the Ordovician ice age could have occurred … GEOCARB III (which Professor Happer also references) is a geochemical model, which estimates past CO2 levels from the chemistry of rocks. Its calculations are run over steps of 10 million years and averaged over 50 million years. It is not sensitive enough to detect shorter-term changes. Direct geological evidence shows that CO2 levels fell sharply during that period, in 1 to 2 million years or less — too small for GEOCARB III to capture. A higher-resolution geochemical model applied just to this period suggests a decline of CO2 levels from ~5000 to 3000 ppm. With differences in solar output, 3000 ppm then is equal to 500 ppm today. Climate models applied to late Ordovician conditions predict icehouse conditions at CO2 levels below about 2240 to 3920 ppm.

The explanation is that changes in the greenhouse effect over time, due to changes primarily in CO2 and methane levels, explain much of the observed climate history. They aren’t the only factors. Orbital cycles influence how much sunlight the Earth receives. The extent of snow and ice changes how reflective the Earth is. The position of the continents matters (land reflects more sunlight than the oceans), and continents shape the flow of ocean currents, influencing heat transport. For around 30 million years, Antarctica has been isolated and surrounded by a huge current, the Antarctic Circumpolar Current, promoting cooling. For many, hundreds of millions of years before, this wasn’t so.” Tamblyn detailed response.

So, 3000 ppm in the Ordovician ice age is equal to 500 ppm today, yet we are currently at 400 ppm? Tamblyn’s point about resolution is valid but does not prove his case and his numbers are inconsistent with his thesis. He lists many valid influences on climate but fails to make the case that CO2 is the dominant influence. The quoted passage appears to weaken Tamblyn’s case and strengthen Happer’s.

4. Climate models have been used to compute the amount of warming caused by human activities, how accurate are they?

Karoly explains that natural forces are separated from human influences on climate with more than 30 computer models that compare well to observations since 1860 and writes:

“The observed significant cooling for one to two years after major volcanic eruptions —Santa Maria (1903), Agung (1963), El Chicon (1982), and Pinatubo (1991) —is simulated very well. The observed global mean temperature variations throughout the whole period lie within the range of all the model simulations with combined forcings, indicating the models simulate well the chaotic interannual variability of global mean temperature. There is very good agreement between the observed long-term global warming since the late nineteenth century and the average global warming across all the model simulations for combined natural and anthropogenic forcing.” From the Karoly statement.

He shows the following illustrations (Figure 6) from IPCC AR5 (IPCC 2013):

Figure 6. (a) The ensemble mean of numerous CMIP3 and CMIP5 climate models are shown in blue and red and compared to observations shown in black. The range of modeled results is shown with yellow and gray shading. The minimum warming in (a) from the models can be almost a degree C lower than the maximum model value for any given date and the error increases with time. This display models both human-caused and natural warming. (b) Same as (a) but only natural warming is simulated. (c) Same as (a) but only greenhouse gas warming is simulated. (c) suggests that net forcing (except for greenhouse gases) is negative, since natural forcings are assumed to be zero by the IPCC, they claim the negative forcings are “other anthropogenic.” The temperature anomalies are computed relative to the mean from 1880-1919. Source IPCC AR5, figure 10.1 (IPCC 2013) page 879.

Thus, the evidence for the magnitude of the human impact on climate is entirely model-based and direct measurements of the impact have not been made. Critics also point out that the warming from 1910 to 1945 and 2000 to 2012 are poorly matched by the models. Karoly responds:

“Of course, a small number of scientists say that the climate models are tuned to simulate the recent observed warming but are unreliable for projecting future warming trends. Others say that they show too much global warming, because the observed warming from 1998 to 2010 was very small, while the simulated warming continued, if you consider the average across all the climate model simulations. As shown already when considering the observed global mean temperature variations, there is large natural variability in global mean temperature in the observations and the models. The observed departure in 2010 from the multi-model mean is no larger than in 1910 or in 1940 and is well within the envelope of all the model simulations.” From the Karoly statement.

Thus, the poor reproduction of 1910-1945 and 2000-2012 is acknowledged, but in Karoly’s opinion the mismatch is acceptable. The error from 1910 to 1945 ranges from -0.2° to +0.4°C, approximately equal to the warming from 1975 to 2010, but human emissions of CO2 were not considered (or modeled) to be significant before 1951. How interesting that both sides use the poor model match from 1910-1945 in their arguments, but with opposite intent.

Happer has the following to say about using climate models to “prove” global warming since 1951 is primarily due to human activity:

“I disagree. This statement is based on excessive faith in computer models. The wide availability of computers and powerful software to make color displays has been a serious problem, since it has blurred the lines between reality and virtual reality. These are not the same. In my Statement and Interview I tried to stick to real satellite pictures of visible and thermal radiation from the Earth, real measurements of ocean pH, real records of tornados, hurricanes, floods, droughts, etc. Essentially all of Dr. Karoly’s claims of warming from greenhouse gases come from computer models, with lurid, threatening reds to represent the supposedly harmful effects of the demon gas, CO2.” Happer’s detailed response.

What is coming next?

The answers the scientists give to these questions highlight a significant and key difference in interpretation. Karoly is comfortable with the results from the climate models and Happer is not. As a result, Karoly is comfortable with the model-based conclusion that CO2 and other greenhouse gases are responsible for most of recent warming. Happer is not convinced the models are accurate and provides his own calculations and observations that show far less warming from CO2. Part C of this series will discuss their thoughts on the accuracy of future temperature estimates. It examines questions five and six. These are:

  • How do we know global warming and more CO2 will have substantial adverse impacts on humans and the planet?
  • Should anything be done to combat global warming?

Equilibrium Climate Sensitivity (ECS) to a doubling of the CO2 concentration has not been measured and is poorly estimated, the IPCC range of possible values is 1.5 to 4.5 and it has stayed at this range since 1979. How much difference does this range make?

Works Cited

Berner, Robert, and Zavareth Kothavala. 2001. “Geocarb III: A Revised Model of Atmospheric CO2 over Phanerozoic Time.” American Journal of Science 301 (2): 182-204.

IPCC. 2013. In Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, by T. Stocker, D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley. Cambridge: Cambridge University Press.

Munshi, Jamal. 2018. “Climate Change, Tropospheric Warming, and Stratospheric Cooling.” SSRN (SSRN).

Quinton, P., and K. MacLeod. 2014. “Oxygen isotopes from conodont apatite of the midcontinent US: Implications for Late Ordovician climate evolution.” Palaeogeography, Palaeoclimatology, Palaeoecology 404: 57-66.

The Fight Against Global Greening – Part 4

Guest Essay by Kip Hansen


This is Part 4 of a four part series.  If you are not familiar with The Fight Against Global Greening – Part 1,  Part 2 and Part 3 you can either read them in their  entirety and then read this, or read the introduction of Part 1 up to the line “Let’s look at #1” and then read this. — kh

Carl Zimmer of the NY Times has said “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”.  In collaboration with Dr. J. E. Campbell of the Sierra Nevada Research Institute, he has stated that position,  offering us these:

Bad Things About Global Greening: (quoted from Zimmer’s article)

1. “More Photosynthesis Doesn’t Mean More Food“

2. “Extra Carbon Dioxide Can Make Plants Less Nutritious”

3. “More Plants Won’t Prevent Climate Change”

4. “Global Greening Won’t Last Forever”

In Part 1, we looked at the question of the relationship between increased photosynthesis and food production (Zimmer’s #1).  In Part 2, we discussed the claim that “extra carbon dioxide can make plants less nutritious”. And in Part 3 we discussed the fact that Global Greening, by itself, would not stop climate change.

In this final and shorter segment, I discuss the implications of the obviously true fact that Global Greening won’t last forever.

Let’s Look at #4:  “Global Greening Won’t Last Forever”

Here’s what Zimmer and Campbell say:

Global Greening Won’t Last Forever

There’s still a lot that Dr. Campbell and his colleagues don’t understand about global greening. Most importantly, they don’t know how long it will last.

As temperatures rise and rainfall patterns change, plants may stop soaking up extra carbon dioxide.

“Plants are quietly scrubbing the air of one China’s worth of carbon. What frightens me is knowing this can’t go on forever,” said Dr. Campbell. “If respiration catches up with photosynthesis, this huge carbon reservoir could spill back into our air.”

“There’s a wild card out there.”

— Carl Zimmer, “NY Times article “Global Greening….it’s Terrible

I’ll try to do a better job of stating Zimmer’s (and Campbell’s) position than they do.

Zimmer admits that the subject of Global Greening is young and still full of unknowns…the usual list includes known unknowns, unknown unknowns, etc.  It is refreshing to see an admission of anything less than Omnipotence and Settled Science.

“Most importantly, they don’t know how long it will last,” Zimmer says.

Well, neither do I (nor do you  or anyone else).   There is pertinent science on the topic though — greenhouse men have been growing flowers and other horticultural crops under enhanced CO2 for many years and there doesn’t seem to be an upper limit of CO2 concentrations that the atmosphere will be reaching, at least in this or the next century.


So, although various plants have their individual CO2 saturation points (the point at which increasing CO2 does not increase photosynthesis – colored orange), the general figure given for maximum benefit by many experts is 1000 ppm.  [The graph above is only illustrative.]  The important bit is that plants generally keep increasing photosynthesis with additional CO2 — up to about 1000 ppm.

The 21st Century average  annual increase in atmospheric CO2 is around 2.5 ppm per year, so that gives us, if everyone keeps emitting CO2 at the same rate, and no one even tries to meet Paris emission reduction targets,  240 more years of possible Global Greening effect from CO2 enhancement.   Of course, some plants will top out at 800 ppm, some at 900 ppm, some plants will find they don’t get enough water and some won’t find sufficient nutrients.

Now Zimmer and Campbell are afraid that at some point the horror-story RCP 8.5 scenario will actually come to pass, the planet’s average surface temperature will rise so high and droughts become so extensive (well, wherever it is not flooding)  that plants will not only stop absorbing China’s portion of emissions, but will die and all that carbon will be released back into the atmosphere — all at once — as CO2 through the breakdown of the plant debris. This is what Campbell means when he says “If respiration catches up with photosynthesis, this huge carbon reservoir could spill back into our air.”

It is certainly true that if all the plants died — or even if just a great percentage of the plants died — decomposition, through natural processes, would begin to breakdown the plant material on the ground and in the ground into simpler compounds and CO2 would be emitted — the principle of biological respiration in the carbon cycle.    Here is The Carbon Cycle.


Zimmer’s catastrophic fears will not be realized because of the grey boxes in the Carbon Cycle diagram — these are Carbon Stores.  They are unlike Campbell’s “reservoir of carbon” analogy — they are not a big dammed lake full of carbon dioxide that is posed to “spill” back into our air.  We see “Respiration” right above the black-and-white cow in the diagram.  More correctly, the flow of CO2 to the atmosphere from Decay and part of the exchange with the oceans can also be considered Respiration in the biological carbon cycle.  The Carbon Stores have been created as  carbon dioxide has been transformed  through photosynthesis and the actions of plant and animal life into vegetation (leaves, stems, tree trunks, woody brush), it has become soil and the organic matter in the soil, some is locked up in the surface waters of the oceans and much has sunk to the deep ocean not to be seen for centuries or millennia, sediments on the ocean floor are carbonaceous and will eventually become sedimentary rock through the process of rock formation,  some has become and will become deposits of oil and coal and gas and some is locked up in the bodies of all the planet’s animal life, including 8 billion human beings.

Dr. Campbell must be very confused if he truly thinks that the “end of Global Greening” would result in any sort of threatening sudden spill of carbon back into the atmosphere.

As I discussed in Part  — it is the bio-sequestration of carbon and once sequestered, the carbon will not return to the atmosphere as carbon dioxide for varying lengths of time — on a time scale ranging from days to millennia.

But Zimmer and Campbell fear another aspect of Global Greening:  What if man keeps emitting 40-50-60 billion tons of CO2 every year and things are being kept in check somewhat by the fact that Nature will have been soaking up 10-12-15 billion tons of that CO2 annually, and then suddenly Nature is CO2-saturated and photosynthesis levels off while CO2 emissions keep rising and rising?    Well, I guess that is within the realm of possibility — but like many alarmists visions of the future, it relies on the assumption that things will only stay the same or get worse — and neglects the more likely possibility that Mankind will mitigate the ill effects and reinforce and take advantage of the good effects of our changing world and climate.

I don’t think that it is overly optimistic to think that in the next 150 years we will see energy breakthroughs that obviate our worries of Global Warming by eliminating the need to produce electricity energy by burning hydrocarbons — oil, gas, coal, wood.

In the last 150 years, we have gone from the burning of peat, wood and charcoal; through the massive coal age; and the petroleum age.  The nuclear age got off to a good start, only to be stalled by the fears of the anti-nuke activists.  One hopes that with the newest designs for nuclear power plants and the hopes of fusion, the nuclear age will really get going again.

What we needn’t worry about are the groundless fears expressed by Dr. Campbell and parroted by Zimmer in the NY Times — the fact that Global Greening will not last forever is a simple biological fact and has no foreseeable downsides for mankind.

Global Greening is not terrible — GLOBAL GREENING  is WONDERFUL.

# # # # #

Author’s Comment Policy:

To those who have managed to read all four of the essays in the series, congratulations, you exceed my expectations….I barely managed enough patience to write them.  In retrospect, I could have combined Parts 3 and 4.   I did think it was important to put the senseless fear mongering of Zimmer and Campbell to rest — countering them with basic science.

What I worry about is that the average NY Times reader is so deficient in basic science education that they will have read  Zimmer’s “Global Greening…Its Terrible” and not seen through the illogic and pseudo-science.    Hope that some of them may read here springs eternal.

As always, appreciate you having  put in the time to read here.

Address your comments to “Kip…” if you are speaking to me personally, and I’ll try to field your question or concern.

# # # # #

Quick Links:

The Fight Against Global Greening – Part 1

The Fight Against Global Greening – Part 2

The Fight Against Global Greening – Part 3

NY Times article “Global Greening….it’s Terrible

bio-sequestration of carbon

The Fight Against Global Greening – Part 3

From Watts Up With That:    Kip Hansen /

Guest Essay by Kip Hansen

Green_Madness_Part_3This is Part 3 of a four part series.  If you are not familiar with The Fight Against Global Greening – Part 1 and Part 2, you can either read them in their  entirety and then read this, or read the introduction of Part 1 up to the line “Let’s look at #1” and then read this. — kh

Carl Zimmer of the NY Times has said “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”.  In collaboration with Dr. J. E. Campbell of the Sierra Nevada Research Institute, he has stated that position,  offering us these:

Bad Things About Global Greening: (quoted from Zimmer’s article)

1. “More Photosynthesis Doesn’t Mean More Food“

2. “Extra Carbon Dioxide Can Make Plants Less Nutritious”

3. “More Plants Won’t Prevent Climate Change”

4. “Global Greening Won’t Last Forever”

In Part 1, we looked at the question of the relationship between increased photosynthesis and food production (Zimmer’s #1).  In Part 2, we discussed the claim that “extra carbon dioxide can make plants less nutritious”.

Let’s Look at #3:  “More Plants Won’t Prevent Climate Change”

Here’s what Zimmer and Campbell say:

“More Plants Won’t Prevent Climate Change

“It’s not just strawberries and other crops that are taking in extra carbon dioxide. So are the forests, grasslands and other wild ecosystems of the world.

When scientists take into account both extra photosynthesis and respiration, they estimate that plants remove a quarter of the carbon dioxide we put in the atmosphere.

“That’s on par with what China emits,” said Dr. Campbell. “And China is the biggest global polluter.”

Even more remarkably, the plants have been scrubbing the same fraction of carbon dioxide out of the air even as our emissions explode.

“Every year we build more power plants, and every year the plants take out more CO2,” Dr. Campbell said.

But that isn’t cause to celebrate. It’s a bit like hearing that your chemotherapy is slowing the growth of your tumor by 25 percent.

Despite global greening, carbon dioxide levels have climbed over the past two centuries to levels not seen on Earth for millions of years. And the carbon dioxide we’ve injected into the atmosphere is already having major impacts across the planet.

The six warmest years on record all occurred after 2010. The weather has already become more extreme. Sea levels have risen. The oceans are acidifying.

If plants keep on absorbing only a quarter of our carbon dioxide in the future, then we can expect all these trends to get stronger.

In other words, if global greening isn’t saving us now, we can’t rely on it to save us in the future.”

Let’s try to figure out the logic to what Zimmer and Campbell are saying.  They accept without argument that:

  1. “plants remove a quarter of the carbon dioxide we put in the atmosphere.”

“That’s on par with what China emits,” said Dr. Campbell. “And China is the biggest global polluter.”

2. “the plants have been scrubbing the same fraction of carbon dioxide out of the air even as our emissions explode.”

“Every year we build more power plants, and every year the plants take out more CO2,” Dr. Campbell said.

Now, if any other process could be credited with removing a full 25% of all CO2 emitted by mankind every year, year after year, it would be labelled heroic.  Governments and laboratories are fielding schemes to hopefully remove fairly small  amounts of CO2  or to prevent them from being emitted in the first place — these pages here at WUWT  feature these ideas, one after another — schemes to convert CO2 into rocks, capture CO2 into fuels like ammonia, capture and store CO2 in caves and oil wells.  Just  imagine for a moment that we were talking about China reducing its CO2  emissions to zero overnight.  This is what Global Greening is currently doing, cost free.

But instead of applauding this biologically-induced geoengineering feat, Zimmer offers us (and I am actually embarrassed, on his behalf,  to quote him) this:

“But that isn’t cause to celebrate.

It’s a bit like hearing that your chemotherapy is slowing the growth of your tumor by 25 percent.”

[ Let’s ignore the insensitivity of this statement — how hurtful it must be to those fighting cancer themselves, or with relatives fighting cancer,  around the world, who would be thrilled to hear that the growth their tumors had been slowed.  The comparison of CO2 emissions to cancer is itself is a vicious bit of insensitive propaganda hype. ]

The reduction of CO2 emissions by an entire “China’s worth” is “not a cause for celebration”?  Apparently, for Zimmer and Campbell, all of the Paris Agreement targets, even if actually being met by any country, would also not be “cause to celebrate”.  After all, they only slow the growth of atmospheric CO2 , they do not eliminate it altogether.

It is difficult to follow this line of reasoning….it doesn’t actually seem to be a line of reasoning, but rather a line of unreasoning.  The majority of the scientific world concerned with atmospheric CO2 is struggling, fighting, to reduce emissions and, if possible, remove CO2  from the atmosphere in order to reduce CO2 concentrations, which the IPCC has claimed to be dangerous.  Yet Zimmer vainly tries to convince us that a no-cost,  no-effort method that annually removes an amount of CO2  equivalent to the entire annual emissions of the world’s worst emitter, China, is “not a cause to celebrate.”

His position is simply paraphrased as:  “There is no good in removing CO2  from the atmosphere unless you can entirely stop its concentration  from growing.”   With this he has  thrown the entire Paris Agreement effort  under the bus.

What effect does Global Greening have on atmospheric CO2 concentrations?  Zimmer and Campbell have stipulated [agreed without the necessity of argument] that Global Greening removes from the atmosphere some about 10 billion tons of CO2 annually.  Not only that, but it keeps removing more each year as the globe greens.

Really?  Yes, here’s the graph:


This graph, from UCSD/Scripps, represents the Earth’s “breathing” — in the Northern spring and summer, growing plants remove COfaster than we emit it and the monthly data points go down. As growth slows in the mid-summer and through winter, plants don’t take up as much CO2 and emissions get ahead.  The Southern hemisphere does not have as much an effect on the graph as does the Northern hemisphere. We see though that as Global Greening takes hold, it takes up more parts-per-million year to year — in the 1960s, the seasonal difference was 6.2 ppm, by 2018 it has risen to 9 ppm.

Then this:


The other thing that is obvious is that CO2 concentrations (in ppm) continue to rise as modern societies (and Nature) continue to emit more CO2 than increased plant photosynthesis takes up.   Since 2000, from the first chart above,  the annual increase in ppm of seasonal uptake of CO2 has been about 0.125ppm/year — or 1/8th of a ppm per year.  In eight years, that increase is 1 ppm.  But CO2  is increasing at an average rate (2010-2017) of 2.54 ppm/year.  Global Greening will not catch up at these rates, will not stop and will not reverse the increase of CO2 atmospheric concentrations by itself.

Zimmer and Campbell are right on this score:

Global Greening, by itself, will not stop the rise in atmospheric CO2. 

Now that we’ve got a good handle on the facts, let’s revisit what claim Zimmer was attempting to refute with his odd claim that “Global Greening is terrible because  “More Plants Won’t Prevent Climate Change””.

Did anyone ever claim that Global Greening would prevent climate change?

In Zimmer’s “Global Greening….it’s Terrible” article in the NY Times, Zimmer says:

“Climate change denialists were quick to jump on Dr. Campbell’s research <b>as proof that increased carbon dioxide is making the world a better place.</b>

“So-called carbon pollution has done much more to expand and invigorate the planet’s greenery than all the climate policies of all the world’s governments combined,” the Competitive Enterprise Institute declared shortly after the study came out.

“The best messages are positive: CO2 increases crop yields, the earth is greening,” wrote Joseph Bast, the chief executive officer of the Heartland Institute, in an October 2017 email obtained by EE News.

In June, Mr. Bast co-authored an opinion piece in The Wall Street Journal in which he cited Dr. Campbell’s work as evidence of the benefits of fossil fuels. Our unleashing of carbon dioxide contributes “to the greening of the Earth,” he said. “

Zimmer engages in a journalistic trick — he jumps in with both boots to refute something that was never claimed in the first place — no one ever claimed that Global Greening would stop climate change.

How many things can you list that are good that will not stop climate change?  World Peace, an AIDS vaccine, ending poverty, an unbiased press.  The list is pretty long.  None of these would be terrible just because they don’t stop climate change, and neither is Global Greening.

It is not that Zimmer and Campbell don’t have a valid point — they do, but they don’t state it and they don’t use it — they do something illogical and try to establish a falsehood as true instead.

It would have been simple enough to say that,  from their viewpoint, while Global Greening may be a positive side effect of rising atmospheric CO2, their concerns about the potential negative effects of global warming/climate change lead them to continue to believe that rising atmospheric CO2 is, on balance, a negative thing, a bad thing, and in their odd choice of words, “terrible”.   We could accept that — they are allowed to have a point of view and to state it along with their reasoning for holding that viewpoint.   But Zimmer seems to have allowed himself to be swept up by emotion-fueled advocacy — his need to fight “climate change” at any cost — and lost his thread of rationality, abandoned his journalistic ethics and destroyed my respect for him as a science journalist.   Had he been writing on the Opinion pages of the NY Times, as Andy Revkin did, he could bang away with his climate change advocacy to his heart’s content —  but personal opinion disguised as facts doesn’t belong in the Science news section of any newspaper.

What he never should have tried to do is to convince his readers that “Global Greening is terrible” — it is not — GLOBAL GREENING IS WONDERFUL

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Author’s Comment Policy:

I was saddened by Carl Zimmer’s descent into irrational advocacy.  He is a sharp guy and usually writes good science journalism.   We often see the same thing here with our readers and their comments — someone who normally writes good comments, makes good observations, raises interesting questions suddenly flips and becomes an irrational advocate blathering illogic about some specialized topic — be it GMOs or Feral Cats.   It takes a very strong mind to keep on the rather narrow path of good science, rational thought, critical thinking and logical argument when dealing with a subject about which one is passionate.  The ability to do so is a trait we ascribe to scientists — who, because they are human like the rest of us, often let us down in this regard.

I hope readers will confine their comments to the subject of this essay.  Hint: it is about science journalism, Global Greening good-or-bad, and how advocacy and science reporting must not be mixed.

Recently, I have noticed that many readers treat every comment thread as an Open Thread — in which they are free to discuss — and endless argue —  whatever is on their minds.  This is not true.  The Policy of WUWT states: “Some off topic comments may get deleted, don’t take it personally, it happens. Commenters that routinely lead threads astray in areas that are not relevant or are of personal interest only to them may find these posts deleted.”   Moderation here is done with a light hand, but the principle of commenting on topic remains.

Address your comments to “Kip…” if you are speaking specifically to me and I’ll try to respond.

Thanks for reading.


The Fight Against Global Greening – Part 2

From Watts Up With That:

Guest Essay by Kip Hanson


GG_is_bad_for_foodNote:  This is Part 2 of a four part series.  If you are not familiar with The Fight Against Global Greening – Part 1, you can either read it in its entirety and then read this, or read the introduction of Part 1 up to the line “Let’s look at #1” and then read this. — kh

Carl Zimmer of the NY Times has said “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”.  In collaboration with Dr. J. E. Campbell of the Sierra Nevada Research Institute, he has stated that position,  offering us these:

Bad Things About Global Greening: (quoted from Zimmer’s article)

1. “More Photosynthesis Doesn’t Mean More Food“

2. “Extra Carbon Dioxide Can Make Plants Less Nutritious”

3. “More Plants Won’t Prevent Climate Change”

4. “Global Greening Won’t Last Forever”

In Part 1, we looked at the question of the relationship between increased photosynthesis and food production (Zimmer’s #1).  Now….

Let’s Look at #2:  “Extra Carbon Dioxide Can Make Plants Less Nutritious”

Here’s what Zimmer and Campbell say:

“A number of studies indicate that plants that grow in extra carbon dioxide often end up containing lower concentrations of nutrients such as nitrogen, copper and potassium.”

As more carbon dioxide gets into the atmosphere, the problem will grow. “There’s definitely strong evidence that quality will be affected,” said Dr. Campbell.

It’s not clear why this happens. In a paper published in the journal Current Opinion in Plant Biology in June, Johan Uddling of the University of Gothenburg in Sweden and his colleagues speculated that microbes are to blame.

Just as carbon dioxide speeds up photosynthesis, it may also increase the rate at which soil microbes take up nutrients, leaving less for plants to suck in through their roots.”

If we eat food that lacks nutrients, we become more vulnerable to a host of diseases. Recently, a team of researchers at Stanford University studied how future changes to crops could affect the world’s health. The findings were grim. In Southeast Asia, for example, the researchers estimated that the rate of iron deficiency may rise from 21.8 percent to 27.9 percent by 2050. Deficiencies in iron and other nutrients could make millions of people more vulnerable to diseases including malaria and pneumonia, leading to many premature deaths.”

Getting rid of the silly part first: “microbes are to blame” — Uddling et al. state very plainly that they have no idea why the differences in (primarily) proteins are found in wheat grown under higher CO2  concentrations.  Quoting from the conclusion:  “At present, none of mechanisms and processes hypothesized can fully explain the CO2-induced declines in crop N [proteins] concentrations.”  Second silly part:  “If we eat food that lacks nutrients”…. If it has no nutrients, it is not food at all.  Every bite of food we eat has either more, the same, or less of any one “nutrient” than every other bite of food — every piece of piece of fruit has more or less nutrients than every other piece of fruit — every grain has different concentrations of nutrients than every other grain.  That there are differences in concentrations of nutrients in foods is not a cause for alarm nor does it “cause” diseases, disabilities, or vulnerabilities.  I will reveal the true causes further on.

The most important point is embodied in the claim that plants grown under enhanced  CO2  conditions  “often end up containing lower concentrations of nutrients such as nitrogen, copper and potassium.”   This is the food faddists fallacy and is responsible for a great deal of nonsense in the food and nutrition fields of science.

There are always differences in nutritional values between individual crops of any food item.  The same food item harvested from the south forty acres of my grandfather’s farm will have different nutritional qualities when compared to the same variety harvested off the north forty acres of the same farm.  This is due to the slightly differing growth conditions, water availability, soil nutrient levels, fertilization schedules, planting dates, maturity at harvest and handling of the crop after harvest.  The south forty crop may have discernibly higher percentages of certain minerals, proteins, and carbohydrates than the north forty crop.  Likewise, the north forty crop may be higher in other measures of “nutritional value”.

When a farmer grows a different variety of the same crop — say a different corn variety — then the game changes wildly.

For instance, there are currently preserved at The Crop Trust   29,401 different varieties of maize (corn to those in the United States).  Here’s an example of the effect on nutritional values of crop varieties of corn:

“Maize is the preferred staple food of more than 1.2 billion people in Sub-Saharan Africa and Latin America. However, maize-based diets, particularly those of the very poor, often lack essential vitamins and minerals. Over 50 million people in these regions are vitamin A deficient, which can lead to visual impairments, blindness and increased child mortality. The white maize eaten in much of sub-Saharan Africa contains almost no pro-vitamin A, while standard yellow maize varieties contain about 2 micrograms per gram (µg/g) – still insufficient in a diet dominated by maize. …. Scientists anticipate producing materials with the ultimate target of 15 µg/g within the next four years by using cutting edge lab tools to help select the best materials for breeding.” 

Some maize contains no pro-Vitamin A at all — another yellow variety contains some, but not enough to prevent Vitamin A deficiency alone.  Through cross-breeding maize varieties, the breeders at The Crop Trust hope to create a variety that will provide the 15 ug/g necessary to prevent Vitamin A deficiency in those for whom maize the major staple food.  We all know the story of Golden Rice — suppressed by Greenpeace and other misguided fanatics — which could eliminate Vitamin A deficiency in areas depending on rice as a staple.

In this case, the corn that is the basic food for these people has virtually no Vitamin A — another variety has a lot more — but that “a lot more” doesn’t change the public health issue, it isn’t enough to guarantee to prevent Vitamin A deficiency.  So the yellow corn is not a superfood despite having many multiples  “more” Vitamin A.  These two varieties are both insufficient…a change of plus or minus 10% or even 50% will make no difference.  Vitamin A will have to be provided by a custom-bred corn variety or from another source.

The UN’s FAO reports:

“Fruits, roots, tubers, and leafy vegetables are the main providers of provitamin A carotenoids. Because of their availability and affordability, green leafy vegetables are consumed largely by the poor populations, but their provitamin A activity has been proven to be less than previously assumed. Among fruits, mangoes constitute an important seasonal source of vitamin A. Yellow or orange sweet potatoes are rich in provitamin A. Red palm oil has a high concentration of provitamin A carotenoids (500–700 ppm/100 g). Extension of new varieties with a high content of bioavailable provitamin A and locally adapted education and counseling on the handling and storage of provitamin A sources can significantly increase the vitamin A intake of vulnerable people.”

The converse can be true as well.  In the Dominican Republic, where I served as a Humanitarian Missionary for many years, we never had to worry about Vitamin C deficiency among the poor.  The fruits that grew wild in abundance provided all the Vitamin C anyone could need.  More or less Vitamin C in the local variety of mango makes no difference — any single mango provides many times the daily requirement of Vitamin C and Vitamin A as well.  But the babies of the poverty stricken desperately needed Vitamin A supplementation — because babies don’t eat mangoes.

This is true generally, all over the world.  The small incremental differences in trace nutrients between crop varieties and between the same varieties grown in different locations is already greater than the differences seen between crops grown at various levels of atmospheric CO2.  All of this was hashed out years and years ago when the latest “scary health story” was that “modern agriculture has depleted our soils so much that food is no longer nutritious.” (Usually followed by an advertisement for vitamin and mineral supplements that far exceed the needs of any human being anywhere).

For a full and exhaustive treatment of this issue, see Mineral nutrient composition of vegetables, fruits and grains: The context of reports of apparent historical declines [pdf] by Robin J. Marles (Health Canada).

The issue is nutshelled in this quote from the Marles study:

“Contemporaneous analyses of modern versus old crop varieties grown side-by-side, and archived samples, show lower mineral concentrations in varieties bred for higher yields where increased carbohydrate is not accompanied by proportional increases in minerals – a “dilution effect”.” 

When modern crops produce more grain or fruit, through plant breeding, better agricultural methods, modern fertilizers and CO2 fertilization, the increased “food” doesn’t contain an equal, proportional, increase in minerals, vitamins, proteins and carbohydrates. Present day biology is not sure why this is.

The Bottom Line important for us from this paper is:

“The benefits of increased yield to supply food for expanding populations outweigh small nutrient dilution effects addressed by eating the recommended daily servings of vegetables, fruits and whole grains.”

Nutritional deficiencies don’t result from eating foods that “lack nutrients” — nutritional deficiencies result from poverty and the inability of people to have enough of the necessary foods to make up an adequate diet.

Nutritional deficiencies stem from not having enough to eat.  Period.

The scary  iron deficiency story from SE Asia alluded to by Zimmer in the Times — “researchers estimated that the rate of iron deficiency may rise from 21.8 percent to 27.9 percent by 2050” — is a Paris Agreement promoting piece of advocacy that assumes that the diets of the poor in these areas will remain unchanged, that there will be no advances in standards of living, food security or primary foods; no public health advances, no health education efforts;  no vitamin supplementation programs where already desperately needed — in other words, the projections are based on a “the world stands still” scenario — and  the only  variable is the “projected” generalized decline in iron concentrations in “crops”, which is based on speculation — not on the foods actually in the diets of the affected peoples.  Iron in human diets comes primarily from meats though there are good plant sources as well.  Iron deficiencies arise where diets include little or no meat due to poverty and where lack of education deprives the people of the knowledge of plant-based alternatives.  Paper @ “Anticipated burden and mitigation of carbon-dioxide-induced nutritional deficiencies and related diseases: A simulation modeling study”.

This small article in the New York Times on Vitamin A — which represents a much larger world-wide problem — exposes the simplicity of dealing with any such problem should it actually arise: “What a Little Vitamin A Could Do”.    A single liquid Vitamin A capsule squeezed into the mouth of each newborn baby averts a very high percentage of Vitamin A Deficiency caused childhood blindness.  Cost?  2 cents (less in bulk).

“Death by Diet” in today’s world is not caused by incremental differences in nutritional values of foods.  That is a myth — the same myth that, on its flip-side,  brings us “SuperFoods” and causes people to buy expensive amaranth, quinoa  and other minor “ancient” grains in preference to inexpensive and abundant wheat, rice, rye and corn.

Of course, diet is important.  But the basis of diet for a majority of the world’s people means “what we can grow or collect”; “what we can afford to buy” and “what we think we should eat”.  Herein lies the entire problem of malnutrition in the world today.  It can be  reliably solved through the process of raising standards of living for the abjectly poor, education of children (especially women who will bear the burden of making diet choices for their families) and  public health care that includes vitamin and mineral supplementation for the poor (particularly children) until their diets can be improved to meet their needs. Some of this education outreach must include agricultural methods to improve yields (which raises standard of living) and encourage the culture of a wider variety of garden items for the family diet (which eliminates vitamin and mineral deficiencies).

Senselessly worrying about small incremental changes in nutritional values of different crops under higher CO2 concentrations does not lead to any solution and does not solve the nutritional problems of the world’s poor.  Just as the “soil depletion” scare passed away under the wheels of time, so will the “CO2-induced lack of nutrients” scare pass away — it is no more significant than its food fad flip-side, SuperFoods.*

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Author’s Comment Policy:

*  SuperFoods are a misnomer, a myth, and categorically do not prevent or cure any disease known to man.  All claims to the contrary are false.  My apologies to AARP, Dave Lieberman and Anand O”Connor (of the NY Times).  If you need dietary advice, you may have mine for free:  Eat Your Chow (meaning a normal, well-rounded diet in moderation).

I will admit to having extended family members that feel that some awful tasting concoction of blended weeds is “better for me” than a simple salad because the ingredients are said to contain “X% more” of some particular nutrient than the food I already eat.  Of course, my diet already has far more of that nutrient than my body could ever possibly use and most of it goes down the toilet with the bodies other excess and unwanted materials.  If you live in a developed nation and eat a reasonably varied diet, you will never suffer from a nutritional deficiency (well, at least until old age finally destroys your ability to absorb some specific vitamin or nutrient — which can happen).

If you live in a developing country and are reading this, you probably have a high enough standard of living that you too are in no danger of vitamin deficiency.

It is the poor that suffer diet-related illnesses and they are caused by not enough of the right foods to eat — and often — from not enough food of any kind.   Very rarely a region’s soil will be deficient in some odd trace element — but these instances of potential deficiency are well known where they occur.  Thus, many countries mandate the adding of iodine to table salt and Vitamin D to milk.

Address your comments to “Kip…” if you are speaking specifically to me and I’ll try to respond.

Thanks for reading.

The Fight Against Global Greening – Part 1

From WUWTKip Hansen /

Guest Essay by Kip Hansen

green_madnessSomething odd happened between April 2017 and July 2018.  I haven’t discovered exactly what prompted it but the rather good science writer and journalist, Carl Zimmer, seems to have flipped his wig.  Well, at least he flipped his viewpoint on Global Greening.

In April 2017, Zimmer wrote a nice article for the New York Times titled “Antarctic Ice Reveals Earth’s Accelerating Plant Growth”.   The article is a straightforward report on research performed by Dr. J. E. Campbell of the Sierra Nevada Research Institute, University of California in Merced, California (and others…) called “Large historical growth in global terrestrial gross primary production” published 5 April 2017 in the journal Nature.

Eric Worral did a WUWT news brief on the 30 July ’18 Carl Zimmer NY Times article.   I thought the issue needed a little more attention — in fact, I thought it needed a series of four essays, of which this is the first.

Zimmer reported in the New York Times (in April 2017):

“Analyzing the ice, Dr. Campbell and his colleagues have discovered that in the last century, plants have been growing at a rate far faster than at any other time in the last 54,000 years. Writing in the journal Nature, they report that plants are converting 31 percent more carbon dioxide into organic matter than they were before the Industrial Revolution.

The increase is because of the carbon dioxide that humans are putting into the atmosphere, which fertilizes the plants, Dr. Campbell said. The carbon in the extra plant growth amounts to a staggering 28 billion tons each year. For a sense of scale, that is three times the carbon stored in all the crops harvested across the planet every year.“   ….

“The pace of change in photosynthesis is unprecedented in the 54,000-year record,” Dr. Campbell said. While photosynthesis increased at the end of the ice age, he said, the current rate is 136 times as fast.

With all that extra carbon dioxide going into plants, there has been less in the air to contribute to global warming. The planet has warmed nearly 2 degrees Fahrenheit since 1880, but it might be even hotter if not for the greening of the Earth.”   ….

More carbon dioxide might spur even more growth. But many climate models project that plants will suffer as temperatures rise and rainfall patterns shift. Despite the extra carbon dioxide, worldwide plant growth may fall, and plants will no longer help to buffer the impact of global warming.

“I’ve been referring to this as a carbon bubble,” Dr. Campbell said. “You see ecosystems storing more carbon for the next 50 years, but at some point you hit a breaking point.”

— Carl Zimmer, writing in “Antarctic Ice Reveals Earth’s Accelerating Plant Growth”

That’s what Zimmer reported in the April 2017 NY Times article.  That is a nicely written, well-balanced piece of writing.  The topic discussed is what is often called “Global Greening”, as shown by NASA in this image.


A bing search for “global greening” returns an interesting set of results.  I am treated to a definition of global greening from The Guardian, then a link to a NASA page “Carbon Dioxide Fertilization Greening Earth, Study Finds”, and then a News About Global Greening section which leads off with “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.” which was  written in 30 July 2018 by the very same Carl Zimmer who  authored of the piece featured at the beginning of this essay.

By July 2018,  Zimmer has flip-flopped and his new piece is trying to convince us that more plant life, more photosynthesis, aka Global Greening,  is a bad thing.  How can that be?

Here’s excerpts from Zimmer’s latest:

“‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”

Rising carbon dioxide levels are making the world greener. But that’s nothing to celebrate.

“Global greening” sounds lovely, doesn’t it? …  Plants need carbon dioxide to grow, and we are now emitting 40 billion tons of it into the atmosphere each year. A number of small studies have suggested that humans actually are contributing to an increase in photosynthesis across the globe.. ….

Elliott Campbell, an environmental scientist at the University of California, Santa Cruz, and his colleagues last year published a study that put a number to it. Their conclusion: plants are now converting 31 percent more carbon dioxide into organic matter than they were before the Industrial Revolution. ….

“Recently I talked Dr. Campbell and …. Here are four reasons he believes nobody should be celebrating “global greening.”

Remember, just the April before, Zimmer talked to Dr. Campbell, and wrote the first news item about Global Greening — a fair scientific approach and mostly positive about the effects of greening.  But now, Zimmer has gone back to Dr. Campbell to find out what is bad about greening…..and he tells us exactly why he is now trying to make a good thing look bad.

Apparently, when Global Greening was Good News, it was also Good News for the Bad Guys.  And you know what that means….all right thinking “good guys” (those in the Climate Alarm business) now have to make sure that the Good News is really Bad News so that the general public won’t listen to those Bad Guys – the Climate Science Skeptics.   Zimmer has to double back and paint his earlier views over with some green-wash — because here’s what the Bad Guys said:

“So-called carbon pollution has done much more to expand and invigorate the planet’s greenery than all the climate policies of all the world’s governments combined,” the Competitive Enterprise Institute declared shortly after the study came out.

“The best messages are positive: CO2 increases crop yields, the earth is greening,” wrote Joseph Bast, the chief executive officer of the Heartland Institute, in an October 2017 email obtained by EE News.

In June, Mr. Bast co-authored an opinion piece in The Wall Street Journal in which he cited Dr. Campbell’s work as evidence of the benefits of fossil fuels. Our unleashing of carbon dioxide contributes “to the greening of the Earth,” he said.

— Carl Zimmer, writing in  “‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.”

So, Zimmer now says, in July 2018, “Recently I talked Dr. Campbell, and as it turns out, he feels people like Mr. Bast are drawing the wrong lessons from his research.”  Let me translate that for you…just guessing of course, but roughly this means — “For heaven’s sake, Campbell, the climate skeptics are making hay out of your global greening study, and pointing to my piece in the NY Times for support!  I’ve had a dozen calls complaining that I’m helping the skeptics — you’ve got to tell me what’s bad about global greening so I can debunk my own April 2017 article on your research!”.  So that’s what Campbell does — together, he and Zimmer manage to squeak out four “bad things” about Global Greening.

Bad Things About Global Greening: (quoted from Zimmer’s article — not my fault if they don’t make sense –kh)

1. “More Photosynthesis Doesn’t Mean More Food“

2. “Extra Carbon Dioxide Can Make Plants Less Nutritious”

3. “More Plants Won’t Prevent Climate Change”

4. “Global Greening Won’t Last Forever”

It is fascinating how Zimmer (and Campbell, we are told) agree that these points, which range from not-true through vaguely-true to trivially-true,  add up to “It’s Terrible!” — but Zimmer has been caught out on the wrong side of the Climate Wars DMZ and must prove his loyalty to the Consensus Team — and makes a fool of himself in doing so.  As each of these points requires their own discussion, this essay will be Part 1 of 4

Let’s look at #1“More Photosynthesis Doesn’t Mean More Food”.

Zimmer quotes Campbell saying    “Yes, we now get far more food from each acre of farmland than we did a century ago. But extra carbon dioxide only accounts for a small fraction of the increase.” “A 30 percent increase in photosynthesis does not translate into a 30 percent increase in strawberries off the land,” said Dr. Campbell.”  This is, of course, trivially true — the increase in photosynthesis doesn’t all go into production of food for humans — it does translate into an equal increase in food for the living things of Earth.

Zimmer should have quoted the IPCC — as  Vanessa Schipani,  writing at, does in her piece  CO2: Friend or Foe to Agriculture?   [ NB: is a left-leaning political “fact checking” site — generally happy to confirm any liberal/progressive statement and deny or denigrate conservative viewpoints] telling readers:

 “The United Nations Intergovernmental Panel on Climate Change’s 2014 report does say that increased atmospheric CO2 has “virtually certainly enhanced [crop] water use efficiency and yields.” So, [Lamar] Smith is right that more CO2 leads to more photosynthesis, which correlates to increased crop yields. And he’s also right that “[s]tudies indicate that crops would utilize water more efficiently” in an atmosphere with more CO2.

But the IPCC adds that the CO2 effect has a greater impact on wheat and rice, than on corn and sugarcane. [NB:  95% of plants are C3, like wheat and rice, and only 5% are C4 like maize and sugarcane – kh]

Photosynthesis in wheat and rice relies more on CO2 in the atmosphere, while corn and sugarcane rely more on “internal cycling” during photosynthesis, Jerry Hatfield, the director of the U.S. Department of Agriculture’s National Laboratory for Agriculture and The Environment, explained to us over the phone.”

Schipani at least quotes the real science as it applies to the question.  CO2 fertilization enhances  both crop water usage and yields — more in some crops than others — but the enhancement is across the entire plant spectrum.  [The difference is due to what are known as C3 and C4 plants ]

Zimmer tries to downplay the increase in production of food crops due to CO2 enhancement —  playing the percentages game, “not all of it is food production.”  Of course, an increase in photosynthesis of phytoplankton in the sea doesn’t produce more strawberries — and no one ever said it did —  it will, however,  produce more fish.  But it has been proven over and over again that enhanced CO2 does increase crop yields and can be expected to increase crop yields into the future.

This question is, you guessed it, a Modern Scientific Controversy — in which there is a Consensus View (informed and dictated by the Climate Consensus) and a Contrarian or Pragmatic View — which is based on real world, on the farm results. Total crop yields all around the world have continued to grow and increase in output per acre, owing to the Green Revolution, improved crop varieties, improved agricultural practices, increased use of fertilizers and atmospheric CO2 enhancement.

It is a questionably true to say “extra carbon dioxide only accounts for a small fraction of the increase” and would only be true to the extent that the other factors are currently so large, depending on the crop and the state of local agriculture.    In areas using modern farming methods, seeds, and fertilizers the increases are largely due to CO2 fertilization.  In areas of more primitive agriculture, the gains from shifting to better seed varieties, modern methods and fertilizers outweigh, but don’t negate,  the contributions of CO2.

As always — the benefits are real in real time — but the “climate models” say “things might/may not keep getting better in the future” therefore ”Global Greening is Terrible!” — especially IF ( the inevitable IF — if climate sensitivity is very high — which is looking less-and-less likely as climate science matures) temperatures rise 5-8 degrees C and current crop areas suffer continual droughts and no one substitutes drought resistant varieties and the Greens keep up their attacks on improved plant varieties.  This argument is rather like saying exercise will improve your health now but it will not prevent your eventual aging  — therefore, Exercise is Terrible!

You may  rest assured that global greening will benefit all life on Earth — it is the evidence  of that benefit that is called global greening — increased plant life (> 30% increase) leads to increased well-being of all animal life, including mankind.  You can’t just wave away basic biology.

Not satisfied with this first nonsensical argument against Global Greening, Zimmer makes an additional hash of some sort of weird attempt to negate the whole concept of carbon bio-sequestration of carbon (CO2) by plants.  Zimmer and Campbell state:

“While photosynthesis does pull carbon dioxide out of the atmosphere, much of that gas goes right back into the air. The reason: At night, the chemical reactions in plants essentially run backward. In a process known as respiration, plants pump out carbon dioxide instead of pulling it in.

“Part of the story is that photosynthesis is going up, and part of the story is that so is respiration,” said Dr. Campbell.”

The basic scientific facts are:  Plants take in carbon dioxide during photosynthesis during the day and release carbon dioxide during respiration at night. This said, plants take up much more carbon dioxide during the process of photosynthesis than they give off in respiration.

The reason for that is that plants use sunlight (energy), CO2 and water to make sugars (carbohydrates) which are used by the plants for energy and to then make more “plant” — fibers, tissues, wood, twigs, leaves, seeds, fruits and all other bio-mass of the plant is constructed from the basic elements of water, oxygen, (oops — kh), CO2 and trace elements taken up by roots and from the air. (Biology professors:  please feel free to expand on my simplistic rendering). Some of the sugars are “oxidized” at night, producing CO2 and water, which the plants give off through their leaves, a process called plant respiration.

It is this process of taking in sunlight, CO2, and water and using them to “manufacture” carbohydrates (sugars, plant tissues, wood, seeds, fruits) that is the basis of “Biological Carbon Sequestration” and the reason Climate Activists run campaigns to urge the planting of trees.


The sequestration takes place in the growth of the plants themselves and where the brown arrow shows carbon-based material entering the soil.  Of course, with trees, the longer term sequestration is the storage of carbon in the wood itself, often for a hundred years or more.  Your home may be made of sequestered carbon in the form of wooden 2x4s, wooden siding and floor joists.  Much of the furniture in your home may be bio-sequestered carbon — like that that fine oak dining room table.

Some of the bio-sequestered carbon is returned to the atmosphere as soil-dwelling life forms consume the plant materials as part of its decomposition.  Some of the bio-sequestered carbon gets pushed further and further into the soil and environment and one day may end up as a peat bog, oil or coal.

In the oceans, phytoplankton undergoes photosynthesis, taking in COfrom the water, and then is eaten by little sea creatures, who themselves are eaten by others.  Eventually, something dies and drifts to the bottom of the ocean, there to decompose and return some CO2 to the sea water and maybe to the atmosphere, much to remain there for a long, long time.

Bio-sequestration of carbon from the atmosphere through the process of photosynthesis (green plant life) is only a good thing — there is no down side.  The lame attempt to paint it as a bad thing mocks a huge part of the Green Movement’s efforts to stop deforestation and encourage reforestation and afforestation, all which are carried out in the name of bio-sequestration.

Increased photosynthesis, aka Global Greening, is the process of increased bio-sequestration of CO2 by plant life.  It is a positive thing, a good thing, a desired thing, a Win-Win for environmentalists as it reduces atmospheric CO2 and adds life to the biosphere.

It is not terrible — it is wonderful.

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Author’s Comment Policy:

The idea that caught my interest was that the Climate Team feels it necessary to throw Global Greening under a bus — based solely on the fact that the skeptics use Global Greening to score points for their side of the Climate Wars.  Unfortunately for Carl Zimmer and Dr. Campbell, their arguments against Greening are ridiculously weak and must be stretched past their breaking points to be made at all.

Comments addressed to me personally (“Kip… ) will elicit a response — especially if on topic and collegial.

If you know of any scientific justification for the position “Global Greening is Terrible!” I’d be happy to read it.

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Quick Links:  (added 10:00 ET 14/Aug/’18)

Carl Zimmer

“Antarctic Ice Reveals Earth’s Accelerating Plant Growth”

“Large historical growth in global terrestrial gross primary production”

“Carbon Dioxide Fertilization Greening Earth, Study Finds” – NY Times

“‘Global Greening’ Sounds Good. In the Long Run, It’s Terrible.” – NY Times

bing search for “global greening”

declared shortly after the study came out

October 2017 email obtained by EE News

contributes “to the greening of the Earth,”

Far more food from each acre of farmland

Vanessa Schipani,

CO2: Friend or Foe to Agriculture?

C3 and C4 plants

“Biological Carbon Sequestration”




WUWT news brief on the 30 July ’18 Carl Zimmer article