Arguments
Why we have a scientific consensus on climate change
Posted on 23 March 2011 by Thomas Stemler
A short piece for the general audience of RTR radio, Perth, Australia.
(listen to the original audio podcast)
Recently a research group analysed the current literature on climate science. Their aim was to find out how many of the active researchers in the field agree on man-made climate change. The answer is, 97 out of 100 agree that the climate is changing and that we are causing it.
From my own experience, such a high proportion is quite unusual. As scientists we are trained to be professional sceptics, who doubt everything and who moreover love a good debate. Therefore putting 3 scientists together in a room sometimes results in an argument with 5 different opinions.
While this is the more enjoyable side of science, the more important one is that being sceptic lets us identify errors and improve our understanding of nature.
Climate science is a very special science. It includes experts who study the dynamics and data from the atmosphere, the oceans, glaciers, and so on. Some of us specialise in building models, others use them to make predictions.
So how come that 97 % of the experts agree that the current warming is not natural but a consequence of burning fossil fuels?
First, it is because all our data show that the global mean temperature is increasing, that the glaciers and the arctic ice are melting and therefore sea levels are rising.
Second, we know that burning fossil fuel releases CO2 into the atmosphere. The properties of CO2 were first studied by John Tyndall in the late 1850s. Tyndall was an experimental physicist interested in how different gases absorb heat. John Tyndall's observations were remarkable. His pioneering work eventually inspired physicists to develop the theory of quantum mechanics, but his results about CO2 also led Arrhenius in 1896 to the conclusion that burning fossil fuel will result in global warming. So climate science is a very old science indeed; we have known about CO2 for more than 150 years.
Nowadays we know how much CO2 we put into the atmosphere by using it as our global garbage bin for fossil fuel. All our climate observations show a global increase in temperature. This increase is consistent with the well established properties of CO2.
Taking this into account it is no longer surprising that 97% of the professional sceptics working in the area of climate science agree that we are currently witnessing man-made climate change. The only question remaining is, what do we do? Ignore the facts or generate energy from other sources?
Dr Thomas Stemler is a physicist who is currently an Assistant Professor of Mathematics at the University of Western Australia. He is an expert in forecasting of complex nonlinear dynamical systems.
This podcast is now available on iTunes (or search for "Climate Podcasts from the University of Western Australia" in the iTunes store). Alternatively, you can subscribe to the stream via feedburner.
The two researchers started by altogether excluding from their survey the thousands of scientists most likely to think that the Sun, or planetary movements, might have something to do with climate on Earth — out were the solar scientists, space scientists, cosmologists, physicists, astronomers and meteorologists. That left the 10,257 scientists in such disciplines as geology, geography, oceanography, engineering, paleontology and geochemistry who were somehow deemed more worthy of being included in the consensus. The two researchers also decided scientific accomplishment should not be a factor in who could answer — those surveyed were determined by their place of employment (an academic or a governmental institution). Neither was academic qualification a factor — about 1,000 of those surveyed did not have a PhD, some didn’t even have a master’s diploma.
To encourage a high participation among these remaining disciplines, the two researchers decided on a quickie survey that would take less than two minutes to complete, and would be done online, saving the respondents the hassle of mailing a reply. Nevertheless, most didn’t consider the quickie survey worthy of response — just 3,146, or 30.7%, answered the two key questions on the survey:
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?
The questions posed to the Earth scientists were actually non-questions. From my discussions with literally hundreds of skeptical scientists over the past few years, I know of none who claims the planet hasn’t warmed since the 1700s, and almost none who think humans haven’t contributed in some way to the recent warming — quite apart from carbon dioxide emissions, few would doubt that the creation of cities and the clearing of forests for agricultural lands have affected the climate. When pressed for a figure, global warming skeptics might say humans are responsible for 10% or 15% of the warming; some skeptics place the upper bound of man’s contribution at 35%. The skeptics only deny that humans played a dominant role in Earth’s warming.
Surprisingly, just 90% of the Earth scientists who responded to the first question believed that temperatures had risen — I would have expected a figure closer to 100%, since Earth was in the Little Ice Age in the centuries immediately preceding 1800. But perhaps some of the responders interpreted the question to include the past 1,000 years, when Earth was in the Medieval Warm Period, generally thought to be warmer than today.
As for the second question, 82% of the Earth scientists replied that human activity had significantly contributed to the warming. Here the vagueness of the question comes into play. Since skeptics believe human activity has been a contributing factor, their answer would have turned on whether they consider a increase of 10% or 15% or 35% to be a significant contributing factor. Some would, some wouldn’t.
In any case, the two researchers must have feared that an 82% figure would fall short of a convincing consensus — almost one in five wasn’t blaming humans for global warming — so they looked for a subset that would yield a higher percentage. They found it — almost — by excluding all the Earth scientists whose recently published peer-reviewed research wasn’t mostly in the field of climate change. This subset reduced the number of remaining scientists from over 3,000 to under 300. But the percentage that now resulted still fell short of the researchers’ ideal, because the subset included such disciplines as meteorology, which Doran considers ill-informed on the subject. “Most members of the public think meteorologists know climate, but most of them actually study very short-term phenomenon,” he explained, in justifying why he decided to exclude them, among others. The researchers thus decided to tout responses by those Earth scientists who not only published mainly on climate but also identified themselves as climate scientists.
“They’re the ones who study and publish on climate science,” Doran explained. “So I guess the take-home message is, the more you know about the field of climate science, the more you’re likely to believe in global warming and humankind’s contribution to it.”
Once all these cuts were made, 75 out of 77 scientists of unknown qualifications were left endorsing the global warming orthodoxy. The two researchers were then satisfied with the findings of her master’s thesis.
Are you?
and don't say that it is just for a "general audience", that is precisely the kind of issues that must be discussed carefully.
-------
Interesting, Harry. And here I was basing my understanding on the science. Were you?
The bandwagon is notorious for breaking down in the middle of the highway. Both the original study and your analysis are based on the assumption that all scientists--or those with degrees in science--understand the physics and dynamic context. This is not nearly true. A number of scientists have been dragged before Congress to give their "expert" testimony, and some of these scientists--perhaps surprisingly--have been shown to be talking out of their depth. If 1000 out of 1000 geologists or meteorologists told me the planet was warming outside of any known cycle, I'd still ask "how."
It's important to understand how statistics and consensus affect the general democratic population, but it has little bearing on the actual science--except in that funding allows greater exploration (and climatologists have, given the importance of their area, been relatively not so good at getting funded). If we come to the conclusion that the Zimmerman study is as you describe (including your "if by whiskey" bits), what does it ultimately mean, other than the general populace simply doesn't have the time, means, motivation, ability, or training to become responsible voters where this issue is concerned?
The bottom line for me is that no scientist has come close to presenting any comprehensive alternative theory that is supported by the evidence and physical model as thoroughly as the theory that human-sourced atmospheric CO2 and CH4 are warming the planet. There are no competing theories. There is only positionless pot-shooting.
HS1:"The researchers thus decided to tout responses by those Earth scientists who not only published mainly on climate but also identified themselves as climate scientists." (No! Not publishing climate scientists! What do those fiends know?!)
HS2: "Once all these cuts were made, 75 out of 77 scientists of unknown qualification were left endorsing the global warming orthodoxy." (but I thought you just said . . .)
"The two researchers started by altogether excluding from their survey the thousands of scientists most likely to think that the Sun, or planetary movements, might have something to do with climate on Earth — out were the solar scientists, space scientists, cosmologists, physicists, astronomers and meteorologists."
That's strange. One of the study's conclusion involves specifically meteorologists, and with researchers at NASA part of the survey, one would expect that would include physicists, astronomers, etc.. Where is the evidence they were excluded?
http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf
"Neither was academic qualification a factor — about 1,000 of those surveyed did not have a PhD, some didn’t even have a master’s diploma."
I like this part. Where's the denominator? Those without a PhD made up 10% of the participants. Those without a PhD or Master's made up 3%. And speaking of qualifications, one would think published climate scientists would be more qualified than general Earth scientists.
Lawrence Solomon's rant
Not the firstclimate [--snip--] to do that, eh?
Lawrence Solomon is part of the group which is being sued by Dr Andrew Weaver (an eminent Canadian climate scientist) for libel.
The National Post and Financial Post have a very long and sordid history of libelling climate scientists, misinforming, distorting and cherry-picking -- they simply cannot be trusted when reporting on climate science and have zero credibility. DeepClimate has more on their antics.
Sad to see that Harry @51 has fallen for their misinformation.
I would also venture to guess that the results are probably skewed high because a skeptical scientist is probably more likely to respond to such a questionaire.
On top of that, didn't Andregg 2010 come up with very similar results using different methods? That would also suggest a robustness within the methods.
Yeah the Anderegg results are discussed in the no consensus thread. It is telling that virtually the same result was obtained with a very different method and larger sample size (in the high expertise category). I have yet to see anything from the skeptic side with a robust denominator, much less two independent studies coming to the same result.
You're not doing science at all, especially when you state that tripe cribbed wholesale from deniersville is "a good piece of science." But then, you've not been long on facts, citations, references, source material, etc, since you arrived here.
Earn some credibility by engaging in fact-based argument and refraining from opinion.
Regardless, the infamous 97% figure does not represent and should not be construed to represent the entire scientific community.
It's not claimed to be a representation of the "entire scientific community". You might want to read the opening paragraph of this post for starters.
[DB] Unsure which one you mean; try this one or this one.
I would much preferred 51% of those democratic peoples to have voted for their leaders, and 51% of scientists to agree on all the main facts of AGW.
Doran et al. surveyed 10,000 earth scientists, more than 3,000 of whom responded (a very large sample size). Of the respondents, 90% agreed that the climate is changing for the warmer and 82% agreed that human activity is a significant contributor to this state of affairs. That's far better than a 51% simple majority.
Furthermore, the more relevant a scientist's knowledge was to climate issues, the more likely they were to agree with the AGW proposition, to the point that once expert climate scientists were questioned they returned 97% affirmative. Polling the experts about a knowledge claim is far more relevant than polling the general populace; likewise, polling climate experts about climate questions is far more informative than polling scientists who may not have any overlap with climate research.
l. 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?
...
Results show that overall, 90% of participants answered "risen“ to question 1 and 82% answered yes to question 2. In general, as the level of active research and specialization in climate science increases, so does agreement with the two primary questions (Figure 1). In our survey, the most specialized and knowledgeable respondents (with regard to climate change) are those who listed climate science as their area of expertise and who also have published more than 50% of their recent peer-reviewed papers on the subject oi climate change (79 individuals in total). Of these specialists, 96.2% (76 of 79) answered "risen“ to question l and 97.4% (75 of 77) answered yes to question 2.
So it would seem your 51% criteria is more than satisfied. Good to know, isn't it?
Beyond direct polling, we also have statements from leading national and international bodies of science that are pretty universal in declaring AGW real. Furthermore, by trawling the scientific literature on climate we can safely say that if there are any who have strong disagreement with the consensus, they simply aren't publishing in peer-reviewed venues about their disagreement and therefore have stopped participating in the machinery of science.
That would be puzzling (for a scientist), but not unprecedented. For example, Roy Spencer has basically withdrawn from peer-reviewed because he didn't like people rejecting his erroneous work, so he chooses to aim lower on the totem pole and only publish in refereed Letters journals at most, and un-peer-reviewed popular press books/blogs as a general case. The weaknesses of this go-it-alone approach become apparent when other people with some mathematical expertise get to sanity-check his climate model and find it fatally flawed. If he had looked for criticism and feedback from qualified people before going to press with it, things might have been different all around.
Having all these different lines of evidence telling you the same thing is generally a sign of robustness.
That's true, I'm not here for that. First i'm not a climate scientist, so my goal is not to discuss climate science - I doubt very much that anybody here is competent enough to settle so complicated issues. Second , citing that X or Y wrote that he made some model or some measurement does not prove per se that it's true - it just proves that he said it. Theologies are very fond of citations, references,and so on. I'm here just to see if people who claim that they've understood everything are able to answer rather simple objections. I'm not really convinced up to now - as I said, it's your burden to convince people that you're right. I am not defending any precise claim about climate - I'm just thinking that there is still much room for debate. So if you don't convince me, I loose nothing - you just miss your goal.
If you wish so sway readers here - you must supply some evidence, preferably peer reviewed. This crowd has notably higher standards for a claim than you may find on other sites.
So what exactly do you think is a debatable point? And what is your evidence that the current consensus view is lacking in that department? What is the competing theory (hopefully as broad and robust as the current climate theory aka AGW)?
Pick your best counter argument and please provide some real data to back it up.
“The most likely value has remained about 3C for a doubling of CO2 in all of the IPCC reports.”
Lynch - NASA, 2010.:
“... Lahouari Bounoua, of Goddard Space Flight Center, Greenbelt, Md. Bounoua is lead author on a paper detailing the results that will be published Dec. 7 in the journal Geophysical Research Letters . Without the negative feedback included, the model found a warming of 1.94 degrees C globally when carbon dioxide was doubled. “
By me Lahouari Bounoua is definitely a skeptic - without values "3C for a Doubling of CO2" theory of catastrophe caused by AGW - it just does not exist ...
How many of these "skeptics" are not included in statistical studies discussed here? 10 - 30 - 50%?
[DB] Arkadiusz, Bounoua et al 2010 doesn't mean what you think it means. It employs an investigative model to examine the effects of an already doubled (with climate at equilibria) CO2 upon evapotranspiration and vegetation density changes. What they found, based on these assumptions, with all other forcings and feedbacks assumed to be net zero, that plants could exert a slight negative feedback upon temperatures through a combination of growth and albedo changes. With all those caveats, Bounoua et al 2010 does not mean what some think it means.
First:
2 + 0.6 it still is far from up to 3 degrees C ...
secondly,
... when we consider "negative feedback":
“The cooling effect would be -0.3 degrees Celsius (C) (-0.5 Fahrenheit (F)) globally and -0.6 degrees C (-1.1 F) over land, compared to simulations where the feedback was not included, said Lahouari Bounoua ...”
Thirdly:
The question relates to a method for determining who is a skeptic - and who is not - no effect "... when carbon dioxide was doubled ... "
P.S. For of caution - supporters of scientific consensus, I will quote “an enlightening” story on the LIA - "black death. " (I think that in this way complements - perfect for me - "logical proof" Gilles).
By 2004, existed (counting a number of years), the consensus in science regarding the direct cause of "black death" - bacteria spread by rats. Confirmed this theory hundreds of peer-reviewed scientific papers, authorities hundreds of “professors titles”.
... and suddenly appeared a work from Scott and Duncan: “Return of the Black Death: the World’s Greatest Serial Killer” - proving "beyond doubt" that a virus - not bacteria - killed millions of people - not only in the LIA, but in many other cool historical periods. At the heart of their chilling scenario is their contention that the plague was spread by direct human contact (not from rat fleas) and was, in fact, a virus perhaps similar to AIDS and Ebola.
I think - faster than we suppose, the theory of AGW also find their: Scott and Duncan ...
In April 2003, Dr. S. Derbyshire wrote that: we live "... among people of exciting information about the upcoming annihilation, in a world of fear of requesting, and awaiting cautions. Warnings mingle with our - timidity - the expectations of the disaster and fear for the planet. "
And this psychological basis - perhaps is the only one undisputed scientific basis - scientific and political consensus on AGW theory - for example, the IPCC ...
Thanks for telling us, at long last, that you are not here to discuss factual matters of science. That is exactly what this discussion does not need.
How can you be convinced of anything when you equate scientific study to theology? Not that the question is relevant here, but how do you personally claim to 'know' anything? Are you really the long-lost scion of Rene Descartes?
What you have lost is any and all credibility in this audience. By denying the value of a fact-based discussion, you give yourself the status of talking hand-puppet; your comments are now little more than spam.
2 + 0.6 it still is far from up to 3 degrees C ..."
What the....? I was saying that roughly 2 degrees, *plus* the 0.6 we've already had, would constitute a catastrophe. When are you going to start talking sense?
"... when we consider "negative feedback":
“The cooling effect would be -0.3 degrees Celsius (C) (-0.5 Fahrenheit (F)) globally and -0.6 degrees C (-1.1 F) over land, compared to simulations where the feedback was not included, said Lahouari Bounoua ...”"
and what negative feed-backs are these? To date I've yet to see too much evidence that we can count on that level of negative feedbacks-if any at all. What about all the possible positive feedbacks that probably have yet to be considered?
As to your third point, it reads like unintelligible nonsense. The consensus remains that Y. pestis was the cause of the Black Death, & that it peaked *before* the start of the Little Ice Age (14th century vs the 16th century). Scott and Duncan are, from what I can see, the Lindzen, Spencer & Choi of Climate Science-claiming the consensus is *wrong* without feeling the need to provide solid evidence.
Nobody - including Scott and Duncan - do not claim that there was Y. pestis in the LIA - as the cause of death - even strong but rare epidemic (in relation to the virus). Skeletons found in Y. pestis DNA (usually port cities ONLY !) confirms this - but just that.
Work cited by ScienceDaily is a little like the views of creationists ... There is one small piece of truth. Shows how big is the resistance to new scientific research.
Scott Duncan and prove that it - in great part Europe - was not species of rats - especially in the UK or Iceland - it could not be there so the plague ...
II. I quote my work - paper, that further warming of 1.34 degree C (land) will have a global catastrophe ...
Again, I don't think that scientific issues can be settled by discussions on a web forum. i'm here just as a citizen who, because of his scientific formation (actually profession), can understand scientific arguments, but I wouldn't try to give definite answers. I understood that this forum was devoted to a presentation of scientific facts towards a large audience - for me it's enough to see the "best arguments" as selected by the most convinced people to see how they sound. And if these "best arguments" don't sound terribly convincing, I'm afraid the others will be still more uncertain. So when I see things like statistics on models, or intuitive fudge factors, or simplistic logics obviously overlooking complex realities, well, that's enough for me to doubt.
I have a question, by curiosity, concerning the position you believe I'm holding : is there any precise statement, that you think I would support, and that would be obviously wrong for you ? (such as "the world was created 5000 years ago", or " planets do influence the psychology of individuals") ? a good criterion to quantify the "obviously wrong" would be, as I said, that you would accept any bet even at very unfavorable odds for you. Is there such statement, in your opinion ?
There is some truth.
There was exactly in 1347 - along with the beginning of the LIA. Ended (as a pandemic) in the years 1660-1670 - the beginning of the LIA maximum cold finished "life of "black death.
This is another - excellent - example the lack of linearity in a world of natural phenomena ...
Warming or cooling - both of which can be both the cause of the disaster and development.
"... with all other forcings and feedbacks Assumed to be zero net ..."
The report quoted my question NASA is not "all" - but only "negative"
[DB] I spoke after having read the paper itself, which I linked to, not the NASA report on the paper. I'm trying to help you understand the context of the paper.
I think you should read your articles fully before before posting them. RIght after where your quote ended:
"Bounoua stressed that while the model's results showed a negative feedback, it is not a strong enough response to alter the global warming trend that is expected. In fact, the present work is an example of how, over time, scientists will create more sophisticated models that will chip away at the uncertainty range of climate change and allow more accurate projections of future climate."
Regarding your "cautionary tale", spending some time on google will tell you that it is far from certain that Scott and Duncan's theory is right. By the way, Scott and Duncan used computer models !
BTW it will be fallacious to assume that all paradigms will shifted because some paradigms have shifted.
Actually I disagree on this precise point : issues are discussed in the peer reviewed literature - and most often not settled. Settled issues are usually presented in textbooks and no more in peer-reviewed literature. [I guess that the correct wording in English is literature and not LITTERature, or litchurtchur ;) - littérature is french BTW ) . That's why I don't think that citing a paper or another is a real answer to contrarians - paper are published to be discussed. Now I cannot oblige you to answer my question, I was just curious whether you thought I was holding a "non scientific" position, and why. But as I said, if your conclusion is to exclude people who don't think like you - I think this is kind of missing the goal of your website.
Sorry I only posted that statement from Happer as a response to his post about radiative forcing being well understood. I posted to try and show that there is disagreement.
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 #1 as generally risen. I don't believe #2 can be answered properly unless the word "significant" clarified, or a quantitative element is added.
The question asked of the climate scientists was "do you think human activity is a significant contributing factor...". The author makes a leap to focusing on CO2. That was certainly not the question asked.
Your general criticism has been made before and addressed by the author.
Also note Anderegg 2010 which found the same conclusions using very different methods. You also have Oreskes 2004 and the positions of nearly all leading national and international scientific organizations, all of which is discussed in the is there consensus main post.
I agree - may be they should have added "anthropogenic component contributes between 1.5 % and 98.5 % of the warming" to justify the 97 % of "yes" ?
Now, the political debate needs to be informed by the best science not disinformation and this site provided invaluable support to this by countering skeptic disinformation with well-referenced supporting science. Serious skeptics can counter with other science and data. As far as I can see, you do neither. If you arent interested in the science, then I suggest your debating style is more appropriate to likes of Climate Progress.
/end feeble attempt at humor.
( Sorry for the CAPS. )
[-----snip------]
Welcome to Skeptical Science! To put it kindly, your friend is misinformed. Fortunately, you do not have to become climate scientists to become better informed on the Urban Heat Island (or any other issue). That's what Skeptical Science is here for!
There is an immense amount of reference material discussed here and it can be a bit difficult at first to find an answer to your friend's questions.
That's why we recommend that Newcomers, Start Here and then learn The Big Picture.
I also recommend watching this video on why CO2 is the biggest climate control knob in Earth's history.
Further general questions can usually be be answered by first using the Search function in the upper left of every Skeptical Science page to see if there is already a post on it (odds are, there is). If you still have questions, use the Search function located in the upper left of every page here at Skeptical Science and post your question on the most pertinent thread.
Remember to frame your questions in compliance with the Comments Policy and lastly, to use the Preview function below the comment box to ensure that any html tags you're using work properly.
Hope that helps!
The Yooper
Question #2 in the oft referenced survey is qualitative instead of quantitative. The question Gilles asked to assign a figure or range is entirely scientific.
Per your rather smug response:
"Your opinion of what 'should have been added' is entirely irrelevant. The survey was taken, the results published. If you disagree with the results, perhaps you can cite the results of a survey of your own."
Between the two camps, let's come up with a short, but better set of survey questions that are quantitative in nature (i.e., something we can measure) and post links to the survey here, and at WUWT and other climate sites and tally up the results.
Now thanks Harry. I could well have been among the 97 % who answered "yes" , it seems to get warmer, and yes, mankind probably contributed to this warming - among other things. Mankind contributed to a lot of environmental changes, actually. And so? should mankind be declared a pollutant ?
The quoted fragment does not change the fact that before „... create more sophisticated models that will chip away at the uncertainty range of climate change and allow more accurate projections of future climate ..." possible to have different scenarios.
Let us assume - for convenience - a direct warming of around 1.2 degrees C for each successive doubling of CO2.
1.94-1.2 = 0.74 degrees C - a positive feedback - by still "imperfect" model of the quoted paper.
IV Report IPCC: “... defi ned as the global average surface warming following a doubling of carbon dioxide concentrations. It is likely to be in the range 2°C to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C”.
What does it say skepticalscience: „The lowest estimate of warming is close to the models - 1.8°C (3.24°F ) on average - but the upper estimate is a little more consistent, at an average of around 3.5°C (6.3°F).”, “All the models and evidence confirm a minimum warming close to 2°C for a doubling of atmospheric CO2 with a most likely value of 3°C and the potential to warm 4.5°C or even more.”
The question is: whether the claim is more likely that the lower limits estimated for whole RF doubling of CO2 - is already skepticism? Does it violate the scientific consensus?
And as the great "the unknown" (for negative feedbacks) we have here, this paper demonstrates example The net climate impact of coal-fired power plant emissions, Shindell and Faluvegi, 2010.:
„More broadly, our results indicate that due to spatial and temporal inhomogenaities in forcing, climate impacts of multi-pollutant emissions can vary strongly from region to region and can include substantial effects on maximum rate-of-change, neither of which are captured by commonly used global metrics.”
Scott and Duncan's theory ...
... when I doubt that science will give us ever satisfactory answers to important questions, then read once again over 280 pages of their work. Despite the criticism I admire the austerity of the statement, their "Benedictine" work.
I'm no epidemiologist but - Haensch et al., 2010.:
“Some epidemiologists and historians have denied this conclusion due to inconsistencies between the clinical and epidemiological characteristics of plague in historical records and those observed in India in the early 20 th century . Alternative putative etiologies of the Black Death include a viral hemorrhagic fever or a currently unknown pathogen.”
This sentence from the above work:"...ends the debate about the etiology of the Black Death, and unambiguously demonstrates that Y. pestis was the causative agent of the epidemic plague that devastated Europe during the Middle Ages."- But this probably just “pious wishes”.
Similar "pious wishes" may contain a question: “Why we have a scientific consensus on climate change ...”
The existence of two (or more) contradictory (even if only partially) the theory of makes it impossible a consensus.
That this is my "caution" ...
For example, my country. Climatologist, a professor A.A. Marsz - a skeptic. He has significant scientific achievements - Arctic climate:
In his paper he writes: “The genesis of the ‘Great warming of the Arctic’ in the 1930s and ‘40s is the same as that of the present day. Both may be considered to be attributable to natural processes and are not demonstrably associated in any way with a supposed ‘Global greenhouse effect’. Changes in the concentration of CO2 in the atmosphere could only explain 9% of variations in the SAT in the Arctic.”
"The existence of two (or more) contradictory (even if only partially) the theory of makes it impossible a consensus.
That this is my "caution" ..."
Shows that you simply don't know what the term 'Consensus" means. Consensus simply means "General agreement among the members of a given group or community, each of which exercises some discretion in decision-making and follow-up action." Note the 'General Agreement'-it does *not* mean that *every* scientist in the field has to be in agreement-only the majority, a fact that your claims have not been able to alter.
Also, when these skeptics provide something called *proof* to back their contradictory ideas, then maybe the consensus might be in danger but-if A.A. Marsz is anything to go by-then its not in danger yet. We *know* what caused the 'great warming' (it wasn't that great) of the Arctic in the 1930's & 1940's-it was this thing called a massive increase in solar irradiance. Yet we *know* the Sun isn't responsible for recent warming, because its been in a state of *decline* for the last 30 years-reaching levels unseen since the 19th century in just this last decade. I think its time for Marsz to go back to school.