Wikipedia's bias - a case study: The Younger Dryas impact hypothesis
Wikipedia is notoriously biased on some subjects. You can find plenty of information about Wikipedia's biases through Google. Also see this video by one of Wikipedia's founders, Larry Sanger. Plenty of other videos like this can be found. The Younger Dryas impact hypothesis Wiki page, along with several related pages, provide clear examples of this bias. One reason this bias occurs is because Wikipedia is not scientific.
Wikipedia is written by its editors. These editors decide which sources should be promoted and which should be neglected according to their judgement about how reliable each source is - they discuss these issues on the associated 'talk' pages. However, these editors are frequently not scientists or academics themselves and can be strongly biased. This means they often use unreliable sources, here-say, or simply their own opinion in reaching these decisions.
This is not how science works. Scientists, like most academics, are trained to evaluate the quality of evidence found, typically, in peer-reviewed journal papers. They base their judgement on the evidence within a paper, ignoring non-scientific arguments such as "ad hominems". This means the background of a paper's authors has no scientific relevance. See Prof. Powell's recent article on a case study involving Mark Boslough where he ignored this rule, and the problems it raised.
Wikipedia's editors, on the other hand, routinely use non-scientific judgments like ad hominem arguments in debating the quality of sources. In fact, they are encouraged to do this by Wikipedia's rules which effectively prioritise social media chatter above peer-reviewed research.
This is not scientific. The result is that Wikipedia's pages on many issues, especially contentious ones, can simply become platforms for promoting the incompetent, biased and unethical views of its editors and the latest social media trends.
It is why most academics regard Wikipedia with suspicion. We typically encourage our students to ignore it. Its only use should be as an initial source of key words and research papers. Students should do their own more competent literature research and come to their own conclusions.
Let's examine the Wikipedia page on the Younger Dryas impact hypothesis (YDIH). You can see from its associated 'talk' page just how incompetent, biased and unethical some of these particular editors are. Comments on each statement are in italics.
-----------------------------
The Younger Dryas impact hypothesis (YDIH) or Clovis comet hypothesis is a speculative attempt to explain the onset of the Younger Dryas (YD) as an alternative to the long standing and widely accepted cause due to a significant reduction or shutdown of the North Atlantic "Conveyor" in response to a sudden influx of fresh water from Lake Agassiz and deglaciation in North America.[1][2][3]
All science is speculative to some degree, so use of that word here is simply expressing the views of the editors. It is not used routinely on other Wikipedia science topics, clearly indicating the editor's bias.
Moreover, the YDIH is not only an attempt to explain the YD climate change, it also seeks to explain many other observations that appear to be related. Most notably, the primary evidence for the impact is geochemical evidence at the YD boundary. The YD climate change is a secondary effect.
The YDIH does not seek to replace the "shutdown of the NA conveyor" mechanism for the YD climate change. It is completely compatible with it. In fact, it augments it by proposing a cosmic trigger for some of the freshwater outbursts. Therefore, it is not accurate to claim the YDIH as an "alternative" theory. A key advantage of the YDIH is that it helps to explain the sudden (sub-annual?) onset of the YD cooling, via an impact winter or cometary dusting for example. This is important, since Renssen et al. (2015) claim the shutdown of the NA conveyor cannot explain this by itself. In fact, Wallace Broecker, a key architect of the NA shutdown theory was a late convert to the YDIH.
However, it seems that none of this is of interest to Wikipedia's biased editors.
The YDIH posits that fragments of a large (more than 4 kilometers in diameter), disintegrating asteroid or comet struck North America, South America, Europe, and western Asia around 12,850 years ago, coinciding with the beginning of the Younger Dryas cooling event. Multiple meteor air bursts and/or impacts are claimed to have produced the Younger Dryas (YD) boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at more than 50 sites across about 50 million km2 of Earth's surface. Some scientists have proposed that this event triggered extensive biomass burning, a brief impact winter and the Younger Dryas abrupt climate change, contributed to extinctions of late Pleistocene megafauna, and resulted in the end of the Clovis culture.[4][5]
All fairly accurate.
A group known as the Comet Research Group advocates for its acceptance.
The CRG includes many distinguished scientists who contribute to research on this topic. To emphasize their role as one of 'advocacy' is highly misleading.
The YDIH remains a minority and disputed view and has failed to gain acceptance by the mainstream planetary impact and paleoclimate communities.
No evidence is provided for this statement. There is no way of knowing how accurate it is. It is simply expressing the biased view of the editors.
Contents
Background
A number of theories have been put forward about the cause of the Younger Dryas climate event. The most widely accepted is that it began because of a significant reduction or shutdown of the North Atlantic "Conveyor" – which circulates warm tropical waters northward – as the consequence of deglaciation in North America. Geological evidence for such an event is not fully secure,[6] but recent work has identified a pathway along the Mackenzie River that would have spilled fresh water from Lake Agassiz into the Arctic and thence into the Atlantic.[7][8] The global climate would then have become locked into the new state until freezing removed the fresh water "lid" from the North Atlantic.
Accurate, but it places too much emphasis on the YD cooling as the main motivation for the YDIH, as discussed above.
An alternative theory suggests instead that the jet stream[clarification needed] shifted northward in response to the melting of the North American ice sheet, which brought more rain to the North Atlantic, which freshened the ocean surface enough to slow the thermohaline circulation.[9] Another proposed cause has been volcanic activity.[10][11] However, this has been challenged recently due to improved dating of the most likely suspect, the Laacher See volcano. In 2021, research by Frederick Reinig et al. precisely dated the eruption to 200 ± 21 years before the onset of the Younger Dryas, therefore ruling it out as a culprit.[12] The same study also concluded that the onset took place synchronously over the entire North Atlantic and Central European region. A press release from the University of Mainz stated, "Due to the new dating, the European archives now have to be temporally adapted. At the same time, a previously existing temporal difference to the data from the Greenland ice cores was closed."[13]
Yes, these other theories have little support. But still Wiki's editors focus on the YD climate change as the primary motivation when actually the YDIH is a much broader theory than just that. So, this section massively unbalances this wiki page, and just reinforces the editors' bias.
In contrast, proponents of the impact hypothesis posit that fragments of a large disintegrating asteroid or comet struck the earth around 12,850 years ago, causing the Younger Dryas cooling event. They also hypothesize that the impact event triggered extensive biomass burning, a brief impact winter, and an abrupt climate change[14] which, they contend, directly brought about the extinction of many species of North American Pleistocene megafauna[14] including camels, mammoths, and the giant short-faced bear.[15] They also claim the event contributed to the transition from Clovis culture to subsequent traditions.[16]
This is repetitive. As has already been expressed, the YD impact climate cooling mechanism is the same as the "NA conveyor shutdown" theory, perhaps augmented by an impact winter or cometary dusting.
And "directly brought about the extinction..." is too strong here. Proponents of the YDIH generally use "contributed to", although there may well be evidence in some extinction cases of a direct effect.
Evidence[edit]
This section appears to written by an incompetent. It has several major flaws.
Proponents have offered what they say is evidence for the impact event that includes microscopic structures (spherules), ...
Not just spherules, but also nanodiamonds, very high temperature melted minerals, combustion products including soot and microcharcoal, and a global platinum anomaly. All of these findings have been replicated on several continents by multiple independent research groups. See Sweatman's review and Powell's review. Replication is the "gold standard" in science. Of course, these scientific facts are ignored by Wiki's biased editors.
... "black mats" of sediment they contend are evidence of widespread fires, ...
This is false. The black mats are generally acknowledged to signify the altered YD climate. In some cases, however, the base of the YD black mat is stained with abundant microcharcoal and soot.
... and the synchronous extinction of megafauna ...
As already stated, the phrase used tends to be "contributed to", which means a species extinction need not be synchronous yet still have been influenced by the YDIH. However, the extinction of some species might have been practically synchronous.
... and associated impacts on prehistoric human societies. Proponents of the hypothesis claim that these data cannot be adequately explained by volcanic, anthropogenic, or other natural processes.[18]
This is false and a misuse of the word "claim". Many YDIH reports "claim" the abundant geochemical signals, which are the primary impact evidence, cannot be adequately explained by volcanic or other natural processes. The impact hypothesis also "proposes", but does not "claim", some secondary effects were triggered by the impact. The aim of YDIH research is to determine whether these proposals for the secondary effects are correct. It is why the YDIH is a "hypothesis".
... their proposed dates for the Hiawatha crater in Greenland in the range of 12,800 ya (though later dates indicated an event from 55 million ya), ...
This is false and used as a 'straw-man' argument. Hiawatha crater has never been claimed by YDIH proponents in their research articles to be a necessary feature of the impact theory, nor has any YDIH proponent attempted to date the crater. There might have been some social media chatter, but this is irrelevant. Therefore, if the crater is 55 Myr old, it says nothing about the YDIH in the same way the Chicxulub crater says nothing about the YDIH. However, if it was found to be only 12,800 years old it would naturally tend to confirm the theory. Currently, its dating is uncertain, with only a few contradictory reports. Nevertheless, given its pristine condition and location under the Greenland ice sheet, it is almost certainly not as old as 55 Myr.
They argue that the Younger Dryas boundary layer should be used as a local stratigraphic marker.[19]
Correct.
Impact debris[edit]
Again, this section appears to be written by an incompetent and highly biased editor. It bears almost no relation to the science.
Proponents have reported materials including nanodiamonds, metallic microspherules, carbon spherules, magnetic spherules, iridium, platinum, platinum/palladium ratios, charcoal, soot, and fullerenes enriched with helium-3 that they interpret as evidence for an impact event that marks the beginning of the Younger Dryas.[1][20]
Yes, but not all these lines of evidence have the same status. Some have been replicated by several independent research groups, others have not, as explained above. There's also no real difference between "metallic microspherules" and "magnetic spherules".
One of the most widely publicized discoveries (nanodiamonds in Greenland) has never been verified and is disputed.[21]
Nobody has yet attempted to reproduce the Greenland nanodiamonds specifically, but that is no reason to dispute these results. Abundant nanodiamonds have been found at the base of the YD boundary layer in many other locations across multiple continents by several independent research groups.
Scientists have asserted that the carbon spherules originated as fungal structures and/or insect fecal pellets, and contained modern contaminants[22][23] ...
The carbon spherules are not one of the main impact indicators.
... and that the claimed nanodiamonds are actually misidentified graphene and graphene/graphane oxide aggregates.[24][25]
This is false. It only applies to the claims made about Lonsdalite, a form of hexagonal diamond. The claims made about other forms of nanodiamond are not disputed in this way.
Iridium, magnetic minerals, microspherules, carbon, and nanodiamonds are all subject to differing interpretations as to their nature and origin, and may be explained in many cases by purely terrestrial or non-catastrophic factors.[26][27]
As stated above, each of the most potent geochemical lines of impact evidence at the YD boundary have been reproduced on several continents by several independent research groups. This is the gold standard in science, and the scientific facts are reviewed Sweatman and by Powell. By neglecting to mention this, the editors are declaring an incredibly strong bias that bears no relation to the science. No reasonable alternative mechanism for the synchronous abundance of platinum, microspherules, high-temperature melts and nanodiamonds at the YD boundary, often found at the base of a YD black mat, is provided by opponents of the YDIH. Arguments against this are often spurious. For example, one YDIH opponent (see below) suggested the nanodiamonds could have resulted from wildfires. If this was true, then nanodiamonds would be ubiquitous in sediments. But they are not. Nor can wildfires create a nanodiamond layer in Greenland's ice.
An analysis of a similar Younger Dryas boundary layer in Belgium yielded carbon crystalline structures such as nanodiamonds, but the authors concluded that they also did not show unique evidence for a bolide impact.[28]
These authors confirm a nanodiamond abundance at the YD boundary and have no realistic alternative explanation for their presence. Their suggestion they might be created by wildfires is spurious, as explained above. However, nanodiamonds are known to be carried by meteorites and are generated by high-energy explosions.
Researchers have also found no extraterrestrial platinum group metals in the boundary layer, which is inconsistent with the hypothesized impact event.[a][29]
This is false. The platinum abundance at the YD boundary on several continents has been confirmed by multiple independent research groups. So, this statement is pure fantasy.
Further independent analysis was unable to confirm prior claims of magnetic particles and microspherules.[31]
This is the only paper that offers evidence contrary to the YDIH among over 100 other papers with evidence that support it. Clearly, this particular research should be repeated.
So far, this Wiki page is extremely biased. The overwhelming majority of YDIH papers are able to reproduce the geochemical evidence for a cosmic impact at the YD boundary. A few papers have attempted to refute these findings, but generally their methods are shoddy (see Sweatman's review) and most of their data actually supports the YDIH. By focussing solely on a few shoddy, negative papers at the expense of the overwhelming majority of positive, high-quality research, Wiki's editors are declaring their own incompetence and major bias.
Physicist Mark Boslough, a specialist in planetary impact hazards and asteroid impact avoidance, has undertaken a sustained critique in social media and in print of the hypothesis that an impact event or air burst was responsible for either a mass extinction of Late Pleistocene fauna in North America or abrupt climate change at the onset of the Younger Dryas. [b][32] He has been especially critical of a group of investigators called the Comet Research Group (CRG) that includes several individuals who have published papers supporting the Younger Dryas impact hypothesis.
Mark Boslough is a long-time critic of the YDIH. But his contributions in journal articles are all easily rebutted because they invariably consist of "straw-man" arguments. Not once has he considered the preferred scenario of the Comet Research Group, i.e. a highly dispersed fragmented comet. The closest he has come to considering this scenario is by suggesting the fragments were all of exactly the same size. No natural process is known to achieve this. His attack-piece in the Skeptic magazine is not peer-reviewed in the usual sense and likely to be highly unethical (see Powell's response). Clearly, he is not a serious commentator. Yet Wiki's editors prioritize the chatter of this single individual on social media above the findings of dozens of peer-reviewed papers in high quality journals authored by many independent research groups. This says all you need to know about Wikipedia's editors.
Comments
Post a Comment