Carbon14 Dating flaw discovered: CO2 uptake isn’t as predictable as once thought

Carbon dating accuracy called into question after major flaw discovery

by Colm Gorey

When news is announced on the discovery of an archaeological find, we often hear about how the age of the sample was determined using radiocarbon dating, otherwise simply known as carbon dating.

Deemed the gold standard of archaeology, the method was developed in the late 1940s and is based on the idea that radiocarbon (carbon 14) is being constantly created in the atmosphere by cosmic rays which then combine with atmospheric oxygen to form CO2, which is then incorporated into plants during photosynthesis.

When the plant or animal that consumed the foliage dies, it stops exchanging carbon with the environment and from there on in it is simply a case of measuring how much carbon 14 has been emitted, giving its age.

But new research conducted by Cornell University could be about to throw the field of archaeology on its head with the claim that there could be a number of inaccuracies in commonly accepted carbon dating standards.

If this is true, then many of our established historical timelines are thrown into question, potentially needing a re-write of the history books.

In a paper published to the Proceedings of the National Academy of Sciences, the team led by archaeologist Stuart Manning identified variations in the carbon 14 cycle at certain periods of time throwing off timelines by as much as 20 years.

The possible reason for this, the team believes, could be due to climatic conditions in our distant past.

This is because pre-modern carbon 14 chronologies rely on standardised northern and southern hemisphere calibration curves to determine specific dates and are based on the assumption that carbon 14 levels are similar and stable across both hemispheres.

However, atmospheric measurements from the last 50 years show varying carbon 14 levels throughout. Additionally, we know that plants typically grow at different times in different parts of the northern hemisphere.

Read more at Silicon republic


 

The paper: (open access) http://www.pnas.org/content/early/2018/05/23/1719420115

Fluctuating radiocarbon offsets observed in the southern Levant and implications for archaeological chronology debates

Significance

We observe a substantive and fluctuating offset in measured radiocarbon ages between plant material growing in the southern Levant versus the standard Northern Hemisphere radiocarbon calibration dataset derived from trees growing in central and northern Europe and North America. This likely relates to differences in growing seasons with a climate imprint. This finding is significant for, and affects, any radiocarbon application in the southern Levant region and especially for high-resolution archaeological dating—the focus of much recent work and scholarly debate, especially surrounding the timeframe of the earlier Iron Age (earlier Biblical period). Our findings change the basis of this debate; our data point to lower (more recent) ages by variously a few years to several decades.

Abstract

Considerable work has gone into developing high-precision radiocarbon (14C) chronologies for the southern Levant region during the Late Bronze to Iron Age/early Biblical periods (∼1200–600 BC), but there has been little consideration whether the current standard Northern Hemisphere 14C calibration curve (IntCal13) is appropriate for this region. We measured 14C ages of calendar-dated tree rings from AD 1610 to 1940 from southern Jordan to investigate contemporary 14C levels and to compare these with IntCal13. Our data reveal an average offset of ∼19 14C years, but, more interestingly, this offset seems to vary in importance through time. While relatively small, such an offset has substantial relevance to high-resolution 14C chronologies for the southern Levant, both archaeological and paleoenvironmental. For example, reconsidering two published studies, we find differences, on average, of 60% between the 95.4% probability ranges determined from IntCal13 versus those approximately allowing for the observed offset pattern. Such differences affect, and even potentially undermine, several current archaeological and historical positions and controversies.

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137 thoughts on “Carbon14 Dating flaw discovered: CO2 uptake isn’t as predictable as once thought

  1. “In a paper published to the Proceedings of the National Academy of Sciences, the team led by archaeologist Stuart Manning identified variations in the carbon 14 cycle at certain periods of time throwing off timelines by as much as 20 years.”

    Surely the discrepancies must be larger than 20 years to even make any difference. OMG 0 BC is actually 20 AD or is it 20 BC? +/- 20 years is only a generation.

    • “Our findings change the basis of this debate; our data point to lower (more recent) ages by variously a few years to several decades.”

      [ … ]

      “Such differences affect, and even potentially undermine, several current archaeological and historical positions and controversies.”

      Sometimes several decades can be important.

    • Many times whether one event occurred at the same time, before or after another impacts how both events are interpreted.

    • +/- 20 years? Once again we have something written by a PR flack who has no clue about what she’s talking about. Such articles are often alarmingly misleading. How accurate is C14 dating anyway?

      If someone tries to use C14 to date something within a year, don’t believe them. If they use it to date something within a thousand years, they’ve got a strong case. link

      I’m not aware of historians basing a chronology solely on the basis of C14 dating. Usually there’s other corroborating evidence.

      • Historians have documents, back 5000 years in the cases of the centers of ancient civilizations. Prehistorians also have corroborating artifacts and material against which to check C14 dates.

        • And a tree that grew beside a cliff will have a different C14 concentration than one that grew in the open prairie….Aaarghh, this science is nowhere near as accurate as a calendar…..

          • no matter which calendar calibration you use. according to some we haven’t arrived at Y2K yet. Or have we? We can be pretty sure it doesn’t really matter.

    • It does not say so, but carbon 14 dating relies on the rates of decay of the radioactive isotope.
      Since this decay gives a curve which is not linear, I believe the implication may be that although the discrepancy may be only 20 years in that particular case, since it is relatively recent the effect of how it differs from previously accepted values likely increases over time in a way with is similarly nonlinear.
      IOW…dating from long ago is far more uncertain than 20 years.
      Plus, the fact that this discrepancy is that big for one particular location, and one time period, may point to potentially larger or small discrepancies over that same time period in other locations, or over that same interval of time in some other historical period.
      IOW…this may mean that the whole process is more uncertain than anyone really knows.
      Perhaps different trees to not take up carbon 14 at the same rate as others, or the amount of variability in the penetration of cosmic rays is more highly variable than has been recognized.
      This makes perfect sense, if one assumes that the variability of the magnetic fields of the Earth and Sun are less well understood than some scientists have given themselves credit for.

      • Here’s an example from the Dead Sea Scrolls.

        http://roberteisenman.com/articles/Redating_the_Radio_Carbon_Dating_of_the_DSS.pdf

        Some of the scrolls, particularly one called the Habakkuk Pesher, have been dated to the 1st century BC. In this case, there were 14 scrolls in a jar which were paleographically the same, but and the two on top tested a century earlier. Based on internal and paleographic evidence, Robert Eisenman dates these to the 1st century AD, which places in the time of Jesus or the decades following. There is a huge difference in context and historical identification, especially since it uses ambigous nicknames for the characters. The linked article is cowritten by the president of a carbon-dating equipment company and argues that the earlier date is flawed in several ways.

        This article seems to support that view.

    • In 2012 I worked on wood from a Roman warship recovered off the coast of Acqualadrone, Sicily. It was 14C dated to 277±83 BCE. putting it in perhaps the first naval battle of the first Punic War.

      To suppose an additional ±20 years is critically important is to not understand the method.

      Apart from that, it’s known for example that the waters off Antarctica are depleted in 14C because of the release of ancient organic matter in melting glaciers. So carbon dating materials from there is very suspect.

      The need for correction factors and the effects of different carbon reservoirs on 14C dating is well known. See here.

      • Arent all the 364 days after the birth of Jesus of Nazereth considered to be in year 0?

        • Technically yes. Take a 4 month old baby, it turns one after 364 days, but you would never refer to it as a 0 year old.

          The timeline is always up to -1 BC, and 1 BC and beyond. 0 is never counted as a valid year.

          • 0 only occurs in astronomic year reckoning, that year is 1 BC in historic timekeeping, or BCE as is now often used (‘ Before Common Era’).

            1 Astronomic -= 1 AD aka CE
            0 Astronomic = 1 BC aka BCE
            -1 Astronomic = 2 BC

            So not -1 BC 🙂

          • 0 is the year following birth. After one year, the year 0, the age of the newborn is 1 [yr].

          • But that’s semantic.

            What the above text says :

            Were constantly transferring / loosing C / CO2 from atmosphere to soil. That transferred, “lost” CO2 is modern talking “fossil fuels”.

        • In our current calendar system, the day after December 31, 1 BC was January 1, 1 AD

        • Our calendar is based on one developed b y the Romans. The Romans didn’t HAVE a zero.

          • In fact those numerals were invented in India, modified by the Arabs and further modified by Europeans.

          • Wrong!

            Sorry, but we only call our current system “Arabic” numerals because they entered Europe via the Arabs.

            The system we use was invented in India, whence the Arabs got it and transmitted it to Europe.

            Pu-leeze! This is well known.

          • Actually, whether or not there is a zero in a number system is irrelevant as far as a calendar is concerned. Zero would be the INSTANT midnight was reached on December 31, 1 BC/January 1, 1 AD. Any instant slightly before midnight would be in 1 BC, any instant slightly after midnight would be in 1 AD. The US uses that same system. If you pay attention, besides AD, government officials say, ‘ this 300th day of the 268th year of the United States. We were in the first year of the US starting July 4, 1776, we were in the year BEFORE the establishment of the US on July 3, 1776.

    • It’s an average of 20 years for dates in the last for centuries. Some dates were off by several decades during that timeframe, meaning that dates from 2,000 years ago could esily be off by more than a century.

      “We measured 14C ages of calendar-dated tree rings from AD 1610 to 1940 from southern Jordan to investigate contemporary 14C levels and to compare these with IntCal13. Our data reveal an average offset of ∼19 14C years”

  2. I guess now that whole Dinosaur extinction time frame theory is wholly and completely inaccurate

    • I assume you’re kidding.

      C14 dating is good for archaeology, but is of limited use in paleontology. At most it’s good only back 40 or 50 thousand years, ie the very end of the Pleistocene Epoch of the Neogene Period of the Cenozoic Era.

      For the Mesozoic Era (non-avian dinosaurs), you need uranium-lead or other radiometric dating systems, not related to C14.

      • Is it true that in the past 30 years climate scientists did not have to take paleontology( because it was an option) but yet were able to go through pal review as long as they confessed to bow down before the Gods of Global warming?

      • Alan,

        I’m pretty sure that real climatologists had to study paleontology, but so-called “climate science”, by contrast, is mostly GIGO computer gaming.

    • No Bryan. The dinosaurs didn’t know about carbon and couldn’t count to 14 so it didn’t effect them.

      • They did however consume vast quantities of carbon made available to them by C3 vegetation at the time, thanks to the air being greatly enriched in life-giving CO2 over today’s near-starvation level. The much warmer seas made this bounty possible.

    • Yeah. It is 65,000,19 years instead of 65,000,000 years.

      Reminds me of the old joke. “This fossil is 5,000,002 years old. -How do you know it so accurately? -Well they told me it is 5,000,000 years old when I started my job here!”

  3. Point One:
    The notion that the earth’s surface is 33 C warmer with a “greenhouse” atmosphere is rubbish.
    The 15 C aka 288 K is a wild ass guesstimate for only the land area’s surface temperature. (IPCC AR5 Glossary)
    The -18 C aka 255 K is an unrelated-to-the-surface & with-atmosphere theoretical “what if?” S-B BB equilibrium temperature calculated from the globally averaged 240 W/m^2 OLR at ToA (100 km).
    The lunar papers by Volokin and Kramm clearly confirm that the earth without an atmosphere and 30% albedo will be hotter not cooler.

    Point Two:
    A fanciful up/down/”back” GHG radiation energy loop attempts to explain a physical mechanism behind this erroneous 33 C warmer premise, an explanation involving copious amounts of QED handwavium.
    This loop violates thermodynamics by 1) creating energy out of nowhere, 2) moving energy from cold to hot without additional work, 3) moving energy in a perpetual 100% efficient loop.
    The upwelling radiation is not a physical fact, but a theoretical “what if?” S-B ideal BB calculation.
    The allegedly “measured” up/down welling radiation is an illusion due to IR instruments not properly corrected for the actual emissivity. (Think of VW et. al. “tweaking” emissions tests.)

    Point Three:
    No GHG energy loop = No RGHE = No human role in climate behavior.

    • Point One: “Den Volokin” is an alias for a scientist who lies to the journals about his own name … and a man who lies to a scientific journal about his own name will lie to them about anything. Only a fool would believe anything he wrote without extensive checking, cross-checking, and then checking again.

      Point Two: His paper about “the earth without an atmosphere” is a scientific joke. For the explanation why, read this from Dr. Robert Brown, who teaches these things at Duke.

      Point Three: A man who feels the need to put letters after his name is trying to lend false weight to his opinion. As Richard Feynmann said, ““Science is the belief in the ignorance of experts.”

      w.

      • Dear heavens, this damn new format will NOT let me put spaces between paragraphs … terrible. Jams everying up into one paragraph. BAD BAD BAD BAD BAD!

        w.

          • Felix is right.
            If a comment is long enough to have (for me the green) “read more…” show up at the end of the comment, then whatever formatting the commenter added will not show up until “read more…” is clicked.

            I saw your spacing after I hit “read more..”.

        • It also won’t accept the “pre” HTML tag. Let me try some others:

          Bold

          Italic

          Blockquote

          w.

        • And if I use “Enter” instead of “Return” it treats that as a paragraph break.

          That’s gonna be fun to remember …

          w.

        • Willis, Willis, Willis:
          I believe the expression you are looking for is —
          Stupid Computer!

      • “Point Three: A man who feels the need to put letters after his name is trying to lend false weight to his opinion. ”

        I wholeheartedly agree!

        • Willis said

          “Point One: “Den Volokin” is an alias for a scientist who lies to the journals about his own name … and a man who lies to a scientific journal about his own name will lie to them about anything. Only a fool would believe anything he wrote without extensive checking, cross-checking, and then checking again.

          Point Two: His paper about “the earth without an atmosphere” is a scientific joke. For the explanation why, read this from Dr. Robert Brown, who teaches these things at Duke.

          Point Three: A man who feels the need to put letters after his name is trying to lend false weight to his opinion. As Richard Feynmann said, “Science is the belief in the ignorance of experts.””

          1) More people than Volokin have written papers regarding the gravity pressure mass theory of global heat balance.

          3) There is nothing wrong with putting letters after your name as long as those letters really are true.

          • Alan. Seems to me a good point you make. I once got into an argument with a fellow instructor about the auto pull up feature of the F111 when a failure ocured within the terrain following radar system while flying in the manual mode. He argued that he had to be right because he had taught his students that it would not auto pull up in the manual mode. I showed him in the manual and on the maintenance trainer that he was wrong. He was embarrassed but accepted he was wrong. The odd thing about this is it probably didn’t ever cause any problem or ever noticed by anyone that he had taught something wrong. I have never given the idea that someone must be right because he teaches something much credit since then.

      • Terrible logical fallacy as well as a simple silly assertion. Nobody lies about everything, everybody lies about something.

        And why believe anything anybody writes without cross checking and checking again?

  4. 20 years??…..anyone that claimed RCD was more accurate than that was fooled anyway

    • Absolutely right.

      The value of this work is that it provides evidence that C14 dating is accurate to ± 20 years, as opposed to more.

  5. In my opinion, no sensible person, no less a scientist, ever thought C14 dating was accurate to anything like +/- 20 years.

    • To this Layman, the CO2 levels have varied through the years. That much is known.
      That should effect the Carbon 14 levels. More or less CO2, more or less Carbon 14.
      Also, some plants can filter out Carbon 14. (I think the Mallow plant is one of them.)

      PS I remember reading a year or more ago about a team that did a Carbon 14 dating on tree rings. They found an unexplained spike for sometime in or around … 743 AD? I think. I think the tree ring as from one the Japanese islands.
      They were going to search ancient records for an, as yet, unreported supernaova to account for it.

      • Doesn’t that make you suspicious of the Vostok ice core CO2 samples? For the last 300000 years the CO2 levels were almost 280 straight line. Nature didnt work that way a million years ago so why should CO2 be level for 300000 years until 1850. Tim Ball doesn’t believe in the Vostok ice cores. Another point is the CO2 data from Mauna Loa It just seems too cute at a 60 degree line ( okay the angle can be determined by the axis divisions) But the neat zigzag line (the zigzag is caused by photosynthesis) just seems unnatural. I know that there are other sites that have confirmed the Mauna Loa data but there have been measurements that show that CO2 is not as well mixed as the IPCC says it is. My 3rd point is that if NASA are measuring the DWIR by considering that the sky (CO2 molecule) is a blackbody then all bets are off with DWIR(back radiation). If all of those main bricks fall along with the GHG theory then the CO2 molecule will be left naked because nothing else makes any sense in this whole scam.

        • CO2 can migrate through ice. It’s a very slow process, but given tens to hundreds of thousands of years at Vostok, you would expect some homogenization.

    • Kip’s post had a +1 rating when I first read it.
      I tried to give the post another + and the original +1 was reduced to zero with the (false) statement that I had already voted for it. What gives? Rating system needs some scrutiny.

      • Hmm, if I give a second vote I get a message that I have already voted.
        Perhaps what’s happening is that the second vote cancels out your first vote. So it’s a toggle one vote, no vote, one vote, no vote.

        • @MarkW
          In my post above perhaps I was not clear. At the time I first read Kip’s post it was ALREADY marked +1, I had not “voted” it at all. When I tried to make an upvote, the system told me I had already voted for it. Go figure… “is a puzzlement!

      • A guess about the +1 going to 0, perhaps voting refreshes the count and someone had hit -1 since you opened the post?
        I’ve no clue why it said you already voted when hadn’t unless you accidentally double clicked.

    • Kip, while a single C-14 measurement may only be accurate to a couple centuries even for a 2,000 year old object, by using squiggle matching, C-14 dating is supposedly very precise. See the long comment I just posted.

      • Greg ==> I would like to see some more groundtruthing on C14 for near-present objects. For example, testing a bit of wood from something with a known date in the last couple of centuries against C14 data.
        It is a question of “fit for purpose” –is C14 fit for purpose in dating recent objects, dating objects to a specific decade? etc.
        Think a criminal trial where someone’s life depends on the correctness of the dating.
        Scientific sounding methods are often over-rated, assumed accurate or infallible, because they are “scientific”.

  6. I suspected this from the beginning. C14 is a product of cosmic radiation and our atmosphere, so how can we possibly be assured that the “carbon footprint” is surely manmade if we do not have a good measurement of how much C14 production is being made by cosmic radiation? No one ever answered this question to my satisfaction, I’m glad to see I’m not the only one who thought to question this problem.

    • From the very beginning of radiometric dating, calibration issues have occupied everyone involved.

      Huge effort has gone into trying to find the right corrections for calendar v. C14 years.

    • “so how can we possibly be assured that the “carbon footprint” is surely manmade”

      If cosmic rays were making Gtons of C14 we’d be in strife. Wiki says there are about 840 kg in the air at any time.

        • What effort has gone into calibrating that measurement? What effort has been made at trying to determine yearly variation of that number through history?

          • Lots. It is ssimple measurement and depends on the cosmic ray intensity that only varies a few percent

        • “about 8 kg is created each year by the cosmic rays.” –>

          about 8 kg C, already in the recycling atmosphere, each year is “transformed” to C14.

          • Correct.

            14C has six protons and eight neutrons. Normal nitrogen has seven protons and seven neutrons. Production of carbon 14 takes place in our N-rich atmosphere, where nitrogen atoms absorb thermal neutrons.

    • If most of the carbon were being created by cosmic rays, then there would be a much higher percentage of C14 than currently exists.

      Beyond that, without a huge increase in cosmic rays, the amount of C14 in the atmosphere will be about the same as it was last year, and the year before, and the year before that …

  7. They do seem to be splitting hairs here. But, I suppose this is how progress is made.
    No analytical determination can be more accurate than it’s calibration curve. If they can cross calibrate and bum out a bit more error from the calibration curves for the time and place of interest, hats off to them.

  8. Our reporting for radio carbon dating for the Tall el Hammam excavations in the Jordan Valley near the Dead Sea are all listed as +/- 50 years.

  9. There are many assumptions, assertions, outside the limited scientific frame of reference, where observations are made and reproducible. Inference of the past; prediction about the future… perhaps also inference. We don’t know the nature of “time”, but speculate about its character, often outside a scientific frame of reference. People want to believe in something.

  10. Archaeologists should welcome this. It means the science of carbon 14 dating is better understood and its relationship to other methods of estimating the age of sites, excavations, and objects.

  11. Carbon-14 dating already has a huge range of error (usually one standard deviation) and it is already known that all sorts of things can affect the dating (like contamination by leaching of sources of carbon above the sample). They already have an age correction chart because scientists were able to match samples up against tree rings where you can reliably count the years back several thousand years (not determine temperature, just count yearly rings). So when you see a date estimate of 1020-1120 you are ordinarily talking about the age has a 68% chance of falling into that range. If an age correction using tree rings was possible on at least one item, then the age range is going to be pretty good – if not, its pot luck (IMO).

    The original idea that living things take up carbon-14 like clock work has long been discarded except maybe in the class room. The idea that Carbon-14 production varies has been discussed for years and should not come as any surprise to an expert in the field.

    Even with the variance, its still a useful tool to help you understand somethings approximate age, especially if you have known things buried in the same area that can be dated in other ways. Once you have something that has a credible date from using different techniques, comparing its carbon-14 date to other nearby (same burial situation) artifacts is a reasonable, but not terribly accurate, approach.

    Those thinking that there is any such thing as “high resolution carbon-14 dating” are living a fairy tale. There are too many variables to try to control for.

  12. supports the notion that climate and growing conditions influence the INTCAL13 14C calibration, that of course feeds into the reconstruction of solar activity in the past.

  13. so much for a “well mixed gas” … I always thought that was nonsense on stilts … this is just empirical proof …

  14. The Vikings dug up in Greenland all carbon dated 400 – 500 years older than they should because of the “Marine Reservoir Effect”. Their diet consisted mostly of fish or marine which has considerably less Carbon 14.

    • Very true , but in the works of , say , jette Anneberg, the reservoir effect is allowed for and explained , and where textiles have been used as grave shrouds eg at Herjolfsnes in the Eastern Settlement the C14 dates for the textile tally with those (corrected ) of the human remains

  15. It is prudent to examine all radiometric age date methods from time to time because all assume initial conditions that might not be found accurate as more observation becomes available over time.
    While the decay constants of relevant isotopes are known adequately, one has to assume there has been no perturbation such as later contamination, or loss, or correct for it. One has to assume that the event that reset the clock did so completely, not partially. One sometimes has to assume that methods involving 2 elements with isotopes, like uranium/lead ages, had certain concentration ratios of those elements before the clock was reset.
    There remains room for discovery of better accuracy through testing of assumptions and more with improvements in instruments. Importantly, it is a method where the proper calculation of uncertainty bounds is critical. Geoff

    • GTB
      I agree with Geoff. Cosmic rays hitting the atmosphere vary with the strength of the earths magnet field too which some have said is slowly decreasing.

  16. Natural production in the atmosphere

    Carbon-14 is produced in the upper layers of the troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. When cosmic rays enter the atmosphere, they undergo various transformations, including the production of neutrons. The resulting neutrons (1n) participate in the following reaction:

    n + 14N → 14C+ p
    The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 49,000 ft) and at high geomagnetic latitudes.

    The rate of 14C production can be modelled and is between 16,400 and 18,800 atoms 14C m^−2s^−1, which agrees with the global carbon budget that can be used to backtrack, but attempts to directly measure the production rate in situ were not very successful. Production rates vary because of changes to the cosmic ray flux caused by the heliospheric modulation (solar wind and solar magnetic field), and due to variations in the Earth’s magnetic field. The latter can create significant variations in 14C production rates, although the changes of the carbon cycle can make these effects difficult to tease out.
    https://en.wikipedia.org/wiki/Carbon-14
    https://cosmicrays.oulu.fi/webform/monitor.gif

  17. Cosmic rays kept the level of carbon-14 in the atmosphere roughly constant (70 tons) for at least the past 100,000 years,[citation needed] until the beginning of above-ground nuclear weapons testing in the early 1950s. This is an important fact used in radiocarbon dating used in archaeology.

    Reaction products of primary cosmic rays, radioisotope half-lifetime, and production reaction.
    Tritium (12.3 years): 14N(n, 3H)12C (spallation)
    Beryllium-7 (53.3 days)
    Beryllium-10 (1.39 million years): 14N(n,p α)10Be (spallation)
    Carbon-14 (5730 years): 14N(n, p)14C (neutron activation)
    Sodium-22 (2.6 years)
    Sodium-24 (15 hours)
    Magnesium-28 (20.9 hours)
    Silicon-31 (2.6 hours)
    Silicon-32 (101 years)
    Phosphorus-32 (14.3 days)
    Sulfur-35 (87.5 days)
    Sulfur-38 (2.84 hours)
    Chlorine-34 m (32 minutes)
    Chlorine-36 (300,000 years)
    Chlorine-38 (37.2 minutes)
    Chlorine-39 (56 minutes)
    Argon-39 (269 years)
    Krypton-85 (10.7 years)
    https://en.wikipedia.org/wiki/Cosmic_ray

  18. interesting that the paper is saying +-20 when real experts on this blog give +- 50. So the conclusion of report should be exact opposite. Reminds me that even the calendar is inaccurate. Didnt we lose 11 days of the calendar back in the 16 or 17th century when the calendar got changed. That would make all yearly comparisons of data back then to be flawed.

  19. “throwing off timelines by as much as 20 years.”

    carbon dating of papyrus from cira 600 AD would have an uncertainly of something like +/- 50 y.

    Since most carbon dating of archaeological finds is on the scale of millennia, how is this even note worthy. This is far less than the accepted uncertainty of any carbon dating.

    This is just another excuse get “climate change” into the literature.

    • results are usually quoted with a 1 sigma uncertainty: which is only 68% confidence level . If this paper really claims “as much as 20y” it’s a spit in the ocean of C14 uncertainty.

    • Greg, to do a highly accurate C-14 dating you need a sequence of tree rings. Papyrus doesn’t have that, so you’re considering a poor test subject in the first place.

  20. One thing that is not in doubt is the fact that all this CO2 rise is caused by human activity.
    I guess that is the reason for today’s doubt-monger du jour from Watts: attempt to cast doubt even on that.

  21. “throwing off timelines by as much as 20 years”

    So x was made in 100 BC now becomes 120 BC. Hardly important is it.

  22. The problem seems like it should be far worse than a 20-year issue.

    I’m surprised “squiggle matching” is not discussed in the article nor has made it into any one’s comments. Maybe there is another word for the process that I don’t know?

    My understanding of best practice prior to the article:

    With a single carbon-14 measurement you can cost effectively date an object, but the accuracy is rather poor and that is where the +/- 250 years for a 2,000 year old test object comes from.

    But, the most accurate method of carbon dating is to perform squiggle matching between the reference timeline and a wooden object being tested. Let’s say an object under evaluation has 50 wood grains in it, that means you have sample wood from 50 consecutive tree rings. Each tree ring would have accumulated carbon-14 originally based on the density of carbon-14 in the atmosphere the year the tree ring grew.

    If all 50 wood grains have their carbon-14 content measured, you now have a 50-year squiggle. You take that 50-year squiggle and overlay it with the reference carbon-14 decay timeline and you should be able to get an exact match for the shape. In particular, any spikes or annual anomalies in the subject squiggle should be able to be aligned with corresponding spikes in the reference carbon-14 decay timeline.

    The reference carbon-14 residual timeline was created by taking core samples of long lived trees such as some trees living in California (2,000 consecutive years of tree rings in some of those trees). Then do the same for a long lived tree that died say 1500 years ago. If it too lived 2,000 years you now have 2 2,000 year carbon-14 decay graphs with about a 500-year overlap. By matching the squiggles of those 2 graphs you can match up precisely how to use the second decay graph to extend the first graph. So now you have a very precise 3,500 year long reference carbon-14 decay graph.

    Now, if you take your 50-year squiggle graph from your test object you can very precisely determine the age of the wooden test object to the individual year of each tree ring.

    The biggest accuracy issue relates to when was the wood from the tree actually used to make something. That is, if I cut down a 100-year old oak today and use lumber from the center of the tree today to make something, then carbon date it immediately via squiggle matching, my brand new object would match the squiggles from 100-years ago.

    Thus, the most accurate object to date is a wooden object with numerous rings and the bark still attached. That way the age of the tree ring next to the bark is the age of the tree when it was cut down and in theory you can know that to the precise year.

    ====
    The problem identified by this article is that a reference carbon-14 decay timeline created by analysing long lived trees in California may not be usable at all for squiggle matching wooden objects from the middle east!

    The good news is reference carbon-14 decay timelines can be built for each region of the globe. But until that happens, I don’t see how the authors of the article can say the newly identified error is only 20 years.

    • This is of very limited practical interest. Such wooden objects (numerous treerings + bark) are very rare, and can usually be directly dated by squiggle matching of the treerings in any case.

      • Squiggle matching sounds better! And none of the commenters here seem familiar with wiggle matching either.

        High-precision carbon dating involves wiggle matching, so most of the comments here are uninformed from what I understand.

        I note that in the link they dated graves from ~600AD +/-14 years via wiggle matching.

        If this new paper changes that to +/- 34 years, that’s a big change.

  23. So C14 dating is accurate to +/- 20 years for a living penguin carbon dated at 8,000 years old.

    • Certainly not. At such a time depth the uncertainty would be on the order of a century. Correction for marine reservoir effect would also be necessary.

      • Apparently you missed my sarcasm. LIVE penguins have been carbon dated to 8000 years old. It’s crappy science.

    • Even if it only works with wood, it works well with wood. The reason being each wood grain (tree ring) can be tested and the aggregate picture used to make an accurate assessment.

  24. I too do not see where 20 years is anything to worry about. I get the impression that this quantity is within ordinary error estimates, and so I wonder how it is even possible to detect a difference that is within the error bars themselves.

    Confused.

    Oh, and I still cannot get an image to post and embed.

  25. One should not overestimate the precision of radiocarbon dates. Modern radiocarbon measurement (AMS (mass spectrometry) + ultrafiltration) usually have measurement uncertainties on the order of a few decades, but the age uncertainty is larger. Multiple measurements that applies to what should be a single point in time (e. g. different parts of the same animal skeleton, pieces of charcoal from a single campfire) typically have a spread of 100-200 years.

    Also there are “radiocarbon plateaus” where changes in the stratospheric production of C14 and/or abrupt changes in the carbon cycle means that a given level of activity can apply for several dates, sometimes several centuries apart. This is a big problem when studying the younger Dryas for example:

    https://journals.uair.arizona.edu/index.php/radiocarbon/article/viewFile/3569/3082

    Twenty years more or less is hardly significant.

    • The paper is talking about bronze age dating. That’s only 3500 years ago and wiggle matching is supposedly accurate enough that adding +/-20 years to the error is significant in many cases.

    • You keep harping on “wiggle matching” which is very rarely practicable, and when it is direct tree-ring dating is at least as reliable.

  26. There were papers years ago that showed plants used various isotopes at different rates. C12 CO2 was more likely to be absorbed than C14. That meant C/O2 from fossil fuels were removed faster than CO2 from respiration or forest fires. The differences were small but measurable.

    • Generally speaking lighter molecules are “preferred” in biological processes, so the lightest CO2 molecule (C12+2O16) is favored. The (very rare) molecule with C14+2O18 is least desirable.

  27. A critter dies and is buried by one inch of soil. His remaining C12 is subject to a certain amount of cosmic radiation. His buddy is buried by four feet of soil. The cosmic radiation reaching the second unfortunate would be less. Make a difference?

    • The neat part is when they find dinosaur bones with bone marrow in them, but are supposedly 65 million years old.

      So where are the billions of bones anyway?

    • “Make a difference?”

      Not really. It’s not the cosmic radiation per se that creates C14. It is thermal neutrons. There are (fortunately) very few thermal neutrons at ground level.

  28. This raises a question in my mind. (so many questions so little mind).

    As I understand it the sun influences the number of cosmic rays striking the earth.

    Wouldn’t this further complicate the issue of C14 dating?

  29. This is why we ‘calibrate’ radiocarbon dates – it’s reallt quite simple and inconsistency with carbon in the atmosphere has been known about for a long time.

  30. How DARE those anti-science DENIERS challenge the consensus that radiocarbon dating is infallible!!!!!

    The science is settled…these deniers must have their careers destroyed immediately!!!

  31. Any archaeologist you actually talk with will tell you that C-14 is a rubber ruler. There are far too many imponderables in the production and uptake to make it a really reliable date. The northern hemisphere standards are easy to undertsand and logically established, but assume a global uniformity in C-14 production that has been know not to be there for decades. Other glitches in C-14 dating include the marine off set. Shell from mariine and freshwater lake environments show consistent offsets from C-14 derived from trees and other organic terrestial matter. In fact, standard practice takes a ratio of stable carbon isotopes because the kind of plant the carbon derives from can make an inportant difference. CAMS cycle and C4 plants segregrate carbon isotopes differently from “normal” plants, so grains like maize for example will yield a different age than charcoal from the tree used as fuel the corn meal was cooked over. “Gold standard” is in the media’s – to be polite – minds. The advantage of C-14 dates is primarily that they can be handled repeatedly. The source and measurements do not change, only the estimated age based on them. So, unlike historic temerpature data where measurements are changed repeatedly to meet expectations, C-14 measures remain fixed. The data is never “adjusted” only the estimated age based on the data.

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