Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?
Earth Science

Fossil Fuels Are Messing With Carbon Dating 108

Taco Cowboy writes: The carbon dating method used in determining the age of an artifact is based on the amount of radioactive carbon-14 isotopes it contains. The C-14 within an organism is continually decaying into stable carbon isotopes, but since the organism is absorbing more C-14 during its life, the ratio of C-14 to C-12 remains about the same as the ratio in the atmosphere. When the organism dies, the ratio of C-14 within its carcass begins to gradually decrease. The amount of C-14 drops by half every 5,730 years after death.

The fossil fuels we're burning are old — so old they don't contain any C-14. The more we burn these fossil fuels, the more non-C-14 carbon we pump into the atmosphere. If emissions continue as they have for the past few decades, then by year 2050 a shirt made in that year (2050) will have the same C-14 signature as a shirt worn by William the Conqueror a thousand years earlier.
This discussion has been archived. No new comments can be posted.

Fossil Fuels Are Messing With Carbon Dating

Comments Filter:
  • by invictusvoyd ( 3546069 ) on Wednesday July 22, 2015 @05:32AM (#50158643)
    humans would have invented a new "dating" method
    • Why do we need a new one? We already replaced carbon dating with online dating. Now our carbon based lifeforms don't even need to be in the same room to date anymore. What more could you want!

    • Tetra Ethyl Lead (Score:5, Interesting)

      by goombah99 ( 560566 ) on Wednesday July 22, 2015 @09:09AM (#50159567)

      Interestingly this isn't the first time this happened.. When they first started Isotopic dating there seemed to be no lab pure enough to get the lead out. Even water taken from the widdle of the ocean had the wrong lead isotope ratios. Eventually, years, they realized it was in the air from all the lead in gasoline. The gasoline companies had the guy's funding cut off to suppress this, and trotted out a bunch of "tobacco scientists" to ridicule the guy who discovered it. But eventually this too became fact. Now it's used in reverse, the isotopic ratio of lead is used to track gasoline spill origins. [] []

    • humans would have invented a new "dating" method

      Ashley Madison?

  • by meglon ( 1001833 )
    It's already having a tremendous effect. Twinkies made 10 years ago have the same C14 signature of Twinkies made right before Vesuvius buried Pompeii.

    Wait, what? When were those Twinkies made?

  • Not remotely news (Score:3, Informative)

    by Anonymous Coward on Wednesday July 22, 2015 @06:19AM (#50158749)

    From []:

    "Krane points out that future carbon dating will not be so reliable because of changes in the carbon isotopic mix. Fossil fuels have no carbon-14 content, and the burning of those fuels over the past 100 years has diluted the carbon-14 content. On the other hand, atmospheric testing of nuclear weapons in the 1950s and 1960s increased the carbon-14 content of the atmosphere. Krane suggests that this might have doubled the concentration compared to the carbon-14 from cosmic ray production."

  • Just look up radiocarbon dating calibration, this has been known since the discovery of said process.

    • which is why just about all RadioX dating methods should be suspect.

      No need to put a thumb on your scale if the thumb is cooked into the firmware (on installed during calibration).

      • damn straight. you go invent quantum dating like star trek has and everything will be fixed.

    • Along with the complication of modern organisms living on abnormally low-14C carbon sources. Organisms living on oil/ tar seeps ; organisms living on carbonates and sulphates from salt domes.

      A known type of problem, which is why raw radiocarbon dates need careful interpretation to get back to absolute dates.

  • 5, 4, 3...

    Huh? No, that this is only due to us burning fuel created millions of years ago and that it offsets results by a few 1000 years tops doesn't mean anything to them.

    • From now on we'll call them Carbon Deniers or some such.
    • Yet another "reason" why using fossil fuels will be painted with an evil brush. OMFG, we won't be able to date anything!! EVERYBODY PANIC!!!
      Oh, 'scuse me, I forgot that they conveniently rebranded it as "climate change" to cover their asses...I mean bases.

      • I used to argue for stopping the climate change.

        Then I realized what a scourge humanity is.

        Now count me in as one of the deniers. Or, kinda, at least. I still believe that climate change is happening. I just welcome it.

        • by jfengel ( 409917 )

          It's not gonna help, though. Climate change doesn't wipe out humanity. It may wipe out other, less tenacious species. And it'll kill tens, maybe hundreds of millions of humans, and cost into the trillions of dollars. You might count it as just punishment, but it won't eliminate the problem. (It might teach them a lesson... but I doubt it.)

          • Anthropogenic climate change probably won't wipe out Homo Sapiens. We're a very adaptable and resourceful species. But it may well wipe out the complex global civilization we've built or at least reduce it to a paltry impoverished echo of what we have now.

          • See, I'm on this a bit like I'm with drunk driving. If it could only affect the idiots that do it, I'd be rooting for it. Darwin should be right and all that.

            Problem is that the rich fuckers along with their denial sheep ain't the ones sitting on the beaches and certainly they won't remain there when the waters are rising. It will hit the poor and defenseless harder than it will hit those that could do something against it but refuse to because it could cost them a few bucks.

            That's the part that gets my pis

  • We need to release more radioactive C14 carbon into the air.

    Thus solving the problem, once and for all.

  • Atmospheric nuclear testing in the 1950's and 60's added so much C14 to the atmosphere that Carbon dating is useless already

  • Easily fixed (Score:5, Informative)

    by quenda ( 644621 ) on Wednesday July 22, 2015 @06:49AM (#50158851)

    ... or already broken, depending on your viewpoint.
    While fossil fuels reduce atmospheric C14, atmospheric nuclear detonations increase it dramatically.
    In 1963, C14 levels reached double the earlier level.
    But even before any of that, radiocarbon dating needed to be calibrated according the varying level of atmospheric CO2 over the aeons.
    And it is already easy to make fake ancient parchment or paper using greenhouses and fossil fuel.

    Combining carbon dating with other techniques should be enough to remove ambiguity in dating.

    • Combining carbon dating with other techniques should be enough to remove ambiguity in dating.

      "Other techniques" not only have different ranges of time for which they're accurate, they also have different levels of accuracy. (And not all are applicable to all materials.) They may or may not be sufficient to resolve ambiguity.

  • by Anonymous Coward

    Carbon dating is already unreliable as it depends on a number of unprovable assumptions

    • Its certainly not as reliable as people tend to make it out/believe it to be.

      This is just an example of how it can become inaccurate, and this is only one example, only god knows what happened seemingly randomly throughout the span of time. What happened to C14/C12 ratios during various asteroid impacts and such? ... no one knows, its all speculation and guesses, and due to confirmation bias the guesses are naturally aligned with what they want to confirm/prove.

      So its a method that fits what the scientists

  • Half every 5,730 years? What kind of scale is that? The whole universe is barely over 6000 years old, dating scales should cover years or dozens of years, like tree-ring dating or biblical character dating, otherwise they don't make any sense. Carbon dating seems like a scam anyway, they are probably trying to find excuses for why it is not working out.

    • by prefec2 ( 875483 )

      Hahaha very funny. However, in case that you really believe that. You made two mistakes:
      a) As the amount of C-14 can be measured very precisely, you can measure deviations from it not only in steps of 50%, but by fractions of that.
      b) The universe is at least 13.82 billion years

      And BTW: C-14 can be calibrated by tree core comparison.

  • Or alternatively: if it is not being "made" or acquired (from the Sun, nuclear tests or emissions etc) then, either way, it can be calibrated for. We know, pretty much, how much coal is being dug out of the ground and, indeed, pretty much which and volume of nucleotides that have been released. If we know this all then we can calibrate for this in the future. So what's the problem exactly?
    • by prefec2 ( 875483 )

      You could have googled that in 5 seconds: []

    • by jfengel ( 409917 )

      It comes from cosmic rays, which are roughly constant over time. They're not completely constant, and so we already have to calibrate our C14 tests. (There's a whole bit of weirdness in the way we report dates as the calibration itself has been refined over time, and when you read an old document you need to know exactly how it was calibrated.)

      But the variations in intensities happen over centuries, rather than years. And instead of covering the whole world, it's going to be localized by the varying factors

  • . . .you insensitive clod!

  • by Anonymous Coward

    We're ruining this planet burning fossil fuels and the "victim" here is carbon dating? If we keep ruining this planet, carbon dating won't be a problem since we'll all be dead and not giving a rat's ass about the carbon date of anything.

    I suppose though, we are ruining it for whatever comes after us and wants to carbon date our stupid-ass carcasses.

  • by mbone ( 558574 ) on Wednesday July 22, 2015 @09:03AM (#50159515)

    Oh, wait, we already did.

    Carbon 14 dating hasn't been reliable (usable) for wood or other biological material formed since 1950, as open air nuclear testing put a lot of C14 into the atmosphere. This C14 has been slowly leaving the atmosphere, but it's not gone yet.

    I think that the writers of the original article were just eager to get some attention, as they surely must have known this.

  • historians whose great, great, great grandparents have yet to be born. And a really easy one to solve. Let's face it, you don't need carbon dating to tell the difference between shirts from the 12th and 21st century. William the Conqueror didn't cross the Channel in a poly-cotton blend.
    • William the Conqueror didn't cross the Channel in a poly-cotton blend.

      You're right. Pure polyester was in vogue back then. It has much better durability, which is very important for a conqueror.

  • by Anonymous Coward

    Carbon Dating unreliable from day one and still unreliable. Nothing new.

  • My understanding is that the current atmospheric carbon isotope ratio is not used for carbon dating but that from tree rings. Knowing the ratio from tree rings and the decay rate of C-14 should give the atmospheric ratio when the tree ring grew. One problem is that the oldest trees are something like 4,000 to 5,000 years old but then 5,000 years ago was well before the industrial revolution when the huge quantities of fossil fuels began to be used. Assuming the isotope ratio wasn't much different before ~2,
  • OK, I'm no expert, but I'm not stupid either, and I do read.

    Scientists have been using various methods to track how much carbon (among other things) is in the atmosphere by various methods. We've got a record of this going back quite some time. That's how we know, for example, how much carbon was in the atmosphere 300 years ago compared to now.

    So if we know how much carbon is in the atmosphere, and we know how much of that is carbon 14 (we are keeping records, right?), then can't we correct for this? Oth

  • Funny how all "science" now seems to support a very particular liberal/environmentalist ideological agenda. Maybe that has something to do with the new scientific method:

    1) Embrace a dogmatic ideological agenda.
    2) Form a hypothesis that supports this agenda.
    3) Carefully exclude or modify all data that contradicts this hypothesis.
    4) Hypothesis confirmed!
    5) Call anyone who challenges your conclusion an ignorant denier.


    • Funny how all "science" now seems to support a very particular liberal/environmentalist ideological agenda. Maybe that has something to do with the new scientific method:

      Or it is because reality has a well-known liberal bias.

      • Or it is because reality has a well-known liberal bias.

        If it did, maybe all those honeybees that were being killed by global warming would still be dying. Yet, once again, reality failed to conform [] to the environmentalist agenda.

        Time to backtrack on yet another failed prediction for you "reality" types, huh?

Houston, Tranquillity Base here. The Eagle has landed. -- Neil Armstrong