How exact is carbon dating used today?

Doesn't carbon dating prove millions of years?

Since I was asked this question twice this weekend I felt I should answer it here.

The answer is no.  Carbon-14 dating, invented by Nobel Prize winner Willard Libby, is also called “radiocarbon dating.”  It can only be used to date organic material, that is, living thing and cannot give dates of millions of years.

In simplified terms, here is how it works:  Carbon, what we see in charcoal and charred wood, comes in many different forms.  The most common is Carbon-12 (C-12).  Carbon-14 (C-14) is a radioactive form of carbon and is much rarer.  There are about a trillion C-12 atoms to one C-14 atom in living things.  C-14 is formed in the atmosphere by cosmic rays  Plants and animals in their interaction with the atmosphere naturally absorb C-14 just like they do C-12.  Thus, a consistent ratio of C-12/C-14 exists in all living things.  That is, at least, until they die and no longer absorb carbon from the atmosphere.  Scientists can then measure the ratio in a dead organism and tell how long it has been dead. 

Many problems are associated with this seemingly simple method.  Robert E. Lee in the Anthropological Journal of Canada said, “In light of what is known about the radiocarbon method and the way it is used, it is truly astonishing that many authors will cite agreeable determinations as ‘proof’ for their beliefs.”

What is “known about” this method that is such a problem?  First of all, the half-life of C-14 is only 5730 years.  For all practical purposes, it has been calculated that dating something more than ten times C-14’s half-life, about 60,000 years, would yield an infinite age.  Not only this, but there are many faulty assumptions that this model makes.  It assumes there is a global equilibrium in the amount of C-14 in the atmosphere and recent studies are showing that this is not the case.  It assumes that influx of cosmic rays into the atmosphere has always been the same.  It assumes that the earth’s magnetic field has been the same, and it has not.  Scientists have shown that the magnetic field is decreasing in intensity.  A stronger magnetic field would mean more protection against cosmic rays.  It assumes the decay rate has never varied during the time span.

Scientists do consider factors like contamination and factors that would influence carbon in the atmosphere like the industrial revolution.  Studies of tree-rings have supposedly been the salvation of C-14 dating.  Scientists claim that tree-rings can tell them about the history of the atmosphere.  This too is built on frail assumptions.  Tree-rings are not always consistent from tree to tree and depend on more than just atmosphere, like how close a tree is to a water source, nutrients in the soil, etc.

Overall, radiocarbon dating has been so inaccurate that it has caused one scientist to say at the Twelfth Nobel Symposium, “If a C-14 date supports our theories, we put it in the main text.  If it does not entirely contradict them, we put it in a footnote.  And if it is completely ‘out of date,’ we just drop it.”

Carbon-14 has dated freshly killed seals to have died 1300 years ago; living snail shells show they have died 27,000 years ago; a 15 thousand year difference has been found in dating a single block of peat; coal from Russia supposedly 300 million years old, was dated at 1680 years.

Lee goes on to say, “Why do geologists and archeologists still spend their scarce money on costly radiocarbon determinations?  They do so because occasional dates ‘appear’ to be useful.  While the method cannot be counted on to give good, unequivocal results, the numbers do impress people, and save them the trouble of thinking excessively.

“No matter how ‘useful’ it is, though, the radiocarbon method is still not capable of yielding accurate and reliable results.  There ‘are’ gross discrepancies, the chronology is ‘uneven’ and ‘relative,’ and the accepted dates are actually ‘selected’ dates.  ‘This whole blessed thing is nothing but 13th century alchemy, and it all depends upon which funny paper you read.’”

The Biblical model could explain some of these variations we see in C-14 dates.  If there was a protective water vapor canopy before the Flood it could mean that the C-14 levels were significantly less than they are now.  The Flood would have also drastically altered the amount of carbon in the world in limestone, coal deposits and oil shale.  This, along with these other factors, could explain longer than expected dates with radiocarbon dating.

Radiocarbon dating data is certainly not compatible with any sort of old-earth model.

5/05/00
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©Tom Carpenter
Originally published in the Rockdale/Newton Citizen