No it isn't. It has been tested literally millions of times, including against countless materials of known age, and found to be extremely reliable. The creationists will "forget" to mention that though, and will only keep bringing up the special cases where it produces results which seem unusual (but are actually well understood -- although the creationists won't tell you that).
Wood freshly cut out of living trees has been carbon dated at 10,000 years,
BECAUSE, Race, that tree grew in a busy airport, and got a significant amount of its CO2 from the nearly constant exhaust of jets which were burning ANCIENT hydrocarbons.
Now, please explain how many actual paleontological specimens grew near a constant source of burning fossil fuels all th eir lives?
Your source sort of "forgot" to mention this so that it could try to cast doubt on ALL radiocarbon dating, didn't it? Lying by omission in order to leave a misleading impression is still lying.
and living mollusks (such as snails) dated at 2,300 years.
...for reasons which are perfectly well understood -- except to creationists. Those snails incorporated ancient limestone minerals into their shells, so of course the radiocarbon dating CORRECTLY indicated that they were a mix of "new" and "old" carbon. This is why molluscs and several kinds of marine animals are known not to be appropriate for carbon-dating, except in specific cases. The vast majority of creatures don't actually ingest limestone, however, and thus this is not a problem in most cases.
Carbon dating falsely assumes a constant rate of decay.
No, it CORRECTLY assumes a constant rate of decay, because the decay rate of 14C has been verified as constant, countless times over. If you know of any exception, Race, now would be the time to post it and win your Nobel Prize, especially since the dynamics of nuclear decay (and thus the actual decay rates) are derivable from first principles using quantum calculations).
excerpted: THE PROBLEMS WITH CARBON-14 DATING
Yawn -- more of the same dishonest twaddle.
If the creationists have such a good case, why do they have to keep lying about it?
First, for carbon-14 dating to be accurate, one must assume the rate of decay of carbon-14 has remained constant over the years. However, evidence indicates that the opposite is true. Experiments have been performed using the radioactive isotopes of uranium-238 and iron-57, and have shown that rates can and do vary. In fact, changing the environments surrounding the samples can alter decay rates.
ANOTHER NICE CREATIONIST LIE!
Uranium-238 and Iron-57, you'll note, are NOT CARBON-14.The FUNNIEST thing here is that Iron-57 is a STABLE isotope. IT DOES NOT DECAY, and contrary to the twaddle above, IS NOT RADIOACTIVE. This creationist garbage is talking NONSENSE. The source of this ridiculous claim has been traced to creationist "scientist" Harold Slusher (member of ICR) who has misunderstood a report of variable rates of GAMMA decay in I-57 (having to do with chemical excitation) for variable NUCLEAR decay. Quite simply, the man's an idiot. He's also a "creation scientist". But then I repeat myself.
As for U-238, I haven't tracked down that specific claim to see if it's at all true or not (knowing the creationists, probably "not"), but you can read this page to learn about how a few select (i.e. special case) isotopes *can* have their nuclear decay rates affected slightly by conditions, but the largest amount of change is a whopping 0.8%... And Carbon-14 is NOT one of those isotopes subject to such minor variations. And even if it were, a 0.8% variation in decay rate would introduce no more than a +/- 1% uncertainty into radiometric dates -- note how the creationists try to imply that this would somehow completely undermine carbon-14 dating, which it certainly would not.
A lie is a lie is a lie...
The second faulty assumption is that the rate of carbon-14 formation has remained constant over the years. There are a few reasons to believe this assumption is erroneous.
...and gosh, real scientists (unlike the ones the creationists use) have been well aware of this for over half a century, and have spent a lot of time DETERMINING what the carbon-14 production rate has ACTUALLY BEEN over the past 50,000 years. The creationists sort of "forget" to mention that, don't they?
There are many, many samples of known age (e.g. tree rings, arctic ice layers, lake bottom layers, etc.) which can be used to multiply and independently determine how much carbon-14 was in the atmosphere in any given year, and thus be used to calibrate Carbon-14 dating methods.
For a quick article on one such study, see http://more.abcnews.go.com/sections/science/dailynews/carbon0220.html
A much more technical treatment: Atmospheric Radiocarbon Calibration to 45,000 yr B.P.: Late Glacial Fluctuations and Cosmogenic Isotope Production
Such studies produce calibration results such as the following:
If the amount of Carbon-14 in the atmosphere had been exactly constant throughout time (and no one expects that it has been), then the results would fall on the straight diagonal line. Instead, the wiggly line indicates how much the actual amount of C-14 in the atmosphere deviated from the "base" amount, and from this we can know how much C-14 was actually present in any given year in the past 50,000 years.
Note that the above graph includes C-14 data from *two* completely independent sources (Lake Suigetsu varves, and ocean corals), and yet the results overlap beautifully, confirming each other. There is similar match from C-14 studies based on tree-ring data and other sources.
From this, we can build a Carbon-14 dating calibration or "correction" curve which can be used to confidently produce an accurate date from a given Carbon-14 measurement. These calibration curves look like this:
There are many databases available which are used to compile massive amounts of data to ensure the proper calibration of carbon-dating. For just one example, Marine Reservoir Correction Database.
Other methods are used to cross-check and calibrate other dating methods to ensure accuracy.
But again, the creationists sort of "forget" to mention that.
Race, are you ever surprised by how often your creationist sources lie to you? And are you ever embarassed at having been gullible enough to believe them, and for repeating their falsehoods, when the obvious flaws in their horse manure are obvious to anyone with a decent knowledge of science?
And can we encourage you to stop posting so much of this manure, so that we can all spend our time doing something more productive than correcting these floods of falsehoods?