Richard Dawkins explains the huge degree of error which scientists must be making if they are wrong about just the age of the earth alone:
McIntosh thinks, on biblical authority alone, that it is less than 10,000 years. We establishment fuddyduddies think, using mutually corroborating evidence from many sources including several different radioactive isotopes in the rocks, that it is about 4.6 billion years. I shall not say here why I think we are right and McIntosh wrong. Instead, I shall simply calculate the magnitude of the difference between the two estimates. We of the "establishment" think the Earth is 460,000 times older than McIntosh's estimate.
It is as though McIntosh estimated the height of a man as 6 feet and then accused the rest of us of believing that the same man was 460,000 times as tall, or 521 miles. Or, looking the other way, it is as though McIntosh looked at the establishment geographers' measurement of the distance from New York to San Francisco and claimed that the true distance from sea to shining sea was 460,000 times smaller, namely about ten yards. Maybe McIntosh is right and all the rest of us wrong. All I have done here is calculate how spectacularly wrong we would be, if McIntosh is right.
In theory, it's possible for the scientific establishment to be mistaken on the age of the earth — they know this too, which is one reason why they tend to give ranges of likely ages rather than precise ones (notice how creationists tend to give more precise numbers). If scientists are mistaken here, they might be mistaken by a little bit or they might be mistaken by a lot — but just how likely is it that they could be mistaken by a factor of 460,000??
If they were off by a factor of 10 or even 100, it would be something of a scandal — scientists would be incredibly embarrassed to be so wrong, and that's true even if it turned out that the earth is much older than scientists currently think. To be off by a factor of 460,000 is almost unthinkable in any scientific field, at least when you have multiple, independent lines of evidence that all point to the same conclusions. Just how likely is it that all those lines of evidence would all be so very, very wrong in the same way without anyone noticing it?
This, however, is precisely what creationists who deny the true age of the earth are claiming. They rely on a single, unreliable source of information to deny multiple lines of independent, reliable, and testable evidence in order to argue that Bronze Age writings provide a more accurate picture of the age (and origin) of the earth than the latest scientific tests. The chances of ever successfully arguing that such a position is true are probably incalculable.