Carbon dating relies on the hypothesis that the date of decay for the element carbon-14 is constant and has remained throughout time. However, this may not be the case and there is evidence to support the opposite case.
Let's set aside the fact that C-14 dating is not used by paleontologists because the half-life is too short to be of any use to them. ( creationists are always incredulous when they learn this, but it's true ) But it is a testable claim. It turns out that the real variation in C-14 dates is not the half-life (which no one has so far been able to alter even with the huge temperatures and pressures that work for some other elements) but the amount forming in the atmosphere, which does vary.
Hence the calibration done by using lake varves. Varves are a particular kind of lamina that form two per year in some lakes. One light layer, one dark layer. So, it's easy to get a core, and analyze the varves by C-14 to see how accurate a simple decay model would be.
Pretty well, as it turns out. But the calibration, which takes into account small variations in cosmic rays that form C-14, is being used to refine the dates.
Again, none of that has the slightest effect on paleontology.
Using iron-57 and isotopes of uranium-238 experiments have demonstrated that rates of decay not only can vary, they do.
Show us that. So far, the variations reported for uranium are at most, a few percent, and none that I've seen so far have been reproduced by other studies.
Carbon dating relies on the assumption that carbon-14 formation remained constant over the years. However, we know that carbon-12 formation was changed by human intervention. The industrial revolution increased carbon-12 concentrations. There is reason to believe that atomic bomb testing carried out in the 1950s may not only have increased neutrons in the surrounding area, but worldwide, causing a change in carbon-14 concentrations. Some scientists now believe that a worldwide flood did occur (similar to the one mentioned in countless religious texts). This would have impacted vegetation and impacted at least carbon-12 and perhaps carbon-14."
See above. Already detected and adjusted for. And as you just learned, C-14 is not used by paleontologists.
