Contrary to creationist Barnes' totally discredited claims, which I've covered in Topic 11, the earth's magnetic field (dipole moment) has, indeed, increased and decreased over time.
Strahler presents a graph of the earth's dipole moment going back 9000 years.
The barrel represents the earth's atmosphere in which the carbon-14 accumulates.
The water leaking out the sides of the barrel represents the loss (mainly by radioactive decay) of the atmosphere's supply of carbon-14.
Carbon 14 is used for this example:, which was put out by Dr. is presently only 1/3 of the way to an equilibrium value which will be reached in 30,000 years. Knowing how faulty creationist "facts" can be, let's do a little research of our own.
Bucha, who has been able to determine, using samples of baked clay from archeological sites, what the intensity of the earth's magnetic field was at the time in question.
Even before the tree-ring calibration data were available to them, he and the archeologist, Evzen Neustupny, were able to suggest how much this would affect the radiocarbon dates.
(Strahler, 1987, p.158) Lingenfelter actually attributed the discrepancy between the production and decay rates to possible variations in the earth's magnetic field, a conclusion which would have ruined Morris's argument.
Henry Morris chose not to mention that portion of the paper!