From the very link you posted. This is silliness.
"Some Young Earth Creationists have investigated the idea of a changing c in 1987[46] as an explanation for the discrepancy between the biblical and measured ages of the universe. This idea was mentioned by Marilyn vos Savant in Parade magazine.[47] This idea has been refuted.[48]"
Actually the speed of light was changed by Satan, in the year 4236 B.C. to confound various angels. This change in the speed of light caused several angels to fly into planets, breaking limbs and mussing their hair.
As a side effect, it confused human beings, who began to believe that the universe was billions of years old, when it was really only 6000 years old.
Yahweh was not amused at all, and fixed the speed of light. Satan was severely chastened and his air conditioning was shut off for 1258 years. The dispute still goes on, although it is generally accepted that the speed of light is approximately 186,000 miles per second.
Some human beings, however, are still confused about this and major arguments have taken place over the years.