Polarity Reversal
Sometimes you won’t have a flip for about 40 million years; other times there will be 10 flips in 1 million years. On average, the duration between two flips is a few hundred thousand years. The last flip was around 780,000 years ago, so we are actually overdue for a flip. ~ Chinese geophysicist Huapei Wang
Earth’s magnetic field sporadically reverses polarity. The duration of continued polarity (a chron) varies by tens of millions of years, with an average of 450,000 years.
Field reversal typically takes 4,000 years, though it may occur in as little as a decade. Changing continental configurations via tectonics may trigger geomagnetic field reversal.
The Earth’s magnetic field is currently weakening 5% each decade. Magnetic north is moving toward Siberia. Current field intensity is twice the historical average, so polarity reversal is not likely for many millennia.
