All scenarios / Earth systems
Magnetic Pole Flip
Compasses confused. Birds furious. Humans mostly fine.
What it is
Earth's magnetic field occasionally flips, so that magnetic north and south swap places. During the transition the field weakens, which lets more radiation reach the upper atmosphere and can confuse migrating animals and navigation systems.
Why it ranks where it does
NASA notes that about 183 reversals have happened over the past 83 million years, and the last one was about 780,000 years ago. Reversals take hundreds to thousands of years to complete. The USGS says none of them has been linked to a mass extinction. That's why this sits near the bottom: it's real and it will happen again, but it's slow and survivable.
Evidence on the board
- Reversals take centuries to millennia and have never been linked to mass extinctions.
What the experts say
Geophysicists say the field has been weakening in some regions, such as the South Atlantic Anomaly, but that this doesn't mean a flip is imminent. Even if one began, the main impacts would be on satellites and power grids, and engineers can plan around them.
Could we survive it?
Life has come through hundreds of reversals, including many during the age of the dinosaurs and early humans. The most recent full reversal, the Brunhes–Matuyama, happened when Homo erectus was alive, and the fossil record shows no mass die-off. The atmosphere, not the magnetic field, blocks most harmful radiation at the surface. A modern reversal would mainly cost money: more satellite failures, more frequent auroras at lower latitudes, and greater grid vulnerability to solar storms.
What would move the number
Up
- A rapid, sustained weakening of the global field
Down
- The field stabilizing in satellite measurements
Live signals we track
The baseline above is set from the evidence as of October 13, 2026. On the live board, your browser adjusts it in real time using these feeds. Chatter can only nudge a score in proportion to its evidence, so attention alone can't make an unlikely scenario look likely.
- Public attention: daily Wikipedia pageviews for Geomagnetic reversal
- Online chatter: Hacker News stories mentioning "magnetic pole" this week vs. the prior eight weeks
Sources
- NASA: Why variations in Earth's magnetic field aren't causing climate change
https://science.nasa.gov/science-research/earth-science/flip-flop-why-variations-in-earths-magnetic-field-arent-causing-todays-climate-change/ - USGS: Do mass extinctions correlate with magnetic reversals?
https://www.usgs.gov/faqs/do-any-mass-extinctions-correlate-magnetic-reversals
Baseline scores are an editorial threat index from 0 to 100 that combines current reporting with published expert estimates. They're meant for comparing risks, not as actuarial forecasts. See how the numbers work.