The problem with Earth’s magnetic field

If you look really close at it, it is a strange, wondrous coincidence that allowed humanity to exist. There are so many factors that need to be just right… but of course we would not be here and wonder about that strange coincidence if it didn’t happen.

One of those things is the magnetic field of the earth that protects us (and every other living being) from deadly rays coming from our sun.

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What is strange about that field is that it changed the poles in irregular times, sometimes a few thousand years apart, sometimes a lot longer.

But while the pole-changing was a relatively deadly but not devastating experience for the life on earth e.g. 41’000 and 34’000 years ago, today it would change everything for us.

Because no magnetic field means not only more sun burns and more cancer, it also means a lot more stress for electricity cables. Costly blackouts would be common. Satellites would be damaged repeatedly and so on.

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The last effect is already measurable at the so-called “South Atlantic Anomaly”. The magnetic field of the anomaly has started to weaken (likely) already 400 years ago, with a rate of 5% per century, and ongoing.
That anomaly was also the center of a new study of historic changes in the earth’s magnetic field.

In short, the current South Atlantic Anomaly develops differently from the two pole change events 41 thousand and 34 thousand years ago, but similar to other events where the magnetic field did weaken, but then got back to strength without a pole change.

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That is a welcome find, but of course only one piece of the puzzle (for example, what about the very fast wandering poles?). And don’t forget we are talking about long times here: the authors also expect the magnetic field of the anomaly to weaken for a few centuries more.

But at least it seems like this is one of the few instances where science has a bit of time to solve the puzzle before it gets really devastating – or not.

study (subscription for full text)
German source