Okay first, this is about the magnetic pole shift . This has nothing to do with a change of direction of the Earth’s axis. The rotation axis changes its direction very very slowly like a top - do you know how if you spin a top the axle goes around a small circle? Well the Earth does that too, but much much more slowly. It takes 26,000 years to go around once. It's heavy and it's a bit fatter at its equator and there's a slightly shorter distance between the poles and the result of that is that our planet's spin is very stable. It can't flip its axis, the only way it can change is in this slowly precessing way.
Magnetic pole reversals do happen but they happen slowly, over a period of centuries to thousands of years, and they happen roughly every few hundred thousand years.
In this diagram the yellow dots track the motion of the north "virtual geomagnetic pole" during a recent unusually rapid pole shift which took 250 years to reverse.
For a couple of science news stories about this research: An extremely brief reversal of the geomagnetic field, climate variability and a super volcano , Ice age polarity reversal was global event: Extremely brief reversal of geomagnetic field, climate variability, and super volcano
It remained reversed for a total of 450 years and the polarity reversal took 250 years. That's very rapid on geological timescales.
For the detailed scientific paper: Dynamics of the Laschamp geomagnetic excursion from Black Sea sediments. This diagram is discussed on page 65.
Our Earth’s magnetic field is currently stronger than average, it’s true that it is decreasing in strength, but only from higher than usual values towards normal values.
The magnetic poles move around all the time, sometimes faster, sometimes more slowly. This only becomes a sign of a pole shift if they move much of the way towards the equator.
If a pole shift was in progress, then over a period of decades, you'd notice that - your compass would start pointing East or West, or even maybe South instead of North. Actually at one point it would have multiple north and south poles and depending which country you are in the compass would point different directions. Like this, it gets very complex.
Anyway - that definitely will happen at some point in our future - that much is true. But it happens every few hundred thousand years, and there is no sign of it happening right now.
At present both magnetic poles are close to the geographical poles and here is not the slightest sign of a magnetic pole shift. On the signs so far, it doesn't seem likely to happen in our generation, not even the beginning of it.
CURRENT SITUATION, NO SIGN OF A REVERSAL
The South dip pole lies at a latitude of 64.28 degrees South, outside Antarctica, in the open ocean, also outside the Antarctic circle.
While the North magnetic pole is far closer to the pole, almost directly at it right now:
As you see the N. magnetic pole is continuing to move closer to the geometric N. pole and the S. magnetic pole is continuing to move away from the geometric S. pole.
In these diagrams, the blue is the geomagnetic pole - treats the Earth as if it were a dipole magnet. So the geomagnetic poles are diametrically opposite each other. The red dots are the dip poles - the point on the surface where your compass needle would point directly downwards or upwards.
More about it here: Magnetic Poles
There's also evidence that the magnetic field is getting weaker. But it’s been much stronger than usual for a while and so far it is not particularly low, just declining towards rather ordinary values
What it will do next is anybody’s guess. If you extrapolate that graph, it reaches 0 so a reversal after 1500 years. But there is no reason to suppose that it’s doing that. Even if it gets very weak, often you get “excursions” where the field gets weak, but then just restores itself in the same direction as before.
So there is no reason to suppose it will reverse based on the magnetic field strength so far. The magnetic poles are continually moving anyway and at present they are close to the poles and the magnetic field strength is normal.
It’s most certainly not going to happen next Friday on 29th July suddenly in one big flip as the conspiracy fearmongers are saying :).
WHAT WOULD THE EFFECTS BE IF IT DID HAPPEN?
On the remote chance it does, then the main thing is that we would have to harden the long distance power lines (main things vulnerable to increased solar storms) and wear more sunblock because of increased UV if the ozone layer gets damaged. There are magnetic pole reversals every few tens / hundreds of thousands of years and they don’t make species extinct. It’s not something to worry about.
The magnetic field gets weaker during a pole reversal but doesn't vanish. And we have our atmosphere above us,which is as heavy as ten meters thickness of water. So we are well protected from solar radiation / flares no matter what happens. And even our computers and such like would not be affected, only the long range power transmission, and if we did find ourselves going into a polar reversal, say a few decades from now (as it isn't happening right now) then there'd surely be more work done to harden those lines, though they need to be hardened anyway because solar storms can break through the Earth's magnetic field anyway and sometimes do. So it doesn't even make a major difference for those either. We should protect against them anyway.
I think main effects, apart from solar storms which we need to protect against anyway, would be
- Confuse migrating birds. Though since they have survived previous pole reversals, presumably they find a way to deal with it
- Ozone layer thinner, so need more sun block protection.
- Would be a puzzle for manufacturers of compasses. Maybe they get more sales for more complex compasses, or fewer because everyone relies on GPS?
But it's not happening for a fair while anyway as it takes from a century to a thousand years to complete and not started yet. and you'd notice for sure if one was in progress by magnetic compasses no longer reliably pointing North.
For more about this, see What will happen if the Earth's magnetic poles reverse? Will we have a catastrophe on our hands?
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