A friendly discussion about the inlfuence of the sun on climate....

NikB

If a pole reversal, or more troubling disappearance of the magnetic field occurs during our lifetime then you can forget modern life continuing as it is. The pole is currently drifting at 30 miles per year and gathering pace - potentially very worrying.

DPinBucks

Why?

NikB

Compasses, gps, satellites, etc will no longer work so no satellite based tv, possibly no flying or sailing so no global trade. Power supplies would probably be knocked out by the alteration of magnetic field so possibly no electricity. No mobile phones.

Animals that rely on navigation via the magnetic field may not be able to navigate. This could impact on insects and therefore pollination - so significant reductions in crops.

Seismic shock could occur due to stresses place in rock formations - possibly resulting in significant numbers of earthquakes.

None of this may happen or all of it could, who knows?

BISHI

North becomes south and vice versa, thats all that happens - I dont think it will result in an extinction event, it happens regularly ,as the ignious rock record will testify, but I m pretty sure there are no corresponding extinctions. I just wonder if whilst the fields dramatically shift right accross the entire hemispheres it will create hot spots where there were none.

DPinBucks

There's no current evidence that a polarity reversal is on the cards. Previous events have been random, and the current migration of the NMP is within normal bounds;Some satellites might be affected. I can't see why that should include GPS;A reversal event takes between 1,000 and 28,000 years, preceded by a dramatic weakening of the field strength. We'll have plenty of time to see it coming.I know of no insects which use the earth's magnetic field for navigation between pollen sources and the hive. It's far too imprecise. Finding your way from Europe to Africa, or the river you were spawned in, maybe. 200 metres from flower to hive: I don't see it.There have been thousands of reversals in the past. Biospheric events were negligible, except perhaps for a few unfortunate species who do rely on the field for an important part of their way of life. In fact, it could be argued that the paucity of species which do use it is at least partially a result of natural selection not being able to rely on it.There'll be no seismic shock. A rock which has already endured hundreds or thousands of reversals is not going to notice another.

GasDad

I don't disagree with most of your response, however, surely it's the weakening of the magnetic field that will put some of modern life in danger. AFAIK, most satellites are not hardened against the bombardment they would receive without the protection of the earth's magnetic field, nor for that matter, passenger airliners.

DPinBucks

That's a good point. It rather depends on how fast it happens. The fastest reversal measured took about 1,000 years; the average is 7,000. The process comprises a gradual weakening by about 90%, the reversal itself, then a gradual strengthening. The weakening effect would take at least 100 years, probably much more. We understand the process and could see it coming. Even 100 years is surely well outside the useful lifespan of any existing satellite or other device, and it would give us time to design something more robust.

DPinBucks

One notable recent absentee from this discussion has been its originator.

It might be nice for him to let us know how he thinks we're getting on.  

NikB

Please can you tell me where you have got your information from because as far as I've managed to read we don't actually know what previous or future pole reversals have caused/will cause.

DPinBucks

Largely from here:

How Long Does It Take for Earth's Magnetic Field to Reverse?

and here:

Geomagnetic reversal - Wikipedia, the free encyclopedia

I'm not sure if they address point 1; I might have read that on another website.

Point 3 is addressed.

Points 2, 4, part of 5, and 6 are personal observations based on the information in the links, open to challenge if you wish. I think they are reasonable, though.

In any case, we've got a bit sidetracked off topic. This is only one, rather unlikely, contribution to imminent climate change. Unless and until it happens, it has nothing to do with the sun's impact on global temperatures.  If it does happen, it will affect the way in which solar radiation is handled by the Earth, and might well have a climatic effect.