Is there anything in the geologic record that would indicate changes in climate, increased extinction rate, and the like, concurrent with the record of past changes in polarity?

As your link says, they happen. It doesn't appear there have been any major ill effects from reversals in the past.

BUT! There weren't people around back then relying on magnetics, no compasses, etc. We can adjust for the slow movement of magnetic north. What we can't adjust for is the period when there is not enough field to use our magnetic stuff.

On the other hand, comapsses are being replaced by GPS devices that don't rely on magnetics They get their information from satellites. I expect we will be OK.

(There's more but I don't feel lke getting into it right now.)

From what I have read, there are indications that there have been changes in types of fauna found in the sedimentary record before and after reversals. So far this has been dealing with the fossil record for microorganisms in core samples from quiet basins such as in the arctic or Antarctic.

One thing that is interesting is that during the Cretaceous (which lasted 140 my) there were no magnetic reversals and the earth was pretty warm.

I haven't read anything about reversals correlated to the Cretaceous-Tertiary boundary (the famous one- you know, end of the dinosaurs) but maybe someone else has?

When the magnetosphere goes, along with the magnetic field,

we will no longer be protected from solar radiation as we are now.

As to the GPS's- they're pretty much universal now- we're probably the last generation that will know how to use a compass.

I haven't seen anything about different flora around reversals but I can see how there might be changes. Since the magnetosphere protects us from solar wind, there will probably be a period of greater evolution caused by more radiation exposure. And more skin cancer.

But the best I can find is the flip is still a millenia or 2 away. Don't think I'm going to worry about it :_)

Unfortunately, I don't believe there's any good data on how fast such a reversal occurs. The geological record isn't very good at illuminating that aspect of it.

I would wonder how well the GPS satellites would fare with no magnetic field to protect them from solar radiation. Just speculating here, but I would imagine they're not hardened the same way as the geosynch birds since they fly in such low orbits.

Dutch

The military's GPS satellites would be hardened though?

We don't know when the flip will start- some people think that it has begun.