Declination / Magnetic variation

[Stick]

I had a bit of a shock today.

When I first started using a map and compass as a kid here in the UK in the mid 80s the magnetic variation was something in the order of 6 - 8 degs west. This meant that after taking a bearing on a map one had to add another 6 or so degs to the compass dial before attempting to walk on the bearing. This became especially important to me as an outdoor professional when leading groups across the Scottish Highlands (especially in whiteouts in the winter) where accuracy became a matter of life or death.

I rarely use a compass now as now I've retired I tend to gravitate towards the hills that I enjoy the most and hence know the best, so haven't really paid too much attention to how much the variation has changed.

Listening to radio recently I was shocked to hear that the geographical point of magnetic north is moving approximately 50km/year. On hearing this I thought I'd better check what the variation is now in my favourite hill ranges. Turns out it's now nearly 2 degs east, meaning that after measuring off on the map, I now have to take away 2 degs on the compass before striking out.

This lump we're stood on sure is a dynamic bit of kit.

 

[D.L.Ruth]

It is pretty crazy. The earth just seems to do what it wants and doesn't take anyone's opinion into consideration, how rude lol

 

[Ozark Wizard]

I recently read an article about that.

https://amp.cnn.com/cnn/2019/02/05/health/north-pole-magnetic-moving-russia-scli-intl/index.html

34 miles a year is quite a clip. Another source from the USGS suggested that a "flip" might be occurring soon. North to South, South to to North. It may be that our brother Timbo will end up in the Northern hemisphere one day!

I would imagine that the speed this is going could possibly impact GPS tracking systems if not carefully monitored.

 

[Stick]

Interesting article Oz and good to see that US / GB agencies are on top the current trend and adjusting nav systems accordingly.

Regular polarity flips have been observed in cross sections of the earth’s crust at the mid-atlantic ridge where new crust is created. This new rock takes on the polarity of the planet at the time that it’s created and recordings show that flips have occurred regularly throughout the earth’s history.

I shouldn’t imagine that it’d happen overnight, but nonetheless the effects of a complete polarity reversal would be enormous, from navigational aids to migrating species.

 

[Fight'n Hampsters]

crazy stuff, thanks for posting!

 

[D.L.Ruth]

I hope I'm around for the polarity switch when it happens, just so I can say "back in my day north was south and south was north"

 

[Ozark Wizard]

Um, yah... Pass that here man, I'm ready and I think you've had plenty! :lol!:

 

[Ozark Wizard]

Interesting article Oz and good to see that US / GB agencies are on top the current trend and adjusting nav systems accordingly.

Regular polarity flips have been observed in cross sections of the earth’s crust at the mid-atlantic ridge where new crust is created.  This new rock takes on the polarity of the planet at the time that it’s created and recordings show that flips have occurred regularly throughout the earth’s history.

I shouldn’t imagine that it’d happen overnight, but nonetheless the effects of a complete polarity reversal would be enormous, from navigational aids to migrating species.

Kind of brings into perspective of how we are just mucking about on a liquid blob with some crusty stuff floating around, eh?