Map of the UK ()
As every hiker knows, there is a difference between the true north lines on their map and the direction of magnetic north from their compass. This difference is called declination, and compasses usually need to be adjusted to make them usable with a map.
Over the next few years, however, map fans in western Europe will be quietly celebrating as magnetic north migrates closer. Here, little or no declination adjustments will be needed.
This is especially true in Great Britain where magnetic north is currently aligned quite near the 2° west line of longitude, also called the 2° west meridian, which runs from the southern cliffs to the northern highlands.
At the prehistoric standing stones of Stonehenge, the declination would only be .066 degrees east; too small to adjust on a regular compass. Driving one hour northwest to the Roman ruins in Bath changes the declination to .066 degrees west. Somewhere along the way, this journey crossed the line where true north and magnetic north matched.
The Two Norths
True North lies on the Earth’s rotational axis at the north pole. This is the convergent point for lines of longitude that run between the north and south poles. It is a human-defined reference point for our mapping.
Magnetic North is changeable. It is determined by the natural magnetic forces within the Earth’s core. Churning metals in the outer core create a dynamo effect when combined with the Earth’s rotation. This action generates a magnetic field that protects our planet from solar damage, visible as the aurora.
The magnetism also creates polarity – with our compasses pulling toward the north. Modern technology like a phone or GPS automatically accounts for the difference between the pull of magnetic north and the true north of maps. They adjust the declination.
Big Changes
For most of the 1900s, magnetic north moved only 10km yearly and was focused near the arctic Canadian islands west of Greenland. This consistency meant that published maps of declination in hiking books remained relevant.
However, in the early 2000s, the Earth’s magnetism began to pull the pole faster across the Arctic Ocean and nearer to true north. At its current rate – roughly 40km yearly – and direction of change, magnetic north will move over Siberia. It has gone back and forth between Siberia and Canada for the past millennia.
This new and speedy change means that map users need to check the declination seasonally.
Add a Third North in Great Britain
Currently, much of Germany is at about +3° of declination. When hiking in Germany, you should adjust a compass to roughly 3° east.
However, in Britain, you will primarily have 0° of adjustment, with details being in fractions of a degree. In Britain, you can even add a third mapping system to your collection of ‘norths.’
Ordinance Survey, or OS, maps are used when hiking in the UK. Like any system of paper maps, they have a grid north. This is the one line of longitude that is not skewed by making a round grid into a flat one. On OS maps, it is 2° west – the same meridian that is lining up with magnetic north.
To gain this mapping trifecta, you’ll need to travel to England and visit sites along the 2° west meridian, and then check to see if the declination at that location is 0.
You can visit www.magnetic-declination.com to find the current situation anywhere in the world.
The small seaside town of Langton Matravers was the first landfall of the #3Norths alignment according to the British Ordnance Survey. As the next three years progress, the line-up will slowly advance north along the 2° west meridian.
Currently, the magic location is in the village of Devizes, home to one of Wiltshire’s white chalk horses. It is only a half-hour north of Stonehenge and 15 minutes from the standing stones at Avebury.
By summer the expected alignment will be near Cheltenham and the nearby walking paths and villages of the Cotswolds. It will then move near Shakespeare’s birthplace of Stratford-Upon-Avon, and on into bustling Birmingham.
Later alignments, likely in 2024-2025, will happen in hiking destinations like the Peak District east of Manchester, the Yorkshire Dales National Park, and Northumberland National Park. The final #3Norths alignment in England will be at Berwick-Upon-Tweed sometime in 2025. It will then skim along the coastal cliffs of far eastern Scotland, north of Aberdeen, around 2026.
For More Information
NOAA’s Historical Declination Map of magnetic north: www.ncei.noaa.gov/maps/historical_declination
Magnetic north declination checker: www.magnetic-declination.com
British OS What happens when 3 ‘norths’ collide video: www.youtube.com/watch?v=18kQrt3KCbM
