<aside> 💡 The nature of the world has been argued for centuries, possibly longer - does the land itself emerge from the frozen south and move slowly northwards through a warm, habitable zone? Or is it the sun that’s slowly spiraling south around the world, thawing out the land to the south as eternal winter follows in its footsteps? One thing is certain: nobody can stay where they are for long. If you sat down on a southern ice sheet and waited for enough years, you would observe the world growing slowly warmer over the decades until noon placed the sun directly overhead; and then you would observe the sun’s noontime position slowly receding south; and you’d notice the temperature growing colder again, until eventually it became too cold to farm, to breathe, to live. Everyone migrates, at every scale - a hermit living in a lean-to must gather his possessions and move south, just as a queen must move her entire kingdom. Some slowly amble southwards all their lives, families plowing and sowing fields a mile further south after each harvest. Some make grand moves every few decades, whole kingdoms charging south with an army’s spears leading the way, the rest of the citizens marching behind with their possessions. Those who can’t? Get left behind to be entombed in the encroaching ice.
This is Scrollworld.
</aside>
The world is not a mystery to be solved, or a problem to be fixed. This is the way the world is, and always has been.
Scrollworld is basically an infinitely long tube, with a 600 mile wide continent running along one side, the rest being composed of ocean. A sun revolves around it, illuminating and warming an area approximately 2,000 miles long from south to north. The sun moves south relative to this tube, resulting in more continent emerging from the south and thawing, and then re-freezing in the north as it leaves the warm, habitable area of the sun.
This is a bit confusing to visualize, but imagine this: you find yourself at the southern-most latitude. It’s cold here. If you look south, you’ll see darkness and ice. If you look north, you’ll see the sun rotating around the world low on the horizon. If you sit down and don’t move for 50 years, you’ll feel the weather getting warmer, and you’ll see the noon-day sun slowly moving closer to you, rising higher in the sky each day, until finally it is directly above you at noon every day. If you continue to sit, you’ll feel the weather get colder, and you’ll see the sun at noon recede towards the south. After 50 years, it will once again be cold, and the sun will be low on the southern horizon, and if you look north, you’ll notice that everything has frozen. If you continue to sit, you’ll freeze as well - permanently, because the sun is always moving south, and there’s no coming back from the frozen north.
The sun’s southward velocity is approximately 20 miles per year, or 0.05 miles - about 90 yards - a day. It takes approximately 100 years for a point to traverse the habitable zone; for a point to emerge from the southern thaw, move through the habitable zone, and be re-frozen in the north.
As new land emerged from the south, it brings with it new minerals; this world can't be stripped bare. Dwarves always have work to do. Trees and other plants continue to grow, and rich soil always emerges. Environmentalism is not a concern on this world; pollution always leaves you behind, and new resources always arrive.
Occasionally, other things emerge from the southern ice.
There are no seasons. Directly under the sun's orbit is an equatorial region; far to the south and north is a permanent winter. Once you're far enough from the sun for it to start snowing, agriculture is unsustainable - only small tribes who subsist on animals that can scavenge in the snow or underground Dwarven civilizations can survive that far north and south.
You can always determine your latitude by measuring the angle of the sun.
There is no real concept of a cyclical year; most time spans are measured in days, weeks and months (we'll be using our familiar Earth day/week/month/year concepts, rather than make players learn a whole new calendrical system.)
There is a constant migration south by wildlife - sometimes fast as they approach cold weather, or sometimes slow as they keep pace with their preferred climate.
The habitable zone is approximately 2,000 miles tall, and the continent is approximately 600 miles across, though this varies with the emerging geography.
The sun spirals down at about 0.05 miles a day - around 90 yards.
It takes approximately 100 years for a point emerging from the frozen south to re-freeze in the north.
At a 5-mile-a-day march, it takes 400 days to cross the word vertically. At at 15 miles-per-day, it takes about 130 days. (This is comparable to the Oregon trail.)
Nobody knows. Once you get far enough from the sun, it gets so cold that the air itself freezes. Expeditions have been sent in both directions, both above and below ground, but those that manage to survive and return report that it’s just a frozen wasteland in either direction.