How to get a world with polar seas
- Thread starter Technomancer
- Start date
Nellisir
Hero
Rel said:
I don't think plate tectonics are a planetary requirement. I'm pretty sure Mars doesn't have plates, and I'm not sure about Venus. Volcanic mountain-building could be a result of simple cracking or fracturing that results in sudden, massive, sustained volcanic eruptions concentrated around the equator, where the stress is the greatest.
I'm not sure if there's a way to arrange it so the surface drops at the poles, but mountains forming around the equator could be forced poleward over time, somehow subducting at the poles. Weathering, glaciers, and etc would ensure that the poleward terrain would be lower and smoother than the intense equatorial terrain.
Warbringer
Explorer
How about just magical? Each pole (or the planet center) is a gate to the elemental plane of water
Nyeshet
First Post
First off, you do not need a solar flare. However, you will need to make a few assumptions:
1) Continental Drift has ending. So long as continental drift exists the low points where the oceans fill will always be moving. However, this also means that volcanism will be largely ended, although a few minor spots might continue to exist for a time (think Hawaii, Yellowstone, and other spots where mantle plumes have caused volcanism well away from plate boundaries).
2) Now, simply presume that the lowest points of elevation are at the polls. Rain clouds will still form but away from these two oceans there will be little available rain to fall. I presume much of the rain falls around the 60-65 latitude, as occurs on earth, but it drains only poleward - perhaps drainage in other directions eventually fading away in the form of inland deltas which themselves suffer wet and dry seasons - think the orinoco (spelling?) in Africa, but further north.
One hard part will be keeping any moisture from the equator. It literally rains year round on an almost daily basis along the equator. Reducing available moisture will not completely remove this rain belt, as it will simply mean that the equator itself will likely be less arid than anywhere except near the polls. Think of it as the thorn scrub savanna - its 'rainy' season being barely enough to turn the grasses green for a month or two, and its dry season almost reducing the lands to a desert.
3) Another possibility is that the lands along the equator are mostly limestone. With the end of plate techtonics, this limestone will not move out of the way, so for a time any rain falling at the equator will carve out immense cavern systems - eventually to the point that whole rivers will exist underground. There are several places on this (real) world whose latitude, altitude, and prevailing rainfall would suggest should be quite well forested, but are in fact near-deserts due to the fact that all the water seeps underground - and stays underground for scores of miles, eventually coming up as aquafier springs, oasises, etc once they reach somewhat lower elevation lands where the land is no longer limestone. Perhaps just before you reach the polar oceans there are deltas, springs, oasises, etc in a band around them, as overland rivers from the poleward regions, underground rivers from the equatorward regions, etc come together, bringing greenery and life prior to meeting the actual oceans.
4) Lastly, for oceans to readily exist and be easily habitable by human civilization as is typically portrayed in games, the world will need to be much much warmer place. Just a few degrees warmer than earth - on average - will be enough to keep the oceans free of ice, but the temperatures will still be significantly low even in the summer - and let's not forget the few months of darkness each year. These are serious issues as far as potential growing seasons go. I think Anchorage, Alaska has a growing season of about a month - and it exists around 60N.
So these oceans should at least take up 30 degrees equator-ward from each pole (90 to 60 degrees) to reduce the amount of darkness per year along their coasts - and in the process allowing most of the rain in the 60-65 degree belt to fall back upon the oceans themselves. This could allow minimal middle ages style civilization as we think of it on the edges of the oceans. Raise the temperature a few degrees - globally - and we could probably increase the growing season at 55-60 degrees to perhaps 2 months ayear. At the 45-50 degrees, where the deltas, emerging underground rivers / aquifiers, and oasises perhaps exist, it might be as long as 3-4 months (maybe even 5 months, if the average world temperature is set high enough) - enough to create civilizations we might consider halfway normal for medieval time periods.
However, while civilizations could exist on the equator, it would be very minor - stone age most likley, and the distances one would have to travel - across deserts so vast as to dwarf anything on earth - would make meaningful trade between the poleward civilizations and the equator civilization (such as they are) virtually impossible. In effect, each pole would be totally separate from the other, as 7k+ miles would exist between them. This is the equivalent of crossing the Sahara Desert twice - west coast to Nile river, without any place to re-supply along the double length route. Even in modern times that would be difficult, especially as no roads would exist, no maps would exist to aid in determining the best route, and if any mistakes are made there is no place to re-supply in water or hunt for food.
Other Considerations:
Perhaps the underground cave systems have become multilayered over the millennia. So water still roars through the lowest layers, but the higher layers are 'dead' cave systems, dry, perhaps a bit unstable, but much cooler than the deserts above. These might allow for travel between the poles, as water could be re-supplied down below (perhaps eco systems exist in which to fish in these vast underground seas and rivers, allowing resupply of food as well as water?). Special caravan tribes might have memorized paths they take over the course of a year or two, moving south then north then south again, trading rare items only found from the distant poles only these caravan tribes can reach. They may need to exit the caves from time to time (cave ins block a path, or perhaps one cave ends and they must seek another to continue further south), so the complex route is not ready written down - presuming they would even consider sharing such sacred tribal knowledge with an outsider. Or perhaps there are several paths, and each time they choose the forks in the paths they choose based on the present circumstances.
Traveling this way cannot be fast. If we presume 5 miles a day (on average, sometimes faster, sometimes slower), it would take 3.5 - 4 years to travel from about 50N to 50S via such a route. Thus anything sold would likely be very expensive, and they would likely only focus on the items that could easily make such a long voyage and are less readily made (or not made at all) on the opposite polar civilization.
In any case, would this work for you? It's not quite a 'pole-only oceans world', as vast seas and rivers exists underground stretching from the equator to at least the 30-40 degree mark, if not as far as the 40-50 degree mark, and it presumes rivers stretch from the 60 degree mark to as far south as the 40-50 degree mark - and some of those flow not into the oceans but instead flow inland, form inland deltas, and dry out in their spreading. Does any of this work for you?
1) Continental Drift has ending. So long as continental drift exists the low points where the oceans fill will always be moving. However, this also means that volcanism will be largely ended, although a few minor spots might continue to exist for a time (think Hawaii, Yellowstone, and other spots where mantle plumes have caused volcanism well away from plate boundaries).
2) Now, simply presume that the lowest points of elevation are at the polls. Rain clouds will still form but away from these two oceans there will be little available rain to fall. I presume much of the rain falls around the 60-65 latitude, as occurs on earth, but it drains only poleward - perhaps drainage in other directions eventually fading away in the form of inland deltas which themselves suffer wet and dry seasons - think the orinoco (spelling?) in Africa, but further north.
One hard part will be keeping any moisture from the equator. It literally rains year round on an almost daily basis along the equator. Reducing available moisture will not completely remove this rain belt, as it will simply mean that the equator itself will likely be less arid than anywhere except near the polls. Think of it as the thorn scrub savanna - its 'rainy' season being barely enough to turn the grasses green for a month or two, and its dry season almost reducing the lands to a desert.
3) Another possibility is that the lands along the equator are mostly limestone. With the end of plate techtonics, this limestone will not move out of the way, so for a time any rain falling at the equator will carve out immense cavern systems - eventually to the point that whole rivers will exist underground. There are several places on this (real) world whose latitude, altitude, and prevailing rainfall would suggest should be quite well forested, but are in fact near-deserts due to the fact that all the water seeps underground - and stays underground for scores of miles, eventually coming up as aquafier springs, oasises, etc once they reach somewhat lower elevation lands where the land is no longer limestone. Perhaps just before you reach the polar oceans there are deltas, springs, oasises, etc in a band around them, as overland rivers from the poleward regions, underground rivers from the equatorward regions, etc come together, bringing greenery and life prior to meeting the actual oceans.
4) Lastly, for oceans to readily exist and be easily habitable by human civilization as is typically portrayed in games, the world will need to be much much warmer place. Just a few degrees warmer than earth - on average - will be enough to keep the oceans free of ice, but the temperatures will still be significantly low even in the summer - and let's not forget the few months of darkness each year. These are serious issues as far as potential growing seasons go. I think Anchorage, Alaska has a growing season of about a month - and it exists around 60N.
So these oceans should at least take up 30 degrees equator-ward from each pole (90 to 60 degrees) to reduce the amount of darkness per year along their coasts - and in the process allowing most of the rain in the 60-65 degree belt to fall back upon the oceans themselves. This could allow minimal middle ages style civilization as we think of it on the edges of the oceans. Raise the temperature a few degrees - globally - and we could probably increase the growing season at 55-60 degrees to perhaps 2 months ayear. At the 45-50 degrees, where the deltas, emerging underground rivers / aquifiers, and oasises perhaps exist, it might be as long as 3-4 months (maybe even 5 months, if the average world temperature is set high enough) - enough to create civilizations we might consider halfway normal for medieval time periods.
However, while civilizations could exist on the equator, it would be very minor - stone age most likley, and the distances one would have to travel - across deserts so vast as to dwarf anything on earth - would make meaningful trade between the poleward civilizations and the equator civilization (such as they are) virtually impossible. In effect, each pole would be totally separate from the other, as 7k+ miles would exist between them. This is the equivalent of crossing the Sahara Desert twice - west coast to Nile river, without any place to re-supply along the double length route. Even in modern times that would be difficult, especially as no roads would exist, no maps would exist to aid in determining the best route, and if any mistakes are made there is no place to re-supply in water or hunt for food.
Other Considerations:
Perhaps the underground cave systems have become multilayered over the millennia. So water still roars through the lowest layers, but the higher layers are 'dead' cave systems, dry, perhaps a bit unstable, but much cooler than the deserts above. These might allow for travel between the poles, as water could be re-supplied down below (perhaps eco systems exist in which to fish in these vast underground seas and rivers, allowing resupply of food as well as water?). Special caravan tribes might have memorized paths they take over the course of a year or two, moving south then north then south again, trading rare items only found from the distant poles only these caravan tribes can reach. They may need to exit the caves from time to time (cave ins block a path, or perhaps one cave ends and they must seek another to continue further south), so the complex route is not ready written down - presuming they would even consider sharing such sacred tribal knowledge with an outsider. Or perhaps there are several paths, and each time they choose the forks in the paths they choose based on the present circumstances.
Traveling this way cannot be fast. If we presume 5 miles a day (on average, sometimes faster, sometimes slower), it would take 3.5 - 4 years to travel from about 50N to 50S via such a route. Thus anything sold would likely be very expensive, and they would likely only focus on the items that could easily make such a long voyage and are less readily made (or not made at all) on the opposite polar civilization.
In any case, would this work for you? It's not quite a 'pole-only oceans world', as vast seas and rivers exists underground stretching from the equator to at least the 30-40 degree mark, if not as far as the 40-50 degree mark, and it presumes rivers stretch from the 60 degree mark to as far south as the 40-50 degree mark - and some of those flow not into the oceans but instead flow inland, form inland deltas, and dry out in their spreading. Does any of this work for you?
Pbartender
First Post
Nyeshet said:
Not necessarily... Just assume that the continents are currently drifting away from the poles and towards the equators. That'll give you oceanic basins at the poles, and an equator girdling mountain range. Remember, plate tectonics takes a long time... tens of millions of years.
Nyeshet said:
You realize that this is only because the vast majority of earth's equatorial regions lies on ocean? Prevailing winds on any planet we can study, typically flow east to west or west to east in bands. If there's no moisture for the winds to pick up in those bands, it'll make rain a lot less likely.
The equatorial continent might not be a complete Sahara, but it would certain rival the Kalahari, the Gobi or the Sonoran deserts... Not impossible to survive in, but exceptionally difficult.
Nyeshet said:
Which sounds awfully close to what he's aiming for... the coasts around the poles could be similar in climate to the mediterranean coasts (especially if the polar seas have a few archipelagos), and the equatorial interior could be more like the deserts, savannas and scrublands of inner Africa.
Technomancer
First Post
Nyeshet said:
Does it work for me? It provides justification for an endless supply of underground dungeon-dwelling monsters, tribes, civilizations, and mad wizards. Good stuff.
Although like the poster above me, I'm not so sure about the equatorial rain.
Nyeshet
First Post
For the equator region (say 5 - or at most 10 - degress north and south of the equator), I was thinking along the lines of the following:
the wet season looking something like this:
(typical savanna)
http://upload.wikimedia.org/wikipedia/commons/b/b3/Male_lion_on_savanna.jpg
(dry woodland / thorn scrubland)
http://upload.wikimedia.org/wikipedia/en/1/14/9706101.jpg
(at height of the rainy season)
http://upload.wikimedia.org/wikipedia/en/c/c9/East_-_Guinean_Savanna_001.JPG
the in-between non-season (ie: late in the rainy season or very early into the rainy season) like this:
http://upload.wikimedia.org/wikipedia/en/f/f0/Joshuatreescape.jpg
http://upload.wikimedia.org/wikipedia/en/e/e4/Tharparkar1_Pakistan.jpg
http://upload.wikimedia.org/wikipedia/commons/1/18/Nullabor_plain_from_the_indian_pacific.jpg
and the dry season looking something like this:
http://upload.wikimedia.org/wikipedia/commons/9/9f/Kingston_Range_from_Emigrant_Pass.jpg
http://upload.wikimedia.org/wikipedia/en/4/48/NamibDesert01.jpg
http://upload.wikimedia.org/wikipedia/commons/f/f5/Baja_California_Desert.jpg
So it would be nearly desert throughout much of the year, but for a few months each year it would be nearly savanna like in its greenery (or at least in the length of its grasses and number of leaves and thorns on its trees).
The problem with presuming that no oceans for winds to blow over would mean desert for the equator is that much of the african rain forest receives its (rain-laden) winds (ultimately) from the sahara desert. The super-dry winds, coming down from the stratosphere, strip the moisture from the air, but the moisture continues to build up in the air as the winds travel over literally thousands of miles toward the equator. Eventually the moisture density finally becomes too much and the moisture begins to fall as rain - first minorly, when it just starts to be enough to fall and thus wetting the savanna, and then majorly once it crashes into the winds coming from the south and move upwards - with both north and south winds dropping all moisture as the winds rise into the stratosphere and dry out due to the chill temperature. Then they travel poleward again until they crash into stratosphere winds coming from the poles, forcing both to move downwards - into the sahara where they soak up whatever moisture might be present and begin again the cycle of taking the moisture towards the equator.
So even if the world is bone dry north and south of it, the slight traces of moisture that exist - but are too minor to fall as rain - would be gathered by these winds and deposited on the equator. Perhaps only for a two to three hundred mile stretch along the equator, and perhaps it would be no better than a savanna, but the combined minimal moisture of literally tens of millions of square miles, compressed to only a few hundreds of thousands of square miles, should be enough for at least a savanna or thorn scrubland / dry woodland, even if it only ranges for 2 to 4 degrees north and south of the equator (rather than 10-15 degrees of rain forest followed by another 5-10 degrees of grassland and thornscrub before becoming desert).
Cacti, tumbleweed, and bare thorn-scrub and thorn-covered trees might dot the landscape most of the year, but when the few months of rain come, the grasses swiftly grow, the seeds of flowers briefly bloom, the trees sprout leaves (and flowers, the fruits falling around the end of the rainy season), and for a time even small lakes and streams exist - until it all dries up or sinks below a month or two later. And then the leaves and the thickly rinded and thorny fruit falls, the grasses yellows, dies, and lies flat upon the ground, the flowers and herbs wither and die, and the land returns to its denuded, arid, withered state for another 8 to 10 months.
Note that without this middle ground at the equator for refueling (and travel plans would have to plan for arriving during the brief wet season even for this), any travel between the north and south polar regions would be nearly impossible. Caverns might help a bit, but many will be underwater or collapsing every few decades at the equator just from the rains that form the caverns (and send the waters of the underworld rivers poleward, forming more caverns and underground seas for your adventurers). Some travel will need to be made (at least occasionally) overland.
the wet season looking something like this:
(typical savanna)
http://upload.wikimedia.org/wikipedia/commons/b/b3/Male_lion_on_savanna.jpg
(dry woodland / thorn scrubland)
http://upload.wikimedia.org/wikipedia/en/1/14/9706101.jpg
(at height of the rainy season)
http://upload.wikimedia.org/wikipedia/en/c/c9/East_-_Guinean_Savanna_001.JPG
the in-between non-season (ie: late in the rainy season or very early into the rainy season) like this:
http://upload.wikimedia.org/wikipedia/en/f/f0/Joshuatreescape.jpg
http://upload.wikimedia.org/wikipedia/en/e/e4/Tharparkar1_Pakistan.jpg
http://upload.wikimedia.org/wikipedia/commons/1/18/Nullabor_plain_from_the_indian_pacific.jpg
and the dry season looking something like this:
http://upload.wikimedia.org/wikipedia/commons/9/9f/Kingston_Range_from_Emigrant_Pass.jpg
http://upload.wikimedia.org/wikipedia/en/4/48/NamibDesert01.jpg
http://upload.wikimedia.org/wikipedia/commons/f/f5/Baja_California_Desert.jpg
So it would be nearly desert throughout much of the year, but for a few months each year it would be nearly savanna like in its greenery (or at least in the length of its grasses and number of leaves and thorns on its trees).
The problem with presuming that no oceans for winds to blow over would mean desert for the equator is that much of the african rain forest receives its (rain-laden) winds (ultimately) from the sahara desert. The super-dry winds, coming down from the stratosphere, strip the moisture from the air, but the moisture continues to build up in the air as the winds travel over literally thousands of miles toward the equator. Eventually the moisture density finally becomes too much and the moisture begins to fall as rain - first minorly, when it just starts to be enough to fall and thus wetting the savanna, and then majorly once it crashes into the winds coming from the south and move upwards - with both north and south winds dropping all moisture as the winds rise into the stratosphere and dry out due to the chill temperature. Then they travel poleward again until they crash into stratosphere winds coming from the poles, forcing both to move downwards - into the sahara where they soak up whatever moisture might be present and begin again the cycle of taking the moisture towards the equator.
So even if the world is bone dry north and south of it, the slight traces of moisture that exist - but are too minor to fall as rain - would be gathered by these winds and deposited on the equator. Perhaps only for a two to three hundred mile stretch along the equator, and perhaps it would be no better than a savanna, but the combined minimal moisture of literally tens of millions of square miles, compressed to only a few hundreds of thousands of square miles, should be enough for at least a savanna or thorn scrubland / dry woodland, even if it only ranges for 2 to 4 degrees north and south of the equator (rather than 10-15 degrees of rain forest followed by another 5-10 degrees of grassland and thornscrub before becoming desert).
Cacti, tumbleweed, and bare thorn-scrub and thorn-covered trees might dot the landscape most of the year, but when the few months of rain come, the grasses swiftly grow, the seeds of flowers briefly bloom, the trees sprout leaves (and flowers, the fruits falling around the end of the rainy season), and for a time even small lakes and streams exist - until it all dries up or sinks below a month or two later. And then the leaves and the thickly rinded and thorny fruit falls, the grasses yellows, dies, and lies flat upon the ground, the flowers and herbs wither and die, and the land returns to its denuded, arid, withered state for another 8 to 10 months.
Note that without this middle ground at the equator for refueling (and travel plans would have to plan for arriving during the brief wet season even for this), any travel between the north and south polar regions would be nearly impossible. Caverns might help a bit, but many will be underwater or collapsing every few decades at the equator just from the rains that form the caverns (and send the waters of the underworld rivers poleward, forming more caverns and underground seas for your adventurers). Some travel will need to be made (at least occasionally) overland.
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