05 September, 2012

The Walkabout World: Part 2

(To see Part 1: Click Here)

In the first part of this series we looked at the changes to the planet due to seizmic events. Ash clouds fill the sky, bringing a volcanic winter to the world for a period of decades.

With a sky engulfed by blackened clouds, vicious electrical storms, and earthquakes shattering the planetary crust, the people of the world have no idea that the axial tilt is shifting and erratic. Most members of the western world are in too much of a panic that the comforts of their life have been obliterated...TV and radio are nothing but static, the Internet produces nothing but "Error 404" messages, credit cards don't work, automated inventory management systems collapse...when the supermarkets are raided, there is no-one to restock them...when the injuries pile up in the rioting, there are no medicines in the hospitals...when the trigger-happy military types get paranoid about terrorists and rebellious uprisings among their own people, they find their high-tech unmanned drones unusable and rely on the few outdated technologies at their disposal such as cold war era ICBMs that have sat shielded in their bunkers for decades (or longer)...these only make things worse.

With a war beyond their control, rampant disease, rioting and eventually a lack of food (and inability to grow new food), the world is reduced to less than 1% of it's current population. The scared survivors greet a new dawn after months of darkness; but while the light returns, the warmth remains at bay.

Eventually, after the dust has settled and the half-life of the nuclear contaminated zones renders them hazardous (but liveable for the short term), the weather stabilises into a more temperate climate.

Global Wind and Temperature Patterns

To pull an image from the Cassini site.


This is the general pattern of wind cell activity on a global level. Once the spin of the earth resumes a steady orbit, there is no reason to believe that the wind patterns would change from this general global pattern.

On the Walkabout map, this means that the general overall wind pattern would look something like this.


The Hadley cells to the north and south of the equator would produce an equatorial climate (not surprising really). This region would start at cool but liveable temperatures immediately following the dispersal of the ash clouds, gradually rising over the following fifty years. The regions once known as New Guinea, The Phillipines and Brazil hardly notice any difference in this regard, staying near the equator after the shift. Dramatic differences are seen in the United Kingdom, Antarctica and the regions which were once southern Argentina and Siberia; each shifting from relatively cold to equatorial climates.

The Ferrel cells further to the north and south would produce a temperate climate. These regions would start with a cold period punctuated by blizzards and howling winds, but gradually get more liveable as the decades pass. Eventually the Ferrel cell regions closer to the equator become the more hospitable and fertile parts of the planet (dependant on other geographical features), while those closer to the poles tend toward temperate forests and rolling grasslands.

The polar cells produce the coldest climates. The changes here become quite noticeable on the former west coast of North America, through to the region once known as Mexico; but the dramatic difference lies in Africa, and especially Madagascar which is now locked in a growing depth of permafrost and ice under the northern pole.

Sea Currents

Not all weather is defined by the currents of the upper atmosphere. Quite a bit is impacted by the flow of ocean currents.

With this in mind, I've roughly defined the flow of water and its relative temperature.


Blue arrows indicate cold currents and red indicate warm.

I have simply directed the flow of water to roughly match the directional low due to the spin of the earth and tides, amending the direction when a land mass is encountered. and pushing it in the direction of the wind cells when there might be doubt in its possible trajectory. It's probably not 100% accurate, but for a thought experiment it's as good as anything.

The region once known as the west coast of North America has found itself in a zone equivalent to the "roaring forties" in our world. Strong winds and currents carry storms around the southern part of the world quickly. With no major land mass to link to, there would be no southern ice cap. This plays a strong role in the weather and sea levels across the planet. When the north is in winter, more ice tends to form and the sea levels drop slightly; when the south is in winter no ice cap grows, and as the north thaws, the sea levels rise.

We can assume that this rise and fall in sea levels is a subtle thing, perhaps a few metres at most. Perhaps not even noticeable against the backdrop of a receding ice age where the sea levels would be returning to their former level at the rate of a few metres every year. While the world thaws, it would probably seem that when the southern winter occurs, the sea levels rise but when the northern winter occurs, they remain the same. Eventually the changing tide levels would stabilise according to the seasons. When the sea level drops there might be larger beaches and more arable land for small island communities, when it rises some groups might find it more fortuitous to move inland.

The Mozambique Channel between Africa and Madagascar would likely be a seasonal ice bridge between the two land masses. Melted away during the summer months, and locked into frozen place during the winter.

In time, the ice currently covering Antarctica would break off and melt away (so the coastal outline of this continent will change accordingly); but as this happens, the new polar ice caps developing over Africa and the generally colder climate due to the ice age will counterbalance this tidal change.



A suggested final outline of Antarctica if its ice crust had melted away and sea levels had stabilised with frozen ice elsewhere on the planet. 

Next Post...the modified vegetation of the planet.
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