May 8th, 2013

Destruction of the N. Hemisphere ecosystem?

Sort of a "what if," and I'll try to keep it short. I'm not necesarily looking for exact answers as much as suggestions or ideas as to what *could* happen.

I'm writing a sci-fi story in which all life in most of the N. Hemisphere instantly ceases to exhist. How it happens and where all that carbon goes is part of the sci-fi (assume it's just gone), but what I'm curious about is what would likely happen to the planet in things such as...

... global climate? (Ice age or warming?)

... weather?

... ecosystem?

... evolution of plants and animals?

This is primarily over the next 250 years and assuming that a) ocean life was mostly preserved and b) humans are out of the picture.

I'm also curious what effects might play a role in the gradual recovery of the global balance, given that all life in the Southern Hemisphere survives the initial catastrophe. What would the Earth look like in 250 years?

Google: I followed a few leads to reading about the impact of supervolcanos on climate, but it looks like most of their effects come from Sulfur, which wouldn't be the case here. This might be more akin to a meteor impact, but I'd still love to hear other ideas. There is also a study that says it takes a forest 140-200 years to recover 40-80% of its growth, but that's assuming that the devastation didn't take up half the planet, so.... *shrugs*

Breaking a sextant

Time/place: Fantasy world with roughly late 1700s/early 1800s level of technology

My characters are at sea in a small sailing vessel when a storm comes up and deposits them ... somewhere. They are on a long voyage and have a sextant with them, but I'd like it to be broken in the storm, so they can only get a vague idea where they are from the stars. (I need them to be thoroughly lost for the next piece of the plot to go into effect.) However, I have only the vaguest notion of how a sextant is put together -- basically what I can figure out from looking at pictures on the Internet -- so I'm not sure of the best, most plausible way to break it so that it can't be fixed. Both main characters are tinkerer types (one leans more to educated book-learning and science, the other is a practical handyman-type guy and skilled sailor), so the trick isn't breaking it so much as breaking it in a way they can't work around.