While personally I think it would be a stretch to believe, that the western world fucked itself economically so much as to fall to a semi-civilized state resembling Africa's civil wars, I think there's no doubt a price will be paid for fueling 50 years of economic growth with public debt and whatnot.

Honestly in the future people could very well look into the past as ask who was the genius who thought an economy could sustain itself indefinitely by making money out of an abstract concept. This and the fact we believed financial, corporate capitalism, our magic solution for the world's ills, could forever sustain a 4-6% growth when through every period of history nations didn't grow much more than 1-2%. 

Also a nation falling doesn't mean that it just disappears off the map. It could end up just meaning the end of its empire. Pax Americana is reaching its end phase, no matter how much neo-cons would want it to be different.

I am probably in the minority here, but I also agree the US is too strong too fall. Just too many other countries rely on the U.S. China relies on the U.S. to buy its goods. Korea, Japan, Vietnam, etc. all export their good to the large market in the U.S. In the Roman times, yes nations like China and Egypt relied on the romans to buy some of their good but mostly each country was self sustaining. Today you just have entire economies based on export. If the U.S. falls, the world falls. Forget the U.S., other countries are screwed too..

Our civilization will survive it. It will be a very hard time period, but we would get through it. It would be like the Great Depression in terms of life.
Gotta remember the cycle of the economy.

Hmm actually at this point if civilization goes down it won't rise again. We may be at the peak of our civilizations and future generations may look upon our works and wonder how we did it.

In the history of the modern world; there have been plenty of economic crisis', these have not resulted in the collapse of civilization.

Even the collapse of the Roman Empire didn't result in that; as most of what was known as the Roman Empire continued to prosper and advance; and most of the Mediterranean entered a golden age that exceeded both the length and the splendor of the Romans. The reason the European areas outside of Spain suffered was largely because of very low technological advancement and all of the wealth being in the hands of a small few instead of spread among the many; both of these factors combined were required. The cost of re-construction was beyond the ability of the people of Europe at the time. Now... This has not really been the case for about 700 years. It is much easier to bounce back from that sort of stuff - the Great depression and WW2 didn't end the world did it? That is concrete evidence of this.

Right now, there's really only one way for civilization to perish, and that is through environmental damage. With so many more people making environmentally friendly decisions, and not having gigantic families of 4+ kids anymore - this likely won't be a big problem; so long as everyone gets rid of their nukes.

I believe civilizations go through periods where current systems, technology, cultural structures, values, etc... break down and are not sufficient to address the current condition.  Humanity has recovered from period like this, albeit by means of bloodshed and massive reductions in population by plague and war.  Will see what happens next.  Could look at several centuries of restructuring.  One hopes that you don't end up with a human dictator on top.

The USA is screwed. It's leaders got greedy and now most of the world will pay for it. The USA might be saved if they had a strong leadership, but not with Obama or Romney, They someone more like Truman for a problem like this. The debts should of been controlled a long time ago, Bush could of done it, but had to give the rich tax cuts and start 2 wars instead. Foolish. Greed needs to stop now, and responsible government spending instead.

All the great civilizations collapse at some point, one day it will happen to the US too. Look, at Ancient Greece, the romans, the ottomans, The USSR and the British Empire, as some examples. All great powers at one time, not any more

They collapse as empires, but it doesn't mean they disappear as nations.  Even Rome is still about, as is England and Russia.  We have had an era of Pax Americana, post-Cold War period, and 9/11 ended up being the transitioning out of that period.  Who knows what the future holds.  No word it will be positive. Those who hold positive determinism have only their own ungrounded optimism to sustain it.