Over 99% of all species that have ever lived are now extinct. Humans will be extinct long before the world ends. To be fair if you read any history book you'll find that human knowledge has expanded but when It comes down to it our nature hasn't and we still have wars, murder, steal, commit adultery etc. All that's changed in the last 100 thousand plus years is that most western men are now more creepy and effiminate than in the past, the population has expanded, we live longer and use up more of the earths resources. Whether it's the Anti christ, a war, a virus, a meteor or something else that takes us out is irrelevant. Statistics and the fact that there's already been at least 5 mass extinctions and a history of ice ages tells me that humans days are numbered, hopefully not in the next 30 years - after that I don't care as I'll (if I live above the average lifespan) be dead before then and it won't matter anyhow.
If there's a nuke war, I'll just top myself rather than die of starvation/radiation poisoning. And if the commies invade, i'll go out fighting as a free man rather than die a slave. Meh! I'm off to make some mac and cheese now to cheer myself up.