People have been saying that throughout the ages. I recently read "The Tale of the Heike" – a medieval Japanese book – and I was just laughing: every two pages, there's some variation on the theme of "even though the end of the world is near, such disrespect towards elders/the emperor/etc. cannot be tolerated"...
And I'm not even talking about medieval Europeans, who expected the end of the world any day now.
But the world is still here! And it seems to be doing pretty well:), and for now – it's getting better and better (if you don't believe me, just imagine what life was like eight hundred years ago – with rampant superstition, incredibly high mortality rates, constant epidemics and famine, cruelty being the norm, a fantastic lack of fresh information and the unimaginable boredom that resulted – brr!!!:mad:).
So, humanity will probably live for many, many more years...:)

Although, in reality, who knows!