I have seen several things in my short life that are/were supposed to signal the end of civilization
The year 2000 and/or Y2K
topsoil erosion leading to famine
lack of freshwater
The year 1989
the creation of superintelligent robots & computer that could destroy civilization
Many of these are due to modern technology. However the concept of the world ending in the near future is always considered present in the horizon. Is this a new thing or have humans always felt they were living in the end times? Is this just some coping mechanism we have to deal with the bad side of life, to tell ourselves its all coming to an end soon or is the idea that civilization is on its last legs something that has always been a trait we have shown? Did an average civilian in the year 700 BC or 700 AD think he was living in the end times? It seems that way, at least with christianity, but I don’t know if these were mainstream opinions or just a marginal few.