I read Forstchen's series regarding this issue and it's a very compelling problem. It is estimated in his books that in the effected area(s) there would be somewhere between an 80-90% mortality rate at one year.

Life was hard in the 1800's for the sturdy people of that era; imagine our being thrown back there generally with out the skills, nohow, and hardiness they developed and learned up to those times?

Revelation speaks about two specific instances where 1/3 and 1/4 of the worlds population are lost in addition to the other calamities. Makes one wonder.

One thing we can say objectively is that the present trajectory of geopolitical politics does not give much reason for optimism.