the demon haunted world

In The Road we know some world altering event has happened and has killed all life on earth, but what is the cause? The description McCarthy gives of ash and weather seems to point to nuclear winter. http://en.wikipedia.org/wiki/Nuclear_winter. This makes sense for me as I was thinking it would have to be a nuclear holocaust or impact. A massive eruption also fits. However I feel there are significant pieces of information in the text that point towards a nuclear holocaust. On 52 we learn the clocks stopped at 1:17, in addition to the power going out before they hear/see the noise and light from the detonation, things caused by nuclear weapons. On Page 32 The man says “On this road there are no godspoke men. They are gone and I am left and they have taken the world with them.” Whatever happened was caused by man. McCarthy is saying something about potential religious contribution to an apocalypse, on the road they find immolated bodies posed in their dying positions or as he describes “like failed Sectarian suicides.” Bodies immolated where they stood, same with other objects like tires and cars indicate an instantaneous death for the victims.