nuclear winter

Possible long-term effect of a widespread nuclear war. In the wake of the destruction caused by nuclear blasts and the subsequent radiation, it has been suggested that atmospheric pollution by dust, smoke, soot, and ash could prevent the Sun's rays from penetrating for a period of time sufficient to eradicate most plant life on which other life depends, and create a new Ice Age.

Even after it had settled, ash would still reflect the Sun's rays and delay the planet's return to normal warmth. Insects, grasses, and sea life would have the best prospects of survival, as well as micro-organisms. The cold would be intense, and a great increase in snow and ice worldwide would occur.