In Chapter 9 of Revelation, a third of the
remaining die, when an awful plague comes
upon the world.

That account of the wrath of God coming
on the world is included in with many
other things.

For instance, the first trumpet:
"The first angel sounded, and there followed
hail and fire mixed with blood, and they
were cast upon the earth; and the third part
of trees was burnt up, and all green grass
was burnt up," Revelation 8:8-9