Revelation 8:12 And the fourth angel sounded, and the third part of the sun was smitten, and the third part of the moon, and the third part of the stars; so as …the third part of them was darkened, and the day shone not for a third part of it, and the night likewise.
13 And I beheld, and heard an angel flying through the midst of heaven, saying with a loud voice, Woe, woe, woe, to the inhabiters of the earth by reason of the other voices of the trumpet of the three angels, which are yet to sound!
We get to the fourth angel and light is decreased and darkness is increased. As God created light He can also take it away. As these four angels have sounded we have one third of most everything destroyed, even human life and animal life and all of this that has happened seems terrible. But there are three more angels to sound and the scripture describes as WOE, WOE , WOE to the unbelievers still alive on the earth, it seems things have been bad but it is nothing compared to what is about to happen.