From: Mineke Schipper, Humanity’s End as a New Beginning: World Disasters in Myths
The end of the world is the central theme of Völuspá, a tragic story in which even the gods are not eternal. Loki represents evil. The gods have tolerated this spirit in their midst for as long time; too late they have realised how wicked he was. And too late have they exiled him to the earth where his fatal influence has made the humans wicked too. Since the highest god Odin gambled away one of his eyes for a drink from the source of life owned by the giant Mimir, he knew that the destruction of the world, including himself and the other gods, was unavoidable. The beginning of the end is announced by signs of nature preceding the day when the whole world, with gods and mortals, will come to an end in Ragnarok, the Twilight of the Gods.
The first sign sets in with Fimbulvetr, the coldest and longest winter ever, three winters in fact, without summers in between. In that time from all directions dazzling snow will blow. It will freeze hard and the winds will be piercing to the very marrow. The sun will be unable to shine or bring warmth. Everywhere in the world people will engage in terrible battles for three years. Evil and violence will reign. For the sake of gain brothers will slay brothers, fathers will not spare their sons nor sons their fathers. That time, before the world is going to be destroyed, will be a time of incest, a time of the axe, a time of the sword, a time of the wind and the wolf.
Wolves will devour the Sun and the Moon, blood will spout over the heavens and fill the air, the stars will disappear. Then the whole earth will quake more than ever before, the mountains fall, and the trees be uprooted. Every bond will be broken, every chain unchained. The sea will pour in over the land in huge billows, as the Midgard Serpent who encircles the land with its tail in its mouth is writhing in fury and wants to come up on land. The wolf Fenrir will come loose, with a wide open mouth: its upper jaw will chafe the vault of heaven and its lower jaw touch the earth. Fire will flash from his nostrils and eyes. The Midgard Serpent will spew so much poison that the sky and the sea will be splashed all over, a terrible spectacle to behold. Amidst all this noise heaven will be torn asunder. Then Loki and the sons of Muspelsheim, the Dwarfs, will appear, and when they ride over the bridge of the rainbow it will break. The sons of Muspell will make their way to the plains of Vigrid where the Wolf Fenrir with his gaping jaws and the Midgard Serpent will meet them. Together they will attack the gods and leave behind a trail of fire that will destroy the earth. Thor, the Thunder God, will slay the Midgard Serpent, but in his last moments the Serpent will spew poison and Thor will drop dead. Surt, the commander of the armies, will cast fire over the earth and burn all and everything. Odin himself will be felled, and all other gods will be felled too, but none of their enemies will survive either.
The vision of the Sibyl has this to say:
The Sun turns black
The radiant stars have been pulled from Heaven
The earth sinks into the sea
Smoke and fire are raging
Flames splutter and their fiery tongues lick as high as the sky
Beating against the vault of heaven
It will be a war without winners and losers, in which all warriors will perish and all things will be destroyed.
But then, what will happen next, when Heaven and Earth and the whole world have been burnt, and all the gods and all Odin’s warriors and the whole human race? Will there still be gods alive, will there still be an earth or a heaven?
After Surt has burnt the world, and the world has been completely destroyed, Alfadur (“All Father”), the eternal one, the God behind all gods, will be the only one left. He will fashion a new earth with new creatures. And there will be two human beings, hidden in Yggdrasil, the tree of life: Lif and Lifthrasir. Their food will consist of morning dew. They will start the human race anew, and their children will be so numerous that they will populate the whole world.