In my final semester of college I took an astrobiology class, because I thought it would be cool to learn about life in space. This was complicated by the fact that we still have not found life in space. Details.
In practice, astrobiology was an all-inclusive science class where we covered astrophysics, chemistry, biology and geology in order to examine how life started on Earth, and therefore evaluate which celestial bodies have the potential for life. The moons of Saturn look promising. Mars, not so much.
This class gave me a whole new layer of appreciation for what an amazing world we live in, how diverse it is, and what luck is involved in being alive at all. It taught me how well science and spirituality can really blend. Ecstasy and awe are just as easily found in data as they are in prayer and ritual, if you know how to look. It also drove home the point that there is still no Planet B, and we can’t bank on it being found any time soon. (Nor should we, I think. Humans don’t have a very good track record.)
Part of this awe is in the fact that no single part of Earth’s habitability is totally exclusive to it. There are other planets with liquid water, light and heat for energy, weather patterns and so on. But all of Earth’s parts are operating in a very particular harmony. If not unique, our planet is still extremely special.
Plate tectonics are part of it. While other celestial bodies have volcanism, Earth is the only one in our solar system with plate tectonics, and for which volcanism and seismic activity are interconnected. While Io is the most volcanically active celestial body in our solar system, its volcanism is spurred by tidal heating. By contrast, our crust is a collection of rocky puzzle pieces floating on molten metal, constantly pushing new rock up to the surface, and old rock down into the stew below to be recycled.
This plays a role in the planet’s climate in a few different ways. In one form, the release of vast amounts of ash can trigger volcanic winter, in which sunlight is blocked, temperatures drop, and life forms reliant on the sun die off en masse. (And then, by extension, so do the life forms that relied on these plants.) This was likely the case during the early 500s, and once again during the roughly 300 year period called the Little Ice Age.
The other way plate tectonics influence the climate is through something called the carbon cycle. In a nutshell, precipitation flushes carbon from the atmosphere, where it ends up in the ocean, groundwater, soil and rock. If you have hard water and a tea kettle, you’ve probably noticed limescale in it at some point–that’s sequestered carbon! Eventually, carbon trapped in rock is pushed down into the mantle when plates slide over each other. If enough carbon is sequestered, the global temperature can drop. Carbon that has been trapped in the mantle may then be reintroduced to the atmosphere through volcanic eruptions. This causes the global temperature to rise again. (It’s hard to actually fit this in a nutshell, so here’s the Wikipedia article.)
Given all this, I’d like to argue that the prophecy of Ragnarok may reflect this pattern, because this has happened before. It is important to remember that mythology not only preserves stories of the gods and their exploits, but also human memories of events. With the Norse in particular, it is probably not a coincidence that extreme cold and explosive volcanism play such a prominent role in the end of the world.
For example, fimbulvinter isn’t just a rough, long winter. It is an extreme winter, where humans destroy each other in a desperate bid for ever-dwindling resources. In poetic terms, it’s not hard to see this being an ice age, or at least a volcanic winter.
Following fimbulvinter and after the gods, jötnar and human dead battle, the world is consumed by fire. Once again, the destructive, firey action described is easy to imagine as volcanic activity. Further, considering that earthquakes are explained in the myths as Loki straining at his bonds underground, and that Surtr is a jötunn who represents fire (H.E. Davidson posits that he represents volcanism in particular), I don’t believe the connection between earthquakes and destruction by fire is a coincidence. The interrelation of seismic and volcanic activity was surely not lost on the composers of these poems, and it makes sense that Loki and Surtr would go into battle on the same side. These are the forces of nature, wreaking havoc on the Æsir full of gods who represent the interests of mankind and civilization.
Like all cataclysms, this inevitably destroys things beyond recognition, but there are often straggling survivors who pick up the pieces and start over. I believe this was the poet’s intention when that task was assigned to Líf and Lífþrasir.
But there’s another thing about Earth’s volcanism, something the original creators of our source material could never have known—the earliest life on Earth originated deep in the frigid ocean, nestled up against hydrothermal vents where heat and dissolved minerals provided all their energy. Life in the ocean also has a distinct advantage over life on land during drastic events like this, as it’s often shielded from the effects, or adapted to conditions that allow it to survive in spite of them. In a way, these myths are surprisingly prescient.
We would do well to remember that Muspellheim’s heat was one half of the beginning of life, colliding with Nifhlheim’s mist in the mythology, and liquid water in Earth’s history. While Surtr’s fire plays a role in ending the world as we know it, it also clears the way for life to begin anew. Like it did in the beginning, a new world rises from the ocean.
Ragnarok is probably not a cycle in itself. But it is a step in a cycle that started long before us, and will hopefully continue far beyond us.
…Provided we don’t fry the planet ourselves, of course. But Diana Paxson has already covered that better than I can.