Climate models turn the weather in Tolkien’s ‘Hobbit’ into science

Gandalf the Grey, played by Ian McKellen, travels J.R.R. Tolkien’s Middle Earth in the film “The Hobbit: An Unexpected Journey.” It turns out Tolkien was quite the climatologist when it came to modeling his mythical land. Photo by Mark Pokorny

It doesn’t take magic to make the climate on J.R.R. Tolkien’s Middle Earth. It takes physics and a lot of computing power.

Fans of Tolkien’s “Lord of the Rings” trilogy praise the fantasy series — which also include “The Hobbit” and “The Silmarillion” — for its detail. Tolkien’s son posthumously published his father’s laborious creations that describe the entire universe of Ea, and the lands beyond Middle Earth. The books contain detailed maps and descriptions of the land’s geography, from the Grey Mountains to the Shire. Even the weather along the hobbits’ journey is painted in meticulous detail based on Tolkien’s own travels around the world, as this 2002 article from the journal Weather points out.

Climatologist Dan Lunt at the University of Bristol in England has been a Tolkien fan since his childhood. He created a climate model of Middle Earth using the university’s supercomputer. Lunt published his findings on the university’s website as a tongue-in-cheek scientific study by Radagast the Brown, the forest-dwelling wizard of the fantasy series. Lunt likens him to the “environmental scientist” of Middle Earth. And according to Lunt, the climate described in the fantasy series holds up to science.

Courtesy of Dan Lunt/University of Bristol

Overall, Middle Earth’s climate was much like western Europe and northern Africa. The model showed that in northern Middle Earth, the wind comes from from the east, allowing the elves to set sail from Grey Havens to reach the Undying Lands in the west at the end of “Return of the King,” the third in “Lord of the Rings” trilogy. And the Misty Mountains creates a rain-shadow, keeping the lands to the east dry and dropping more rain and snow on lands to the west. Those rain patterns leave warm deserts covered with small shrubs over Mordor in the south, comparable to West Texas, Los Angeles, California or Alice Springs in Australia. The Shire, home to the series’ hobbits — the diminutive characters that inhabit Middle Earth — has an annual average temperature of 44 F, and 24 inches of rain each year, making it very similar to Belarus, Leicestershire, England, or north of Dunedin on New Zealand’s South Island.

Running climate simulations for Middle Earth shows the wind patterns that let the elves set sail from Grey Haven to the Undying Lands in the West. Courtesy Dan Lunt/University of Bristol.

The climate model also maps the vegetation of the rest of the world. While it can’t account for deforestation by dwarves, dragons or the “wanton destruction by orcs,” most of Middle Earth is covered with forests, says Radagast in the paper, remarking: “This is consistent with reports I have heard from Elrond that squirrels could once travel from the region of the Shire all the way to Isengard.”

The paper, which is also published in the Tolkien-invented languages of Elvish and Dwarvish, was just a fun exercise in his free time, Lunt said, but it has a serious point to make.

“These are the same models we use to predict our future and the climate on lands we’ve never been to, whether it’s our future (Earth), Mars, Venus or Middle Earth,” he said. “These models are complex and they are based on such fundamental science that they can model anything.”

Map of Wilderland from Tolkien’s “The Hobbit” give geographical details to the fictitious country. © 2012 by Wayne G. Hammond and Christina Scull. Used by permission of Houghton Mifflin Harcourt. All rights reserved.

This exercise shows climate modeling isn’t magic; it’s physics, said Gavin Schmidt, a climate scientist from NASA’s Goddard Institute for Space Studies. Supercomputers run millions of lines of code, processing fluid dynamics calculations to determine how air and water will move over our spherical planet. These formulas explain the formation of clouds, wind, rain, snow, hot summers, cold snaps and droughts. Over the past 30 years, faster computers brought these calculations into finer detail, modeling the Earth’s present, past and future climates in 100 square kilometer blocks, Schmidt said.

It’s a matter of plugging specific data and boundaries into the complex formulas, Lunt said. What does the surface of the planet look like? How tall are the mountains? What is the atmosphere made of? Lunt fed the descriptions of Middle Earth’s geography into the supercomputer and ran the simulation for about 5 days, generating 70 years worth of climate data. Everything in model starts in stasis — there’s no wind, no clouds, no plants, and the oceans are still. As the calculations continue, waves form on the oceans, storms and hurricanes form and fade, vegetation grows and pictures of the climate on Middle Earth take shape.

But relying on those models’ predictions takes proof that they’re right. That’s why scientists model the Earth’s past climate in the same way Lunt modeled Middle Earth, feeding the supercomputers data based on the Earth’s past geography. Then they measure the model’s outcome against evidence from ice core data, tree rings and other paleolithic records.

“We try to predict things that have already happened; that’s why you go back to the past and you poke and you prod and see if it reacts the same way the real world did. Does it respond to greenhouse gases the way we think it did over the last 50 million years? Does it change to the climate in the same way?” Schmidt said.

Manipulating a model not only shows scientists how the climate changed in the past, it builds their confidence in the model’s ability to predict future climates.

“We can look at things happening now and in the past and in the future and look at things that are more fanciful and get a sense of how that whole system reacts when it changes,” Schmidt said. “It turns out Tolkien wasn’t such a terrible climatologist.”

(Although, Tolkien didn’t account for how dragons breathing fire would have affected his world’s atmosphere, which could have led to a real “Smaug situation,” he joked, referring to the mythical creatures.)

Climate models are pretty robust, but they aren’t the same as a weather forecast, Lunt said. Chaos theory means a small change can have a large impact down the line. In other words, a butterfly flapping its wings in the Shire may cause a hurricane in Mordor, he said.

And they aren’t perfect. The more scientists learn, the more they can add to the equations and make the future projections more accurate, Schmidt said. For example, ten years ago climate projections did not predict that Arctic sea ice would melt as rapidly as it has today, he said. Scientists recently reran the calculations with modern supercomputers; still the models didn’t quite match reality.

As a result, scientists are asking what other factors need to be included in climate models to make those predictions better. Now scientists are learning how drifting dust and soot in the atmosphere, like the smog from growing cities like Beijing, moves and affects the climate around the world, Schmidt said. With each change to the Earth’s atmosphere and geography, climate scientists return to the models to add information with the hopes of making their predictions more accurate.

Lunt said he has had lots of requests from science fiction authors to model their dream planets, but no plans to do another fantasy climate model. But he’s been touched by the number of teachers who have already used this as an example in their classrooms. By learning about modelling Middle Earth’s climate, he hopes people will better understand how climate modelling works.

“In some way, it lends confidence to future projections, where we can predict a different world than the one we’re living in today.”