 Deep in the bowels of the University of Bristol. A climate scientist is developing a computer model. A climate model of Middle-Earth. Middle-Earth is the world of the acclaimed books The Hobbit and Lord of the Rings, written by Oxford scholar J. R. R. Tolkien. Tolkien was a linguist. He created Middle-Earth as an imaginary world for the languages he invented. In his books, he also described the lands and climate of Middle-Earth in great detail. But Tolkien's expertise was in linguistics, not climate science. Do the climates of Middle-Earth that Tolkien imagined make sense? A climate scientist from the University of Bristol decided to find out. Dan Lunt builds computer models that simulate the climate of Earth. From an early age, Lunt was attracted to the works of Tolkien. Ever since I've been a child, I've been really into the Tolkien books. I've probably read them tens of times, if not more. I think the stories have always really grabbed me. They're very exciting. They're extremely well written. And also one of the things that's really fascinated me, and actually one of the reasons I got into this, is that there's a huge backstory as well. You have, for example, The Hobbit and The Lord of the Rings, behind that there's a whole mythology that's only just hinted at really in those books. So Lunt set himself the goal of simulating the climate of Middle-Earth. As well as a Tolkien fan, Lunt's expertise especially equipped him to tackle the unique challenge of modelling a fantasy world like Middle-Earth. And one of the things I do a lot with the climate model is actually simulate the climate of millions of years ago. And so millions of years ago the continents were in different positions and so it's something that I'm actually quite used to is adapting these models for worlds that are quite different from the earth that we live in today. So a good question is what actually is a climate model? So a climate model is a piece of, or the usual use of the word for climate model is a piece of computer code, a list of instructions to a computer that encapsulate our very best understanding of the way that the atmosphere of our planet and the ocean work in a physical sense. Climate models that simulate today's conditions can also be applied to the earth's deep past. It was this principle that enabled Lunt to simulate the climate of Middle-Earth. So a question that many people have asked is how can a model that is really designed or people's view of it is designed to simulate our earth? How can that model also be used to simulate Middle-Earth? Now the answer to that is that actually the core of the climate model itself is not our world, is not a map of our world or is not tied in any way to our world but is actually just based on the fundamental physical rules that were found by Newton and others. As long as we can accept that Middle-Earth maybe obeys those same fundamental physical rules as well there's no reason we can't use this model in the same way that we could use it to simulate Mars or Venus or Earth to use it to simulate Middle-Earth. So long as we have those what we call these rather peripheral things called boundary conditions which is really just a map of the world saying where the continents were and how high the mountains are and how deep the valleys or the ocean are so long as you have that information this same climate model can be used to simulate any planet in the universe. Unfortunately, Tolkien's Middle-Earth had been described in such great detail that Lunt was able to create the boundary conditions needed for his model. His son Christopher Tolkien actually published a lot of his works posthumously and those you can look at now and that includes a lot of the backstoring in there for example lots of maps of Middle-Earth that aren't actually in the original story and it was those maps that enabled us originally to actually model the whole of Middle-Earth because actually for in the Lord of the Rings itself a lot of the action only occurs in a small part of the world like equivalent to the size roughly of Europe but obviously if you're going to simulate the whole climate of the world then you need a lot more and we were able to use those maps for that. However Middle-Earth came with its own unique set of challenges that you wouldn't normally find in an ordinary climate model. Tolkien never discussed the CO2 levels in Middle-Earth so this was an assumption that we had to make and actually we considered this for some time and thought we could take something similar to perhaps pre-industrialization on the Earth but then we thought well no that's probably wrong actually because dragons like smorg and the activities of the wizards and Sauron for example may well have raised the CO2 level on Middle-Earth. After he dealt with issues such as the greenhouse gas emissions from dragons Lance said about building a climate model of Middle-Earth. The way that the climate models work is that they divide the world up into a series of boxes so it's very like Lego if you like so you can imagine sort of building up Lego and each one of those Lego blocks represents perhaps a box in which the climate model has a value for temperature it has a value for the amount of air or water within that box it has a value for how fast the air or water within that box is moving and how much moisture is contained within it if it's the atmosphere so you can imagine you've got sort of this matrix if you like surrounding the world of these boxes that go up in the atmosphere, down in the ocean. Next week Dan Lunt will undertake the epic quest to set up his Middle-Earth simulation. In the end I was able to pretty much finish set up the simulations in one evening although it was a very long evening in the morning because I got quite into it. He'll describe the challenge of conducting secret Tolkien research on university supercomputers. So I didn't tell anyone I was doing it actually but I did get to a point where I thought maybe people who were trying to discover a cure for cancer or something might get a bit annoyed that I was running Middle-Earth simulations. Find out more next week in the climate of Middle-Earth. Just to get really geeky, I mean with the grounding of Numenor, didn't the seas curve? No, okay well, so we actually simulated because the only maps that I could find that covered the whole of Middle-Earth or the whole of, well actually it turns out again it's a bit geeky but it turns out that the whole world is called Arda and Middle-Earth is actually only a small part of that and actually the only maps that I could find of the whole of Arda that were drawn by Tolkien were actually of probably what they called the first age or the second age which was prior to the drowning of Numenor. So actually if you look in the paper I show a map of the whole of the world of Arda and in there you'll actually see for the Tolkien geeks out there there's actually Numenor is actually part of that. So we weren't actually technically simulating the climate of the Lord of the Rings but maybe a few thousand years beforehand.