The climate of Middle Earth

0

An outline of the (spoof) paper: The climate of Middle Earth. by Radagast et al.

An amusing “pseudo-paper” on planetary atmospheres has appeared last week: Dan Lunt from Bristol University has applied the climate simulator of the UK’s Met Office to the geography of Tolkien’s Middle Earth, the setting of the Lords of the Rings and other works by the famous Oxford linguistics professor.

It turns out that in the simulation the climate of the Shire (the land of the Hobbits) resembles that of places like Belarus or Eastern Poland, while Mordor is like Western Texas. The Shire being deep inland in a bulky continent, it can be expected to have a much more continental than Tolkien’s England, with harsh winters.

Temperature and precipitations on Middle Earth.

Temperature and precipitations on Middle Earth.

To run the model, the planet of the hobbits is assumed to be exactly Earth-like in terms of orbital parameters. The layout of the continents is taken from notes and drawings from Tolkien’s work.

I was surprised to find, however, that the author places the Shire at a very northernly latitude, polewards of 60 degrees North, the latitude of Anchorage in Alaska. To keep the climate realistically warm at this latitude, the carbon dioxide concentration has to be set to 1220 ppm, four times the Earth’s pre-industrial level (which the author attributes tongue-in-cheek to the volcanic emissions in Mordor, the home of the baddies with the big central volcano).

In the books, the Shire is noticeably Oxfordshire-like in vegetation and climate, and a quick internet search showers that indeed Tolkien intended it to be placed at the latitude of Oxford (Letter 294 in “the Letters of J.R.R. Tolkien”, 1981), which is 51 degrees North. It seems that the whole Middle Earth should be moved southwards compared to the assumptions of the paper, alleviating the need for an enhanced CO2 content. I don’t know how it would change the results of the climate model. Specific features, such as wind directions, rain patterns and vegetation types would probably be affected.

This raises two interesting points. First, the wonderful complexity and colourful outputs of General Circulation Models can be intimidating, but sometimes the results are dominated by a few key assumptions in the boundary conditions, allowing the authors to tune, consciously or not, the results to some pre-conceptions (in this case a temperate climate for the hobbits). This issue is often at the core of the debate over global warming predictions.

Second, latitude shifts and CO2 concentration can compensate each other to first order. This leads to a very interesting way to conceive of the impact of climate change on ecosystems, the “latitude migration of isotherms”. For the ecosystems of Europe and North America for instance, the warming of the past 30 years has been analogous to a displacement of about 50 kilometers southwards (Hansen et al. 2006, PNAS). The expected rate in coming decades is about 6 kilometers per year, which does not sound forbidding if you are a squirrel, but can be more of a challenge if you are an oak tree.

Migration rate of isotherms according to Hansen et al.

Migration rate of isotherms according to Hansen et al.

Back on Middle Earth, the giant walking trees, the “Ents”, could solve the problem in two ways: (1) pack up and move the whole forest north, or (2) smash the climate-changing orcs once and for all. Come to think of it, not entirely unlike our own options…

Feature image: Rob / Jules (Flickr)

Share.

About Author

I am a professor of planetary science at the University of Exeter. My specialty is the study of exoplanets, in particular the observation and modelling of exoplanet atmospheres. I have done my PhD a the University of Geneva and worked in Chile, France and Switzerland.