we simulated the climate of the planet Arrakis to see if humans could survive on it.

Scientists specializing in climate simulation models recreated Arrakis, the planet DUNE, to see if humans could survive on it.

Alex Farnsworth, Bristol University; Michael Farnsworth, University of Sheffield and Sebastian Steinig, Bristol University

Dune, the sci-fi book saga created by Frank Herbert, and which was recently adapted to film with a film of the same name, takes place in the far distant future on the desert planet of Arrakis. Herbert describes in detail a world that, at first glance, seems so real that we could imagine living in it.

However, if this world existed, what would it really be like?

To find out, and because we are scientists specializing in building climate simulation models, we reproduced the Arrakis climate. We wanted to know if the physical laws and natural environment of this world could be represented in a real climate model.

Here we offer a simulation of our Arrakis climate model.

You can explore certain features or emphasize elements such as temperature or wind speed on our website. Climate Archive.

When we were done, we were very happy that Herbert had designed a medium that broadly matched our simulation. It is true that we sometimes had to ignore our disbelief, but the truth is that Arrakis would be a largely habitable place, but also inhospitable.

How do you reproduce a fantasy world like Arrakis?

We start by applying a climate model commonly used on Earth to predict weather and climate. The use of these models starts with the establishment of physical laws (something well known in the case of the Earth) and then all kinds of data must be entered, from the shape of mountains to the intensity of solar radiation, passing through the composition of the atmosphere. Once this is done, the model can simulate the weather and say approximately what the weather would be like.

First, we decided to maintain the same fundamental physical laws that govern the Earth’s weather and climate. If our model later gave absolutely strange and eccentric results, it would indicate that these laws are different in Arrakis or that Frank Herbert’s fantastic vision of Arrakis is just that, Fantastic.

Later, we had to introduce certain data about Arrakis into the climate model, for which we drew on the detailed information available both in the main novels of the saga and in the Dune Encyclopedia. There we find information about the planet’s topography or its orbit, which is essentially circular, as the Earth is today. The shape of an orbit can have a big impact on climate, as demonstrated by the long, irregular winters of Game of thrones.

Finally, we told the model what the composition of the atmosphere was. It was very similar to what the Earth has today, but with less carbon dioxide (350 parts per million compared to our 417). The big difference was the ozone concentration. On Earth there is very little ozone in the lower layers of the atmosphere, around 0.000001%, but on Arrakis this percentage is 0.5%. Ozone is a very important element as it presents 65 times more efficient than CO₂ in warming the atmosphere, measured over 20-year periods.

After entering all the necessary data, we sit and wait; complex models like this take time to produce results, in this case more than three weeks. We needed a huge supercomputer capable of processing the hundreds of thousands of calculations needed to simulate the climate of Arrakis. However, what we got made the wait worth it.

Arrakis climate is basically plausible

Both the books and the movie describe a planet with a relentless sun and desolate lands of sand and rock. However, if we approach the polar regions, towards the cities of Arrakeen and Carthag, in the books it is described that the climate begins to change until it composes a situation that is perceived to be more benign.

However, our model told us something different. In our climate simulation of Arrakis, during the hottest months in the tropics, the surrounding temperatures were reached at 45 degrees, while the coldest temperatures were below 15 degrees. the land. The most extreme temperatures, however, occurred in mid-latitudes and polar regions. There, during the summer, temperatures in the sand reached 70 degrees (something that is also suggested in the books). And winters would be equally extreme, with temperatures of -40 degrees at mid-latitudes and -75 at the poles.

All of this is counterintuitive, as the equatorial regions receive more solar radiation. However, in our model, the polar regions of Arrakis had significantly higher atmospheric moisture levels and a greater presence of tall clouds that did not allow light to pass through. This contributes to the rise in temperatures, as water vapor is a greenhouse gas.

In books, it is stated that it does not rain on Arrakis. However, our model suggested that small rainfall can be recorded at high latitudes and exclusively in plateaus and mountainous areas, although only in summer and autumn. On the other hand, depending on the season, there would be some clouds in both the tropics and polar latitudes.

The books also claim that polar ice caps exist, at least in the northern hemisphere, and that they have been around for a long time. Perhaps this is where the books differ most from our model, which points out that the high temperatures during the summer would melt all the polar ice and that in the winter there would be no snow that could cause the ice caps to recover.

hot but livable

Could humans survive on such a deserted planet? First, we would have to start from the premise that the humanoids in the movie and in the books have the same heat tolerance as we do. And if that were so, and contrary to what happens in fiction, one might think that the tropics would be the most habitable areas. Since there is very little moisture there, the wet bulb temperatures (a measure of habitability that combines temperature and humidity) that mark survival limits would never be exceeded.

The mid-latitude areas, where most of the inhabitants of Arrakis live, are actually the most dangerous because of the heat they cause. In the lowlands, the average temperature generally fluctuates between 50 and 60 degrees Celsius, with even higher daily highs. These are temperatures in which humans cannot survive.

We know that all humanoid life forms that live on Arrakis outside of habitable places ​​must wear survival clothing designed so that its wearer stays cool and is able to turn all the moisture generated by the body in the form of sweat into drinking water., Urine and breathing. This is important, as the book claims that there is no rain on Arrakis, that there are no static bodies of water, and that there is almost no moisture in the atmosphere to enjoy.

The planet gets very cold beyond the tropics, to such an extent that winter temperatures would be deadly without the aid of technology. The cities of Arrakeen and Carthag would suffer the effects of heat and cold. It would be like an extreme version of certain real places in Siberia, which can suffer from extremely hot summers and brutally cold winters.

It is important to remember that Herbert wrote Dune’s first novel in 1965. This was two years before the 2021 Nobel Prize winner Syukuro Manabe developed the first climate model. Herbert didn’t have the advantage of today’s supercomputers (in fact, he didn’t have any kind of computer at all). With that in mind, six decades later, the world he created looks remarkably solid.

The authors modified a well-known climate model designed for exoplanet surveys and applied it to the planet Dune. This work was done in his spare time and is intended to be a reliable and accessible investigation to show how climate scientists use certain mathematical models to better understand our world and exoplanets. This work will support future academic research on desert worlds and exoplanets..

Alex Farnsworth, Senior Associate Researcher in Meteorology, Bristol University; Michael Farnsworth, Electrical Machinery Manufacturing Center of the Future Leading Research, University of Sheffield and Sebastian Steinig, Associate Researcher in Paleoclimate Modeling, Bristol University

This article was originally published in The conversation. read the original.