Dune, Frank Herbert's epic sci-fi series, has been made into a movie. It is set on Arrakis in the distant future. Herbert created a world so richly detailed that it seems almost real.
But, what would it look like if such an existence were possible?
Because we are climate scientists, we created a simulation of Arrakis' climate. We wanted to see how the environment and physics of this world compares with a real climate model.
Here is a visual representation of the climate model for Arrakis.
Our website Climate Archive allows you to zoom in on specific features and highlight them like wind speed or temperature.
We were delighted to find that Herbert had created an environment that was in line with our expectations when we left. Although we might have to suspend our disbelief from time-to-time, much of Arrakis would be habitable, even if inhospitable.
How can you create a fantasy world like Arrakis'?
We began with a climate model that is commonly used to predict weather here on Earth.
These models require that you first decide on the physical laws, which are well-known for planet Earth. Next, input data about everything, from the shape and strength of the sun to the composition of the atmosphere. The model will then simulate the climate to give you an idea of what the weather may look like.
We chose to maintain the basic physical laws that govern weather here on Earth. If the model was completely outlandish or exotic, it could indicate that those laws are different on Arrakis. Frank Herbert's fantasal vision of Arrakis may also be a possibility.
Arrakis height map in meters (Author supplied)
The climate model needed to be told certain facts about Arrakis based on detailed information in the main novels as well as the Dune Encyclopedia.
These were the topography of the planet and its orbit. This was similar to Earth's current orbit. You can have a significant impact on the climate by the shape of your orbit. See Game of Thrones' long and irregular winters.
We then explained to the model the composition of the atmosphere. It is very similar to the Earth's current atmosphere, but with 350 parts per million of carbon dioxide, as opposed to our 417ppm.
The ozone concentration is what makes the biggest difference. The lower atmosphere on Earth has a very low concentration of ozone, around 0.000001 percent. It is 0.5% on Arrakis. Because Ozone has a 65-fold greater effectiveness at warming the atmosphere than CO 2, over a 20 year period, it is vital.
After submitting all data, we sat back and watched. Complex models such as these take time, and in this case it took more than three weeks. To simulate Arrakis, we needed a supercomputer capable of processing the hundreds of thousands calculations. But, the reward was well worth it.
The climate of Arrakis is essentially plausible
Film and books portray a planet with unforgiving sunlight and desolate wastelands made of sand, rock and sand. As you get closer to the polar regions, towards the cities Arrakeen or Carthag, the climate begins to change to something more welcoming.
Yet our model tells a different story. Our model of Arrakis shows that the tropics are warmest at 45C while the coldest months are below 15C. Similar to Earth.
Extreme temperatures are found in the mid-latitudes, polar regions. The book also suggests that summer temperatures as high as 70C can be achieved on the sand. Winters can be just as extreme with temperatures as low as 40C at mid-latitudes, and as low as 75C at the poles.
This is counterintuitive, as the sun's energy in the equatorial regions is higher. The model shows that the polar regions in Arrakis have significantly higher atmospheric moisture and cloud cover, which act to warm the climate because water vapor is a greenhouse.
Monthly temperatures calculated from Arrakis poles show very cold winters, and hot summers. (Author supplied)
According to the book, there is no rain at Arrakis. Our model suggests that rainfall could occur but only very little. It would be limited to the higher latitudes during the summer and fall, and not on mountains or plateaus. Some clouds would occur in the tropics and polar latitudes. These variations will vary from season to season.
The book mentions that there are polar ice caps, at least in northern hemispheres, and they have been for a while. This is the area where the books differ from our model the most. Summer temperatures would melt any of the polar ice and snowfall would not replenish them in winter.
Models of Stillsuits, Autumn 10191 Collection. (Chiabella James/Warner Bros)
Hot, but still habitable
Can humans survive on a desert planet like this? First, let's assume that the film and book depict human-like characters who have similar thermal tolerances as humans.
If this is the case, then the tropics, contrary to film and book, would seem the most habitable. Survivable wetbulb temperatures, which combine temperature and humidity, are never exceeded because there is not enough humidity.
Mid-latitudes are where most Arrakis residents live and they have the highest heat risk. The lowest regions have temperatures that average between 50-60C and higher maximum daily temperatures. These temperatures can be deadly for people.
We know for certain that humanoid life on Arrakis must use "stillsuits", which are designed to keep them cool and to reclaim body water from sweating, urine and breathing in order to provide drinking water.
This is crucial, since the book states that there is no rain on Arrakis and no bodies of water open. There is also very little atmospheric moisture that can reclaimed.
It also experiences extreme cold temperatures outside the tropics. Without technology, winter temperatures would be impossible to live on. Cities such as Arrakeen or Carthag would be affected by both heat and cold stress. This is similar to Siberia, which can experience both extreme hot summers, and extremely cold winters.
It is important to recall that Herbert wrote the first Dune novel in 1965. This was two years prior to Syukuro's Nobel-winning publication of his seminal first climate modeling. Herbert also did not have supercomputers or any other computer.
This is why the world he made looks so consistent 60 years later.
The authors modified an existing climate model that was used for exoplanet research, and applied it on Dune. This outreach piece demonstrates how climate scientists can use mathematical models to better understand the world and other exoplanets. It was done in their spare time. This will be used to inform future academic outputs about desert worlds and exoplanets.
Alex Farnsworth is a Senior Research Associate in Meteorology at the University of Bristol. Michael Farnsworth is Research Lead Future Electrical Machines Manufacturing hub, University of Sheffield. Sebastian Steinig is Research Associate Paleoclimate Modeling, University of Bristol.
This article was republished by The Conversation under Creative Commons. You can read the original article.
