Snow planets? Forest worlds? Here's what science has to say about life on single-biome planets

If there’s one thing sci-fi writers love, it’s a single-biome planet.

There’s the water world Kamino in Star Wars, desert planets like Arrakis from Dune and the forest planet Kashyyyk that’s home to the Wookie species.

Unlike Earth, which is made up of different biomes, these planets are characterised by their homogeneity.

Their landscapes can resemble other planets known to exist, like the arid, cold deserts of Mars, the ‘ice planets’ Uranus and Neptune, and the hellishly hot, volcanic world Venus, cloaked in clouds of sulphuric acid.

Of course, there is no evidence yet of life on any of the other planets in our Solar System.

It’s likely that this is exactly why there is such consistency in their landscape, because the evolution of life here on Earth has impacted the geology of the planet.

We know that humans are today affecting Earth’s climate and composition, but even the very first microorganisms had a part to play in shaping the world.

Early microbial life is linked to the oxygenation of our atmosphere and our oceans.

If life leads to the creation of several biomes within one planet, then we would expect to see more complexity in the inhabited planets of our favourite science fiction.

Worlds where life is only just emerging may be less diverse at their surface, but when intelligent lifeforms have evolved, the possibility of a single-biome planet seems very unlikely.

This article appeared in the February 2025 issue of BBC Sky at Night Magazine