Introduction to Planetary Engineering

What is planetary engineering?

To put it simply, planetary engineering refers to the deliberate modification of a planetary environment.

It could mean making changes to any part of a planet, however it almost always refers to modifying its surface environment, which may include:

• the average temperature
• the weather or climate
• the mass or composition of any of the 4 spheres: the atmosphere, hydrosphere, biosphere or lithosphere

Altering the mass of the planet would also be considered planetary engineering, although this is rarely discussed since substantially changing a planet's mass is pretty hard (although it does occur with every meteorite impact).  What is also usually not included in study of planetary engineering is human colonisation, although in fact this would qualify, since humans are biological organisms that tangibly affect their environment.

The recognised bible of planetary engineering is Martyn Fogg's "Terraforming: Engineering Planetary Environments", in which he defines planetary engineering as follows:

Planetary Engineering is the application of technology for the purpose of influencing the global properties of a planet.

Terraforming

The field of planetary engineering has largely developed from the intriguing idea of terraforming Mars or Venus.  "Terraforming" means the modification of a planet other than Earth with the specific goal of making it more like Earth, ideally so that it can support life from Earth.  Terraforming is therefore a specialised application of planetary engineering.

While terraforming Venus has been shown to be, shall we say, tricky, there has been considerable research into the terraforming of Mars which is now widely thought to be possible - although estimates of the time needed to complete such a project varies from hundreds to hundreds of thousands of years.

Geoengineering

"Geoengineering" refers to planetary engineering of Earth, an idea which has gained attention lately because of global warming.  The question is, having 'accidentally' changed our planet's environment, are we able to deliberately change it back?  Or change it to whatever ideal state we can conceive?  Planetary engineering principles suggest that this is possible.

Interconnectedness

The tricky thing about planetary engineering is the inescapable interconnectedness between all of a planet's systems.  As in medicine, just as a doctor must consider, for example, the effects of a heart drug on the patient's brain, so a planetary engineer must consider how the effects of changing one aspect of the environment affects some other aspect.

For example: increasing the temperature of a planet automatically increases evaporation or sublimation rates, which in turn affects weather patterns and ocean currents.  It also affects the habitable zones for many organisms, which must then migrate or perish, affecting food supplies for other organisms, and so on.  Increasing atmosphere pressure affects wind patterns, as well as the amount of liquid water on the surface, which in turn affects weather, habitable zones, etc.

The complex relationships between all of a planet's systems (especially a biosphere-hosting planet such as Earth) means that it is very difficult to accurately predict the effects of certain global actions that may be included in a planetary engineering strategy.  Despite this difficulty, it should still be possible to engineer planets successfully, simply because they change very slowly.  The long time-frames allow us to monitor the effects of our actions and refine our approach as required.  After all, we have been affecting Earth's environment in an uncontrolled way for at least 2 centuries, and life still flourishes despite significant environmental changes.  If we now commence a program of geoengineering with more care, we will soon learn what works and what doesn't, and in theory should be able to shift our planet steadily towards a more desirable state.