Ecopoeisis


 * "Three scientific meetings on the topic of making a second home on Mars were held, and at one of them, Robert Haynes, a distinguished geneticist from Toronto, coined the word ecopoeisis--literally, "the making of a home"--for the practice of transforming an otherwise uninhabitable environment into a place fit for life to evolve naturally. I prefer it to the word terraforming, often used when considering this act for planets.  Ecopoeisis is more general.  Terraforming has the homocentric flavor of a planetary-scale technological fix."


 * - James Lovelock, The Ages of Gaia, p. 186.

Ecopoeisis, more commonly referred to as "terraforming," is the process of creating a self-sustaining ecology where none previously existed. Arguably, the process of Gaia taking charge of Earth's geochemistry is the first and only known example of planetary-scale ecopoeisis. If humans were to establish a global ecology on a planet such as Mars using modified life from Earth, or perhaps even if we did so on a much smaller scale (e.g. inside a hollow asteroid), the result could be considered a true child of Gaia. However, James Lovelock prefers to consider the potential living Mars as a "brother of Gaia" called Ares.

One advantage to the term "ecopoeisis" is that it doesn't imply a target environment matching that of Earth, as "terraforming" does. Thus, the term can also apply to alien ecosystems elsewhere in the Universe growing to become Gaian systems.

Ecopoeisis on Earth
While "terraforming the Earth" may sound like an extreme idea, small-scale versions of it are happening all the time and appear to be largely benign. A prominent example is the practice of ecosystem restoration as applied to regions where the ecosystem has been effectively destroyed, whether by human action (e.g. paving it over or poisoning it) or natural forces (e.g. volcanic eruptions or intense wildfires). For example, a southern California organization called Mountain Communities Wildfire ReLeaf holds volunteer tree-planting events in forests that have been killed by fire, making it clear to the volunteers that they are starting a 400-year-long process of ecosystem renewal.

Some members of the Permaculture movement describe their agricultural practices as "creating an ecosystem" that produces food and also interacts beneficially with the surrounding natural ecosystems, e.g. by providing habitats for migrating birds.

Speed of the process
It took over 1.5 billion years for Gaia to transform Earth's atmosphere into one that could provide animals with the oxygen they need. Hopefully, an ecopoeisis project initiated by humans would take far less time, but most terraforming experts agree that at least several centuries will be required before the new biosphere is self-sustaining and human-habitable.

Abiotic methods
Most treatments of terraforming assume that we will need to modify the target environment somewhat using brute-force methods to speed up the process and enable more complex life to become established early on.

Solettas
One abiotic method for ecopoiesis involves building giant mirrors in space called solettas, which either block some sunlight from reaching the target body's surface or, more commonly, reflect additional sunlight onto the body that would otherwise have gone past it. These mirrors could be in orbit or placed near the Lagrange-1 point, where a planet's gravity just balances that of its parent star. In the case of a small space habitat, the mirror would reflect light into the interior of a spinning structure such as a hollow asteroid or O'Neill cylinder. Because the structure would likely be extremely thin, with a tiny amount of mass per unit area, light pressure from the sun would probably affect its movement through space.

Albedo modification
The temperature of a celestial body is determined by how much sunlight it absorbs. Darker (lower-albedo) surfaces absorb more light and hence become warmer, so an overly cold body could be heated just by spreading a layer of dark dust over its surface (note that this could also be accomplished using living organisms, as described in the Daisyworld model). Conversely, increasing albedo using light-colored surfaces can cool the climate, and has been proposed on Earth as a countermeasure against global warming.

Emitting greenhouse gases
Speaking of global warming, most of humanity's impact on Earth's climate has resulted from our emissions of carbon dioxide from burning of fossil fuels. This could be done deliberately to warm other planetary environments, likely using a more powerful greenhouse gas such as hydrofluorocarbons.

Comet impacts
To rapidly thicken a planet's atmosphere and provide it with extra water, a comet's orbit could be shifted so that it impacts the planet's surface, using the same techniques involved in deflecting killer asteroids to prevent such impacts. Given the destructive potential of such an impact, it would become much less desirabe to do this later in the terraforming process when complex life has already established itself on the surface.

Orbit modification
In some cases, particularly when performing ecopoeisis with a very small celestial body such as a hollow asteroid, it may be possible to modify the body's own orbit to change the amount of sunlight available to it.

Developing Closed Ecological Life Support Systems
Although CELSS is mainly conceived as a means of supplementing or replacing some of the mechanical systems that keep humans alive on spaceships and space stations, it has the potential to evolve in the direction of creating fully self-sustaining ecosystems. In a sense, a celestial body where a full-scale ecopoeisis project has succeeded is a giant CELSS. This is particularly clear in the case of hollow asteroids, but since planets are largely materially-closed systems, the principle applies there as well.

Deploying extremophiles
Extremophiles are organisms adapted to environmental parameters very different from the most common environments on their home planet. This makes it possible that some extremophiles could thrive on another world with a very different environment.

Creating genetically modified organisms
Some places in the solar system are so hostile that no existing Earth being can survive there, except perhaps in the form of a dormant spore. Even in somewhat more benign environments such as Mars, genetic engineering may well be necessary in order to establish enough species to form a functioning ecosystem.