Martyn Fogg, a forerunning scientist in terraforming issues who has been cited by NASA (“Terraforming Mars”), defines terraforming as
"...a process of planetary engineering, specifically directed at enhancing the capacity of an extraterrestrial planetary environment to support life. The ultimate in terraforming would be to create an uncontained planetary biosphere emulating all the functions of the biosphere of the Earth--one that would be fully habitable for human beings." (Fogg 1998, 415)
As one might imagine, the process of terraforming a planet into a habitable biosphere would be an enormous undertaking, one that would involve numerous, complex sub-processes and hundreds if not thousands of years to complete. Although we may not be able to inhabit the planet being terraformed for such a long time, every step in the process yields us with invaluable information for research, which could lead to insights into the genesis of our own planet. The first and most researched biological stage in terraforming is what Haynes named ecopoiesis (from Greek, “dwelling place” + “fabrication”) (Fogg 1998, 416). Ecopoiesis is the formation of the first biosphere, which will be uncontained, that is, lacking an atmospheric boundary like the one that separates us from the vacuum of space, and thus only able to support anaerobic life forms (forms not requiring atmospheric oxygen) such as cyanobacteria (see Friedmann 243). This first stage will require an increase in temperature, in atmospheric mass, in the availability of liquid water, and a reduction in “surface UV and cosmic ray flux” (Fogg 1998, 416). Near the end of this stage, atmospheric oxygen and nitrogen levels will have to be increased to make way for consequent stages including the introduction of basic plant life and finally the introduction of complex life forms such as reptiles and finally mammals and humans.
Most models for terraforming Mars rely on the so-called ‘runaway greenhouse gas effect’ (Fogg 1998, 417) for achieving the ecopoiesis stage. This effect is called ‘runaway’ because only a relatively small amount of carbon dioxide needs to be initially released, which will in turn heat up the Martian polar ice caps, consequently releasing more and more CO2 and increasing the effect. This approach assumes that adequate levels of CO2 will be present in Mars’ surface. Other possible ways of warming up Mars’ surface and releasing CO2 include the use of greenhouse gas-producing factories, the detonation of thousands of nuclear bombs, tractoring meteors to collide with Mars, or building giant mirrors to concentrate the Sun’s energy on Mars’ surface in order to evaporate the Martian ice caps and release subsurface carbon dioxide. These scenarios can transform Mars “into a planet habitable for anaerobic life in roughly a century”, according to Fogg (1998, 418).
However, According to Richard Taylor, evidence suggests that the nitrogen “inventory of Mars is now severely depleted” and therefore complete terraforming may not be possible (421). Taylor suggests the solution of this problem can be found in ‘paraterraforming’, which is the creation of a “deliberately restricted ecospheric environment (DREE)” or “world-house” (421), an enclosure in which Earth’s biosphere is replicated through engineering. Proponents of this approach (see also Cathcart) argue that world-houses can give us relatively immediate results and require much smaller technological advances than terraforming. In fact, according to Cathcart, paraterraforming “is achievable using already patented technology” ([1], 117). Furthermore, this approach has much less detrimental effects on the planet’s original environment, so that this original environment can still be studied. I will argue that this approach is more suitable to our current capacities, more likely to be successful, and strikes a middle ground for the varying approaches of environmental ethics.
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