Perhaps one of the most profound problems of philosophy is the age-old question of why we exist- here, on Earth, in the short time period which has been allotted to humankind. It probably concerned our prehistoric ancestors: we know it has occupied philosophers from at least the time of Aristotle to the present. Although many answers have been proposed, they seem little closer to a universally accepted truth than are the musings of the average person who gazes awestruck at the night sky. It now seems possible that a combination of the Gaia hypothesis (possibly as the “Intelligent Designer”- more on this later) and modern palaeogeochemistry might provide a solution.
2. Gaia and climate stabilization:
Ever since its introduction by James Lovelock (1979), the Gaia hypothesis has generated intense public interest and considerable controversy among earth scientists and ecologists. Indeed, in recent times the Gaia hypothesis has garnered such respect as to be considered “mainstream” (Peat, 2006). The key aspect of the hypothesis is that Gaia operates (or is) a feedback mechanism that maintains, within limits and subject to some cycling, relatively constant environmental conditions on our planet (Lovelock, 2001). Watson & Lovelock (1983) and Lovelock (1988) proposed a simple biological model which might accomplish this, which they called “Daisyworld”. In this model, two forms of plants occurred. One was to be a highly reflective plant (as “white daisies”), which could thrive under high temperatures. The other, a dark and hence radiation-absorbing form (“black daisies”), was a better competitor under lower temperatures. The white form would spread when the planet was warm, but by reflecting the sun’s radiation away from the planet, would cause it to cool (acting as “air-conditioners” in the terminology of Hsü, 2001). At some lowered temperature, the dark form would be able to outcompete the light one, and by absorbing radiation, would cause the temperature to rise again (= “heaters”: Hsü, 2001). The relative abundances of the two forms were shown by a simple model to be able to maintain the planet’s temperature within a narrow range, over a considerable range of solar input strengths. Hsü (2001), noting that actual “black daisies” had never evolved, nonetheless supported the concept, noting that “The biologic evolution on earth has been an alternate dominance of the ‘air-conditioners’ and the ‘heaters’ to moderate the climate changes on Earth.”
However, this biological activity would of necessity have other consequences. As Lovelock (1988) concisely summarized, we know that before photosynthesis began, most oxygen was locked up in oxidized minerals on the Earths’s surface. There were several climate cycles moderated by various types of “heaters” and “air-conditioners”, and carbon burial in the form of shales and limestones (Hsü, 2001). When Gaia caused green plants (or “daisies”) to evolve they accelerated the process of removing carbon dioxide from the atmosphere, splitting off the carbon to incorporate in their tissues, and expelling free oxygen to the atmosphere (e.g., Dahl et al., 2010). Thus, pre-life and early-life Earth had an atmosphere much richer in carbon dioxide than the present earth. By incorporating and locking up carbon dioxide from the atmosphere in their tissues, the plants (“daisies”) would have threatened their own growth by the diminishment of their resource. It also would have reduced the greenhouse effect, leading to lower temperatures, and if the loss of carbon were to go too far, the “black daisies” would be unable to grow enough to effectively oppose the temperature changes. Gaia’s first solution to this “disappearing carbon” problem was the evolution of decay organisms, which could break down the organic remains of the “daisies” (whatever they actually were) and release carbon back into the atmosphere when the plants died, and in the process also produce nutrients for the plants. To help shortcut the recycling process, Gaia also developed herbivorous and then carnivorous animals, which could control excess plant production, providing both faster recycling and fertilizer for the plants, while meanwhile absorbing some of the excess atmospheric oxygen and expelling carbon dioxide directly back into the atmosphere. At death, of course, the tissue carbon of both animals and plants was re-released to the atmosphere by the normal biological decay organisms. For a while this well-designed ecosystem was able to provide adequate stability.
3. Geological processes interfere with “heater” mechanism:
But geological processes were also at work on the remains of these animals and plants, and due especially to sedimentation out from aquatic environments and subsequent burial in sea and lake bottoms, significant quantities of carbon (limestone, shale, coal, oil) were being lost to the system (Dahl et al., 2010). When carbon was buried out of reach and away from oxygen, it could not be recycled back to the atmosphere by biological processes. Over time this created a problem for the plants, and hence for Gaia, as permanent carbon loss would again threaten the stability of the ecosystem, and the problem could not be solved using the organisms developed up to that time. Failure to stop this process would lead to a carbon-poor atmosphere and an eventual diminution of all carbon-based life, and give rise to an overall global cooling trend (e.g. from 65 Ma forward: Zachos et al., 2001). It seems clear in retrospect that Gaia’s response to this crisis was to encourage the evolution of a life-form that would mine this sequestered carbon and return it to the atmosphere (Pearre, 2002). That was, of course, us, filling the latest role of “heaters”. We were apparently equipped with brains wired not only for ingenuity in recovering fossil carbon from its deep deposits but for inventing methods for oxidizing it. We were also apparently programmed to hinder its reburial- for example, by our compulsion to colonize coastal areas, thus removing from the biosphere some of the most potent areas for carbon burial, e.g. salt marshes, seagrass beds and mangrove forests (Duarte et al., 2005). We can be pleased to think that, as Mr. John Ashcroft is said to have opined, our exploitation of fossil fuels is indeed part- or perhaps the whole- of God’s (or Gaia’s, or the Intelligent Designer’s) plan for us. In fact, this is probably the answer to perhaps our greatest philosophical question of all time, posed at the start of this essay: “Why are we here?”: Our purpose is to return the buried carbon to the atmosphere.
4. Gaia as Intelligent Designer:
Does an “Intelligent Designer” exist? It has been pointed out that the designer, if divine, cannot be “intelligent”, as intelligence necessarily implies the ability to learn (Webster, 2010). A supernatural or divine being is defined as omniscient, but if omniscient, has nothing to learn, and hence no possibility of demonstrating intelligence. Therefore, it is more appropriate to refer to an “Omniscient Designer”, or “O.D.” (e.g. Paley, 1802: quoted in Ayala, 2004).
Critics have argued against the concept of an Intelligent or Omniscient Designer on several grounds. Firstly, because most species which have existed have become extinct, which seems wasteful (Hull, 1992, and others). However, the number of “wasted” extinct species is merely a consequence of the trial-and-error process used to derive the species needed to keep the world in homeostasis: some wastage is inevitable, and many of the extinct species were, after all, progenitors of more modern ones. Perhaps more importantly, a number of critics (e.g. Darwin, 1859 and later writers) have remarked on the sub-optimal design of our eyes, our backs, and many other bodily systems: they argue that an Intelligent or Omniscient Designer (“I.D.” or “O.D.”) would have devised better solutions (see Avise, 2010). However, besides being anthropocentric, that perspective is very naïve. On the contrary: good, elegant and economical engineering involves making a machine which is sufficient to do the job for which it is meant- it is wasteful of time and effort to make a perfect machine if a sub-optimal, more quickly produced one will suffice. Our physical imperfections have not, after all, prevented us from doing our part in returning the buried carbon to the atmosphere, and so may, in fact, actually further argue for the sophistication of the Designer.
If such an O.D. exists, is he/she/it identifiable with Gaia? As both the Omniscient Designer and Gaia have been said to be responsible for our creation, this would seem only reasonable. Therefore, it will be convenient to combine the concepts as “Gaia-the-Omniscient Designer”, or “G.O.D.”, who has indeed assigned to us a special place in creation.
5. Our purpose: fulfilled.
That said, some of us will probably find it worrisome that, when the fossil fuels have all been extracted and burned, humanity’s purpose will have been fulfilled. At current rates this will be within a vanishingly short time (in geological terms), and G.O.D. will have no further need for us. Lovelock (2001) felt that we should trust the Gaian mechanism to keep our world habitable for us (but see Lovelock, 2006). However, once the carbon is successfully returned to the atmosphere, Earth’s temperature regime will have been restored to its Daisyworld range, and we, an extraordinarily rapidly developed species (a “quick fix”), will have done the job for which we were created (Pearre, 2002). If he/she/it can muse on such things, Gaia-the-Omniscient Designer will, perhaps gratefully and certainly with satisfaction, bid us farewell- we had faithfully and predictably fulfilled our intended part as “heaters” in our cycle of the Great Homeostasis Scheme. We should get a great deal of job satisfaction from this.
Gaia even seems to have arranged our psychological constitution so that not only would we carry on with our intended program until all the buried carbon was returned to the atmosphere, but that we would be self-extinguishing at the end of our useful life as a species. This can be considered analogous to design of an automobile or other appliance which breaks down as soon as its warranty runs out. We have been programmed for inventing societies which always drive us to consume whatever resources we depend on even though it means destroying our life-support systems (Diamond, 2004; Wright, 2005; see also Kolbert, 2005). As a backup system, G.O.D. also equipped us with brains apparently genetically wired (e.g. Hamer, 2004) for fanatical beliefs in supernatural entities. These differ between societies such that the “sacred truths” of one contradict those of another, and so inevitably lead to hatred and religion-sanctified slaughter.
In another interpretation of Robert Frost’s (1923) famous metaphorical poem “Fire and Ice”- (“Some say the world will end in fire, some say in ice…”) either of these programs- “fire” (our entanglement in religious- perhaps bioagent or nuclear- wars), or “ice” (our condition when we have exhausted our resources) might well be sufficient to end at least our role in the world- as Gaia intended.
Our purpose in being here is to return buried carbon to the atmosphere. This, while worth knowing, is not particularly good news for us.
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