The Gaia Hypothesis, also known as the Gaia Theory or the Gaia Principle proposes that the Earth system operates as one (named Gaia). The theory states that organisms interact with their inorganic surroundings on Earth to form a complex, self-regulating system that in itself maintains conditions for life on the planet.
The hypothesis, which is named after the Greek Goddess Gaia, was formulated by scientist James Lovelock and co-developed by the microbiologist Lynn Margulis in the 1970s. Lovelock and Margulis are interested in how the biosphere and the evolution of life forms affect the stability of global temperature, ocean salinity, oxygen in the atmosphere and other environmental variables that affect the habitability of Earth.
The Gaia Hypothesis suggests that organisms co-evolve with their environment. That is they ‘influence their abiotic environment (for example, temperature and atmosphere) and that in turn the environment influences biota by Darwinian processes. James Lovelock (1995) gives evidence of this in his second book, showing evolution of the world from bacteria such as Stromatolites, towards the oxygen enriched atmosphere today that supports more complex life.
Less accepted versions of the theory state that changes in the biosphere are brought about by coordination of all living organisms and conditions are maintained through homeostasis. However, most scientists accept that each individual pursues its self-interest, and that their combined actions have a counterbalancing effect on environmental change (Wikipedia 2014).
However, humans are changing everything. Our actions have far exceeded the level of activity that is required by the Earth to keep its systems in homoeostasis. As a species we have not only brought about environmental change through our interaction with the abiotic systems, but by the elimination of biota that keep Earth operating as a self-regulating system.
Rockstrom and colleagues (2009) identified nine planetary boundaries that humans must not transgress in order to preserve the planet in its current state of homoeostasis that is imperative for our survival. This can be described as a ‘safe operating space for humanity’ (Steffen et al 2011). These include climate change, ocean acidification, stratospheric ozone depletion, biochemical flow cycles, global freshwater use, biodiversity loss, atmospheric aerosol loading and chemical pollution and change in land use.
If the Gaia hypothesis is to be taken into account, as a species, the single most important chance we now have to survive is retention of biodiversity. However, worryingly, biodiversity is the boundary that we have exceeded the furthest- due to our actions of creating pollution, removing forest and changing land use, burning fossil fuels and changing climate, and many other factors, which has sent many systems into dangerous positive feedback cycles rather than self-regulating negative ‘re-setting’ feedback loops. As a result, we are currently losing biodiversity at a rate of 150 – 200 species per day (Rockstrom et al 2009).
A study this decade shows that 13 – 37% of species will be ‘committed to extinction’ by 2050 if we are to continue in our harmful and wasteful vein (Midgley et al 2004).
The Gaia Hypothesis has been criticized for being teleological and contradicting the principles of natural selection- in that, a process or action in nature is designed to work together for a final cause, that is, to maintain the homoeostasis as we know it today.
This idea of ‘feedback-coupling’ assumes that evolution means survival of the individuals who do well in the environment that they and co-occurring species have created. Both feedbacks will evolve because any trait that improves conditions will also give reproductive advantage to its biota. In contrast, natural selection favours any trait that gives biota a reproductive advantage, whether it improves or degrades the environment, for example the human species.
However ‘degradation’ of the environment in one species’ eyes may not be degradation for another, adapted species. Life and the environment evolve together as a single system so that not only does the species that leaves the most progeny tend to inherit the environment but also the environment that favours the most progeny is itself sustained (Lovelock 1986).
At the same time, organisms that retain or alter conditions optimising their fitness leave more of the same- in this way conditions are retained or altered to their benefit (Lovelock and Margulis 1974).
A puddle would say ‘well, this depression in the ground here is really quite comfortable isn’t it? It’s just as wide as I am, just as deep as I am, it’s the same shape as I am… in fact, it conforms exactly to me in every detail. This depression in the ground must have been made just for me!’– Douglas Adams.
It would seem plausible that organisms must adapt to the constraints of the environment else they don’t survive. ‘It is inevitable that that sentient life should view its world as Eden, for any evolutionary linages to which this world were a Hell would not persist long enough to develop intelligent life forms’ (Kirchner 2002).
However, humans are changing Earth’s conditions so rapidly that most species that we co-inhabit this planet with, and reply so heavily upon for our survival, cannot evolve fast enough. The time has come to perhaps either attempt to re-set the systems that we need to keep within the threshold to support life as we know it, or accept that we will eventually meet the same demise as so many other species.
We may think we are one step ahead of nature, but in reality, the rate at which we are changing the Earth will probably deem it impossible for us to adapt fast enough to survive. Are we really clever enough to save ourselves from our own collective actions?
Perhaps, it is time to consider, rather than seeing our demise as the ‘destroying of the planet’ we are instead simply changing the planet ready to start over again from the simplest life-forms, which will eventually support the next generation of complex life. Our actions could all be indeed, part of Gaia’s great master plan.
Geogger 