What is the Gaia Hypothesis?
The Gaia hypothesis, also known as the Gaia principle, proposes that all organisms and inorganic environments on Earth are closely integrated to form a single, self-regulating complex system that maintains the conditions for life on the planet. In other words, it is the view that argues that the planet is a living organism in itself. Its name comes from the Goddess called “Gaia” in Greek mythology, who symbolizes the earth and is the embodiment of the earth (“mother earth”).
Scientists investigating the Gaia hypothesis focus on observing how the evolution of the biosphere and life forms in a preferred homeostasis (internal conservation) contributes to the balance of global temperature, ocean salinity, atmospheric oxygen, and other habitability factors. The Gaia hypothesis was formulated by chemist James Lovelock and developed with Lovelock by microbiologist Lynn Margulis in the 1970s. Although initially met with hostility by the scientific community, it is now studied in the disciplines of geophysiology and earth system science; Additionally, some of its principles have been adopted in fields such as biogeochemistry and systems ecology. This ecological hypothesis, under an unclear philosophy and movement, has also inspired analogies and various interpretations in the social sciences, politics and religion.
The Gaia hypothesis proposes that the Earth is a complex, self-regulating system that includes the biosphere, atmosphere, hydrosphere, and pedosphere, tightly coupled as an evolving system. The hypothesis suggests that this system, called “Gaia”, seeks the most suitable physical and chemical environment for contemporary life as a whole.
Gaia develops through a cybernetic feedback system operated unconsciously by the biota, and many processes necessary for conditions of habitability in complete homeostasis depend on the interaction of living forms, especially microorganisms, with inorganic elements. These processes form a global control system that regulates Earth’s surface temperature, atmospheric composition, and ocean salinity, supported by a state of global thermodynamic disequilibrium of the Earth system.
The existence of a planetary homeostasis influenced by living forms has previously been observed in the field of biogeochemistry and is being investigated in other fields such as Earth system science. The originality of the Gaia hypothesis is based on the fact that some kind of homeostatic balance is actively maintained in order to maintain optimal conditions for life, even when threatened by internal or external events.
Regulation of Salinity in the Oceans
Ocean salinity has remained stable at 3.4% for a very long time. Salinity stability is important in oceanic environments because most cells require a fairly constant salinity and generally cannot tolerate values above 5%. Ocean salinity constancy has been a long-standing mystery; because river salts should have increased ocean salinity much more than observed.
It has recently been suggested that salinity may be strongly affected by seawater circulation through hot basaltic rocks, exposing hot water vents at mid-ocean ridges. However, the composition of sea water is far from equilibrium, and this fact is difficult to explain without the influence of organic processes. One explanation, for example, lies in the formation of salt plains throughout Earth history. It is assumed that these are created by colonies of bacteria that fix ions and heavy metals during their life processes.
Regulation of Oxygen in the Atmosphere
Atmospheric composition remains fairly constant, providing ideal conditions for life. All gases except the noble gases in the atmosphere are either produced by or processed by organisms. The Gaia hypothesis states that the Earth’s atmospheric composition is maintained in a dynamically stable state by the presence of life. The stability of the atmosphere on Earth is not a result of chemical equilibrium, as on non-living planets.
Oxygen is the second most reactive nonmetal after fluorine and must normally combine with the gases and minerals of the Earth’s atmosphere and crust. Traces of methane (up to 100,000 tonnes per year) must be absent, as methane is flammable in an oxygen atmosphere. Dry air in Earth’s atmosphere contains roughly 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases, including methane, by volume. Although air content and atmospheric pressure vary in different layers, it is known that air suitable for the survival of land plants and land animals is currently found only in the Earth’s troposphere or artificial atmospheres. Oxygen is a very important element for the life of organisms that have a constant need for it.
Control of Global Surface Temperature
Since life began on Earth, the energy provided by the Sun has increased by 25% to 30%; however, the planet’s surface temperature remained within habitable levels and reached low or high levels fairly regularly. Lovelock also hypothesized that methanogens produced high levels of methane in the early atmosphere, giving it an appearance similar to that found in petrochemical plumes, which in some respects resembled the atmosphere on Titan (Saturn’s largest moon).
This suggests that ozone tends to block out ultraviolet until it forms, maintaining some degree of homeostasis. As a result of “oxygen shocks” and declining methane levels that caused the Earth to become a nearly solid snowball during the Huronian, Sturtian, and Marinoan/Varanger Ice Ages, Snowball Earth research suggests that cryogenic periods ended through biogeophysiological processes. Although it fits well with Lovelock’s hypothesis, it conflicts with the Gaia hypothesis.
The processing of the greenhouse gas CO2, described below, plays a critical role in keeping Earth’s temperature within habitable limits. Inspired by the Gaia hypothesis, the CLAW hypothesis proposes the existence of a feedback loop operating between ocean ecosystems and Earth’s climate. Specifically, the hypothesis suggests that certain phytoplankton that produce dimethyl sulfide respond to climate changes, and that these responses lead to a negative feedback loop that acts to stabilize the temperature of the Earth’s atmosphere. Currently this Gaian homeostatic balance becomes difficult with the increase of human population and the impact of their activities on the environment. The proliferation of greenhouse gases may cause Gaia’s negative feedback to become homeostatic positive feedback. According to Lovelock, this could lead to accelerated global warming and mass human deaths.
James Lovelock and Andrew Watson mathematical model showing how temperature regulation can arise from organisms interacting with their environments; Developed Daisyworld. The purpose of the model is to show that feedback mechanisms can develop from the actions or activities of self-interested organisms rather than classical group selection mechanisms.
Daisyworld examines the energy budget of a planet filled with two different types of plants: black daisies and white daisies. The color of the daisy is such that black daisies absorb light and warm the planet, while white daisies reflect light and cool the planet. Competition between daisies due to temperature effects on growth rates leads to a population equilibrium that tends to favor a near-optimal planetary temperature for daisy growth.
Biodiversity and Stability of Ecosystems
The importance of multiple species in an ecosystem has led to two views in the Gaia hypothesis about the role biodiversity plays in the stability of ecosystems. A system of thought called the “species redundancy” hypothesis, proposed by Australian environmental scientist Brian Walker, proposes that most species contribute little to overall stability, such as passengers in an airplane playing little role in successful flight. The hypothesis posits each species that is part of a healthy ecosystem as a rivet on a plane representing the ecosystem. Progressive type loss reflects the progressive loss of rivets from the aircraft, weakening it until it is no longer sustainable and collapses. Subsequent extensions of the Daisyworld simulation involving rabbits, foxes, and other species have led to a surprising finding; It has been concluded that as the number of species increases, the healing effects such as temperature improvement on the entire planet also increase. It has also been shown that the system is robust and stable even when faced with disturbances.
Daisyworld simulations, where environmental changes were stable, gradually became less diverse over time; Conversely, slight disturbances led to an explosion of species richness. These findings supported the idea that biodiversity is valuable.
This finding was later confirmed by David Tilman and John A. Downing in an 11-year study of species composition, dynamics, and diversity factors in successional and native grasslands in Minnesota, stating that “primary production is greater in more diverse plant communities and that these plants can survive a major drought.” It has been proven that they have discovered that they are resilient” and stated as follows;
Our results support the diversity stability hypothesis but not the alternative hypothesis that most species are functionally redundant.
Processing of CO2
Gaia scientists view the participation of living organisms in the carbon cycle as one of the complex processes that provide suitable conditions for life. The only significant natural source of atmospheric carbon dioxide (CO2) is volcanic activity, while the only significant removal is the deposition of carbonate rocks. Carbon precipitation, solution and fixation are affected by bacteria and plant roots in soils where they improve gas circulation, or in coral reefs where calcium carbonate accumulates as a solid on the seabed. Calcium carbonate is used by living organisms to produce carbonaceous tests and shells. After they die, the external structures of living organisms fall to the bottom of the oceans, where they form deposits of chalk and limestone.
One of these organisms is Emiliania huxleyi, a moss that produces abundant coccolithophores, which also play a role in the formation of clouds. The excess CO2 is compensated by increased coccolithophorid lifespan, which increases the amount of CO2 locked on the ocean floor. Coccolithophorids increase cloud cover, thereby controlling surface temperature, helping to cool the entire planet and supporting precipitation essential for terrestrial plants. Atmospheric CO2 concentrations have increased recently, and there is some evidence that concentrations of ocean algal blooms have also increased.
While lichens and other organisms accelerate the decomposition of rocks on the surface, faster decomposition of rocks occurs in the soil thanks to the activity of roots, fungi, bacteria and underground animals. The flow of carbon dioxide from the atmosphere to the soil is therefore regulated with the help of living things. When CO2 levels rise in the atmosphere, the temperature increases and plants grow. This growth brings with it the consumption of more CO2, which plants absorb into the soil and remove it from the atmosphere.
From Hypothesis to Theory!
James Lovelock called his first proposal the Gaia hypothesis, but the term now established is Gaia theory. Lovelock explained that the formulation was based on observation, but still lacked a scientific explanation. The Gaia hypothesis has since been supported by a number of scientific experiments and has yielded a number of useful predictions; hence it was aptly named Gaia theory. In fact, larger studies proved the original hypothesis wrong; In other words, it was not life alone that regulated, but the entire world system.
In 2001, 1,000 scientists at the European Geophysical Union meeting signed the Amsterdam Declaration, starting with the declaration that “The Earth system behaves as a single self-regulating system with physical, chemical, biological and human components.” In 2005, the Ecological Society of America invited Lovelock to participate in their work, and in 2016 the Geological Society of London awarded Lovelock the Wollaston Medal for his work on Gaia Theory.
Today, Gaia theory is being further researched, especially in the multidisciplinary fields of Earth system science and biogeochemistry. It is also increasingly applied to climate change studies. It has also been called the Gaia paradigm.
What are the Counter Criticisms?
After initially being largely ignored by most scientists from 1969 to 1977, for a period the initial Gaia hypothesis was ridiculed by a number of scientists, including Ford Doolittle, Richard Dawkins, and Stephen Jay Gould. Lovelock noted that the Gaia hypothesis was derided as a kind of neo-pagan Modern religion, naming his theory after a Greek goddess defended by many non-scientists. In particular, many scientists have criticized the approach adopted in his popular book “Gaia; A New View of Life on Earth” as a teleological approach, meaning the belief that everything has a predetermined purpose. Responding to this claim in 1990, Lovelock stated;
Nowhere in our writings do we express the idea that planetary self-regulation is purposeful or involves foresight or planning by biota.
Stephan Jay Gould criticized Gaia as merely a metaphorical description of Earth processes, and he himself wanted to know the actual mechanisms regulated by self-regulating homeostasis. David Abram has argued that Gould did not know that the mechanism itself was merely metaphorical. Lovelock stated that no single mechanism was responsible, that the connections between the various known mechanisms could never be known, that this was of course accepted in other areas of biology and ecology, and that a certain hostility was held towards his theory for other reasons.
In addition to clarifying his language and understanding what is meant by a life form, Lovelock attributes criticisms currently to his critics’ lack of understanding of non-linear mathematics and to the linearizing form of reductionism that all events must be in, greedy and immediately finding certain causes before the facts. He also points out that his theory suggests experiments in many different fields, but few of them are in biology, where most of the critics are trained.
The concept of a living world, similar to the famous science fiction Solaris, has been the subject of debate many times, partly due to the different qualities and connotations attributed to the hypothetical life, and partly due to the simple language used by Lovelock in his writings. For example, evolutionary biologists such as the late paleontologist Stephen Jay Gould and ethologist Richard Dawkins wrote in the first paragraph of Lovelock’s book, “The search for Gaia is an attempt to find the largest living thing on Earth.” They attacked his statement. James Lovelock argues that it is not possible to agree on a rational answer because science has not yet formulated a complete definition of life. The basic criterion for the empirical definition of a life form is its subjection to natural selection and its ability to copy and transmit its genetic information to the next generation. Dawkins ultimately emphasized that the argument against the idea that Gaia is a living organism is the fact that the planet is not the child of any parent and cannot reproduce.
However, Lovelock describes life as a system of self-maintaining, self-similar feedback loops, like Humberto Maturana’s autopoiesis; It can be a living cell as a self-similar system, an organ embedded in a larger organism, or an individual in a larger interdependent social field. The greatest context of interdependent living beings is the Earth. The problematic empirical definition “makes the edges blurry.” While highly specialized bacteria such as E. coli, which cannot thrive outside their habitat, are considered “living”, why are not mitochondria, which evolve independently of the rest of the cell? However, mitochondria were once primary cells (See Endosymbiosis theory).
William Irwin Thompson argues that Chilean biologists Humberto Maturana and James Lovelock provide an explanation for the phenomenon of life through the deductive definition of autopoiesis. Reproduction becomes dependent on desire; Bee swarms proliferate while the biosphere does not need it. Lovelock states in the original Gaia book that even this is not true; Considering the possibilities, the biosphere could proliferate in the future by colonizing other planets, as humanity could be the forerunner of Gaia’s reproduction. Humanity’s exploration of space, colonization of other planets, and even interest in terraforming lend some credibility to the idea that Gaia may in fact be regenerating.
Natural Selection and Evolution
Lovelock postulates a systematic Darwinian evolutionary process for such biofeedback mechanisms. Creatures that improve their environment for survival are better than those that damage their environment. However, some scientists dispute the existence of such mechanisms. In 1981, W. Ford Doolittle wrote the CoEvolution Quarterly article “Is nature mother?” In his paper, he argued that nothing in the genome of individual organisms could provide the energy feedback mechanisms proposed by the Gaia theory, and so the Gaia statement was like a non-scientific theory of the maternal kind without any explanatory mechanisms.
In his 1982 book “The Extended Phenotype”, Richard Dawkins states that organisms cannot act together; because it required foresight and planning from them, he argued. Like Doolittle, he rejected the possibility of feedback loops stabilizing the system. Lynn Margulis, a microbiologist who collaborated with Lovelock to support the Gaia hypothesis, stated in 1999;
Darwin’s grand vision was not wrong, just incomplete. By emphasizing direct competition between individuals for resources as a selection mechanism, Darwin and especially his followers created the impression that the environment was simply a static arena.
He wrote that the composition of Earth’s atmosphere, hydrosphere, and lithosphere is organized around set points, as in homeostasis, but that these set points change over time.
He also wrote that biospheres have no particular tendency to protect their current inhabitants and certainly not to make them comfortable. For him, the World is a kind of trust community that can exist at many different levels of integration. Not all multicellular organisms live or die at the same time, nor do all cells in the body die instantly. Homeostatic set points are also not fixed throughout an organism’s life. W. D. Hamilton, one of the greatest evolutionary theorists of the 20th century, called the concept the “Gaia Copernican” concept and said that it would take another “Newton” to explain how Gaia self-regulation occurs through Darwinian natural selection.
Range of Opinion
Some have found it useful to suggest James Kirchner’s spectrum proposed in the First Gaia Chapman Lecture, that the original Gaia hypothesis can be divided into a spectrum of hypotheses ranging from the undeniable (weak gaia) to the radical (strong gaia).Range of Opinion
Some have found it useful to suggest James Kirchner’s spectrum proposed in the First Gaia Chapman Lecture, that the original Gaia hypothesis can be divided into a spectrum of hypotheses ranging from the undeniable (weak gaia) to the radical (strong gaia).
At one end of this spectrum, there are undeniable statements that it is changing the composition of organisms on Earth. A stronger position is that the earth should be more comfortable acting as if the biosphere were effectively a self-organizing system, operating to keep its systems in a kind of “meta-equilibrium” that is broadly conducive to life. It is believed that the history of evolution, ecology, and climate has shown that the precise features of this balance have undergone intermittent rapid changes, resulting in extinctions and the collapse of civilizations. Weak Gaian hypotheses suggest that Gaia co-evolved. In this context, my home together is defined as; “Biota affects abiotic environments, and this environment affects biota through a Darwinian process.” In his second book he gave evidence showing the evolution from the world of early thermo-acidophilic and methanogenic bacteria to the oxygen-enriched atmosphere that supports more complex life today.
The weakest form of the theory has been called “effective Gaia”. It states that biota minimally affects certain aspects of the abiotic world, such as temperature and atmosphere. Weak versions are more acceptable from the perspective of orthodox science because they do not assume homeostasis. They state that the evolution of life and its environment can influence each other; One example is how in Precambrian times the activity of photosynthetic bacteria completely changed the Earth’s atmosphere to become aerobic, thus supporting the evolution of life, especially eukaryotic life. However, these theories do not claim that atmospheric modification occurs in coordination and through homeostasis, nor do such critical theories yet explain that conditions on Earth are not altered by the runaway positive feedbacks affecting Mars and Venus.
Biologists and geoscientists often view the factors that stabilize the properties of a period as an undirected emergent property or “entelechy” of the system; for example, as each species pursues its own interests, their combined actions tend to have stabilizing effects on environmental change. Opponents of this view sometimes cite examples of life actions that result in a dramatic change rather than a stable equilibrium, such as the transformation of the Earth’s atmosphere from a reducing environment to an oxygen-rich environment. However, while proponents argue that these atmospheric changes improve the environment’s suitability for life, some go a step further and posit that all such life forms are part of a single living planet called Gaia. According to this view, the atmosphere, seas, and terrestrial crust will be the result of Gaia’s interventions through the coevolving diversity of living organisms. While it is arguable that the Earth as a unit does not fit generally accepted biological criteria for life itself (e.g. Gaia has not yet reproduced or spread to other planets through human space colonization and terraforming) many scientists would be comfortable characterizing the Earth as a single system.
One version, called “Optimizing Gaia,” claims that biota manipulate their physical environments to create biologically appropriate, or even optimal, conditions for themselves. The Earth’s atmosphere is beyond abnormal; It appears to be an invention created specifically for a purpose. Moreover, the fact that temperature, pH, and the availability of compounds of nutrients are merely optimal for surface life over enormous periods of time is unlikely to be coincidence alone. Another strong hypothesis is the so-called “Omega Gaia” hypothesis. Theilhard de Chardin argued that the Earth evolved through stages of cosmogenesis, the biogenesis of the biosphere, and the noogenesis of the noosphere, culminating at the Omega point. Another form of the strong Gaia hypothesis was proposed by Guy Murchie, who extended the quality of a holistic life form to galaxies. “After all, we are made of stardust. It is inherent in life itself.” Murchie identifies sand dunes, glaciers, fires, and similar geological phenomena as living organisms and describes the lifespan of metals and crystals “The question is not whether there is life outside our planet, but whether it is possible to have non-life.”
There are also speculative versions of the Gaia hypothesis. There are also versions arguing that the Earth is conscious or part of some universe-wide evolution as expressed in the “Selfish Bicosm” hypothesis of a larger speculative Gaia philosophy. These extreme forms of the Gaia hypothesis, that the entire Earth is a single unified organism that consciously manipulates the climate to make conditions more conducive to life, are metaphysical or mystical views that have no evidence and cannot be determined scientifically. The political arm of the Gaia hypothesis is the Gaia movement, which is a collection of different organizations operating in different countries, but all share a concern about how humans can live more sustainably within the living system.
The idea of the Earth as an integrated living entity has a long tradition. The mythical Gaia was the Greek version of the first Greek goddess, “Mother Nature,” or Mother Earth, who personified the Earth. James Lovelock gave this name to his hypothesis, basing it on an alternative spelling of the Greek goddess’s name, Gea, at Golding’s suggestion (at the suggestion of the novelist William Golding, who lived in the same village as Lovelock). Geology was consolidated as a modern science in the 18th century when James Hutton proposed that geological and biological processes were interconnected.
Later, naturalist and explorer Alexander von Humboldt realized that living organisms, climate, and crust evolved together. Already in the 20 century, Vladimir Vernadsky developed the theory of Earth Development, which is now one of the foundations of ecology. The Ukrainian geochemist was one of the first scientists to realize that oxygen, nitrogen and carbon dioxide in the earth’s atmosphere originate from biological processes. In the 1920s he published studies arguing that living organisms could reshape planets as surely as any physical force.
Vernadsky was an important pioneer of the scientific foundations for environmental sciences. His visionary statements were not widely accepted in the West and received the same kind of initial resistance from the scientific community a few decades after the Gaia hypothesis. Also back in the 20th century, in the development of modern environmental ethics and before the wildlife conservation movement, Aldo Leopold proposed a living Earth in his biocentric or holistic ethics regarding land.
In Animate Earth, Stephan Harding states:
Parts of the Earth—soil, mountains, rivers, atmosphere, etc. It is at least not impossible to consider organs such as organs or parts of organs of a coordinated whole, each part having a specific function. And if we could see this as a whole over a large period of time, we would be able to perceive not only the organs with coordinated functions, but also the process of consumption, which in biology we call metabolism or growth. In such a case, we have all the visible characteristics of a living thing that we cannot realize is such because it is so large and its life processes are so slow.
Another impact for Gaia theory and the environmental movement in general came as a side effect of the space race between the Soviet Union and the United States. In the 1960s, the first humans in space were able to observe what the Earth looked like as a whole. The Earthrise photo taken by astronaut William Anderson during the Apollo 8 mission in 1968 became an early symbol of the global ecology movement.
Creating the Hypothesis
James Lovelock began describing the idea of a self-regulating Earth controlled by a community of living organisms in September 1965, while working on methods for detecting life on Mars at the Jet Propulsion Laboratory in California. The first paper to mention this was “Planetary Atmospheres: Composition and Other Changes Associated with the Presence of Life,” co-authored by C. E. Giffin. The main concept was that life could be detected at the planetary scale by the chemical composition of the atmosphere. According to data collected by the Pic du Midi observatory, planets such as Mars or Venus had atmospheres in chemical balance. This difference with the Earth’s atmosphere was considered evidence that there was no life on these planets.
Lovelock formulated the Gaia hypothesis in journal articles in the 1970s and subsequently published the popular 1979 book “Gaia: A New Look at Life on Earth.” By 1975 the hypothesis was almost completely ignored. An article in New Scientist magazine dated February 15, 1975, and a popular book-length version published in 1979 as “The Quest for Gaia” began to attract scientific and critical attention.
Lovelock first called this the earth feedback hypothesis, and it was a way to explain the fact that combinations of chemicals such as oxygen and methane remain at constant concentrations in the earth’s atmosphere. Lovelock proposed detecting such combinations in the atmospheres of other planets as a relatively reliable and inexpensive way to detect life.
Other relationships later emerged and helped support the theory, such as marine creatures producing approximately the same amounts of sulfur and iodine as needed by land creatures. In 1971, microbiologist Dt. Lynn Margulis joined Lovelock to develop the initial hypothesis into scientifically defined concepts, contributing information about how microbes affect the atmosphere and different layers on the planet’s surface. The American biologist also aroused criticism from the scientific community with his theory on the origin of eukaryotes and organelles and his contributions to the “endosymbiotic theory” that is accepted today. Margulis dedicated the last 8 chapters of his book “The Symbiotic Planet” to Gaia. He criticized the personalization of Gaia and emphasized that Gaia is not an “organism” but a “property revealed by the interaction between organisms.” He defined Gaia as “a set of interacting ecosystems that form a single large ecosystem on Earth.” Nevertheless, Margulis argued that “the surface of the planet behaves as a physiological system in certain limited ways.” Margulis seemed to agree with Lovelock that the earth’s surface is best viewed as alive when it comes to these physiological processes. The book’s most memorable slogan was actually quoted by a student of Margulis; “Gaia is symbiosis as seen from space.” This ties the Gaia theory neatly into Margulis’s own theory of endosymbiosis.
First Gaia Conference
In 1985, he wrote on the Gaia Hypothesis “Is the Earth a Living Organism?” The first public symposium called was held at the University of Massachusetts between 1-6 August. The primary sponsor was the National Audubon Society Expedition Institute. Speakers included James Lovelock, George Wald, Mary Catherine Bateson, Lewis Thomas, John Todd, Donald Michael, Christopher Bird, Thomas Berry, Michael Cohen and William Fields. Approximately 500 people attended, and Paul Winter’s concert completed the programme. The symposium was produced by James A. Swan and Roberta Swan.
Second Gaia Conference
In 1988, to draw attention to the Gaia hypothesis, climatologist Stephen Schneider organized the American Geophysical Union’s first Chapman Gaia Conference in San Diego in 1989, solely to discuss Gaia.
At the conference, James Kirchner criticized the Gaia hypothesis for its inconsistency. He claimed that Lovelock and Margulis presented not just 1 but 4 different Gaia hypotheses;
Co-evolutionary Gaia; It claims that life and the environment evolve interdependently. Kirchner stated that this has already been proven evolutionarily and is not a new claim.
Homeostatic Gaia; He claims that life maintains the balance of the natural environment and that this stability ensures the survival of life.
Geophysical Gaia; He says that Gaia theory sparks interest in geophysical cycles and therefore leads to interesting research into terrestrial geological dynamics.
Optimizing Gaia; Gaia shaped the planet as a whole to make it an optimal environment for life. Kirchner stated that this was not testable and therefore not scientific.
For homeostatic Gaia, Kirchner proposed two alternatives. “Weak Gaia” claims that life tends to stabilize the environment so that all life can thrive. According to Kirchner, “Strong Gaia” claimed that life tends to stabilize the environment to enable all life to thrive. Kirchner claimed that Strong Gaia was untestable and therefore unscientific.
However, Lovelock and other scientists who support Gaia have tried to refute the claim that the theory is not scientific because it cannot be subjected to controlled experiments. For example, to counter the charge that Gaia is theological, Lovelock and Andrew Watson presented the Daisyworld model as evidence against many of these criticisms. Citing the Daisyworld simulations, Kirchner suggested that these results were predictable due to the intent of the Lovelock and Watson programmers who selected the examples that produced the response they wanted. Many of these issues were later answered by Lovelock, who wrote, “The Daisyworld model demonstrates that self-regulation of the global environment can emerge from competition between forms of life that modify their local environments in different ways.” he stated. Lawrence E. Joseph, in his book “Gaia: The Growth of an Idea”, stated that Krichner’s opposition was fundamentally contrary to Lovelock’s integrity as a scientist. Lovelock did not challenge Kirchner’s views for a decade until the publication of his autobiography, “Homage to Gaia,” which Kirchner called the wisdom of the position.
Lovelock was more careful to present a version of the Gaia hypothesis that did not claim that Gaia deliberately or consciously maintained the complex balance in the environment that life requires to survive. The claim that Gaia acted “intentionally” was apparently a metaphorical statement in her popular debut book and was not intended to be taken literally. This new handling of the Gaia hypothesis was more acceptable to the scientific community. Accusations of teleologism largely dropped after this conference.
Third Gaia Conference
During the “2nd Chapman Conference on the Gaia Hypothesis” held in Valencia, Spain on June 23, 2000, the situation improved significantly in accordance with the advancing science of bio-geophysiology. Rather than discussing teleological views of Gaia or “genres” of Gaia theory, the focus was on the specific mechanisms by which basic short-term homeostasis is maintained within a framework of significant evolutionary long-term structural change. The main questions were as follows;
How has the global biogeochemical/climate system called Gaia changed over time? What is its history? Can Gaia maintain the stability of the system on one time scale, but undergo vectorial change on longer time scales? How can this happen? Can the geological record be used to examine these questions?
What is the structure of Gaia? Are the feedbacks strong enough to influence the evolution of climate? Whatever disciplinary work is being done at any given time, are there pragmatically determined parts of the system or is there a set of parts that need to be done? Can it be considered correct to understand that Gaia contains organisms that evolved over time? What are the feedbacks between these different parts of the Gaian system, and what does the close confinement of matter mean for the structure and productivity of Gaia as a global ecosystem?
How do Gaian models of processes and phenomena relate to reality and how do they help capture and understand Gaia? What would be the consequences of transferring Daisyworld to the real world? What are the main candidates for “daisies” and is this important to Gaia? Is there a theory as to whether we find daisies? How should we search for daisies and intensify our search? How can we investigate Gaia mechanisms using process models or global models of the climate system that include iodine and allow for chemical balance?
In 1997, Tyler Volk argued that a Gaian system is almost inevitably produced as a result of an evolution towards far-from-equilibrium homeostatic states that maximize entropy production, and Kleidon stated in his 2004 statement:
…homeostatic behaviors can arise from a MEP state associated with planetary albedo … the resulting behavior of a biotic Earth in a MEP state can lead to near-homeostatic behavior of the Earth system over long time scales, as stated in the Gaia hypothesis.
Staley stated similarly in 2002:
…an alternative form of Gaia theory has emerged, based on more traditional Darwinian principles…[In this] new approach, environmental regulation is a result of population dynamics, not Darwinian selection. The role of selection is to favor organisms that are best adapted to the prevailing environmental conditions. However, the environment is not a static backdrop for evolution but is greatly influenced by the presence of living organisms. The resulting coevolving dynamic process eventually leads to the convergence of equilibrium and creates optimal conditions.
Fourth Gaia Conference
A fourth international conference on Gaia theory, sponsored by the Northern Virginia Regional Park Authority and others, was held in 2006 at the Arlington, VA campus of George Mason University. The event was hosted by NVRPA chief naturalist and long-time Gaia advocate Martin Ogle. Lynn Margulis, Distinguished Professor in the Department of Earth Sciences at the University of Massachusetts-Amherst and a long-time proponent of Gaia theory, was the keynote speaker. Many other speakers include: Tyler Volk, Co-Director of New York University’s Earth and Environmental Science Program; Donald Aitken Associates Director Dr. Donald Aitken; President of the Heinz Center for Science, Economics and Environment, Dr. Thomas Lovejoy; Robert Correll, Senior Fellow, Atmospheric Policy Program, American Meteorological Society, and renowned environmental ethicist J. Baird Callicott. The theory’s pioneer, James Lovelock, created a video specifically for the event.
This conference approached Gaia theory as both science and metaphor as a way to understand how we can begin to address 21st century issues such as climate change and ongoing environmental destruction.
Resources and Further Reading
Source: Harvard University | Archive Link