Atmospheric homeostasis by and for the biosphere: the gaia hypothesis

Lovelock, J. E.; Margulis, Lynn

doi:10.1111/j.2153-3490.1974.tb01946.x

Cited by 405 publications

(184 citation statements)

References 10 publications

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“…The core of this discussion is the role of biotic processes (Kirchner 2003;Volk 2003a,b). Lovelock and Margulis formulated a theory (Lovelock & Margulis 1974) that the self-organization in a global scale is an emergent characteristic of the Earth's biota (Gaia theory). The biotic effect on the Earth's functioning can be measured with the help of the net entropy exchange associated with the solar energy conversations on the Earth's surface (Kleidon et al 2000;Kleidon 2002Kleidon , 2006Kleidon & Lorenz 2004;Lenton & Wilkison 2003).…”

Section: Introductionmentioning

confidence: 99%

Plant transpiration and net entropy exchange on the Earth’s surface in a Czech watershed

et al. 2007

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Abstract:The influence of plant transpiration on the entropy exchange was quantified as associated with the degradation of solar energy on the Earth's surface covered by plants. Two surfaces were studied: (1) productive surface -plant transpiration taken as equal to the potential one, (2) non-productive surface -plant transpiration taken as equal to zero. The entropy exchanges associated with the absorption of solar radiation and with the conversion of absorbed solar radiation into the sensible heat and latent heat were taken into account. These processes were examined in the experimental watershed Liz (828-1074 m a.s.l.) located in the Bohemian Forest (Czech Republic). We found that in the growing season 1992 the net entropy exchange in humid hydrologic period (the Earth's surface is productive) was considerably higher than in the arid one (the Earth's surface was productive in 39% of days, and non-productive in 61% of days). Considering that the biotic effect on the Earth's functioning can be measured with the help of the net entropy exchange, we can assume that the theory that biotic activities -represented by plant transpiration here -are the cause of the self-organizing processes in Earth's environment is proved in the watershed scale.

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Section: Introductionmentioning

confidence: 99%

Plant transpiration and net entropy exchange on the Earth’s surface in a Czech watershed

et al. 2007

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“…For instance, Schwartzman & Volk (1989) estimated that biotic activity accelerated the rates of silicate rock weathering by one to three orders of magnitude, thereby altering the geological carbon cycle and planetary habitability (also Berner 1997). From this thermodynamic view, Lovelock later developed the controversial Gaia hypothesis (Lovelock 1972a(Lovelock ,b, 1975Lovelock & Margulis 1974). This hypothesis, roughly speaking, conjectures that Earth's unique thermodynamic state is caused and maintained by life, and that life regulates Earth into a most habitable state that is in atmospheric homeostasis.…”

Section: Introductionmentioning

confidence: 99%

Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution

Kleidon

2010

Phil. Trans. R. Soc. A.

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The present-day atmosphere is in a unique state far from thermodynamic equilibrium. This uniqueness is for instance reflected in the high concentration of molecular oxygen and the low relative humidity in the atmosphere. Given that the concentration of atmospheric oxygen has likely increased throughout Earth-system history, we can ask whether this trend can be generalized to a trend of Earth-system evolution that is directed away from thermodynamic equilibrium, why we would expect such a trend to take place and what it would imply for Earth-system evolution as a whole. The justification for such a trend could be found in the proposed general principle of maximum entropy production (MEP), which states that non-equilibrium thermodynamic systems maintain steady states at which entropy production is maximized. Here, I justify and demonstrate this application of MEP to the Earth at the planetary scale. I first describe the non-equilibrium thermodynamic nature of Earth-system processes and distinguish processes that drive the system's state away from equilibrium from those that are directed towards equilibrium. I formulate the interactions among these processes from a thermodynamic perspective and then connect them to a holistic view of the planetary thermodynamic state of the Earth system. In conclusion, non-equilibrium thermodynamics and MEP have the potential to provide a simple and holistic theory of Earth-system functioning. This theory can be used to derive overall evolutionary trends of the Earth's past, identify the role that life plays in driving thermodynamic states far from equilibrium, identify habitability in other planetary environments and evaluate human impacts on Earth-system functioning.

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“…This state far from TE is then reflected into an atmospheric composition with 21 per cent reactive oxygen and an atmosphere that is mostly non-saturated with vapour. This notion of an atmospheric composition far from TE in turn has been interpreted as a sign of widespread life on Earth (Lovelock 1965) and resulted in the formulation of the controversial Gaia hypothesis (Lovelock 1972a,b;Lovelock & Margulis 1974).…”

Section: Introductionmentioning

confidence: 99%

A basic introduction to the thermodynamics of the Earth system far from equilibrium and maximum entropy production

Kleidon

2010

Phil. Trans. R. Soc. B

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The Earth system is remarkably different from its planetary neighbours in that it shows pronounced, strong global cycling of matter. These global cycles result in the maintenance of a unique thermodynamic state of the Earth's atmosphere which is far from thermodynamic equilibrium (TE). Here, I provide a simple introduction of the thermodynamic basis to understand why Earth system processes operate so far away from TE. I use a simple toy model to illustrate the application of non-equilibrium thermodynamics and to classify applications of the proposed principle of maximum entropy production (MEP) to such processes into three different cases of contrasting flexibility in the boundary conditions. I then provide a brief overview of the different processes within the Earth system that produce entropy, review actual examples of MEP in environmental and ecological systems, and discuss the role of interactions among dissipative processes in making boundary conditions more flexible. I close with a brief summary and conclusion.

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Atmospheric homeostasis by and for the biosphere: the gaia hypothesis

Cited by 405 publications

References 10 publications

Plant transpiration and net entropy exchange on the Earth’s surface in a Czech watershed

Plant transpiration and net entropy exchange on the Earth’s surface in a Czech watershed

Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution

A basic introduction to the thermodynamics of the Earth system far from equilibrium and maximum entropy production

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