All You Wanted To Know About The Gaia Theory

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All You Wanted To Know About The Gaia Theory

• Pietro Paolo Bertagnolio
• 23 January 2008
• Proseminar Presentation Techniques

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Gaia is NOT (only) a goddess.
FACTS Chemical Disequilibrium, Time
Records, Daisyworld
HYPOTHESIS The Earth System actively (Gaia
Hypothesis) self-regulates.
PARADIGM The Earth is like (Gaia Theory) a
living being.
RESEARCH Feedback loops, (Geophysiology) Self
-regulation mechanisms
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The History of Gaia

• 1785 James Hutton (the father of geology) the
  Earth as a superorganism.
• 1927 Vladimir Vernadsky the biosphere drives
  geological evolution.
• 1966 Lynn Margulis the cells are communities
  of once-independent microorganisms
  (endosymbiosis)
• 1979 James Lovelock Gaia A new look at life
  on Earth.

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Living planets, dead planets
From Lovelock (1990)
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What do they have in common?

• Defined boundary
• Atmosphere
• Constant properties
• Oxygen conc.
• Ocean salinity
• Surface temperature

• Defined boundary
• Membrane
• Constant properties
• pH
• Osmotic pressure
• Ionic charge

HOMEOSTASIS
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Homeostasis and Daisyworld
From Olbers (2001)
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Homeostasis and Daisyworld
From Lenton (1998)
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Homeostasis and Earth
From Lovelock (1990)
O2 and CH4 are produced by bacterial
metabolism. Could these be the Earths daisies?
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Definition of Paradigm
Scientists develop problems, theories, models and
experiments in a given frame, called paradigm.
At the core of each paradigm there is often an
analogy.
Thomas S. Kuhn (1922 - 1996)
From Kuhn (1962)
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Examples of Paradigm (1)

The universe
is like
Earth-centered spheres
Sun-centered spheres
an infinite space
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Examples of Paradigm (2)

is like
microscopic particles
Light
microscopic waves
a quantum wavefunction
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Gaia as a paradigm

an electronic circuit
The Earth system
is like
a living being
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DMS cycle Main characters
Clouds
Phytoplankton
Dimethylsulfide (DMS)
Dimethylsulfonio propionate
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DMS cycle CLAW
From Charlson et al. (1987)
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DMS cycle Anti-CLAW
From Charlson et al. (1987)
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Summary

• Lovelock speculates that the Earth system could
  have some self-regulating mechanisms. (Gaia
  hypothesis)
• This leads to investigate the Earth system as it
  was a living organism. (Geophysiological
  paradigm)
• New research has been stimulated by this new way
  to look at the Earth. (DMS cycle - CLAW
  hypothesis)

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Thats all, folks!

• References
• Charlson, R. J., Lovelock, J. E., Andreae, M. O.,
  and Warren, S. G., (1987), Oceanic phytoplankton,
  atmospheric sulphur, cloud albedo and climate.
  Nature 326, 655-661.
• Kuhn, T. S. (1968), The structure of scientific
  revolutions, University of Chicago Press.
• Lenton, T. M. (1998), Gaia and natural selection,
  Nature 394, 439-447.
• Lovelock, J. E. (1990),The Ages of Gaia, Bantam
  Books.
• Olbers, D. (2001), A gallery of simple models
  from climate physics, Stochastic Climate Models,
  Progress in Probability, 49, 3-36.