In my previous essays I considered that the Earth acted as a thermal amplifier.
In this essay I will expand and consider the concept of GAIA as introduced by James Lovelock. I have called this paper the modified Gaia hypothesis, and intend to show that the evolution of intelligence and Anthropogenic Global Warming are both necessary components of GAIA.
Evolution of human intelligence has allowed the biosphere to counteract dangerous carbon sequestration, in a process which I intend to show has been going on for tens of thousands of years. Without anthropogenic carbon emissions the earth would be heading for its next mass extinction, and period of SNOWBALL EARTH.
I also intend to show that:
Humans through Fuel extraction have replaced plate tectonics as the key positive driver of atmospheric C02 , but if we hadn’t our civilization would have vanished under ice 12,000 yrs ago
Temperature graphs can be obtained from the 65 Myr record which will aid predictions of future global temperature.
The Biosphere is the control mechanism, and humans have their hands on the thermostat, but currently we do not have the correct set of instructions
And that the solution is within our reach, but god help our children in the face of political corruption and corporate greed.
I have divided the essay into two parts, part 1 is a consideration of Gaia and my modification to this hypothesis and part 2 is my essay called ‘modeling and function of the earth as a thermal amplifier’ which I have previously submitted to the IOP environmental group as an essay.
1.Insolation(total INcident SOLar radiATION) is the variation in solar radiation received by the earth due to its orbital dynamics and the total solar radiation available. This is described in the theory of Milankovich cycles.
2.The earth has a dynamic hydrosphere due to its position in the theoretical circumstellar habitable zone. This is one of the known conditions for the evolution of carbon based life.
3.The earth has a developed atmosphere which contains trace amounts of greenhouse gases, i.e. C02, CH4 and water vapour.
4.The earth has an active lithosphere, which appears to alternately out-gas and sequester carbon and in doing so affects the average C02 levels over millennial timescales.
5.The biosphere is intimately involved in the carbon cycle, it uses C02 for fuel, emits CO2 as a waste product and acts as a reservoir of carbon, i.e. a carbon sink and transfers organic carbon to the lithosphere.
6.Feedback, for the purpose of the amplifier theory only two feedback mechanisms will be considered, i.e. C02 and ice.
1.The Modified Gaia Hypothesis
‘the Gaia hypothesis, which postulates that the biosphere is a self-regulating entity with the capacity to keep our planet healthy by controlling the chemical and physical environment.’
This hypothesis/theory by J E Lovelock has as its basic premise that the earth is a single complex organism in homeostasis. This hypothesis is fine for millenial scale considerations of the earth, but breaks down when applied over billions of years and when homeostasis fails mass extinctions occur. The most extreme cases of this breakdown can lead to either greenhouse or snowball earth states.
Greenhouse earth is a state when
‘A runaway greenhouse effect occurs if positive feedbacks lead to the evaporation of all greenhouse gases into the atmosphere. A runaway greenhouse effect involving carbon dioxide and water vapor is thought to have occurred on Venus.’
‘Snowball Earth refers to the hypothesis that the Earth’s surface became entirely or nearly entirely frozen at least once, some time earlier than 650 million years ago’
‘A Snowball Earth has profound implications in the history of life on Earth. While many refugia have been postulated, global ice cover would certainly have ravaged ecosystems dependent on sunlight. Geochemical evidence from rocks associated with low-latitude glacial deposits have been interpreted to show a crash in oceanic life during the glacials. ‘
The current best science believes that at least 1 period of Snowball earth and 0 periods of greenhouse earth have occurred.
The Gaia hypothesis, Gaia theory or Gaia principle is an ecological hypothesis or theory proposing that the biosphere and the physical components of the Earth (atmosphere, cryosphere, hydrosphere and lithosphere) are closely integrated to form a complex interacting system that maintains the climatic and biogeochemical conditions on Earth in a preferred homeorhesis
For significant periods in the early earth and during postulated snowball events the contribution to the atmospheric and thermal status of the earth from the biosphere has been zero. Under the initial conditions there was no life and the temperature of the earth was a function of insolation and atmospheric greenhouse effect. During snowball events ‘homeorhesis’ and the return to acceptable atmospheric conditions and temperature was a function of chemical weathering.
True homeostasis has not yet been achieved.
The Modified Gaia Hypothesis attempts to answer this problem.
During periods when the biosphere has been an active part of the total planetary system, the maintained conditions over millenia is best described as an homeorhesis rather than an homeostasis.
That is the effect of the biosphere has been a slightly negative trended opposition to the CO2 content of the atmosphere. This has allowed the biosphere to apply an opposition to ‘greenhouse’ tendency during periods of high CO2 emissions and to apply a negative slope to temperature during low tectonic/volcanic periods.
The biosphere appears to have constrained the global average temperature in predictable ways between 0 degC and 12 degC Vostok equivalent over the last 65 Myr. This trend has of course been interrupted on several occasions but after the temperature has stabilized the temperature has returned to homeorhesis. There is proof available that positive temperature intrusions have been caused by extreme volcanic events leading to CO2 spikes, and negative temperature intrusions by decreased Insolation at the surface either due to increased Albedo or atmospheric opacity.
The biosphere has a predominantly negative feedback on CO2 and temperature due to both the evolution and population dynamics of lower organisms. During the last 65 Myr the contribution of higher life forms to atmospheric composition by emission of CO2 as a waste product has been insufficient to overcome this negative feedback.
The thermal amplifier model and its application to problems with Milankovich theory shows that the temperature of the earth has been decreasing steadily for over 20 Myr due to falling CO2 levels. As the temperature has fallen to below 0 degC vostok equivalent increased CO2 absorption and Albedo have ushered in a period of glacial cycles. The flip from interglacial to glacial occurs at approx -5 degC vostok equivalent and the milankovich cycles occur in a new metastate for approx 110 kyr. This trend should have continued for many tens or hundreds of kyrs without further major volcanic activity.
The earth has finally achieved a quasi homeostatic state, the evolution of human intelligence has given the biosphere a tool to counteract the negative feedback which has prevailed in the system for billions of years. Anthropogenic Global Warming due to manipulation of the carbon cycle for at least 15,000 years has cancelled the current glacial flip, and saved the planet from snowball earth and mass extinctions.
Human intelligence is the final component of GAIA.
The irony is if we kill ourselves off the biosphere will probably survive for millions of years because of anthropogenic CO2 before the glacial cycles resume.