By Paul Kieniewicz
© Paul Kieniewicz 2012 All Rights Reserved
Is the Earth as alive? Sure it is, with worms, birds, bacteria, animals — the creatures we watch on Richard Attenborough nature shows. The diversity of the biosphere has been also recently highlighted in Richard Dawkins’ The Greatest Show on Earth. Is the Earth alive, in the sense that it behaves as one living organism? Perhaps intelligent, with feelings of its own? That’s more like science fiction along the lines of Stanislav Lem’s Solaris where a planet consisting of an ocean, turns out to be the form of a single conscious being. An ecosystem of one.
The notion of the Earth as a living organism sounds preposterous, and yet these days it’s entertained by many scientists. Most agree that the Earth behaves as if it were a living organism. It appears to be able to regulate its own environment, appears to have a purpose. Is the Earth a life form? We don’t know because we still don’t have a clear idea on what constitutes life and a living organism.
The Earth is undoubtedly a very special place. Its environment is perfectly suited for the development and evolution of a vast array of life forms. There’s nowhere, except perhaps in the heart of a volcano, where you won’t find living organisms of some sort.
Take the ambient temperature. It has remained roughly constant over the past 3 BY. A remarkable achievement because over the same period the sun’s output (luminosity) has risen by 30%. There have been ice ages and warmer spells, but the average hasn’t varied a lot. There appears to be a regulatory mechanism at work, a thermostat of sorts that warms the planet when it’s about to turn into a snowball. Cools it off to as the sun grows in luminosity.
What about atmospheric composition? It’s almost entirely the result of the biosphere’s activity. Curiously the proportion of Oxygen has remained constant for a long time, about 20%; high enough to support the metabolism of large mammals, but low enough to prevent raging fires from spreading. Carbon dioxide is low, compared to other planets, at 390ppm, but rising. Other gases such as nitrogen and methane are all derived from living organisms.
Around 1971, James Lovelock and biologist Lynn Margulis proposed a startling idea, that the above particular conditions are no accident, but the result of a self-regulating mechanism they called Gaia. The biosphere not only creates the environment best suited for its growth and evolution, but has maintained those optimum conditions over time.
The Earth’s temperature is regulated by a variety of mechanisms: primarily the greenhouse effect, but clouds, ice cover, and forests play a role in varying the Earths reflectivity (albedo). One way Gaia controls the Earth’s temperature is by varying the concentration of greenhouse gases. Carbon dioxide, methane and nitrous oxide make the atmosphere partially opaque to infra-red radiation. The sun’s radiation penetrates our atmosphere unhindered, but the heat that it generates doesn’t easily escape.
Figure 2 — Carbon Dioxide concentration since the Cambrian
Figure 2 shows how over the history of the Earth, the concentration of carbon dioxide fell steadily, while the sun’s luminosity increased. Because 4 BY ago the sun was so dim, the Earth almost turned into a giant snowball with frozen oceans. That it didn’t, was because the early atmosphere was rich in methane, a strong greenhouse gas. It created an atmospheric blanket that kept the Earth warm.
What has caused the carbon dioxide, over the past 4BY to decrease so fortuitously as the sun grew brighter? It was squirreled away in carbonate rocks by the weathering of granite-like rocks, absorbed by small marine organisms such as cocoliths. Finally plate tectonics took the carbonate rocks down into the Earth’s interior. Plant life played no small role in helping erode the rocks and accelerate their weathering. Whenever there was an excess of carbon dioxide in the atmosphere, plant and animal life assisted in its removal. This was Gaia at work.
Paleontologic evidence shows that the Earth has experienced several episodes when all life was almost obliterated. Most significant was the Permian extinction, 280MY ago, when 90% of all marine life forms and 70% of land biota died. It happened most likely as a result of massive volcanic activity over Siberia, followed by the release of gas hydrates from the ocean. The sudden release of carbon dioxide created such a growth spurt in marine life that all oxygen was sucked out of the waters. Was Gaia on vacation when this happened?
It wasn’t the only extinction. 60MY ago a large meteor probably slammed into the Earth in the vicinity of present-day Yucatan, raised dust to the extent that sunlight was dimmed, and much of plant life died off. Other casualties were dinosaurs that relied on massive amounts of plants for their sustenance.
In both cases the Earth’s biosphere recovered, but only after a few million years. A sudden influx of carbon dioxide into the atmosphere resulted in the acceleration of rock weathering, the burial of carbonates, development of new life forms in the ocean that in time, removed the carbon dioxide from the atmosphere. Gaia was hard at work to re-establish the equilibrium, but she took her time in getting there.
Intelligence or Natural Selection
The Gaia Theory as originally proposed was criticized by many biologists as appearing to run counter to accepted Darwinian mechanisms of evolution. Particularly natural selection and competition. Plus the idea that the Earth as a whole is intelligent smacked of New Age mysticism, unacceptable to the serious scientist.
In 1981 Lovelock along with several associates created a mathematical model describing Gaia — Daisyworld. It’s easier to explain through animation. The model explains how a diverse community of plant life on the imaginary Daisyworld can control the temperature of that world, using natural selection as required by Darwinian evolution. Gaia is then seen not as a mystical Earth force that maintains biodiversity through divine intervention, but as the collective workings of many organisms, at random. And yet that random behaviour, along with natural selection has the effect of creating that regulatory mechanism. Now Gaia became respectable, something that scientists could talk about without getting laughed at.
While I welcome the development of Gaia, from a hypothesis to an established theory, I feel that the matter of whether or not the planet is a living organism is far from settled. Fine and well if Daisyworld shuts up the Neo-Darwinian sceptics, but that doesn’t make the workings of Gaia less mysterious. Why does life behave as if she had a purpose even though we claim that she doesn’t? Why the progression to complex systems? To consciousness. Biologists hide behind that term, randomness, but no one can explain what it is. Is there such a thing as randomness or it each event unique in its own way? Scientists also struggle with the notion of human consciousness — what it is and whether it is an illusion. Do we describe people as intelligent, capable of choice, or slaves to their brain impulses and chemistry? With so many unanswered questions on the nature of intelligence, do we have the right to say that the Earth is not intelligent? That is has no consciousness, albeit one that is definitely non-human?
The Present Day
The present day concentration of carbon dioxide in our atmosphere (Figure 3) was last this high 50MY ago during the Eocene thermal maximum. It’s not a result of massive volcanism or other natural sources, but a result of human activity — burning of fossil fuels, farming, the destruction of tropical forests. Also, our biological diversity being destroyed at an alarming rate. If Gaia’s role is to preserve the greatest biodiversity, her options are limited. The sun’s luminosity is at an all-time high. Many plants communities that could have absorbed the increased carbon dioxide are gone.
During the Earth’s history Gaia has responded to a higher concentration of greenhouse gases by raising the Earth’s temperature. This appears to be happening now. Along with a temperature increase (2-5deg C depending on the model), we find a dramatic decrease in the thickness of Arctic ice, glaciers melting, and sea-level rise.There are reports of increased methane release from melting permafrost. There are also serious concerns that gas hydrates (methane in a solid form close to the ocean bottom) may release their methane and drive the Earth’s temperature even higher. Put bluntly, we’re on a course that will result in a warmer Earth, perhaps similar to 50MY ago during the Eocene warm period. Our chances of avoiding such a scenario appear bleak.
If we are headed for a warmer Earth, what should we do now? Drive our Hummers, jet around the globe because tomorrow we die? Is the human race cooked no matter what we do?
No one who has read Gaia’s Children can accuse me of being pollyanish about the current crisis. Personally I don’t have a stomach for political activism, but I respect those who do. Moving our energy generation to a low carbon model that utilizes fewer fossil fuels is probably important, but how soon will that be done? These days, to rely on government action and international agreements to fix things is a bit like waiting for Godot. Not surprisingly, there’s a lot of talk about “hacking the planet” — geoengineering projects such as creating a stratospheric haze to cool down the planet. Lovelock likened geoengineering to putting a kidney patient on dialysis. The side effects are unknown; the cure could turn out to be worse than the disease. At the best, it could buy us a bit of time, but the basic problem remains.
If we cannot stop the changes, perhaps we can alleviate the worst consequences. When global warming kicks in, food production will be a key issue. While I recognize the need for large farms, especially for cereal farming, I believe that the food producion problem must be addressed on the local, community level, through the development of small -scale farming. In the UK most people have forgotten how to grow their own food so that the vitality of the land is preserved. We need to bring back the “dig for success” movement that saw the country through the deprivations of World War Two. Kenya won’t always be there to farm the UK’s vegetables. I believe that the appearance of eco-villages, communities for growing food and the cottagers in Russia are all a positive step and that their proliferation will continue. Hopefully, with appropriate government action more city dwellers will have access to some land, and that the knowledge of how to grow one’s own will spread.
Healing the Earth
In The Revenge of Gaia, Lovelock suggests that Gaia is responding to the travails caused by the human race the way a diseased body responds to a virus, by killing it off, subjecting us to war, famine and disease to cut down our numbers.
I reject that doom-and-gloom interpretation as a callous, self-fulfilling prophecy. We have wounded the Earth badly through our thoughtless behavior, treating the Earth as an inanimate object, there for our exploitation instead of as a living being that demands our respect. Supposing that our mother were lying in a hospital bed with a fever; trying to get well again? Wouldn’t we do everything in our power to provide the environment necessary, the food, water and medicine for her to find healing? At least we’d stick around her bed. What family would poke our mother with needles, hit her or ignore her because, “she’s going to die anyway?” Even when the situation looks hopeless we do our utmost, out of love for the sick mother to care for her. I suggest that we do likewise for our Earth. Stop the harm that we are doing.
In order to act convincingly we must recover our lost relationship with the Earth, a sense of compassion, and an appreciation for her life. The global appearance of eco-villages, garden allotments, the burgeoning nature programs testifies to a growing passion for nature that can only be good. I’ve no doubt that in mysterious ways the Earth responds positively to our caring for her. We may not know the outcome of our care, but we must act, in hope that our Earth will shake her fever and find healing.