As people looked at growing environmental problems, many have taken to blaming humanity for everything that is currently wrong on the planet. As the human population grew and our thirst for energy and materials grew along with it, many came to the conclusion that humans were an evil and destructive species. They concluded that humans were a cancer on the planet. The only way to save Earth was to remove most of the Earth's population, return to a pre-industrial (or primitive) way of life, or to become extinct.
How depressing. And people wonder why people have become cynical and nihilistic. As much as I like the Gaian Hypothesis, I don't like the conclusions many have drawn from it. I like to take a different view of the matter, one that was hinted at by the author of The Millennial Project, and one expressed by many other space enthusiasts and space activists. What if humans were evolved for a purpose? As much destruction as we have caused, Gaia might have evolved humanity to become agents of its creation. If Gaia is a living organism, then we should expect that it will do what all organisms do. Gaia will die whether or not humans are the cause of its demise. It may happen tomorrow, or maybe not for billions of years. The only way to "escape" it is to reproduce. That is the idea of the Pregnent Mother Earth metaphor. By evolving an intelligent and "handy" species, Gaia has evolved a reproduction system. As it stands, humanity is the only species with the ability to travel from Earth and into space, and is thus the only means for the transmission of life into space.
In the Pregnant Earth metaphor, Gaia is increasingly sick because she is pregnant with humans. As David Buth explains it,
space colonies are like children (a fetus right now)
the biosphere is like a pregnant woman
humanity is like the biosphere's reproductive system
A pregnant woman experiences unsustainable growth in her abdomen, specifically in the reproductive organs. Imagine how frightening this would be if you didn't know about pregnancy. Similarly, the Earth is experiencing unsustainable growth of the human population -- which in our metaphor is Mother Earth's reproductive system.
A pregnant woman experiences changes in her body chemistry. Similarly, the biosphere is experiencing changes in air and water chemistry as a result of man-made pollution.
Pregnancy and birth, particularly before the advent of modern medicine, can be a very dangerous time for a woman. Death of the mother and/or the child was once quite common. Similarly, nuclear weapons, pollution, and other problems threaten civilization (although the biosphere has survived much worse).
A wise woman treats her body with extra care during pregnancy -- eating well, getting plenty of sleep, avoiding drugs, and seeking appropriate medical attention. The implications for ourselves are obvious, especially since that there are no experienced doctors or midwives.
Pregnancy has been dangerous in the past, and can still be dangerous today. There have been four outcomes.
In the first one, the mother dies giving birth while the baby survives. The pregnancy was too much for the mother. The child, however, is able to survive the trauma of birth. This is the scenario in which Gaia experiences a catastrophe and dies (or at least experiences a major global extinction event equivalent to the one which killed the dinosaurs 65 million years ago) and the surviving humans settle space, while bring life from Earth into space. Many people have referred to this as the "disposable earth policy." That just because we can settle space, we can do whatever we want to Gaia.
The second outcome is the one in which the the baby dies while the mother survives. There was a miscarriage in which either humans destroyed themselves (through pollution and war) while Gaia survives, or Gaia killed humanity herself when natural disaster (such as the Toba eruption with its near extinction of humanity 75,000 years ago) struck. Either way, human civilization ends, billions die, and the remaining humans revert to primitive living conditions, becoming hunter-gatherers, if they don't become extinct.
In the third outcome, both the mother and the baby don't make it. A massive extinction sweeps across the planet, at least on par with the K/T extinction 65 million years ago that killed the dinosaurs. If humans don't go the way of the dinosaurs, theirs numbers will dwindle until there are perhaps only thousands left. Maybe, Gaia merely got too sick. Or, perhaps, some outside event killed the mother and baby. In this scenario, a stray bullet strikes and kills a pregnant woman. This is also the asteroidal/cometary doomsday scenario.
In the fourth outcome both the mother and baby surviving and thriving. In this scenario, Gaia is healed. Using technology wisely, Gaia is restored to full health while and after giving birth. Technology also enables humanity to enjoy a high standard of living and high quality of live on Earth. Humanity is traveling in space and is settling the solar system. Humans bring Earth life with them into space. Like a huge family, Gaia and her offspring all protect each other from harm, providing comfort to each.
The fourth scenario is by far the best. It is a future that we can definitely still have. A healthy Earth, and her healthy offspring. Settlements in orbit will be the first of her children, with bubbles containing living matter (humans, plants, animals) inside them. Lunar settlements will come next, also with bubbles of life inside of them. Asteroids and comets will be turned into living matter themselves through mining and through settlement in bubbles of life. The outer planets and their moons will host the offspring of Gaia. Gaia will give birth to Aphrodite and Ares with the terraformation of Venus and Mars. Perhaps, humans will enhance their bodies (and other life forms) to live in harsh non-terrestrial conditions.
Humans, realizing that they are perhaps the only ones capable of saving Earth and helping her reproduce, accept a new responsibility to all life. Humans have decided to protect the lifeforms on this planet. They have decided to help life thrive everywhere possible. There are now turtles living in space habitats on the Moon. There are forests on a terraformed Mars. There are fish and Dolphins swimming in the newly formed seas of Venus. There are bears and birds living in closed ecosystem bubbles 50 AU from the Earth in some large habitat in a Kuiper Belt settlement made up of several comets. And some of these life bubbles are moving away from the solar system, and towards the stars. This is the future I want. One with a healthy Earth, and an expanding human presence in space, extending the frontiers for the existence of life.