.... They depend upon the tolerances of the organisms themselves. All life forms have a lower, an upper, and an optimum temperature for growth and the same is true for acidity, salinity, and the abundance of oxygen in the air and water. Consequently organisms have to live within the bounds of these properties of the environment.
Evidence... shows the Earth's crust, oceans, and air to be either directly the product of living things or else massively modified by their presence. Consider how the oxygen and nitrogen from the air come directly from plants and microorganisms and how the chalk and limestone rocks are the shells of living things once floating in the sea.
- The goldilocks property
- The kudzu property
- Darwinian natural selection
- Life's ability to change its environment
Gaia is an evolving system, a system made up from all living things and their surface environment, the oceans, atmosphere, and crustal rocks, the two parts tightly coupled and indivisible. It is an 'emergent domain' – a system that has emerged from the reciprical evolution of organisms and their environment over eons of life on Earth. In this system the self-regulation of climate and chemical composition are entirely automatic. Self- regulation emerges as the system evolves. No foresight, planning, or teleology are involved.
I argued that if there was life on Mars it would have to use the atmosphere as a source of raw materials and as somewhere to deposit its wastes; this would change the atmosphere's composition and make it recognizably different from a dead planet.
.....to see the Earth from space forces questions about the composition of the air we breathe not previously asked.
......Why is everything on our planet so comfortable and well suited for life? .......The air is a mixture that almost always keeps constant in composition. My flash of enlightenment that afternoon was the thought that to keep constant something must be regulating it and that somehow the life on the surface was involved.
.....Our task as individuals is to think of Gaia first. In no way does this make us inhuman or uncaring; our survival as a species is wholly dependent on Gaia and on our acceptance of her discipline.
The climate crisis also offers us the chance to experience what very few generations in history have had the privilege of knowing – a generational mission; the exhilaration of compelling moral purpose; a shared and unifying cause. The thrill of being forced by circumstances to put aside the pettiness and conflict that so often stifle the restless human need for transcendence, the opportunity to rise...
It is about who we are as human beings. It is about our capacity to transcend our own limitations, to rise to the new occasion, to see with our hearts, as well as our heads, the response that is now called for. This is a moral, ethical, and spiritual challenge.We should fear this challenge. We should welcome it. We must not wait. In the words of Dr. King, “tomorrow is today.”