(Click on any image to enlarge.) In the sciences, Earth's anatomy and physiology (i.e., its physical components, and how those components function and interact) is generally divided into four broad areas of study called spheres:
- the hydrosphere, which describes the combined mass and behavior of water found on, under and over the surface of the planet;
- the atmosphere, the layer of gases surrounding the planet and retained by Earth's gravity;
- the lithosphere, the rigid outer shell of our rocky planet, which includes the crust (the outermost shell) and the mantle (the predominantly solid but more viscous layer lying between the crust and the planet's molten outer core);
- the biosphere, the global sum of all ecosystems -- the zone of life on Earth.
Earth's spheres include half a dozen other subsystems, perhaps the most fascinating of which is the anthroposphere, "that part of the environment which is made or modified by humans, for use in human activities and human habitats." Given a moment's reflection, one quickly realizes that the anthroposphere now includes nearly every molecule of matter and life accessible to the surface of the planet -- and much that lies beneath the surface. This is a heady prospect, but it also is freighted with a high cost. With power comes responsibility. Our responsibility to ourselves, to all other life forms on the planet, and to future generations of living organsisms, can be summed up in one word -- stewardship. It is incumbant upon us as powerful, sentient and self-aware beings to assume the mantle of caring for all things less powerful, less sentient, or less self-aware.
In thinking about our relationship to the planet, I find it useful to think in terms of animism, "the set of philosophical, religious, and/or spiritual beliefs that souls or spirits exist not only in humans, but also in all other animals, plants, rocks, natural phenomena such as thunder, geographic features such as mountains or rivers, or other entities of the natural environment." While I am not a religious person, nor a New Age freak, as a scientist I do not discount the possibility that natural forces or influences we do not yet understand may operate in the world.
Writer and scientist Arthur C. Clarke famously said, "Any sufficiently advanced technology is indistinguishable from magic." Similarly, any natural process which we have not yet come to perceive or understand, may be dismissed as nonexistent. We humans tend to let our own preconceptions get in the way of wrapping our imaginations around the clues before us. Animism is for me a form of lateral thinking, a thought experiment which allows me to perceive the world in a new light. Whether souls or spirits actually exist, I do not know. I prefer to focus on phenomena for which there is credible evidence, but we all know that over human history, evidence often takes time to accumulate.
In the meantime, the evidence is overwhelming that our activities in the anthroposphere are destructive to other life forms, and ultimately to our own survival. Too few of us have donned the mantle of stewardship. Even if all of the nearly seven billion people on Earth did so, the question remains, is it too late? Over a thousand species go extinct every year. How soon before that list includes homo sapiens?