The Earth System is the collection of interconnected biological, chemical, and physical subsystems that store, transform, or transfer energy and matter on our planet. In simple terms: the Earth System is the name given to the whole collection of smaller systems (water, air, life, and rocks) that are mutually affected by one another.
The four basic subsystems of the Earth System are:
1. The Geosphere – the rock and rocky materials that make up the Earth’s crust.
2. The Atmosphere – the layer of gases that surround the Earth.
3. The Hydrosphere – the total water on the Earth including liquid water, ice and snow, water vapour and water that is beneath the surface.
4. The Biosphere – the interrelated global ecosystem or web of all things alive.
Some other subsystems sometimes explored by earth systems scientists include the pedosphere, magnetosphere, and cryosphere.
What about Us?
The human system is a subsystem of the biosphere. We are made of the same stuff as all other living things on the Earth. Not only are we made of the same stuff, but we are woven into the same tapestry. We consume organic matter to live and are consumed by organic matter when we die.
Pull a string anywhere in the biosphere and you can bet we unravel a little too. In recent years our population has increased dramatically. Consequently, our economic activities and living preferences have begun to disrupt the previously balanced cycles that exists between the hydrosphere-atmosphere-biosphere-geosphere (carbon cycle, nitrogen cycle, etc). We are also contaminating the Earth System with unnatural (man-made) materials and reducing the biodiversity of life as we clearcut wild spaces to suit our desire for growth.
A clear understanding of the closed nature of the whole Earth System and the dynamic exchanges that occur between its subsystems is critical for designing human activity that can exist sustainably within the Earth’s boundaries. Fortunately, along with our boom in population and economic activity we have also grown in our ability to create useful prediction tools such as climate models. We now have an in depth understanding of the importance of the principles of conservation.
An interesting theory, The Gaia Hypothesis, first postulated by James Lovelock, can help us to further understand the interrelatedness of the systems of the Earth. It suggests that the collective organic components (biosphere) of the Earth have evolved in such a way that they can affect and adjust the inorganic components so as to maintain the parameters within the Earth System that are most conducive to life. Through his research, Lovelock was able to produce compelling evidence to support his theory. He showed evidence of the biosphere reactively regulating atmospheric gasses important to living beings (oxygen, methane, carbon dioxide, etc.). Similarly, air temperature, ocean alkalinity, and other environmental factors can also be shown to be regulated by life.
As we face the great challenge and ethical responsibility of modifying our societies to fit sustainably within the closed system of the Earth, the most critical question of our time seems to be whether or not the natural processes in place, such as evolution and the adaptive functions of the biosphere, can keep pace with the rapid changes that we are inflicting on our Earth System.