Introducing Planet Earth: Three Principles

Three Principles

	MATTER CYCLES
	Each of the elements that is vital for life exists on Earth in a closed loop of cyclical changes. From a systems point of view, Earth is essentially a closed system with respect to matter.

	ENERGY FLOWS
	The functioning of our planet relies on a constant input of energy from the sun. This energy leaves Earth in the form of heat flowing to outer space. From a systems point of view, Earth is an open system with respect to energy.

	LIFE WEBS
	A vast and intricate network of relationships connects all Earth's organisms with each other and with the cycles of matter and the flows of energy. From a systems point of view, Earth is a networked system with respect to life.

These three principles can help us understand essentially all environmental issues. When we confront an environmental issue, we should first explore the roles of matter, energy and living organisms. Where does the matter (carbon, water, pollutant) come from and where does it go? Does the issue involve changes to our planet's energy flows? How do plants, animals and microorganisms influence the issue and how are they affected by it? As a result of answering these kinds of questions, we will discover that the three guiding principles provide an organizing framework that makes common sense out of complicated issues.