Major purpose of this lecture is to present on What is the source of Earth’s Energy. Energy is transferred between Earth’s spheres, but it is not created or destroyed. Any addition of energy to one sphere must be balanced by an equal subtraction of energy from another sphere. The movement of energy through Earth’s system forms an energy budget. When Earth’s energy flow is balanced, global temperatures stay relatively stable over long periods of time. Sometimes, changes in the system cause Earth’s energy budget to become unbalanced.