Earth’s Energy Budget

Earth’s Energy Source The Sun is the source of Earth’s energy Most of the Sun’s energy is in the form of visible light

Earth’s energy balance Just like a family’s financial budget, a stable energy budget must be balanced: Energy In = Energy Out The energy coming in from the Sun should equal the energy leaving Earth (going back out into space)

Incoming Sunlight About 30% is reflected directly back to space this % is called albedo Some is reflected by clouds and the atmosphere A little is reflected from Earth’s surface e.g., bright snow-covered areas About 70% is absorbed by Earth and heats it up

Radiated energy Most incoming sunlight is radiated back out as heat to space Radiation means releasing heat in waves or particles Some heat is trapped by water and other gases in the atmosphere and is sent back to the surface This is the greenhouse effect

The greenhouse effect

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