1. 8.3 Earth’s Climate System
Earth has a global climate system that includes air, land, liquid water, ice, and living things.
The climate system is powered by energy from the Sun.
The Sun emits different types of radiation:
ultraviolet radiation
visible light
infrared radiation
When the Sun’s radiation reaches Earth, some is absorbed (70%) and some is reflected back (30%).
climate system
ultraviolet radiation
infrared radiation
visible light

2. The Balance of Energy on Earth
8.3

3. 8.3 The Balance of Energy on Earth
Warmed soil radiates energy off again (heat).
Earth behaves like the lamp and gravel model:
Earth’s surface absorbs energy from the Sun, gains thermal energy, and warms up.
Earth’s warm surface emits infrared radiation back out.
The amount of energy Earth’s system absorbs from the Sun equals the amount of energy radiated by Earth’s system. As a result, Earth’s global temperature stays fairly constant.
thermal energy

4. 8.3 The Balance of Energy on Earth
The complete picture includes energy radiated by the Sun and energy radiated by Earth.
There is a balance of energy on Earth.

5. 8.3 Latitude and Climate Zones
Latitude is a measure of distance from the equator.
Recall that latitude is one of the factors affecting climate zones.
The climate is warmer at lower latitudes (close to the equator) and colder at higher latitudes (far from the equator).
Near the equator, the Sun’s energy is more direct and is spread out over a smaller area. It is therefore more intense.
Near the equator, the Sun’s energy passes through less of the atmosphere. Less energy is absorbed by the atmosphere, and more reaches Earth’s surface.