Modern climate change

Greenhouse Effect

Not all of the radiation emitted by the earth's surface escapes to space. The longwave radiation interacts with gases and water in the atmosphere on its way out. The interactions with gases cause them to vibrate. Let's take a look at how it works in the diagram at the right.

The important greenhouse gases in the atmosphere are:

• water vapor (H20)
• methane (CH4)
• carbon dioxide (CO2)
• nitrous oxide (N20)

These molecules absorb thermal infrared radiation - which also happens to be the radiation emitted by the earth's surface. Some wavelengths emitted from the surface escape to space, but others are absorbed by the greenhouse gases. The re-emission of energy from these gases heats up the atmosphere and keeps the earth at a "liveable" temperature.

Back to climate topics

Links and resources