The greenhouse effect
Without The gases responsible for global warming - carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons). in its The layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide., the Earth would be about 32掳C colder on average than it is now. Greenhouse gases:
- absorb heat radiated from the Earth
- then release The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. in all directions, which keeps the Earth warm
An example of greenhouse gases are carbon dioxide, methane and water vapour.
Electromagnetic radiation with a wavelength longer than visible light. from the Sun is only partly absorbed by the Earth. The rest is radiated into the atmosphere. Although some of the infrared radiation escapes, some is absorbed by greenhouse gases. This keeps the energy in the atmosphere, warming it up. This gradual warming of the atmosphere over many years is referred to as The rise in the average temperature of the Earth's surface. .
The diagram gives more details about this process. It is called the The retention of heat in the atmosphere caused by the build-up of greenhouse gases..