The greenhouse effect refers to a change in the temperature of the Earth caused by the presence in the atmosphere of gases that absorb and emit radiation. They include water vapor, carbon dioxide and methane. They warm the atmosphere by absorbing infrared radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds. As a result the atmosphere radiates thermal infrared to the Earth’s surface. Thus, greenhouse gases trap heat in the surface of the planet.
The sun emits infrared radiation towards the Earth which is then bounced back into space, greenhouse gases absorb the escaping heat and send it back to the Earth’s surface, thereby causing an increase in surface temperatures. Hence, the greenhouse effect, that is, the trapping and accumulation of the sun's heat within the layer of the atmosphere closest to the Earth’s surface, is responsible for global warming, the increase in global surface temperatures.
4. Download the U4energy questionnaire, an initiative funded through the Intelligent Energy Europe programme.
This questionnaire has been filled in by pupils and teachers participating to the U4energy competition period in order to monitor the development of awareness and practice with regard to energy use. The questionnaire can also help to discuss and debate in the classroom and inspire in the setting up of an energy saving plan.