Answer:
A greenhouse gas is a gas in the Earth's atmosphere that absorbs and emits infrared radiation, trapping heat within the atmosphere and causing the greenhouse effect. This effect is essential to the Earth's climate and allows life on Earth to thrive, but it can also be amplified by human activities that increase the concentration of greenhouse gases in the atmosphere, leading to global warming and climate change.
The main greenhouse gases in the Earth's atmosphere are:
1. Carbon dioxide (CO2): The most important greenhouse gas emitted by human activities, produced primarily by the burning of fossil fuels like coal, oil, and natural gas.
2. Methane (CH4): Produced by natural sources like wetlands and termites, as well as human activities like agriculture and fossil fuel production.
3. Nitrous oxide (N2O): Produced by natural sources like soils and oceans, as well as human activities like agriculture, fossil fuel combustion, and industrial processes.
4. Fluorinated gases: A group of synthetic gases used in a variety of industrial applications, including refrigeration and air conditioning, that are extremely potent greenhouse gases.
These gases are referred to as greenhouse gases because they trap heat within the atmosphere, acting like the glass walls of a greenhouse. When sunlight enters the Earth's atmosphere, it warms the surface of the planet. Some of this heat is then radiated back out into space as infrared radiation. However, greenhouse gases in the atmosphere absorb this radiation and re-emit it back towards the Earth's surface, trapping the heat and warming the planet.