Glossary · Khoa học Trái Đất
Greenhouse effect
The process in which greenhouse gases, clouds and some aerosols in the atmosphere absorb infrared radiation given off by a planet's surface, so less heat escapes to space and the surface stays warmer. Earth's natural greenhouse effect keeps the planet warm enough for life.
The IPCC defines the greenhouse effect as the infrared radiative effect of all infrared-absorbing constituents in the atmosphere. These substances absorb radiation emitted by Earth's surface and by the atmosphere, then emit infrared radiation in all directions. Because temperature falls with height in the troposphere, the amount of radiation that escapes to space is normally less than it would be without these absorbers.
Greenhouse gases include water vapour, carbon dioxide (CO₂), methane, ozone, nitrous oxide (N₂O) and chlorofluorocarbons (CFCs). Without the natural greenhouse effect, Earth's surface would be much colder than it is today.
Raising the concentration of greenhouse gases strengthens the effect; the added part is sometimes called the enhanced greenhouse effect. According to NASA and the IPCC, the carbon dioxide and other greenhouse gases released by human activity, mainly the burning of fossil fuels, have disrupted Earth's energy balance and are driving temperatures up.