Greenhouse gas Greenhouse gas A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone. Without greenhouse gases, the average temperature of Earth's surface would be about , rather than the present average of . The atmospheres of Venus, Mars and Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have produced a 40% increase in the atmospheric concentration of carbon dioxide (), from 280 ppm
Greenhouse effect heated) "greenhouse" with a cover of rock salt (which is transparent to infrared) heats up an enclosure similarly to one with a glass cover. Thus greenhouses work primarily by preventing convective cooling. Heated greenhouses are yet another matter, having an internal source of heating they leak heat out, which must be prevented. So it again makes sense to try to prevent radiative cooling through the use of adequate glazing. The anti-greenhouse effect is a mechanism similar and symmetrical to the greenhouse effect: greenhouse effect is about atmosphere letting radiation in, while not letting thermal radiation out, which warms the body