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
Carbon dioxide in Earth's atmosphere dioxide is often mentioned in the context of its increased influence as a greenhouse gas since the pre-industrial (1750) era. In the IPCC Fifth Assessment Report the increase in CO was estimated to be responsible for 1.82 W·m of the 2.63 W·m change in radiative forcing on Earth (about 70%). The concept of atmospheric CO increasing ground temperature was first published by Svante Arrhenius in 1896. The increased radiative forcing due to increased CO in the Earth's atmosphere is based on the physical properties of CO and the non-saturated absorption windows where CO absorbs outgoing long-wave energy. Atmospheric carbon dioxide