The greenhouse effect is the heating of the surface of a planet or moon due to the presence of an atmosphere containing gases that absorb and emit infrared radiation.Greenhouse gases are almost transparent to solar radiation but strongly absorb and emit infrared radiation. Thus, greenhouse gases trap heat within the surface-troposphere system. This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection. The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.
In the absence of the greenhouse effect and an atmosphere, the Earth’s average surface temperature of 14 °C (57 °F) could be as low as 18 °C (0.4 °F), the black body temperature of the Earth. Anthropogenic global warming (AGW), a recent warming of the Earth’s lower atmosphere as evidenced by the global mean temperature anomaly trend, is believed to be the result of an “enhanced greenhouse effect” mainly due to human-produced increases in atmospheric greenhouse gases.