Glossary term: Greenhouse Effect

Description: The greenhouse effect is a warming of the atmosphere due to the emission of certain gases such as water, methane, and carbon dioxide. Visible light from the Sun reaches the surface of a planet and is re-emitted as infrared radiation. Greenhouse gases trap this infrared radiation within the atmosphere and hence the radiation cannot escape to free space; this makes the planet warmer than it would have been without these gases. Without the greenhouse effect, Earth's temperature would be tens of degrees below 0 degrees Celsius. However, the equilibrium temperature that results from the greenhouse effect is very sensitive to the concentration of greenhouse gases in the atmosphere.

Human-made emissions of greenhouse gases since the beginning of the Industrial Revolution in the 19th century have led to global warming on Earth due to the greenhouse effect.

In certain circumstances, this heating can lead to more greenhouse gases in the atmosphere, causing a runaway greenhouse effect. This is what has happened in the atmosphere of the planet Venus.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".