What is Greenhouse effect?
[[File:Greenhouse Effect (2017 NASA data).svg|thumb|222x222px]] [[File:The green house effect.svg|thumb]] The '''greenhouse effect''' occurs when certain gases in the [[Earth's atmosphere]] (the [[air]] around the [[Earth]]) trap [[infrared radiation]]. This makes the planet become warmer, similar to the way a [[greenhouse]] becomes warmer.<ref>IPCC, 2013: [https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_AnnexIII_FINAL.pdf Annex III: Glossary] [Planton S. (ed)]. In: ''Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change'' Stocker T.F. D. Qin G.-K. Plattner M. Tignor S.K. Allen J. Boschung A. Nauels Y. Xia V. Bex and P.M. Midgley (eds). Cambridge University Press, Cambridge, United Kingdom and New York.</ref> The most important [[greenhouse gas]]es in [[Earth's atmosphere]] are: [[water vapor]], [[carbon dioxide]](CO<sub>2</sub>), and [[methane]]. When there is more greenhouse gas in the air, the air holds more heat. This is why more greenhouse gases cause [[climate change]] and [[global warming]].<ref> {{cite book | title = The Earth's biosphere: evolution, dynamics, and change| author = Vaclav Smil | publisher = MIT Press | date = 2003 | isbn = 978-0-262-69298-4 | page = 107 | url = https://books.google.com/books?id=8ntHWPMUgpMC&pg=PA107}}</ref> The greenhouse effect is natural. It is important for life on Earth. Without the greenhouse effect, the Earth's average temperature would be around {{ndash}}18 or –19 degrees [[Celsius]] (0 or 1 degree Fahrenheit). Earth would be locked in an [[ice age]]. Because of the greenhouse effect, the Earth's actual average temperature is 14 degrees Celsius (57 degrees Fahrenheit). The problem is that recently, the greenhouse effect has become stronger. This is because humans have been burning large amounts of [[fossil fuel]]s, which releases carbon dioxide. Since carbon dioxide is a greenhouse gas, it has [[global warming|caused the planet to warm]] over the p