Editing Effective temperature (section)

===Earth effective temperature===
{{see also|Stefan–Boltzmann law#Effective temperature of the Earth}}

Earth has an albedo of about 0.306 and a [[solar irradiance]] ({{mvar|L / 4 π D<sup>2</sup>}}) of {{nowrap|1361 W m{{sup|−2}}}} at its mean orbital radius of 1.5×10<sup>8</sup>&nbsp;km. The calculation with ε=1 and remaining physical constants then gives an Earth effective temperature of {{cvt|254|K|°C|0}}.<ref>{{cite web|url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html|title=Earth Fact Sheet|website=nssdc.gsfc.nasa.gov|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20101030234253/http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html|archive-date=30 October 2010}}</ref>

The actual temperature of Earth's surface is an average {{cvt|288|K|°C|0}} as of 2020.<ref>{{cite web |url=https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature |title=Climate Change: Global Temperature |publisher=NOAA |accessdate=6 July 2023}}</ref> The difference between the two values is called the ''[[greenhouse effect]]''. The greenhouse effect results from materials in the atmosphere ([[greenhouse gas]]es and clouds) absorbing thermal radiation and reducing emissions to space, i.e., reducing the planet's emissivity of thermal radiation from its surface into space. Substituting the surface temperature into the equation and solving for ε gives an [[Emissivity#Effective emissivity due to atmosphere|effective emissivity]] of about 0.61 for a 288&nbsp;K Earth. Furthermore, these values calculate an outgoing thermal radiation flux of {{nowrap|238 W m{{sup|−2}}}} (with ε=0.61 as viewed from space) versus a surface thermal radiation flux of {{nowrap|390 W m{{sup|−2}}}} (with ε≈1 at the surface). Both fluxes are near the confidence ranges reported by the [[IPCC]].<ref>{{Cite book  |ref={{harvid|IPCC AR6 WG1|2021}}
 |author= IPCC |author-link= IPCC
 |year= 2021
 |title= Climate Change 2021: The Physical Science Basis
 |series= Contribution of Working Group I to the [[IPCC Sixth Assessment Report|Sixth Assessment Report]] of the Intergovernmental Panel on Climate Change
 |display-editors= 4
 |editor1-first= V.     |editor1-last= Masson-Delmotte
 |editor2-first= P.     |editor2-last= Zhai
 |editor3-first= A.	|editor3-last= Pirani
 |editor4-first= S. L.  |editor4-last= Connors
 |editor5-first= C.     |editor5-last= Péan
 |editor6-first= S.     |editor6-last= Berger
 |editor7-first= N.     |editor7-last= Caud
 |editor8-first= Y.     |editor8-last= Chen
 |editor9-first= L.     |editor9-last= Goldfarb
 |editor10-first= M. I. |editor10-last= Gomis
 |publisher= Cambridge University Press (In Press)
 |place= 
 |isbn= 
 |url= https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Full_Report.pdf
}}</ref>{{rp|934}}