Effective temperature: Difference between revisions

The actual temperature of Earth's surface is an average {{cvt|288|K|°C|0}} as of year 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> One reason for theThe difference between the two values is called the atmospheric ''[[greenhouse effect]]''. The greenhouse effect involves materials ([[greenhouse gas]]es and clouds) in the atmosphere absorbing thermal radiation, whichreducing thermal emissions to space, i.e., hindersreducing 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 288K Earth. Furthermore, these values calculate an outgoing thermal radiation flux of 238&nbsp;W m{{sup|-2}} (with ε=0.61 as viewed from space) versus a surface thermal radiation flux of 390&nbsp;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}}