Editing Radiative forcing (section)

== Uses ==
[[File:ESSD Radiative Forcing 1750 to 2022.png|thumb|300px|An assessment of effective radiative forcings in 2022 using a baseline year of 1750.<ref>{{cite journal |last1=Forster |first1=Piers M. |last2=Smith |first2=Christopher J. |last3=Walsh |first3=Tristram |display-authors=et al. |title=Indicators of Global Climate Change 2022: annual update of large-scale indicators of the state of the climate system and human influence |journal=Earth System Science Data |number=15 |pages=2295–2327 |year=2023 |volume=15 |doi=10.5194/essd-15-2295-2023 |doi-access=free|bibcode=2023ESSD...15.2295F |hdl=20.500.11850/625497 |hdl-access=free }}</ref>]]

=== Climate change attribution ===
{{main|Causes of climate change}}

Radiative forcing is used to quantify the strengths of different natural and man-made drivers of Earth's energy imbalance over time. The detailed physical mechanisms by which these drivers cause the planet to warm or cool are varied. Radiative forcing allows the contribution of any one driver to be compared against others.

Another metric called ''effective radiative forcing'' or ERF removes the effect of rapid adjustments (so-called "fast feedbacks") within the atmosphere that are unrelated to longer term surface temperature responses. ERF means that climate change drivers can be placed onto a more level playing field to enable comparison of their effects and a more consistent view of how [[global surface temperature]] responds to various types of human forcing.<ref name="Nauels-2019" />

=== Climate sensitivity ===
{{main|Climate sensitivity}}

Radiative forcing and climate feedbacks can be used together to estimate a subsequent change in steady-state (often denoted "equilibrium") surface temperature (Δ''T''<sub>s</sub>) via the equation:

: <math>\Delta T_s =~ \tilde{\lambda}~\Delta F</math>

where <math>\tilde{\lambda}</math> is commonly denoted the [[climate sensitivity]] parameter, usually with units K/(W/m<sup>2</sup>), and Δ''F'' is the radiative forcing in W/m<sup>2</sup>.<ref>{{cite web |title=IPCC Third Assessment Report - Climate Change 2001 |url=http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/222.htm |url-status=dead |archive-url=https://web.archive.org/web/20090630133202/http://www.grida.no/publications/other/ipcc_tar/?src=%2Fclimate%2Fipcc_tar%2Fwg1%2F222.htm |archive-date=30 June 2009}}</ref> An estimate for  <math>\tilde{\lambda}</math> is obtained from the inverse of the [[climate change feedback|climate feedback]] parameter <math>\lambda</math> having units (W/m<sup>2</sup>)/K. An estimated value of <math>\tilde{\lambda}\approx0.8</math> gives an increase in global temperature of about 1.6 K above the 1750 reference temperature due to the increase in {{CO2}} over that time (278 to 405 ppm, for a forcing of 2.0 W/m<sup>2</sup>), and predicts a further warming of 1.4 K above present temperatures if the {{CO2}} mixing ratio in the atmosphere were to become double its pre-industrial value. Both of these calculations assume no other forcings.<ref>{{cite web |title=Atmosphere Changes |url=http://www.epa.gov/climatechange/science/recentac.html |url-status=dead |archive-url=https://web.archive.org/web/20090510053004/http://www.epa.gov/climatechange/science/recentac.html |archive-date=10 May 2009}}</ref>

Historically, radiative forcing displays the best predictive capacity for specific types of forcing such as greenhouse gases. It is less effective for other anthropogenic influences like [[soot]].<ref name="Nauels-2019">{{Cite journal |last1=Nauels |first1=A. |last2=Rosen |first2=D. |last3=Mauritsen |first3=T. |last4=Maycock |first4=A. |last5=McKenna |first5=C. |last6=Rogelj |first6=J. |author6-link=Joeri Rogelj |last7=Schleussner |first7=C.-F. |last8=Smith |first8=E. |last9=Smith |first9=C. |date=2019-12-02 |title=ZERO IN ON the remaining carbon budget and decadal warming rates. The CONSTRAIN Project Annual Report 2019 |url=https://eprints.whiterose.ac.uk/154082/8/CONSTRAIN-Zero%20In%20On%20The%20Remaining%20Carbon%20Budget%20%26%20Decadal%20Warming%20Rates-Full.pdf |language=en |doi=10.5518/100/20 |archive-url=https://web.archive.org/web/20191209110854/https://constrain-eu.org/ |archive-date=2019-12-09 |access-date=2020-01-20 |website=constrain-eu.org}}</ref>