Wood Romances

In a previous post  (see that post for the cited literature), I calculated ECS from data provided in the Indicators of Global Climate Change for 2025 (IGCC25). I made 4 calculations using  ΔT from two  different baselines (1850-1900 and 1790-1839) and two different means for current temperature (the last 4 years and the last 12 years). I'd like to share again just one of these so I can illustrate how feedbacks amplify a warming signal. These are the values I used that was based on a ΔT = 1.23°C (the difference between 2013-2025 and 1850-1900). ΔT = 1.23°C (HadCRUT5) ΔF = 2.60 W/m² (IGCC25) EEI = 1.12 W/m² (IGCC25) ΔFc = 3.93 W/m² (AR6) Where  ΔF is total forcings since 1850 and  ΔFc is the forcing for doub ling CO2 .  Using these values and the Energy Balance Equation, we can calculate ECS to be: λ = ΔT/(ΔF - EEI) λ = 1.23/(2.60-1.12) = 0.83°C/W/m² ECS = λ*ΔFc = 0.83*3.93 = 3.26°C Notice here that to calculate ECS, we didn't have to quantify any f...

Update (6/6/2025): I edited the text for clarity (especially in the first couple paragraphs), changed g to  g̃ to distinguish the normalized GHE from the acceleration due to gravity,  and added more references with excerpts at the bottom of the post. The Earth's effective temperature - the mean surface temperature of Earth if the atmosphere contained no GHGs but with current albedo can be calculated since we know that ASR (hereafter Fin) =  (1-α)*S/4 and OLR (hereafter Fout) is governed by  εσ*T^4. At equilibrium, ASR = OLR (Fin = Fout). With no greenhouse effect (GHE), the Earth's emission temperature (Te) would be at the surface, meaning that Te = Ts, so we can solve for Te with (1-α)*S/4 = εσ*Te^4 If we solve for Te with a surface emissivity ( ε) o f 0.98 and albedo ( α) of 0.306, we end up with Te = 255.3 K.  So, if the earth had no atmosphere with albedo roughly the same as today, the average surface temperature of the earth would be about  -18°C. ...