By far, the strongest greenhouse gas is water vapor, not because it is very strong of itself, but it absorbs nearly all outgoing energy in the infrared spectrum except in the so called atmospheric window, where it only partially absorbs. Yet water vapor is missing from the IPCC calculations. instead they put in a forcing multiplier to account for the addition of water.
IPCC has consistently treated the effect of greenhouse gasses as additive, but it is impossible to absorb more than 100% of all emitted energy for a given wavelength. This leads to an overestimation of absorption when 2 or more gasses are present. For example, if CO2 absorbs 90% of available energy at 13 μm and water vapor another 50%, the sum is 90% + (1 -0.9} * 0.5 = 95%, not 140%.
Between 2022 and 2050 CO2 concentration is expected to increase from 415 ppm to 460 ppm and Methane from 1.9 ppm to 2.23 ppm. these are the most important greenhouse gasses except water vapor.
Summary of all greenhouse effect causes for temperature rise from 2022 until 2050:
Effect from water vapor increase: 0.13 C or 0.62 W/m2;
Effect from rising CO2: 0.025C or 0.12 W/m2;
Effect from rising Methane: 0.02C or 0.08 W/m2,
Effect from rising N2O: 0.004C or 0.02 W/m2
Effect from rising Ozone: 0.0011C or 0.005 W/m2
Effect from rising HFCs : 0.0060 C or 0.027 W/m2
TOTAL TEMPERATURE CHANGE 2022 to 2050: 0.1861C or 0.8720 W/m2
Summary of all non-greenhouse effect causes for climate change from 2022 to 2050:
Long term warming of the sun: 0.0000005C
Temperature decrease from the Milankovitch cycle: – 0.011 C or 0.05 W/m2
Temperature decrease from changing solar spot activity – 0.007 C or 0.021 W/m2
Temperature rise from decreasing cloud cover of 0.05 C or 0.24 W/m2.
Change from temperature rise of the Arctic 0.05 C or 0.24 W/m2
Pollution aerosols cause a temperature decrease of – 0.05 C or 0.24 W/m2
Temperature increase from greening of the earth 0.0035C or 0.017 W/m2
Temperature decrease from areas of desertification – 0.0008C or 0.004 W/m2.
TOTAL TEMPERATURE RISE FROM OTHER THAN GREENHOUSE GASES FROM 2022 to 2050: 0.0363 C or 0.182 W/m2
TEMPERATURE CHANGE FROM 2022 TO 2050 FROM ALL CAUSES: 0.2224 C or 1.054 W/m2
Summary of all causes for climate change from now until 2050:
Long term warming of the sun: 0.000005C
Effect from the potential Eddy Grand Solar minimum: 0 to – 1C. Yes,that’s cooler
Effect from the Milankovitch cycles: – 0.0135C
Effect from reversing the magnetic poles: undetermined.
Direct effect from rising CO2: 0.025C
Effect from increasing CO2 increasing water vapor : 0.03 C
All other greenhouse gasses combined 0.032 C
Temperature rise from decreasing cloud cover 0.27C
Temperature increase from greening of the earth 0.063C
Temperature decrease from areas of desertification 0.0015C
TOTAL TEMPERATURE CHANGE 2023 to 2050: 0.384 C rise to 0,616 C decrease if the Dodd grand solar minimum occurs
The temperature data from 1980 to 2022 is the control group, and is based on real data.It was then the basis for doing the 2022 to 2050 calculation assuming no mitigation efforts, the most likely result if none of the Paris accord is implemented. The climate target is to stay under + 1.5 C, and this model, that worked better than 95% accurate between 1980 and 2022, comes up with a temperature rise of 1.28C, well below the 1.5C maximum rise since the late 1800s