The radiative forcing due to clouds and water vapor

From “The radiative forcing due to clouds and water vapor V. Ramanathan and Anand Inamdar
Center for Atmospheric Sciences, Scripps Institution of Oceanography,
As the previous chapters have noted, the climate system is forced by a number of factors, e.g., solar impact, the greenhouse effect, etc. For the greenhouse effect, clouds,
water vapor, and CO2 are of the utmost importance. the data needed to understand two fundamental issues in radiative forcing of climate: cloud forcing and atmospheric greenhouse effect. Clouds  reduce  the  absorbed  solar  radiation  by  48  W  m2 while enhancing the greenhouse effect by 30 W m2 and therefore clouds cool the global surface–atmosphere system by 18 W m2 on average. The mean value of C is several times the 4 W m2 heating expected from doubling of CO2 and thus Earth would probably be substantially warmer without clouds.”
I take these authors to be saying that clouds and water vapor should be considered in Radiative Forcing, not ignored. That they give a negative feedback according to the best science has to offer and that this needs to be taken into account in assessing ECS.
How long something resides in the atmosphere is different to how much stuff is residing at any one time in the atmosphere which is the basis on which RF of the atmosphere needs to be assessed.
Just asserting one can ignore it does not mean one can ignore it.


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