A number of posters have continued to state, with various degrees of smarmy smirkiness, that the 'warmers' never take clouds and water vapor into account. Besides once again demonstrated their incredible ignorance, they sometimes spread doubt among those that have not researched the subject. So, here is a chapter from a text on the subject by a leading expert in the field of climatology. http://www-ramanathan.ucsd.edu/FCMTheRadiativeForcingDuetoCloudsandWaterVapor.pdf 5.1 Introduction 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 emergence of computers as a viable scientific tool in the 1960s in conjunction with the availability of spectroscopic data enabled us to treat the numerous complexities of infrared-radiative transfer in the atmosphere. While such calculations set the stage for estimating accurately (decades later in the 1990s) the radiative forcing due to greenhouse gases and clouds, they did not yield the necessary insights into the physics of the problem nor did they yield any explanation of the relevant phenomenon. Such insights needed physically based analytic approaches to the problem. It is in this arena that Dr. Robert Cess excelled and provided the community with important insights into numerous radiative processes in the atmosphere of Earth and other planets including Mars, Venus, Jupiter, and Saturn. A few examples that are relevant to the main theme of this chapter are given below.