Vapor clouds chemical absorption

As such, it is absolutely clear that the chemical composition of the atmosphere as well as the physical characteristics of condensed phase trace species are of leading importance as determinants of climate. A well-known example is the increase in the temperature of the Earth s surface due to the absorption of infrared radiation from the Earth s surface by CO2 in the air (see box). Without CO2, the Earth s surface would be several degrees cooler than at present, depending on cloud cover, water vapor, and other controlling factors. Of course, there is substantial concern over the secular increase of CO2, which will double from its pre-industrial level by the early to mid-twenty-first century. 

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