The atmosphere is a dynamic system that is continuously changing, and provided with a number of active subsystems. Carbon dioxide is of great interest to meteorologists because it is an efficient absorber of energy emitted by Earth and thus influences the heating of the atmosphere. The precise impact of the increased carbon dioxide is difficult to predict, but most atmospheric scientists believe that it will bring about the warming of the lower atmosphere and thus will trigger global climate change. The cornerstone of the standard atmosphere is a defined variation of temperature with altitude, based on experimental evidence. All atmospheric parameters like temperature, pressure, etc., could be measured at any altitude and location through flight test by using an appropriate measurement device. Although these are parameters of meteorology, both the pilot and the aircraft performance engineer must be familiar with atmospheric conditions for a safe flight.