Jet Plane Traffic Enhancing Global Warming

At each point on the surface of the earth, as we go up in altitude the temperature drops. As the altitude increases, at some point this temperature-decrease stops, that point is called the tropopause. The earth's avarage temperature at ground or sea level is about 16$^{0C}$, it drops to an average temperature of about $- 65^{0C}$ at the tropopause. The height of the tropopause varies from about 16 kilometers over the equator to about 10 kilometers over the north and south poles. The layer of air between the ground or sea level and the tropopause is called the troposphere. All the earth's weather (water vapor, clouds, rain, snow) occurs in the troposphere. The next layer of air above the troposphere is called the stratosphere, it begins with the tropopause and ends at its upper boundary called the stratopause at an altitude of about 48 kilometers. Within the troposphere the temperature of the air decreases as the altitude increases. In the stratosphere the temperature of the air increases with altitude (from about $- 65^{0C}$ at the tropopause to about $- 2^{0C}$ at the stratopause). The change of the temperature gradient with respect to the altitude from negative values to positive values beginning at the tropopause is called temperature inversion. The stratosphere is nearly cloudless and mostly very dry. By the time we reach the stratosphere, almospheric pressure drops to about 9 m.b., less than 1% of the atmospheric pressure of 1013 m.b. at sea level. So the air in the stratosphere is highly rarified. That's why when jet planes fly in the stratosphere, they encounter very little air resistence, and fuel consumption goes down significantly. Hence most jet planes are flown in the stratosphere as far as possible. In spite of this, a commercial jet planes burns 8 times as much fuel per passenger mile as a public transport land vehicle like a bus $[ 5 ]$. Each flying jet plane spews large quantities of green house gases all along its flight path in its exhausts. Since the atmospheric pressure there is low, the air composition changes easily even with the introduction of small quantities of external materials. Besides, there is no vegetation or water vapor in the stratosphere to absorb the $CO_2$, so it remains there until it descends into the troposphere. $CO_2$ released in the stratosphere takes many years before it descends to the troposphere due to the temperature inversion at the troposphere-stratosphere boundary. Because of this, the increasing jet plane traffic is causing the percentage of $CO_2$ in the stratosphere to be higher than that in the whole atmosphere. This results in enhancing global warming. Plane travel is going up very rapidly all over the world, since people find its higher speed very convenient. The price of this convenience is enhanced global warming.