The Ozone Hole and Petroleum Release
The atmosphere can be divided into four layers based on temperature variations. The closest layer to the Earth is called the troposphere and it extends from Earth's surface up to 7 km (23,000 ft) at the poles, and about 17-18 km (56,000 ft) at the equator. Above this layer is the stratosphere which extends from the top of the troposphere to about 50 km (32 mi; 170,000 ft). The upper boundary between troposphere and stratosphere is known as the tropopause. Temperature variations in the four layers are due to the way solar energy is absorbed as it moves downward through the atmosphere. The Earth’s surface is the primary absorber of solar energy. Some of this energy is reradiated by the Earth as heat, which warms the overlying troposphere. The global average temperature in the troposphere rapidly decreases with altitude until the tropopause, the boundary between the troposphere and the stratosphere.
The temperature begins to increase with altitude in the stratosphere. This warming is caused by a form of oxygen called ozone (O3) absorbing ultraviolet radiation from the sun. Ozone protects us from most of the sun’s ultraviolet radiation, which can cause cancer, genetic mutations, and sunburn. Scientists are concerned that human activity is contributing to a decrease in stratospheric ozone. Nitric oxide, which is the exhaust of high-flying jets, and chlorofluorocarbons (CFCs), which are used as refrigerants, may contribute to ozone depletion.
At the stratopause, the temperature stops increasing with altitude. The overlying mesosphere does not absorb solar radiation, so the temperature decreases with altitude.
At the mesopause, the temperature begins to increase with altitude, and this trend continues in the thermosphere. Here solar radiation first hits the Earth’s atmosphere and heats it. Because the atmosphere is so thin, a thermometer cannot measure the temperature accurately and special instruments are needed. At the same time, it is all too clear that humans and other constituents of the biosphere affect environment significantly. Human activities during the last century involving particularly landscape modification, resource exploitation and effluent flow have reached sufficient magnitude as to bring unpredictable effects on eco-system. These anthropogenic changes have raised many serious global environmental issues, particularly the destruction of earth's protective stratospheric ozone layer by manmade chemicals like chlorofluorocarbons (CFCs), halons (H), carbon-tetrachloride (CTC), 1,1,1-Trichloro-ethane (TCA), methyl-bromide etc.
Ozone Depletion effects
The major effect of the stratospheric ozone depletion is an increase in the amount of Ultraviolet Beta radiations (290-320 nm) reaching the biosphere. This increase in solar Ultraviolet Beta radiation has potential impacts on the biosphere, human health and natural eco-systems, both aquatic and terrestrial, and agriculture (UNEP...