Control and Remedial Measures of Greenhouse Effect, Ozone Layer Depletion, Acid Rain Part 4

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Control and Remedial Measures of Greenhouse Effect

The following measures may be adopted to reduce the ever-increasing greenhouse effect.

  1. CO2 concentration can be reduced by drastic cut in the consumption of fossil fuels in the highly developed and industrialized countries such as USA and Japan and developing country like China and India.

  2. Scientific efforts should be made to develop alternative efficient fuels. Development of hydro-electric and thermal power is better alternatives.

  3. There should be a restriction on the emission of dangerous CO2, CFCs, and as NO2 from the factories and automobiles.

  4. Limiting the driving days in megacities can be another option. Cities like Singapore and Mexico are following the practice.

  5. Biogas plants should be used which is another source of conventional energy for domestic use.

  6. Enhancing afforestation will certainly reduce the CO2 level thereby decreasing the greenhouse effect.

Ozone Layer Depletion

Image of Ozone Layer Depletion

Image of Ozone Layer Depletion

Image of Ozone Layer Depletion

Ozone is a form of oxygen that has three atoms (O3) rather than the more common two atoms (O2). It is created in the upper atmosphere by the action of solar radiation on oxygen molecules. It is found in the form of a thin layer in the stratosphere between 15 to 48 km. About 90% of all atmospheric ozone is found in this layer. Ozone constitutes only less than 0.002 % of the volume of the atmosphere. It strongly absorbs ultraviolet radiation from the sun. Ultraviolet radiation is biologically destructive in many ways. It causes skin cancer and cataracts, suppresses the human immune system, and disrupts the aquatic food chain by killing micro-organisms on the ocean surface.

Certain recent human activities have injected certain chemicals in the stratosphere which consume ozone and reduce its concentration. Depletion is mainly caused by chlorofluorocarbons (CFCs), halons, methyl chloroform and carbon tetrachloride. These chemical substances are mainly either chlorine or bromine which can reach the stratosphere and catalytically break down ozone into oxygen.

Not only is the ozone layer thinning, in some places it has temporarily disappeared. A hole in the layer has developed over Antarctic since 1979 and that hole has persisted for a longer and longer time every year. In 1988, an ozone hole was found over the Arctic for the first time and it too has lasted longer and longer each year since then.

Since the last two decades, certain actions have been initiated at global level. Among these Montreal Protocol of 1987 and London Conference of 1992 are important. In both these conferences it was decided that the developed countries would totally ban CFC production by 2000 and the developing countries by 2010.

Acid Rain

The term acid rain refers to the deposition of wet or dry acidic materials from the atmosphere on the earth’s surface. Sulphuric acid and nitric acid are considered as the principal agents responsible for acid rain. Smokes emitted from the industries is the major source of sulphur dioxide whereas smokes emitted from the motor vehicle is the major source of nitrogen oxide. These emissions mixed with atmospheric moisture form the sulphuric acid and nitric acids which, sooner or later precipitate on earth in various forms.

Acidity is measured on a pH scale based on the relative concentration of hydrogen ions. The scale ranges from 0 to 14, where the lower end represents extreme acidity and the upper end extreme alkalinity. Acid rain is associated with various forms of precipitation. If we look at rainfall in clean and dust free air, a pH value varies between 5.6 to 6.0, which is slightly acidic in nature. Whenever or wherever the pH value is below 5.6, then the damage becomes noticeable.

The long-term effects of acid precipitation on human health and agricultural production have not yet been ascertained precisely. However, the most conspicuous damage is being done to aquatic ecosystem. The ecosystem of a stream or lake may be severely affected when its pH falls below 5. Total biomass in such systems is reduced from two to ten times because few organisms can tolerate acid. The diversity of species also decreases. The most severe effect of acidification is on fish. Acidic conditions affect the reproductive capabilities of fish, resulting in a slow decline of fish population. In Norway, thousands of lakes and streams have largely lost their fish population, over an area of 33,000 square kilometre.

Several lakes in Eastern United States and Canada have become biological deserts during the last quarter century. It is responsible for forests dieback which is occurring in each continent. Forest dieback is a German word which means death or decline of forest. Even buildings and monuments are being destroyed because acid deposition accelerated erosion capacity.