The Greenhouse Effect and Global Warming!
The phenomenon commonly known as ‘greenhouse effect’ occurs due to emission of certain gaseous pollutants in the air, which, after the heating of the atmosphere, causes the average global temperature to rise. The effects produced by certain gases, such as carbon dioxide or water vapor, cause a warming of the earth’s atmosphere by absorption of infrared radiation.
The atmosphere protects us by serving as a light scattering and heat mediating blanket. A large portion of heat emitted from the earth is re-absorbed by the atmosphere and is, in effect, conserved, with the result that the surface of the earth is warmer than it otherwise would be. In simple words, this warming is called the greenhouse effect.
The atmospheric concentration of these gases has relatively increased since the advent of the industrial era. There has emerged a growing consensus in the scientific community that the anthropogenic greenhouse gas emission of carbon dioxide, nitrous oxide, CFCs, methane and low level ozone threatens to disrupt human societies and natural ecosystems.
The developed world accounted for nearly 80 per cent of the total industrial carbon dioxide emissions and the rest of 20 per cent originated in the developing world. On the other hand, 98 per cent CFCs are produced in developed and only 2 per cent in developing world.
With the current trend of emissions, a WHO study speculates that the combined effects of the six most important greenhouse gases could by the early years of 2030s be equivalent to doubling of pre-industrial concentrations of carbon dioxide. The scientists are of the opinion that the earth will be hotter by 2° to 4°C by the middle of the 21st century.
The atmospheric blanket keeps the earth habitable and protects living forms from fatal radiations of the sun. The atmosphere intercepts solar radiation, reflecting a third of it, while the rest is absorbed by the atmosphere, ocean, ice, land and biosphere.
The energy absorbed is balanced by the outgoing radiation from the atmosphere and the earth. This vital balance will be altered with infringement of greenhouse effect resulting in an overall rise in the average global temperature.
Amongst the most dramatic consequences of the greenhouse climatic disruption is an unprecedented rise in global sea levels to the extent of 8 to 25.5 inches by the middle of the 21st century if gas emissions continue at the present rate. Melting of polar ice and glaciers, as well as thermal expansion of seas, would cause worldwide coastal flooding and rise in sea level will result in submergence of many coastal areas.
It will not only affect the ecological balance but will also be a threat to the people and economy of the countries like Bangladesh, Netherlands, as well as too many coastal and island countries. In fact, the impact of world-wide climatic disruption could have hazardous, for the survival of the planet both biologically and economically.
The Montreal Protocol was a step in this direction but an overall solution requires combined efforts on the part of all nations and international bodies. Apart from this, scientific and technological research in this field can also reduce the risk to a great extent, provided it reaches all nations, especially to the developing nations.