Write short note on global warming.
Over the past 50 years, the average global temperature has increased at the fastest rate in recorded history.
Global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter.
Global Temperature increase
- It is estimated that average temperature of earth may increase by 1.4°C to 5.8°C by the year 2100 from year 1990. In the 20th century, the global mean temperature has increased by about 0.6°C.
- Rise in sea level: With increasing global temperature polar icecaps and glaciers will melt. It will also cause thermal expansion of seawater resulting in further rise in sea level.
Effect on human health
- The global warming will lead to changes in the rainfall pattern in many areas, thereby affecting the distribution of vector – borne dieses like malaria, elephantiasis etc.
Effect on food production
- Global warming will reduce crop production due to increased incidence of plant diseases and pests, explosive growths of weeds. It is estimated that the yield of rice along in South East Asia will decrease by 5% for each 1°C rise in temperature.
Other climatic effects
- Unequal distribution of rain which may results in flooding in some areas and drought in some areas.
- In temperate regions, the summers will be longer and hotter whereas the winters will be shorter and warmer.
- The already dry sub-tropical regions may become drier and the tropical regions may become wetter.
Control of Global Warming
- Reduction in greenhouse gas emission by reducing the use of fossil fuels and by developing alternative renewable sources of energy like solar energy, wind energy etc.
- Reduction in N2O emission by minimizing the use of nitrogen fertilizers in agriculture.
- Increase of the vegetation cover, particularly forest as it is sinking for CO2 absorption. Phasing out chlorofluorocarbon and developing its substitute.
- Trapping and use of methane as fuel.
- Stabilize population growth.
- Using energy resources judiciously.
