Discuss the causes and effects of global warming. What measures need to be taken to control global warming?
Global warming is a rise in the mean temperature of the lower atmosphere and the earth’s surface.
Causes: increase in the quantity of radioactively active greenhouse gases CO2, CH4, N2O, CFCs. They allow heat waves to reach the surface and prevent their escape.
They are produced by combustion of fossil fuels, biomass [CO2]; burning of nitrogen-rich fuels [N2O]; paddy fields, fermentation in cattle and wetlands [CH4]; refrigerators, aerosols, drying, cleaning [CFCs].
Effects: Heating of earth surface [mean temperature is increased] Climatic changes e.g.: El Nino effect.
Increased melting of polar ice caps and Himalayan snowcaps. Increased sea levels and coastal areas will submerge.
Measures - Decreased use of fossil fuels, improve the efficiency of energy usage, Reduce deforestation, plant trees Control of man-made sources of greenhouse gases like vehicles, aerosol sprays.