Global warming has become the most important environmental problem of our world today. The increase of temperature over the earth’s surface as a result of the emission of greenhouse gases into the atmosphere is known as global warming. The main cause of global warming is emission of greenhouse gases.
Gases that can trap the energy reflected back by the earth’s surface, viz, carbon dioxide (CO₂), methane (CH), nitrous oxide (N₂O), water vapour, etc. increase the atmospheric temperature.
These gases are called greenhouse gases and constitute about 0.1% of the total volume of atmospheric gases. Variation in composition of such gases has increased the atmosphere’s temperature leading to global warming.
Among all the greenhouse gases, the role of carbon dioxide gas has been most significant, as it alone has increased by 30% in the atmosphere in the last 150 years. After industrial revolution, use of fossil fuels and deforestation greatly increased. This has led to a rise in carbon dioxide gas in the atmosphere and hence a rise in the atmospheric temperature. Volcanic eruptions have increased the composition of greenhouse gases in the atmosphere; increase in the proportion of chloro fluoro carbons (CFC) has also increased in the atmosphere all contributing to global warming.