Think about a time when your car was parked in the middle of a parking lot, in the middle of the day. The minute you opened the car door, you must have felt currents of hot air blowing past you. The moment you sat down, you might have felt as if your car was radiating heat! This is a small, yet effective example of a process called the GREENHOUSE EFFECT. This effect involves a certain body of matter, be it a car, or a green house in which plants are grown, or the earth itself, absorbing heat or radiation from another body, in our case – the sun. In case of the car, the glass enables the absorption of the heat, and traps the heat inside, and does not let it out. Similarly, the earth's atmosphere contains certain gases called GREENHOUSE GASES such as Carbon Dioxide or water vapour or Ozone or Methane, which absorb the radiations we receive from the sun, and trap the heat from it inside. In other words, our atmosphere, which contains the greenhouse gases acts like a blanket; it absorbs heat from the sun, and prevents the heat inside from going away from the earth's surface. The more greenhouse gases in the atmosphere, the more the heat gets trapped, the more the temperature rises. This phenomenon of increase in the average temperature of the Earth's near-surface air and oceans is called GLOBAL WARMING.

So, what if the temperature rises? Due to global warming, there are serious, profound consequences that occur. These include:
1. Increased evaporation of water, which would increase the amount of water vapour (a greenhouse gas) in the atmosphere, making the process of global warming even worse.
2. Heightened melting of the icebergs and glaciers in the Arctic Ocean and the icecaps and mountain snows of Antarctica, which will result in the rise in sea level.
3. Expansion of water on heating, which means the sea level will further rise due to higher temperatures.