• The atmosphere of the earth is heated by the process of convection. 
• In cases of liquids and gases, the transfer of heat takes place through convection. It is a process by which heat travels through water, gas, air, or other liquids.
• In convection, the heat energy is transferred by the actual movement of the particles from one place to another. Whenever a liquid or a gas is heated, the molecules of these substances become lightened and move upwards and then cooler molecules settle downwards and heated. In this way, the atmosphere of our earth is heated by the process of Convection. 
• Radiation is the propagation or emission of energy in the form of waves or rays.
• Conduction is the process of movement of electricity or heat through a passage or medium.
• The discharge and production of radiations and gases is known as emission.

Note: Radiation and Conduction processes are also involved but Convection is dominant.