T he Greenhouse Effect is a process where energy can enter a system but then is largely prevented from exiting the system. The energy in the form of heat, though, is prevented from leaving because heat transfer through the glass walls is rather slow compared to light transfer. T he process on the Earth, though not identical, is similar in its result, that is why it is called the Greenhouse Effect.
Radiation released by the Earth's surface is primarily longwave.
Longwave radiation is an easier target for reflection and absorption by the aerosols and water vapor in the atmosphere. As a result, a lot of it is either reflected back to the surface or winds up heating the atmosphere. This is because there is more of these two gases in the atmosphere than the other Greenhouse gases. These gases are called Greenhouse gases because they have properties that help them enhance the Greenhouse Effect. That is, these gas molecules are very good at absorbing and storing longwave radiation, like the radiation that is released from the Earth's surface.