What are green house gases ? and how is it related with green house effect ?

Gases that trap heat in the atmosphere are often called greenhouse gases. These gases absorb and emit radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. Greenhouse gases greatly affect the temperature of the Earth.

Some greenhouse gases such as carbon dioxide and water vaour occur naturally and are emitted to the atmosphere through natural processes and human activities. Other greenhouse gases (e.g., fluorinated gases) are created and emitted solely through human activities. The principal greenhouse gases that enter the atmosphere because of human activities are  CO₂,  methane, nitrous oxide and fluorinated gases.

Human activities since the start of the industrial era around 1750 have increased the levels of greenhouse gases in the atmosphere. The greenhouse effect is the heating of the Earth due to the presence of greenhouse gases.  It is named this way because of a similar effect produced by the glass panes of a greenhouse. The more the greenhouse gases in the atmosphere, more significant will be the greenhouse effect, leading to global warming.