Green house effect and Green house gases

Greenhouse Effect
The greenhouse effect is a natural process by which certain gases in Earth's atmosphere trap heat from the Sun, keeping the planet warm enough to support life.

How it works:
The Sun emits solar radiation (mostly visible light and UV rays), which passes through the atmosphere and reaches the Earth's surface.
The Earth's surface absorbs this radiation and warms up. It then re-emits energy as infrared radiation (heat).
Greenhouse gases in the atmosphere (carbon dioxide, water vapor, methane, nitrous oxide, ozone) absorb this outgoing infrared radiation and re-emit some of it back toward Earth.
This trapping of heat warms the Earth's surface and lower atmosphere.

Without the natural greenhouse effect, Earth's average temperature would be about -18°C instead of the current average of +15°C — too cold to support most life.

Greenhouse Gases (GHGs):

Carbon dioxide (CO₂): produced by burning fossil fuels, deforestation, and respiration.
Methane (CH₄): produced by livestock, rice paddies, and landfills.
Nitrous oxide (N₂O): produced by fertilizers and combustion.
Water vapor (H₂O): the most abundant greenhouse gas, regulated by temperature.
Ozone (O₃): present in the stratosphere (protective) and lower atmosphere (a pollutant).
Chlorofluorocarbons (CFCs): man-made gases used in refrigerants and aerosols that also deplete the ozone layer.

The problem today is that human activities are increasing the concentration of greenhouse gases (especially CO₂), enhancing the greenhouse effect beyond its natural level — leading to global warming.