The correct option is Carbon dioxide.
Explanation
The greenhouse effect is the process by which radiatively active gases in the atmosphere absorb and re-emit energy radiated from the Earth's surface, thereby warming the lower atmosphere. These gases are known as Greenhouse Gases (GHGs). They are characterized by being transparent to incoming shortwave solar radiation (insolation) but opaque to outgoing longwave terrestrial radiation.Analysis of Options
- Nitrogen (N2) and Oxygen (O2): Together, these two gases constitute approximately 99% of the atmosphere. However, they are diatomic molecules that do not absorb infrared radiation effectively. Therefore, they do not contribute to the greenhouse effect.
- Ozone (O3): Ozone is a greenhouse gas and plays a crucial role in the stratosphere by absorbing ultraviolet radiation. However, in the context of the overall greenhouse effect relative to the options provided, its contribution is secondary to that of Carbon Dioxide.
- Carbon Dioxide (CO2): Among the options provided, Carbon Dioxide is the gas largely responsible for the greenhouse effect. It is meteorologically a very important gas because it absorbs a significant portion of the terrestrial radiation and reflects some of it back towards the earth’s surface. This trapping of heat is essential for maintaining the Earth's average temperature.
Key Takeaway
Carbon Dioxide is the most significant greenhouse gas among the major dry atmospheric constituents because it efficiently absorbs outgoing terrestrial radiation while allowing incoming solar radiation to pass through.