The maximum contribution to the greenhouse effect is caused by water vapour.


The greenhouse effect refers to the process by which certain gases in the Earth's atmosphere trap heat from the sun and prevent it from escaping back into space. This phenomenon is essential for maintaining a habitable temperature on Earth and supporting life as we know it.


There are several greenhouse gases that contribute to the greenhouse effect. These gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). While all of these gases play a role in trapping heat, their individual contributions vary.


Water vapor is the most significant contributor to the greenhouse effect. It is the most abundant greenhouse gas in the Earth's atmosphere, accounting for approximately 70% of the total greenhouse effect. Water vapor is a natural component of the atmosphere and is primarily generated through evaporation from oceans, lakes, and rivers. It also enters the atmosphere through transpiration from plants.

Key Points:
- Water vapor has a high capacity to absorb and emit infrared radiation, which is responsible for trapping heat in the atmosphere.
- The amount of water vapor in the atmosphere is highly variable and depends on temperature and other atmospheric conditions. Warmer air can hold more water vapor, leading to a positive feedback loop where increased temperatures result in more water vapor, which further enhances the greenhouse effect.
- However, water vapor has a relatively short lifespan in the atmosphere compared to other greenhouse gases. It condenses into clouds and falls back to the Earth as precipitation, limiting its long-term impact on climate change.


While water vapor is the most significant contributor to the greenhouse effect, other greenhouse gases also play important roles.

Carbon dioxide (CO2): It is the second most abundant greenhouse gas and is primarily released through human activities such as burning fossil fuels, deforestation, and industrial processes. CO2 has a long lifespan in the atmosphere and can remain there for decades to centuries.

Methane (CH4): It is a potent greenhouse gas that is emitted from various sources, including agriculture, livestock, waste management, and natural gas production. Although methane concentrations are much lower than CO2, it has a higher warming potential.

Nitrous oxide (N2O): It is primarily released through agricultural and industrial activities, as well as combustion processes in vehicles and power plants. Nitrous oxide has a long lifespan and is known for its potent warming effect.


While all greenhouse gases contribute to the greenhouse effect, water vapor is the most significant contributor due to its abundance in the atmosphere and its ability to absorb and emit infrared radiation. However, the impact of other greenhouse gases such as carbon dioxide, methane, and nitrous oxide cannot be ignored as they also play important roles in influencing Earth's climate.

According to NCERT data base.
The four major gases responsible for Green house effect is
co2 (carbon dioxide) 60%
ch4 (methane) 20%
cfc (chloro fluoro carbon) 14%
n2o (nitrous oxide) 6%

I am not sure if (b) water vapours is correct.