One of the main greenhouse gases is ________.
Methane
Understanding Greenhouse Gases and Their Impact
Greenhouse gases are components of the atmosphere that absorb and re-emit infrared radiation. This process traps heat within the atmosphere, leading to the greenhouse effect, which warms the planet. Without this natural process, Earth's temperature would be much colder. However, human activities have increased the concentration of certain greenhouse gases, intensifying the greenhouse effect and causing global warming and climate change.
Analyzing the Options for Main Greenhouse Gases
Let's look at the options provided and determine which one is considered a main greenhouse gas:
- Oxygen ($\text{O}_2$): Oxygen is a major component of Earth's atmosphere, making up about 21%. However, oxygen molecules do not absorb infrared radiation in the way that greenhouse gases do. Therefore, oxygen is not a greenhouse gas.
- Hydrogen ($\text{H}_2$): Hydrogen is a very light gas and is not a significant component of Earth's atmosphere. Like oxygen and nitrogen, hydrogen molecules do not absorb infrared radiation effectively. While hydrogen can indirectly influence the concentration of some greenhouse gases, it is not considered a main greenhouse gas itself.
- Nitrogen ($\text{N}_2$): Nitrogen is the most abundant gas in Earth's atmosphere, making up about 78%. Similar to oxygen and hydrogen, nitrogen molecules do not absorb infrared radiation. Thus, nitrogen is not a greenhouse gas.
- Methane ($\text{CH}_4$): Methane is a hydrocarbon and is produced from natural sources like wetlands and termites, and from human activities such as livestock farming, rice cultivation, natural gas production, and waste decomposition in landfills. Methane molecules are very effective at absorbing infrared radiation. Although its concentration in the atmosphere is much lower than carbon dioxide, methane has a significantly higher global warming potential per molecule over a shorter timescale. Methane is considered one of the main greenhouse gases contributing to climate change.
Identifying Methane as a Main Greenhouse Gas
Based on the analysis of the options, methane ($\text{CH}_4$) fits the description of a main greenhouse gas. It plays a significant role in trapping heat in the atmosphere and contributing to the greenhouse effect and global warming.
Revision Table: Key Atmospheric Gases
| Gas | Chemical Formula | Approximate Atmospheric Concentration (Dry Air) | Is it a Main Greenhouse Gas? | Why? |
|---|---|---|---|---|
| Nitrogen | $\text{N}_2$ | 78% | No | Does not absorb infrared radiation significantly. |
| Oxygen | $\text{O}_2$ | 21% | No | Does not absorb infrared radiation significantly. |
| Argon | $\text{Ar}$ | 0.93% | No | Does not absorb infrared radiation significantly. |
| Carbon Dioxide | $\text{CO}_2$ | ~0.04% (increasing) | Yes | Strong absorber of infrared radiation. |
| Methane | $\text{CH}_4$ | ~0.00018% (increasing) | Yes | Strong absorber of infrared radiation, high global warming potential. |
| Water Vapor | $\text{H}_2\text{O}$ | Varies (up to 4%) | Yes | Strong absorber of infrared radiation. Most abundant greenhouse gas, though concentration depends on temperature. |
Additional Information on Greenhouse Gases
Besides methane, other primary greenhouse gases include carbon dioxide ($\text{CO}_2$), water vapor ($\text{H}_2\text{O}$), nitrous oxide ($\text{N}_2\text{O}$), and fluorinated gases. These gases differ in their abundance, their ability to absorb heat (radiative efficiency), and their lifespan in the atmosphere. Methane is particularly potent, although it remains in the atmosphere for a shorter period compared to carbon dioxide.
Understanding which gases are greenhouse gases is crucial for studying climate change and developing strategies to mitigate its effects.
Important Questions from Climate Change & Global Warming
Greenhouse gas, which is present in the highest quantity in the atmosphere, is
Which one of the following gases have higher Global Warming Potential?
Which of the following two sources of carbon is released?
A) Volcanic eruption
B) Combustion of fossil fuels
C) Landslide
D) Open mining
Choose the correct answer from the options given below:
Given below are two statements:
Statement I: The consumption of oxygen has increased after the Industrial Revolution in 1860.
Statement II: Brazil and India use more oxygen annually than other countries of the world.
In the light of the above statements, choose the correct answer from the options given below:
Considering the global warming potential of CO 2as one, the global warming potential of CH 4has been estimated to be approximately :
