PREVIOUSLY ASKED IN:
PSC Miscellaneous Prelims 2018
Answer
Hydrogen
Explanation
Greenhouse gases are those that absorb and emit radiant energy within the thermal infrared range, causing the greenhouse effect which warms the Earth's surface. The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Hydrogen (H2) is a diatomic gas that does not absorb infrared radiation and therefore is not a greenhouse gas.
Key Points
- > Hydrogen is not a greenhouse gas.
- > Carbon dioxide (CO2) is the most significant contributor to human-induced global warming.
- > Methane (CH4) is highly potent and emitted from wetlands, agriculture (paddy fields), and livestock.
- > Nitrous oxide (N2O) is also known as laughing gas.
- > Chlorofluorocarbons (CFCs) are synthetic greenhouse gases that also deplete the ozone layer.
- > Abundant atmospheric gases like Nitrogen (N2) and Oxygen (O2) are not greenhouse gases.
Additional Information
Major Greenhouse Gases and Sources
| Gas Name | Formula | Major Source |
|---|---|---|
| Carbon dioxide | CO2 | Burning fossil fuels, Deforestation |
| Methane | CH4 | Agriculture (paddy fields), Livestock |
| Nitrous oxide | N2O | Agricultural fertilizers |
| CFCs | CFC | Refrigerants, Aerosols |
Memory Tips
- Diatomic Rule of Thumb: Simple homonuclear diatomic molecules like $H_2$, $O_2$, and $N_2$ do not absorb infrared light and are absolutely NOT greenhouse gases.