The reason for global warming is

Options

A. long wavelength radiations are absorbed by the atmosphere
B. short wavelength radiations are absorbed by the atmosphere
C. atmosphere traps radiations to increase the temperature
D. UV and infrared radiations

Answer

### Step-by-Step Solution:

1. **Understanding Global Warming**:
- Global warming refers to the gradual increase in the Earth's average surface temperature due to rising levels of greenhouse gases in the atmosphere. These gases trap heat from the sun, preventing it from escaping back into space.

2. **Identifying Causes**:
- The primary cause of global warming is the increase in greenhouse gases, such as carbon dioxide (CO2) and methane (CH4), which are largely produced by human activities like burning fossil fuels, deforestation, and industrial processes.

3. **Analyzing the Options**:
- The question provides several options regarding the reasons for global warming. We will evaluate each option to determine which one correctly explains the phenomenon.

4. **Evaluating Option 1**:
- "Long wavelength radiations are absorbed by the atmosphere."
- This statement is correct. Greenhouse gases absorb long-wavelength infrared radiation emitted from the Earth's surface, which leads to an increase in atmospheric temperature.

5. **Evaluating Option 2**:
- "Short wavelength radiations are absorbed by the atmosphere."
- This statement is incorrect. Short-wavelength radiation, such as ultraviolet light from the sun, is mostly absorbed by the ozone layer and does not contribute to global warming.

6. **Evaluating Option 3**:
- "Atmosphere trapped radiation to increase the temperature."
- While this statement has some truth, it is vague and does not specifically address the mechanism of long-wavelength radiation absorption which is crucial for understanding global warming.

7. **Conclusion**:
- Based on the analysis, the correct answer is **Option 1**: "Long wavelength radiations are absorbed by the atmosphere," as it accurately describes the process that leads to global warming.