If there is no greenhouse effect , then the average temperature of the earth will be

Options

A. `-18^@C`
B. `0^@`
C. `-10^@C`
D. `15^@C`

Answer

To solve the question regarding the average temperature of the Earth if there were no greenhouse effect, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Greenhouse Effect**: The greenhouse effect is a natural phenomenon that warms the Earth's surface. It occurs when the Sun's energy reaches the Earth and is reflected back to space. Greenhouse gases in the atmosphere trap some of this energy, preventing it from escaping, which keeps the Earth warm.

2. **Identify Greenhouse Gases**: The main greenhouse gases include carbon dioxide (CO2), methane (CH4), chlorofluorocarbons (CFCs), and nitrogen oxides (NOx). These gases contribute to the greenhouse effect by absorbing and re-emitting infrared radiation.

3. **Current Average Temperature**: The current average temperature of the Earth is approximately 15 degrees Celsius due to the greenhouse effect.

4. **Temperature Without Greenhouse Effect**: If there were no greenhouse gases to trap heat, the average temperature of the Earth would drop significantly. It is estimated that without the greenhouse effect, the average temperature would be around -18 degrees Celsius.

5. **Select the Correct Option**: Given the options:
- A) -18 degrees Celsius
- B) 0 degrees Celsius
- C) -10 degrees Celsius
- D) 15 degrees Celsius

The correct answer is A) -18 degrees Celsius.

### Final Answer:
If there is no greenhouse effect, then the average temperature of the Earth will be **-18 degrees Celsius**.

---