In the absence of greenhouse gases, the temperature of earth's surface will fall to

Options

A. `0^(@)C`
B. `-5^(@)C`
C. `-7^(@)C`
D. `-20^(@)C`

Answer

To solve the question regarding the temperature of Earth's surface in the absence of greenhouse gases, we will follow these steps:

### Step 1: Understand Greenhouse Gases
Greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, play a crucial role in the greenhouse effect. They trap heat in the atmosphere, preventing it from escaping back into space.

**Hint:** Remember that greenhouse gases are essential for maintaining the Earth's temperature by trapping heat.

### Step 2: Explain the Greenhouse Effect
The greenhouse effect is a natural process where the Earth's atmosphere absorbs some of the solar energy that reaches it. This process warms the Earth's surface, allowing for a habitable climate.

**Hint:** The greenhouse effect is beneficial because it keeps the Earth warm enough to support life.

### Step 3: Consider the Absence of Greenhouse Gases
If greenhouse gases were absent, the heat from the sun would not be trapped in the atmosphere. Instead, it would escape back into space, leading to a significant drop in temperature.

**Hint:** Think about what happens when heat cannot be retained—temperatures will drop significantly.

### Step 4: Estimate the Temperature Drop
In the absence of greenhouse gases, the Earth's surface temperature is estimated to fall drastically. It is commonly understood that without these gases, the average temperature could drop to around 0 degrees Fahrenheit or approximately -20 degrees Celsius.

**Hint:** Look for common estimates in scientific literature regarding temperature changes without greenhouse gases.

### Step 5: Choose the Correct Answer
Based on the understanding that the absence of greenhouse gases leads to a much colder Earth, the correct answer to the question is that the temperature of the Earth's surface will fall to -20 degrees Celsius.

**Hint:** Compare the options provided in the question to find the one that matches your estimation.

### Final Answer
In the absence of greenhouse gases, the temperature of Earth's surface will fall to -20 degrees Celsius.