In order of decreasing contribution to the green house effect, the three main gases are _____, __________ and ______

Answer

To answer the question regarding the three main gases contributing to the greenhouse effect in order of decreasing contribution, we can follow these steps:

### Step 1: Identify the Gases
The first step is to identify the gases that are known to contribute to the greenhouse effect. The three main gases are:

1. Carbon Dioxide (CO₂)
2. Methane (CH₄)
3. Chlorofluorocarbons (CFCs)

### Step 2: Rank the Gases
Next, we need to rank these gases based on their contribution to the greenhouse effect. The ranking is based on their global warming potential and the amount present in the atmosphere.

1. **Carbon Dioxide (CO₂)**: This gas is the most significant contributor to the greenhouse effect due to its large volume in the atmosphere and its long atmospheric lifetime.
2. **Methane (CH₄)**: This gas is less abundant than CO₂ but is much more effective at trapping heat in the atmosphere, making it the second most significant contributor.
3. **Chlorofluorocarbons (CFCs)**: These are synthetic compounds that have a much higher global warming potential than CO₂ and CH₄ but are present in smaller quantities.

### Final Answer
In order of decreasing contribution to the greenhouse effect, the three main gases are:
1. Carbon Dioxide (CO₂)
2. Methane (CH₄)
3. Chlorofluorocarbons (CFCs)

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