Question

The two gases with the highest relative contribution to the Green House Gases (GHG) are

• A. CO2 and N2O
• B. CO2 and CH4
• C. N2O and CH4
• D. CO2 and CO

Hint:

Greenhouse Gas (GHG) Contributions: 1. $\text{CO}_2$ ($pprox 76\%$) + 2. $\text{CH}_4$ ($pprox 16\%$) represent the top two greenhouse gases. Nitrous oxide is 3rd ($pprox 6\%$).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Atmospheric radiative forcing: carbon dioxide ($ ext{CO}_2, pprox 76\%$) and methane ($ ext{CH}_4, pprox 16\%$) account for over 90% of global greenhouse gas emissions.
Key Formula or Approach:
\[ \text{Global Anthropogenic GHG Contribution: } \text{CO}_2 (\approx 76\%) + \text{CH}_4 (\approx 16\%) + \text{N}_2\text{O} (\approx 6\%) + \text{F-gases} (\approx 2\%) \]

Step 2: Detailed Explanation:
In environmental science and livestock greenhouse gas emissions:
- Global warming and radiative forcing are driven by atmospheric greenhouse gases:
1. Carbon Dioxide ($\text{CO}_2$): Contributes approximately 76% of total global anthropogenic GHG emissions (from fossil fuel combustion, deforestation, industrial processes).
2. Methane ($\text{CH}_4$): Contributes approximately 16% of total GHG emissions (from enteric fermentation in ruminants, rice paddies, manure management).
- Together, $\text{CO_2$ and $\text{CH}_4$} represent $> 92\%$ of the total radiative forcing of global greenhouse gas emissions.

Step 3: Final Answer:
Therefore, the two gases with highest contribution are CO2 and CH4, matching option (B).