Step 1: Understanding the Concept:
Global warming is the long-term heating of Earth's climate system observed since the pre-industrial period due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth's atmosphere.
Step 2: Detailed Explanation:
The primary gases responsible for the greenhouse effect include water vapor, carbon dioxide (\(CO_2\)), methane (\(CH_4\)), nitrous oxide (\(N_2O\)), and ozone.
While Nitrogen (\(N_2\)) and Oxygen (\(O_2\)) make up about 99% of the atmosphere, they are not significant greenhouse gases because their molecular structure does not allow them to effectively absorb long-wave (infrared) radiation.
Carbon dioxide (\(CO_2\)), produced mainly from the burning of fossil fuels, deforestation, and industrial processes, is the most significant long-lived greenhouse gas in Earth's atmosphere, making it the main driver of global warming.
Step 3: Final Answer:
Among the given options, Carbon dioxide is the gas primarily responsible for global warming.