What is the role of carbon dioxide in the atmosphere, and how does increasing CO2 influence Earth's climate?

• A. CO2 is inert in the atmosphere.
• B. CO2 cools the planet by reflecting sunlight.
• C. CO2 traps heat in the atmosphere (greenhouse effect); increasing CO2 enhances warming and drives climate change.
• D. CO2 is removed by oceans without any climate effect.

Answer: (C)

CO2 in the atmosphere acts as a greenhouse gas by absorbing infrared radiation emitted from Earth’s surface. This absorption traps heat within the lower atmosphere and on the surface, warming the planet. When CO2 levels rise, more heat is retained, intensifying the greenhouse effect and driving warming and climate change.

CO2 isn’t inert; it interacts with infrared light, which is why it has a warming effect. It doesn’t cool the planet by reflecting sunlight. While oceans do take up some CO2, this removal doesn’t erase its climate impact—the increased atmospheric CO2 continues to trap heat, and ocean uptake can lead to other problems like acidification.