Question

Why is an excess of CO₂ in the atmosphere considered undesirable even though it is required by plants?

Answer 1

Carbon dioxide is vital for photosynthesis, but too much intensifies the greenhouse effect. $$\mathrm{CO_2}$$ traps outgoing infrared radiation, raising Earth's temperature. This causes global warming, melting glaciers, rising sea levels, extreme weather events, and ocean acidification, thereby disturbing the delicate balance necessary for life.