Question

solar radiation travels through the earths atmosphere and warms the planets surface. greenhouse gases like carbon dioxide in the earths atmosphere reabsorb the heat and warm the planet. the amounts of greenhouse gases have been increasing over the past century, causing the earths surface temperature to increase. this gradual temperature change is thought to have many negative environmental consequences. select which of these might be a positive effect of the increase in carbon dioxide levels? a rise in sea levels b decrease in plant growth c increase in plant growth d increased melting of ice caps

Explanation:

To determine the positive effect of increased carbon dioxide levels, we analyze each option:

• Option A (rise in sea levels) is a negative consequence of global warming (from increased CO₂), as melting ice caps cause this.
• Option B (decrease in plant growth) is incorrect. Plants use CO₂ for photosynthesis, so more CO₂ generally supports more growth, not less.
• Option C (increase in plant growth) is correct. Higher CO₂ levels can enhance photosynthesis, leading to more plant growth (a positive effect in terms of plant productivity, though other environmental impacts of CO₂ increase may be negative overall).
• Option D (increased melting of ice caps) is a negative consequence, contributing to sea - level rise and habitat loss.

Answer:

C. increase in plant growth