Question

why do melting ice caps make earth warmer?
a. the ground under the ice has a lower albedo.
b. the salinity of ocean water increases.
c. more solar energy is reflected.
d. polar ocean water cools off.

Explanation:

Albedo is the measure of the reflectivity of a surface. Ice has a high albedo, meaning it reflects a large amount of solar energy. When ice caps melt, the ground (or water) underneath is exposed. Ground and water have a lower albedo than ice. A lower - albedo surface absorbs more solar energy instead of reflecting it. This increased absorption of solar energy contributes to warming the Earth.

• Option B: Melting ice caps actually decrease the salinity of ocean water (as ice is freshwater), so this option is incorrect.
• Option C: Since the surface with lower albedo (after ice - melt) absorbs more solar energy, less solar energy is reflected. So this option is incorrect.
• Option D: Melting ice caps do not cause polar ocean water to cool off in a way that would make the Earth warmer. In fact, the overall effect of ice - melt (due to albedo change) is warming. So this option is incorrect.

Answer:

A. The ground under the ice has a lower albedo.