Question

which of these is part of a feedback loop that results in a cooling effect on earth?

a. as snow and ice melt, the underlying surfaces absorb heat from solar radiation.

b. rising carbon dioxide levels fuel the growth of algae and plants, which increases carbon dioxide absorption.

c. burning fossil fuels increases the concentration of greenhouse gases in the atmosphere.

d. when permafrost melts, methane is released into the atmosphere.

Explanation:

• Option A: Snow/ice melt exposes surfaces that absorb heat, leading to warming (positive feedback for warming, not cooling).
• Option B: Rising CO₂ helps algae/plants grow, which absorb more CO₂. This reduces atmospheric CO₂, a greenhouse gas, leading to a cooling effect (negative feedback loop for cooling).
• Option C: Burning fossil fuels increases greenhouse gases, causing warming (positive feedback for warming).
• Option D: Permafrost melt releases methane (a greenhouse gas), causing warming (positive feedback for warming).

Answer:

B. Rising carbon dioxide levels fuel the growth of algae and plants, which increases carbon dioxide absorption.