How does the ice-albedo feedback amplify warming in polar regions?

• A. As ice melts, darker surfaces are exposed, absorbing more sunlight and accelerating warming in a positive feedback loop.
• B. Melting ice exposes more reflective surfaces, increasing albedo and cooling.
• C. Ice-albedo feedback only occurs in polar regions during winter.
• D. Ice-albedo feedback has no impact on warming.

Answer: (D)

Ice-albedo feedback is a positive feedback mechanism: when bright ice and snow melt, the darker underlying surfaces—like ocean water or land—absorb more solar energy instead of reflecting it. This extra absorption warms the surface, causing more ice and snow to melt, which reveals even darker surfaces and leads to further warming. In polar regions, where large expanses are covered by ice and snow, this loop is especially powerful because small losses of reflective surface translate into larger gains in absorbed heat, speeding up warming and accelerating further ice loss.

So, the best description is that as ice melts, darker surfaces are exposed, absorbing more sunlight and accelerating warming in a positive feedback loop. The idea that melting ice would expose more reflective surfaces and promote cooling is incorrect, because the exposed surfaces are darker and absorb more energy. The notion that this only happens in winter misstates the process, which operates with seasonal changes but is driven by the contrast between high albedo ice/snow and lower albedo underlying surfaces. And saying it has no impact contradicts extensive evidence of feedbacks amplifying polar warming.