Answer :
Final answer:
Due to climate change, the zone of accumulation on glaciers is shrinking, and the zone of ablation is expanding, contributing to overall glacial retreat and rising sea levels.
Explanation:
In the context of climate change, the zone of accumulation on glaciers, where more snow accumulates each year than melts, is generally shrinking. Conversely, the zone of ablation, the area where the glacier loses ice mass due to melting or sublimation, is expanding. This is primarily a result of rising global temperatures, which increase the amount of melting during the summer. Hence, the correct answer to the question is: a) Zone of accumulation is shrinking, zone of ablation is expanding.
As a glacier's budget is affected markedly by climate, a warmer climate leads to more ablation in comparison to accumulation, causing the glaciers to retreat. With the increasing temperatures brought about by climate change, glacial retreat is now a significant concern, resulting in diminished glacier sizes and contributing to rising sea levels.
This expansion of the zone of ablation and shrinking of the zone of accumulation are indicative of the broader changes in earth's cryosphere, which include the unprecedented melting rates of major Alpine glaciers, as well as the significant ice mass losses in Antarctica and Greenland.