Final answer:
Glaciers melting due to global warming result in rising sea levels, which threaten coastal cities with flooding, can lead to a shortage of freshwater, and could disrupt established urban centers and trade routess.
Step-by-step explanation:
Glaciers melting due to global warming will cause sea levels to rise, potentially leading to flooding in coastal cities. As the glaciers retreat, they add meltwater to the oceans, and warmer ocean water expands, contributing further to the rise in sea levels. This inundation could reduce the size of islands and even cause some to disappear completely.
Another concern is the alteration of the natural cycle of melting and refreezing of polar ice, which has provided freshwater to ecosystems for centuries. As a result, there could be an overabundance of salt water and a shortage of fresh water. Additionally, many urban centers are located in coastal areas, and an increase in sea level could threaten these cities with flood damage, impacting trade and disrupting the lives of large populations.