Final answer:
Ice sheets, like those of Antarctica and Greenland, can be several kilometers thick. They play a vital role in influencing climate and sea levels, particularly in the context of climate change.
Step-by-step explanation:
Ice sheets can be several kilometers thick. One notable example is the Antarctic ice sheet, which has an average ice thickness of 1.9 km and holds about 70% of the Earth's fresh water. The Greenland ice sheet is also immense, with an estimated volume of 2.85 million cubic kilometers and an average depth of 1.7 km. These ice masses are significant because they influence global sea levels and climate patterns. As such, understanding their dynamics is crucial, especially in the context of climate change and global warming, which may lead to melting and rising sea levels.