Decrease in Arctic Sea Ice
Sea ice forms and melts in sea water, as opposed to land-based ice such as glaciers. Sea ice begins to form when water temperature dips just below freezing, at around -1.8°C (or 28.8°F). It grows into small sheets that look like pancakes, and eventually merge together to form large sheets that can span miles.
Here are two important facts about sea ice you will need for the following question:
