Sea ice is frozen seawater that forms in the polar regions, primarily in the Arctic and Antarctic. It plays a crucial role in regulating the Earth's climate by reflecting sunlight and helping to maintain cooler temperatures in these areas. Sea ice can vary in thickness and extent, depending on seasonal changes and environmental conditions. The formation of sea ice typically occurs during the winter months when temperatures drop. As the ice melts in the summer, it creates a dynamic ecosystem that supports various marine life, including seals and polar bears, which rely on sea ice for hunting and breeding.