Merijäätikön

Merijäätikön, which translates to "sea ice" in Finnish, refers to frozen seawater that forms on the surface of the ocean. It is a crucial component of the Earth's climate system, playing a significant role in regulating global temperatures and influencing ocean currents. Sea ice forms when the temperature of the ocean surface drops below its freezing point, which is typically around -1.8 degrees Celsius (28.8 degrees Fahrenheit) due to the presence of salt. As seawater freezes, most of the salt is expelled, leaving the ice with a much lower salt content than the surrounding water.

The formation and melting of sea ice are dynamic processes that vary seasonally and geographically. In polar regions, large areas of the ocean are covered by sea ice for extended periods, sometimes year-round. This ice can range from thin, newly formed ice to thick, multi-year ice that has survived multiple melt seasons. The extent and thickness of sea ice are important indicators of climate change, as warming temperatures lead to reduced ice cover.

Sea ice has profound impacts on the environment. It reflects a significant amount of solar radiation back into space, a phenomenon known as the albedo effect, which helps to cool the planet. When sea ice melts, it exposes darker ocean water, which absorbs more solar radiation, leading to further warming in a feedback loop. Sea ice also serves as a habitat for various marine organisms, including seals, polar bears, and microorganisms. Its presence affects shipping routes and coastal erosion.