As the Earth warms, its ice melts. This global melting is an early and obvious sign of climate change, but its implications go far beyond merely losing snow and ice. For starters, some people and ecosystems depend on the ice - glaciers for water supply in areas of seasonal rainfall, for example, and sea ice for habitat.
The melting of land ice is already raising sea levels. In some
fairly likely scenarios, oceans would rise by meters worldwide with
devastating results. A sea level rise of just one metre would
displace tens of millions of people in Bangladesh alone. All of
this melting ice could dilute the world's oceans – changing the
salinity enough to hurt fish stocks and disrupt ocean circulation
patterns globally.
Then there is the chance that melting ice will cause a feedback effect
due to the fact that snow and ice reflect more sunlight than bare
ground or water so less ice means more warming (which melts more ice,
etc.).
See also:
Arctic and Antarctic melting,
Glaciers,
Sea level rise and
Ocean circulation