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.).