"Ice retreat" refers to the process of ice shrinking or melting, usually due to warmer temperatures. It means that ice is moving or receding back, as it turns into liquid water or evaporates. Full definition
Second, the rate of sea ice retreat in recent years is also unprecedented in the historical record. (dotearth.blogs.nytimes.com)
Each year is different: sometimes ice retreats from the shores in dramatic fashion and other years have a more gradual melt. (earthobservatory.nasa.gov)
When seasonal ice retreat occurs early, low - albedo open water areas are exposed early, which gain a lot of energy from the sun. (nsidc.org)