It is called the Holocene Interglacial Period, and the ice has been melting for the last 11,700 years.  It is not "unprecedented" either.  The Holocene Maximum, Minoan Warming, Roman Warming, and Medieval Warming periods have all seen warmer temperatures than today.  Furthermore, this is just one of ~50 interglacial periods in the last 2.58 million years.  The last Eocene Interglacial Period, from 130,000 to 115,000 years ago was even warmer than the current one.