The above map illustrates the different definitions of the ice edge.

Mass and Height Change: Polar Portal

Plate tectonics - Wikipedia

Columbian Exchange - Bill of Rights Institute

Sea ice Copernicus

Arctic Sea Ice Minimum Extent Vital Signs – Climate Change: Vital Signs of the Planet

Piri Reis map - Wikipedia

PDF) Mapping ice in the Norwegian Arctic – on the edge between

Graphing Sea Ice Extent in the Arctic & Antarctic

A massive cavern beneath a West Antarctic glacier is teeming with life