Sea ice is important because it reflects more incoming solar radiation than the sea surface (i.e., it has a higher albedo), and it insulates the sea from heat loss during the winter. Therefore, reduction of sea ice gives a positive feedback on climate warming at high latitudes.
El hielo marino es importante porque refleja más radiación solar incidente que la superficie del mar (es decir que tiene un albedo mayor) y protege al mar de la pérdida de calor durante el invierno.