The sea ice is leaving us a bit more every year. It's time to start contemplating its absence, which is why I teamed up with Kevin McKinney to write an extended version of the shorter piece you might see pop up here and there.
The first world in ancient Norse mythology, Niflheim,
sounds just like the Arctic ice. Its snow- and ice-melt gave rise to the frost giant Ymir, from whose body the whole cosmos was formed. Today, science tells us a different story about the sea ice, but in that story, too, the ice is far older than humans. According to Polyak et al. (2010):
…sea ice became a feature of the Arctic by 47 [million years before the present], following a pronounced decline [in carbon dioxide concentrations]… Ice was apparently most widespread during the last 2–3 million years, in accordance with Earth's overall cooler climate.
Since modern humans are just 200,000 years old, the ice might as well be eternal.
But not unchanging. We live in that part of an ice age that is termed an interglacial, when some of the ice retreats in summer. During modern human history the ice cap has melted back each summer as Earth tipped toward the sun, then grown again with new freezing as the year turned toward the Winter solstice.