Arctic Basin Rapidly Losing Older, Thicker Ice; "I Don't Think There's Any Going Back At This Point"

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Concentration Of Multi-Year Sea Ice, Early March 1984


Concentration Of Multi-Year Sea Ice, Early March 2018

EDIT

Some of the new ice melts each summer, but some of it lingers to grow thicker over the following winter, forming second-year ice. The next summer, some of that second-year ice survives, then grows even thicker and more resilient the next winter, creating what is known as multiyear ice. Some ice used to last more than a decade.


Percentage of Arctic Ice in Early March


Today, Arctic sea ice is mostly first-year ice. While the oldest ice has always melted when currents pushed it south into warmer waters, now more of the multiyear ice is melting within the Arctic Ocean, leaving more open water in its wake.

This is especially bad for animals like narwhals, the so-called unicorns of the sea, that use sea ice to avoid predators like killer whales. As the sea ice disappears, killer whales spend more time in narwhal waters, eating the narwhals and driving them from the richest feeding grounds.

“I’ve been on record saying that it may be 2030 that we could see a seasonally ice-free Arctic Ocean,” said Mark Serreze, director of the National Snow and Ice Data Center. “Some people have said that that’s too aggressive, that we’re looking at maybe sometime in the 2040s. But we are definitely on track to lose that summer sea ice cover. Honestly, I don’t think there’s any going back at this point.”

EDIT/END

https://www.nytimes.com/interactive/2018/05/14/climate/arctic-sea-ice.html