The Last Time the Arctic Was Ice-Free in the Summer, Modern Humans Didn’t Exist

Ice has been a relatively constant feature of the Arctic for most of the past 36 million years, but there have been some gaps.  Scientists aren’t exactly sure what happened during the most recent major ice-free period, but it’s often considered an analog to our future, warmer Earth.  The only difference is, the gap in Arctic sea ice that scientists believe will happen by midcentury is being caused by us.*

Scientists are now piecing together the puzzle in an increasingly urgent attempt to understand what might happen once Arctic ice goes away again, effectively for good. One new study, published last week in the journal Nature Communications, attempts determine what happened during that last major gap in Arctic ice.

The study provides new evidence that the last major gap ended about 2.6 million years ago, after which ice sheets spread southward and humanity’s ancestors began to respond to colder temperatures in Africa, forcing adaptation like the use of stone tools.  Humans themselves wouldn’t evolve for more than a million more years.

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