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Tammy Rittenour

Tammy Rittenour, Utah State University

An aerial picture shows bergy bits and growlers floating in front of the Apusiajik glacier, near Kulusuk (aslo spelled Qulusuk), a settlement in the Sermersooq municipality located on the island of the same name on the southeastern shore of Greenland. (JONATHAN NACKSTRAND/AFP via Getty Images)

When Greenland was green: Ancient soil from beneath a mile of ice offers warnings for the future

Paul Bierman, Tammy Rittenour