Oceanic sediment cores offer researchers a valuable archive of Earth's climate history. Ancient pollen, plankton, dust, and other clues collected from seafloors provide the bulk of what scientists know about global changes to the planet's ecosystems over time. In 2011, Feakins devised a novel way of harnessing this technology to test one of the oldest questions of human evolution: Did our ancestors actually climb down from trees because of expanding savannas in Africa? By poring over cores from the seas off East Africa, she would be able to peel back layers of ancient, windblown carbon isotopes associated with grasslands, settling...
