scientists once predicted. Geologically speaking,
it’s thawing almost overnight. As soils like the
ones at Duvanny Yar soften and slump, they’re
releasing vestiges of ancient life—and masses of
carbon—that have been locked in frozen dirt for
millennia. Entering the atmosphere as methane
or carbon dioxide, the carbon promises to accel-
erate climate change, even as humans struggle
to curb our fossil fuel emissions.
Few understand this threat better than Zimov.
From a ramshackle research station in the
gold-mining outpost of Cherskiy, about three
hours by speedboat from Duvanny Yar, he has
spent decades unearthing the mysteries of a
warming Arctic. Along the way, he has helped
upend conventional wisdom—especially the
notion that the far north, back in the Pleistocene
ice ages, had been an unbroken desert of ice and
thin soils dotted with sage.
Instead, the abundant fossils of mammoths
and other large grazers at Duvanny Yar and other
sites told Zimov that Siberia, Alaska, and west-
ern Canada had been fertile grasslands, rich withThe nonprofit National Geographic Society, working
to conserve Earth’s resources, helped fund this article.THE THREAT BELOW 79