On a warm Thursday in July, Natalia Rybczynski and I paddle our kayaks up the Gatineau River near Ottawa. Fluffy-topped, flat-bottomed clouds speckle the sky, and blooming cornflowers poke through old railroad tracks leading to a dock. We glide past a long-abandoned beaver lodge, its sticks cut at a distinctive angle and spilling helter-skelter down the riverbank into the bourbon-colored water.
Rybczynski (pronounced rib-CHIN-ski) is a big fan of beavers, Canada’s official wildlife mascot; she’s conducted research showing they gnaw sticks with just one front tooth at a time. But our 2013 outing to the river is a consolation trip. Normally she spends her Julys at a beaver pond site that’s millions of years old and 800 miles north of the Arctic Circle, looking for clues about past global warming.
But this summer, Rybczynski, a paleobiologist, is confined to her home base, the Canadian Museum of Nature in Ottawa, as she recovers from a cross-country skiing accident that left her with a concussion. She’d much rather be wrapped in Gore-Tex, wavy brunette hair in a bandana, her dirt-ringed fingernails turning purple on the cold, dry tundra of Ellesmere Island.
Today, Ellesmere, which lies next to Greenland on the eastern edge of Canada’s Arctic Archipelago, supports only ankle-high tufts of cotton grass and mossy ground cover; the nearest tree is almost 1,200 miles south. But Rybczynski and her colleagues have unearthed evidence of a balmier Arctic from a slice of time referred to as the mid-Pliocene warm period, roughly 3 million to 3.3 million years ago. The island’s treasure trove of fossils, preserved in permafrost, suggests the area was once an ancient boreal-like forest of larch, cedar and birch grazed by miniature beavers, three-toed horses and black bear ancestors.
