As climate change sweeps through the Arctic, decades-old divisions between the indigenous people who live there and the scientists who parachute in and out are slowly dissolving. Projects that draw on traditional knowledge of animal migrations, ice patterns, shrubbery, and weather are popping up from Baffin Island, Canada, to Rovaniemi, Finland. The goal is to use local information, about the health of individual caribou or about whales killed by hunters-to supplement and enrich scientific data, such as sea-ice or vegetation changes.