Recent environmental changes are having, and are expected to continue to have, significant impacts in the Arctic as elsewhere in the world. Detecting those changes and determining the mechanisms that cause them are far from trivial problems. The use of multiple methods of observation can increase confidence in individual observations, broaden the scope of information available about environmental change, and contribute to insights concerning mechanisms of change. In this paper, we examine the ways that using traditional ecological knowledge (TEK) together with scientific observations can achieve these objectives. A review of TEK observations in comparison with scientific observations demonstrates the promise of this approach, while also revealing several challenges to putting it into practice on a large scale. Further efforts are suggested, particularly in undertaking collaborative projects designed to produce parallel observations that can be readily compared and analyzed in greater detail than is possible in an opportunistic sample.