Environmental law depends on the regular collection of accurate information about the state of the natural environment (“ambient monitoring”) in order to assess the effectiveness of current regulatory and management policies and to develop new reforms. Despite the central role that ambient monitoring plays in environmental law and policy, the scholarly literature has almost ignored the question of whether and how effective ambient monitoring will take place—even though there is ample evidence that our current ambient monitoring data has significant flaws. Moreover, the importance of ambient monitoring will increase in the future with the shift to a new paradigm of adaptive management in which regulatory decisionmaking is kept purposefully flexible for future adjustment.