Targets are an integral component of management control systems and play a significant role in achieving desirable performance outcomes. We focus on a key environmental performance objective—reduction of carbon emissions—as a setting in which to examine how target difficulty affects the degree of target completion in long-term non-financial performance. We use a novel dataset compiled by the Carbon Disclosure Project (CDP) and find that firms setting more difficult targets complete a higher percentage of such targets. We also find that this effect is negatively moderated by the provision of monetary incentives. We corroborate this evidence by showing that target difficulty is more effective for carbon reduction projects requiring more novel knowledge and in high-pollution industries. We discuss limitations and suggest avenues for future research.