As defined in the recent Millenium Ecosystem Assessment (MA), biodiversity scenarios are "plausible alternative futures." They do not attempt to predict the precise future state of biodiversity, but rather they identify the consequences of the different paths that human society may follow for biodiversity. Scenarios are designed to assist decision makers by identifying costs and benefits, in terms of biodiversity, of alternative actions. Within the framework of the MA, the first stage in developing biodiversity scenarios was to identify the major drivers of biodiversity change in the next 50–100 years. Land-use change, climate change, and nutrient enrichment were identified as the major drivers of biodiversity change in terrestrial and freshwater ecosystems. The next steps in constructing successful biodiversity scenarios are (1) assessing changes in drivers of different socioeconomic scenarios and (2) developing the algorithms that relate changes in drivers with changes in biodiversity. This Special Feature focuses on a key component of the second of these two steps: evaluating the current tools used by ecologists to develop scenarios based on changes in drivers of biodiversity change.