Alternative scenarios for sustainable development. The two scenarios for sustainable development published in the 2015 Report both assume the realisation of a set of sustainable development goals by 2050, but they differ in the distribution of the key roles to producers or consumers. In the SET-Consumption scenario (SET refers to socio-ecological transition, the necessary social and ecological transition), consumers drive the change and producers follow. In the SET-Production scenario, the producers take the initiative and drive the consumers. In both cases, they are supported by the public authorities.

The scenarios are explorations of a future in sustainable development. They are by no means to be viewed as outlooks or plans. Preparing such scenarios allows fuelling the democratic debate on the wanted societal development and shows that it is possible to mark out pathways to a plausible vision for 2050 in agreement with the principles of sustainable development.

Backcasting and objectives of sustainable development. In general, foresight helps the federal government and the civil society develop an idea on the wanted evolution and on measures to attain their objectives. In that manner, they contribute to the societal debate on which development pathway to choose. There are numerous foresight and participation methods. Since 2003, the FPB's TFSD has been innovating by studying and combining existing methods in order to apply them on sustainable development.

A backcasting approach was chosen to elaborate the sustainable development scenarios for the Federal reports. Such an approach presupposes a wanted future, e.g. in 2050, and its description based on a long-term vision issued from from a scientific and participatory process. The vision, discussed in expert panels, contains a series of objectives founded, among others, on international commitments for sustainable developments (e.g. a vision on sustainable development was adopted by the federal government in 2013).

The next step consists in examining the possible pathways to attain that wanted future in 2050 (see: Onze consumptie en productie houdbaar maken. Rendre nos consommations et nos productions soutenables. Federal report on sustainable development 2015, p. 64). Each scenario which was elaborated in the backcasting approach presents a pathway to attain the wanted future in the long term, starting from the current situation.