Scenario assumptions

This USS represents the elaboration of the SRES narrative storylines into scenarios using the IMAGE 2.2 model. These scenarios are a reflection of the authors' interpretations and valuation on the basis of a limited part of past and present events, behaviours and structures. Therefore, each IMAGE 2.2 scenario is only one of the many possible elaborations of the corresponding SRES storylines.

The population and GDP scenarios were harmonized for four aggregated world regions and the world as a whole on the basis of criteria presented in IPCC (2000). Starting from these scenarios, the interpretation of the narrative storylines involved the description of a number of regional developments in:

• economy
• population
• the land use system including consumption, production and trade of agricultural products;
• emissions associated with agricultural production, biomass burning and waste management;
• the energy/industry system;
• emissions associated with energy use and industrial production.

The A1 storyline has been elaborated upon in three different scenarios for the energy/industry system, depending on assumptions with regard technology development for different energy sources (the A1B, A1F and A1T scenarios).

For the B1 scenario (lowest greenhouse gas emissions) and A1F scenario (highest greenhouse gas emissions), two additional scenarios for each have been added with high and low values for climate sensitivity. The differences between these 'scenarios' are described under uncertainties.