Sustainable development has become an overarching policy target for the global policy arena. However, the international policy-making process and that of the individual countries remains largely sectoral in nature: a wide spectrum of international policies pursue narrow sectoral concerns and do not contribute fully enough to the achievement of broader sustainability targets. New policy tools such as Sustainability Impact Assessment (SIA) have therefore been adopted by the European Union to ensure that sectoral policies can be evaluated in relation to their wider sustainability impacts. However, what is really needed is a cross-sectoral approach to assessing sustainable development at an even higher, much more strategic level: Integrated Sustainability Assessment (ISA). ISA involves a longterm, comprehensive assessment of international and national policy programmes against sustainability targets and criteria. In order to perform ISA at the international level, new assessment tools and methods are needed which are rooted in a new paradigm. Sustainable development is a complex, multi-dimensional phenomenon, with a breadth and depth that cannot be fully covered by the current portfolio of ISA tools. We therefore need a new generation of ISA tools, in particular modelling tools that can (semi-)quantitatively assess the multiple dimensions of sustainable development, in terms of multiple scales, multiple domains and multiple generations. Although a new paradigm is on the horizon and its contours are gradually becoming clearer, it will take a while before it can be used to develop practical ISA tools. Within the context of the European MATISSE project we therefore propose a two-track strategy: find new ways to use the current portfolio of ISA tools as efficiently and effectively as possible, while at the same time developing building blocks to support the next generation of ISA tools.
