Large-scale scenarios as “boundary conditions”: A cross-impact balance simulated annealing (CIBSA) approach

There is increasing interest in cross-scale scenario development, driven in part by developments in climate scenarios. Climate mitigation and adaptation studies have long emphasized the link between global change and local action. Recent climate community scenarios have been developed with cross-scale application in mind.

One way to treat cross-scale interactions is to use global scenarios as external conditions for regional and local scenarios. This paper gives the idea some structure using a methodology called “cross-impact balances”, or CIB.

The authors allow for weak cross-scale interactions and treat global scenarios formally as states of the world, which are stable under small disturbances from local and regional activity. They provide a way to identify such states and show how a simplified cross-impact balance can replace a full multi-scale balance when a stable set of global scenarios is adopted at large scale.