Multi-system dynamics and the speed of net-zero transitions: Identifying causal processes related to technologies, actors, and institutions

Reaching net-zero GHG emission targets will require transitions in all socio-technical systems, including electricity, mobility, heating, and agri-food. While most research focuses on transitions in single systems, it is essential to also investigate multi-system interactions since innovations like electric vehicles, heat pumps, or circular economy initiatives will require interactions between multiple systems. Although extant research acknowledges this topic to some extent, it offers limited understandings of the causal processes underpinning multi-system interaction. Building on multi-system research in the sustainability transitions literature, the paper therefore aims to develop a first inventory of causal processes of multi-system interactions in net-zero transitions, focused on technological, actor, and institutional dimensions. To elaborate and substantiate this contribution, the paper applies a narrative review methodology to identify six causal processes based on integration of insights from relevant social science theories with a multi-system dynamics approach based on the Multi-level Perspective. We illustrate causal processes with examples from the net-zero transition and articulate their implications for the speed of change.