Environmental and geopolitical shocks – i.e. sudden, often unpredictable, changes with sweeping social and economic consequences – are often associated with large-scale migration flows both within and across borders. All these events have, to different degrees, put legal migration and protection systems under strain.The chapter analyses how OECD countries have responded to major shock-related migration in recent times and identifies key lessons learnt. It also explores the various options for more structural responses – notably the use of alternative legal migration pathway for refugees – with the objective of improving the responsiveness and efficiency of migration and protection systems to both environmental and geopolitical shocks. The chapter also analyses the actual and potential use of alternative migration pathways in response to the Syrian crisis.The analysis highlights three important lessons: i) effective international co-operation cannot be taken for granted; ii) protracted crises generate growing tensions between the need to find durable solutions and the general preference for short-term protection measures; iii) selection, which is a common feature of most migration systems, needs to be rethought in the context of the international protection framework.