Climate action post-Paris: how can the IPCC stay relevant?

Abstract The Intergovernmental Panel on Climate Change (IPCC) has been a crucial facilitator of climate change research and governance. After its sixth assessment cycle, the organization is at a critical juncture. The amount of climate science has grown tremendously over the past three decades, but so has global emissions of greenhouse gases. If the world is to reach the objectives implied by the Paris Agreement, climate action must accelerate on an unprecedented scale and pace, across widely differing contexts. Scientific knowledge will play a key role in this endeavour. Everyone who produces or relies on climate knowledge needs to wrestle with this pivotal question: How can IPCC processes and outcomes be reformed to produce knowledge that is more relevant for climate action? The organizational and resource constraints of the IPCC must be considered when searching for answers. This is an introduction to a special collection of research articles, reviews and perspectives dealing with this question from many different angles. In this introduction, we present four possible reform agendas for the IPCC in the form of ideal types, all with their advantages and disadvantages. This introduction does not advocate a certain set of reforms but rather attempts to spur discussions and reflections on the IPCC and its future