The role of conceptual models in climate research

Climate variability occurs on a multitude of temporal and spatial scales and the associated phenomena are studied using observations and a hierarchy of climate models. The aim of this paper is to describe the role that relatively simple models, usually referred to as conceptual climate models, have in the understanding of climate variability phenomena. To illustrate the importance of these conceptual models, we focus here exclusively on the tipping of the Atlantic Meridional Overturning Circulation (AMOC) under a changing surface freshwater forcing. In this case, results from the full hierarchy of models are available. Conceptual climate models and their mathematical analysis have generated basic physical concepts of AMOC tipping. In addition, these results have served as an important interpretation framework for more detailed models up to state-of-the-art global climate models.