Climate extremes occurring close together in time or space can pose amplified risks for societies, due to inter-relations among hazards and affected sectors. Examples include (i) multivariate extremes (same time and place); (ii) concurrent extremes (same time, multiple places); and (iii) sequential or preconditioned extremes (multiple times, same place). To understand their physical drivers and mitigate their impacts in a changing climate requires joint efforts from a broad range of scientific communities across disciplines and temporal and spatial scales — from local to global extent, synoptic to decadal variability, and hazard characterization to detailed risk and impact assessment. We invite contributions that aim to understand compound climate extremes through evaluation of their dynamical, hydrological, and/or land-surface mechanisms; that use innovative numerical modeling and/or statistical methods applied to models or observations to improve their detection, attribution, or projections; or that evaluate their impacts on specific human or natural systems.