How does the ocean hemispheric asymmetry impact the climate system?

The global ocean transports heat northward and carbon southward. The magnitude of this asymmetry between the two hemispheres is a key factor of the climate system through its influence on the ocean carbon uptake and the displacement of tropical precipitation north of the equator. Despite their importance to climate, the asymmetric influences on carbon and heat are not well constrained by observations or models. Uncertainties and inaccuracy in the ocean asymmetry limit our understanding of the climate system and our ability to provide robust future climate projections, in particular concerning shifts in rainfall associated with climate change and carbon sinks partition between the land and the ocean. Here, we show novel biogeochemical observations that bear on those questions. We provide new constraints on the ocean asymmetry, discuss the implications for future climate projections and present the remaining challenges.