The role of baroclinic activity in controlling Earth's albedo in the present and future climates

International audienceWe find a strong connection between the magnitude of midlatitude storminess and cloud-albedo, thereby linking the large-scale circulation to the planetary albedo. We use this linkage to propose a mechanism for the observed similarity in reflected sunlight between the two hemispheres: The presence of more ocean causes the southern-hemisphere to absorb more sunlight; however, it also makes it stormier, increasing cloud-albedo and balancing the difference in reflected sunlight. Due to the changes in storminess predicted by CMIP6 models, this link also implies less cloud-albedo with warming and a possible break of hemispheric albedo symmetry. For this symmetry to persist, the distribution of southern-hemisphere storms should shift to fewer but stronger storms, as predicted by climate-change models