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Double-diffusive effects on sea ice in a warming ocean

Under the sea ice of the polar oceans, warm salty water flows below cold fresh surface water. In sea water, heat diffuses a hundred times faster than salt which, in this environment, leads to an unbalanced system. The unstable temperature gradient competes with the stabilizing salinity gradient, creating conditions which are unstable to double-diffusive convection. Observations indicate that this instability is prevalent in both hemispheres and has been identified as an important mechanism controlling the vertical heat transport to the surface. However, the evolution of this instability in a warming ocean is not well understood. Inspired by results from double-diffusive convection’s more popular cousin, fingering convection, I suggest one way to potentially predict this evolution and explore its possible consequences on both Arctic and Antarctic sea ice trends.