Re-thickening Arctic Sea Ice

Sea ice forms naturally by water freezing on the bottom of existing ice which floats on the ocean’s surface, the latent heat of freezing must be conducted through the ice and then transferred to the cold Arctic air or radiated into space. As the ice grows it becomes a thicker insulating layer between the cold Arctic air above the ice and the water below it, so the rate of freezing reduces. Any snow on the ice’s surface is an even better insulator and further slows the rate of ice growth. The Centre for Climate Repair is researching two techniques to thicken sea ice by pumping seawater through the ice and onto the surface during the Arctic winter which we call Surface Thickening and Snow Flooding:

Surface Thickening aims to increase the sea ice thickness directly when there is no snow by pumping seawater onto the surface, so it is directly exposed to the cooling and thickens the ice from above.

Snow Flooding aims to fill the air voids in snow that make it so insulating with seawater thereby consolidating the snow into solid ice which is less insulating so there is more natural freezing at the ice’s base.

The research happening in Cambridge focuses on modelling and lab experiments in a cold room to investigate the two techniques. It aims to answer core questions regarding the freezing process, particularly the increase in ice thickness that can be achieved and the behaviour of brine in the sea ice.