Over recent decades, opposite trends in sea ice extent have been found between the Arctic and Antarctic. However, early Antarctic expeditions provide much information regarding sea ice. Here summer sea ice positions recorded during 1820–1843 have been compared to recent satellite observations. The key findings of this study indicate a 19th century summer northernmost sea ice latitude in much of the Weddell Sea that was further north than during the modern era.

Icebergs fertilize the Southern Ocean, enhancing phytoplankton production, but this link is yet to be found in the Arctic. This study seeks such a relationship in the NW Atlantic. A one-month-lagged correlation between iceberg flux and chlorophyll levels is found, with the likely cause for this link through advection of the nutrients entrained in iceberg meltwater. The impact of iceberg meltwater on Arctic phytoplankton is much less pronounced than in the Southern Ocean, but it is discernible.

Calved icebergs account for around 50% of total freshwater input to the ocean from the Greenland and Antarctic ice sheets. As they melt, icebergs interact with the ocean. We have developed and tested interactive icebergs in a state-of-the-art global ocean model, showing how sea ice, temperatures, and currents are disturbed by iceberg melting. With this new model capability, we are better prepared to predict how future increases in iceberg numbers might influence the oceans and climate.