PLEA Network

30 January 2018, The Conversation, Climate scientists explore hidden ocean beneath Antarctica’s largest ice shelf. Antarctica’s Ross Ice Shelf is the world’s largest floating slab of ice: it’s about the size of Spain, and nearly a kilometre thick. The ocean beneath, roughly the volume of the North Sea, is one of the most important but least understood parts of the climate system. We are part of the multi-disciplinary Aotearoa New Zealand Ross Ice Shelf programme team, and have melted a hole through hundreds of metres of ice to explore this ocean and the ice shelf’s vulnerability to climate change. Our measurements show that this hidden ocean is warming and freshening – but in ways we weren’t expecting. A hidden conveyor belt  All major ice shelves are found around the coast of Antarctica. These massive pieces of ice hold back the land-locked ice sheets that, if freed to melt into the ocean, would raise sea levels and change the face of our world. An ice shelf is a massive lid of ice that forms when glaciers flow off the land and merge as they float out over the coastal ocean. Shelves lose ice by either breaking off icebergs or by melting from below. We can see big icebergs from satellites – it is the melting that is hidden. Because the water flowing underneath the Ross Ice Shelf is cold (minus 1.9C), it is called a “cold cavity”. If it warms, the future of the shelf and the ice upstream could change dramatically. Yet this hidden ocean is excluded from all present models of future climate. All major ice shelves are found around the coast of Antarctica. These massive pieces of ice hold back the land-locked ice sheets that, if freed to melt into the ocean, would raise sea levels and change the face of our world. An ice shelf is a massive lid of ice that forms when glaciers flow off the land and merge as they float out over the coastal ocean. Shelves lose ice by either breaking off icebergs or by melting from below. We can see big icebergs from satellites – it is the melting that is hidden. Because the water flowing underneath the Ross Ice Shelf is cold (minus 1.9C), it is called a “cold cavity”. If it warms, the future of the shelf and the ice upstream could change dramatically. Yet this hidden ocean is excluded from all present models of future climate. Read More here