Though most of my work is currently focused in the Arctic – with emphasis on Alaska – this time last year I was preparing to go to Antarctica with Aurora Expeditions. I have been thinking back to wonderful memories of an amazing land and oceanscape full of vibrant penguin, whale and seal life. Antarctica is also a very important part of our planet: an ice sheet covers about 98% of the continent and this is the single largest mass of ice on Earth, storing ~70% of the planet’s fresh water. When snow falling on Antarctica eventually compacts to form glacier ice, these rivers of ice make their way down towards the ocean. Where the ice meets the ocean, vast floating ice shelves form that either eventually melt or naturally break (calve) icebergs off into the water.
Back in July 2017, an iceberg the size of the US state of Delaware broke off an ice shelf called Larsen C on the east coast of the Antarctic Peninsula. Since then, the iceberg (called A68a) has traveled thousands of miles, passed the tip of the Peninsula and floated into “Iceberg Alley,” so called because more than 90% of Antarctic icebergs get swept along this path from the Weddell Sea and towards the South Atlantic due to ocean currents. Given iceberg A68a is so big (and likely extends 500 – 600 feet underwater), it has survived – for over three years – in the relatively warm iceberg-killing waters of the South Atlantic and is on a collision course with South Georgia Island, a remote British island in the region. Why is this a concern? A collision could wreak havoc on ecosystems both on the island and in the waters off-shore by blocking foraging routes for the penguins and seals that inhabit the island, and by crushing life on the seafloor, disrupting the food chain.
As of a month ago, the iceberg has begun splitting into multiple pieces. Scientists believe the smaller (but still city-sized!) part may have already struck the seafloor around the island, given the shallowness of the water in the region, and remains grounded (“stuck” to the floor). Time will tell what happens with the remainder of the ice and how much of a threat it will be to the wildlife. For now, all we can do is sit, wait and observe. Though the genesis of such icebergs is a natural process, the warming climate – particularly in the Peninsula, which is the fastest-warming region in Antarctica – could be a sign of the (unstable) times ahead.