An ancient freshwater Arctic ocean

About 70% of our planet is covered in water, and the vast majority of that water is in the salty oceans. But in a paper published recently, scientists from Germany propose that the Arctic Ocean was - at a relatively recent few points in Earth’s history - actually entirely freshwater. Rivers and meltwater flushed out the salt, and lower sea levels worldwide at the time meant it couldn’t come back, at least for a while. Getting to grips with how and exactly when this was happening is critical to our understanding of how climate change affects the Arctic, as Katie Haylor heard from Walter Geibert.