An icebreaker carrying scientists on a year-long international effort to study the high Arctic has returned to its home port in Germany carrying a wealth of data that will help researchers better predict climate change in the decades to come. The RV Polarstern arrived Monday in the North Sea port of Bremerhaven, from where she set off more than a year ago prepared for bitter cold and polar bear encounters — but not for the pandemic lockdowns that almost scuttled the mission half-way through.