Despite a run-in with an iceberg and the world’s worst sailing conditions, Saildrone 1020 successfully completed its 13,670-nautical-mile journey around Antarctica, and indicated that parts of the Southern Ocean emit carbon dioxide in winter.

The most recent maximum (September 2020) was above the long-term average, and the most recent minimum (February 2021) was below the long-term average, but neither set a record. Antarctic sea ice has greater year-to-year variability than the Arctic, and little evidence of long-term change.