Satellite image showing the Artic sea ice annual minimum on 19 September 2023. The sea ice has shrunk through the northern hemisphere summer and reached its minimum extent. At 4.23 million square kilometres, this was the sixth-lowest year in the satellite record. Scientists track the seasonal and annual fluctuations because sea ice plays a large role in Earth?íG polar ecosystems and global climate. Data collected with the Advanced Microwave Scanning Radiometer 2 (AMSR2) onboard the Japan Aerospace Exploration Agency's (JAXA's) Global Change Observation Mission 1st-Water 'SHIZUKU'(GCOM-W1) satellite.