Sea ice concentration
Sea ice plays a critical role in regulating the Earth’s climate – when it disappears, the exposed ocean absorbs sunlight that ice would have reflected, with far-reaching effects on weather patterns. This map shows the September 2025 anomaly in Arctic sea-ice concentration, how much of each area of ocean is covered by ice, with deeper red indicating less ice than average and blue more. September marks the annual minimum, and recent studies show that Arctic summer sea-ice extent has declined by around 12% per decade since satellite observations began. Concentration adds another dimension to extent, helping to reveal where ice is thinning and breaking up.
Sea ice records are used in a wide range of ways, including to evaluate and improve climate models, to support weather and climate prediction, and to plan shipping routes. The current time series runs from the late 1970s to September 2025, following an interruption in the satellite data supply, with work to continue the record under way. The data record is produced by EUMETSAT’s Satellite Application Facility on Ocean and Sea Ice (OSI SAF), and the service includes polar stereographic views for viewing both the Arctic and Antarctic.