Knowing how much heat is stored in the ocean, how fast the sea levels are rising and sea ice is melting, is essential to understanding the current state and changes in the ocean and climate. This information is critical for assessing and confronting oceanic and atmospheric changes associated with global warming and they can be used by scientists, decision-makers, environmental agencies, the general public, and in measuring our responses to environmental directives. The OMIs expand the Copernicus Marine Service portfolio to provide not only ocean data products but also key reference information on the state of the ocean.
The Ocean Monitoring Indicators are free and available on the Copernicus Marine Service website as digital files (click here). They include observations starting in 1993, hindcast and forecast data of global and regional ocean heat content, the global mean and regional sea level, and the Antarctic and Arctic sea ice extent (the Arctic time series is from 1979 onwards). These three variables are extracted from the Copernicus Marine Service Ocean State Report because they represent the oceanic symptoms of a heated planet. These trends were found to be of particular importance in the Copernicus Marine Service Ocean State Report, an annual peer-reviewed publication that provides scientific context and a thorough analysis on the state of the ocean, trends, and severe/notable events (the 2018 report will be published in the coming months). The OMI products were developed through a long process of scientific analysis and validation, with the consensus of around 100 Copernicus Marine Service scientific experts after their review. The OMIs were created through a strong collaboration with other Copernicus services such as the Copernicus Climate Change Service (C3S).
Following various Earth observation initiatives like those of NASA and NOAA in the USA, the Copernicus Marine Service independently produced the OMIs, as a part of the European Union’s Copernicus Programme, the world’s single largest Earth observation programme. The data is based on historical satellite and in situ observations of the ocean and sea ice as well as numerical ocean models.
The key findings of the Copernicus Marine Service OMIs and Ocean State Report:
-Global mean sea level rise amounts to 3.4 millimeters per year from 1993 to 2016 (with an uncertainty of ±0.5mm/year). About 30% of global sea level rise can be attributed to ocean thermal expansion due to the ocean warming.
-The upper global ocean has continuously warmed since 1993 at a rate of 0.8 ±0.1 Watts per meters squared (with an uncertainty of ±0.1 watts/m2). More than 40% of this subsurface warming can be attributed to heat storage in the 700-2000m depth layer.
-Following a prominent sea ice decrease in the Antarctic Ocean in 2016, both the Antarctic and the Arctic oceans are currently at record lows in terms of sea ice extent. Since 1993 in the Arctic Ocean, the sea ice extent has decreased significantly at an annual rate of -0.78*106 km2 per decade. Ten of the lowest Arctic summer sea ice extent values took place in the last ten years. Since 1993 in the Antarctic Ocean, the annual sea ice extent has slightly increased at a rate of 0.21*106 km2 per decade. However, in the last quarter of 2016, there was a record-setting rapid loss of Antarctic ice starting in early September.