Updated on 30 Nov. 2023
Japan Meteorological Agency
The ocean acted as a sink for atmospheric carbon dioxide (CO2) over the 30-year period from 1990 to 2022.
The estimated mean annual global ocean CO2 uptake during this period was 2.1 GtC/yr. The annual CO2 uptake has shown an increasing trend since the 1990s.
Time-series representations of global ocean CO2 uptake from 1990 to 2022
Time-series representations of (a) monthly and (b) annual CO2 uptake. The dotted line in (b) shows the 2.1 GtC/yr average for the period from 1990 to 2022.
Global ocean CO2 uptake was estimated using an empirical method based on the approaches of Iida et al. (2021). The ocean releases CO2 into the atmosphere in the equatorial region throughout the year, and absorbs it from the atmosphere in the subtropical and subarctic regions, especially in winter. The ocean acts as a sink for atmospheric CO2. The estimated mean annual global ocean CO2 uptake was 2.1 GtC/yr for the period from 1990 to 2022. The total amount of anthropogenically emitted CO2 is about 10.9 GtC/yr (IPCC, 2021), meaning that ocean uptake accounts for a quarter of total emissions as 0.6 GtC/yr comes from rivers (IPCC, 2021).