Correction to: Nature Geoscience https://doi.org/10.1038/s41561-018-0136-2, published online 28 May 2018.

In the version of this Article originally published, in the ‘Acknowledgements’ section the authors neglected to include the following text: “The Surface Ocean CO2 Atlas (SOCAT) is an international effort, endorsed by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS) and the Integrated Marine Biosphere Research (IMBeR) programme, to deliver a uniformly quality-controlled surface ocean CO2 database. The many researchers and funding agencies responsible for the collection of data and quality control are thanked for their contributions to SOCAT.” This has now been added in the online versions of the Article.