As atmospheric carbon dioxide rises, Earth’s oceans are absorbing more carbon, changing the chemistry of ocean water. Observations from satellites can be used to measure parameters that indicate changing ocean water, such as temperature, salinity and chlorophyll content. Satellite and in-situ surface observations are combined using a machine learning technique to generate global monthly maps that characterise the changing chemistry of the ocean. Ocean acidification is shown by the steady fall in seawater pH values over the last 30 years.

Read full story: Satellites highlight a 30-year rise in ocean acidification