- Global warming has ramped up the planetary water cycle since records began in 1950.
- The salinity of different parts of the oceans serves as a rain gauge for researchers.
- An army of 3,200 autonomous ARGO buoys gathered data used in this study.
The supercharging of Earth's water cycle by global warming is already making some parts of Earth's oceans much saltier while others parts are getting fresher.
A new study by Australian scientists shows a clear link between salinity changes at the surface and changes in the deeper waters over the last six decades caused by the warming seen over the same period.
The reasoning goes like this: The saltiness, or salinity, of the oceans is controlled by evaporation and rainfall at Earth's surface, explains Paul Durack of CSIRO, the Australian government's research agency.
The more evaporation there is at a given patch of ocean, the more concentrated the salts get in the seawater, and the higher the salinity. In places where lots of rain is falling, the water gets more diluted, becoming fresher.