When you hear about climate change it’s most often about melting glaciers and sea ice, increasing frequency of heatwaves and powerful storms. Maybe, just maybe, you’ll hear about the acidification of the oceans too. What you don’t hear about is the saltiness of the seas. But that’s changing too, according to a new piece of research just published in Geophysical Research Letters.

The saltiness, or salinity, of the oceans is controlled by how much water is entering the oceans from rivers and rain versus how much is evaporating; what my kids recognize as “The Water Cycle.” The more sunshine and heat there is, the more water can evaporate, leaving the salts behind in higher concentrations in some places. Over time, those changes spread out as water moves, changing the salinity profiles of the oceans.