Rising sea level is pushing saltwater farther up estuaries

Estuaries are places where rivers meet oceans and their waters mix. As climate change makes sea level rise, that mix includes a higher proportion of salty ocean water — as, for example, in Chesapeake Bay.[[Hilton, T. W., R. G. Najjar, L. Zhong, and M. Li. “Is there a signal of sea-level rise in Chesapeake Bay salinity?” (Abstract) Journal of Geophysical Research 113 (2008).]]  Rising salinity can in turn affect the health, growing zones and abundance of diverse plants and animals.

Other factors besides global sea level rise also influence salinity in estuaries.  Heavy rain can add more freshwater to the mix, for example, and drought can remove it by reducing river flows; while the sinking of coastal land can make local sea level rise greater than the worldwide average.